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Irrigation is vital for Philippine agriculture, particularly in regions like Bohol, where water resources are under pressure due to competing demands and seasonal droughts. Despite introducing automated irrigation technologies designed to enhance efficiency, many areas still need to rely on updated manual methods, leading to water wastage and reduced productivity. This study explores the potential of automated irrigation systems to improve water use efficiency by evaluating soil's physical and electrical properties in Bohol's greenhouses. Specifically, it investigates soil texture, bulk density, pH, moisture content, and the performance of resistive and capacitive soil moisture sensors under varying conditions. Using a randomized complete block design, the research analyzed soil samples from greenhouses in six municipalities: Antequera, Bilar, Calape, Carmen, Jagna, and Loay. Laboratory experiments assessed soil properties, and a custom Arduino-based soil moisture meter was developed for sensor calibration. The study found significant variability in soil properties across locations, with sandy clay loam soils exhibiting the highest electrical resistivity and lower water retention than silty clay and clay soils. The findings highlight that soil pH varied from slightly basic to strongly acidic, and sensor voltage output inversely correlated with soil moisture content, reflecting changes in electrical conductivity. The results underscore the importance of selecting appropriate sensors and calibration methods for accurate soil moisture measurement. Recommendations include further testing for sensor variability, preference for capacitance over resistive sensors, and rigorous calibration procedures. Enhancing these practices will improve the effectiveness of automated irrigation systems and support sustainable agricultural development in Bohol. [ABSTRACT FROM AUTHOR]

The development of methods that aim to increase the water use efficiency in agricultural systems should be part of the objectives of research, and the cultivation of plants of lower water requirements, such as cactus pear, can be a good option. The purpose of this study was to evaluate the effect of the association of potassium (K) and nitrogen (N) levels from coated urea, in two harvest years, on the agronomic characteristics and nutritive value of Nopalea cochenillifera cv Doce. A randomized block design in a 2 × 4 × 2 factorial arrangement was adopted. The factors corresponded to two levels of K (40 kg and 60 kg ha−1 year−1), four levels of N (0, 60, 120, and 240 kg ha−1 year−1) and two harvest years (Years I and II). The plants were evaluated for growth, yield, chemical, and mineral composition, and nutritive value. The levels of K affected only plant height and K content in the plant. The agronomic variables and contents of ether extract and crude protein (CP) linearly increased along with the levels of N from the coated urea. There was a significant effect of interaction between N levels and harvest year on the contents of NDF, NDFap, NFC, fraction A+B1, Ca, and Mg. The level of 40 kg K ha−1 year−1 associated with 240 kg N ha−1 year−1 from coated urea provided the best results for the characteristics of growth, yield, and nutritive value of the cactus pear. [ABSTRACT FROM AUTHOR]

Strawberry production is significantly affected by the climatic conditions (mainly light, temperature, and humidity). Thus, management of climate is of utmost importance for improving the plant growth, yield, and quality of strawberries. Keeping this in view, a study was undertaken to study the impact of greenhouse climate on performance of strawberry cultivated in soilless media under time-differential supplemental lighting. This research included three levels of supplemental lighting (I) viz. 235 (I1), 169 (I2), 132 μ mol m−2 s−1 (I3), and 3 levels of photoperiod (P) viz. 12 (P1), 14 (P2), and 16 h (P3) replicated thrice in a factorial completely randomized design (CRD) layout. The supplemental lighting of 132 μ mol m−2s−1 and photoperiod of 16 h resulted in highest fruit yield of 450.0 g/plant with an average value of 408.9 g/plant. The results indicated a significant increase in yield, water use efficiency (WUE) and fertilizer use efficiency (FUE) of camarosa strawberry with decrease in supplemental lighting from 235 to 132 μ mol m−2s−1 and increase in photoperiod from 12 to 16 h. Thus, subjecting the camarosa strawberry plants to light in the range of 362.5–430.6 μ mol m−2s−1 (including supplemental light of 132 μ mol m−2s−1) for about 16 h, keeping the temperature and humidity in the range of 19.5–25.0 °C and 65.0–75.0%, respectively, is desired to record the improved plant growth and quality fruit production, when cultivated in soilless media inside a greenhouse. [ABSTRACT FROM AUTHOR]

Continuous high ambient temperature in hot summer months leads to a sharp decline in turf quality of cool‐season turfgrass. Verticillium dahliae Aspf2‐like protein (VDAL) is a secretory protein of V. dahliae that can improve crop yield and resistance to disease, but its role in improving heat tolerance of cool‐season turfgrass has not been reported so far. The objectives of this study were to explore the effect and mechanism of foliar application of VDAL on improving heat tolerance in cool‐season creeping bentgrass (Agrostis stolonifera) and to further examine the advantage of foliar spraying with VDAL in mitigating summer bentgrass decline (SBD) in the US transition zone or other regions with similar climate. The results demonstrated that the optimal dose of VDAL for improving thermotolerance of two creeping bentgrass cultivars (heat‐tolerant 13 M and heat‐sensitive Seaside II) was screened as 0.2 g L−1 based on analyses of chlorophyll content, photochemical efficiency of PSII, and cell membrane stability under controlled heat stress conditions. Foliar application of the optimal dose of VDAL significantly restricted chlorophyll loss under heat stress and also alleviated heat‐induced declines in net photosynthetic rate, transpiration rate, stomatal conductance, and water use efficiency. In addition, overaccumulations of superoxide anion radical and hydrogen peroxide could be significantly alleviated by the exogenous application of VDAL through improving the activity of antioxidant enzymes including superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase in two cultivars. A further 2‐year field trial showed that foliar application of VDAL improved turf quality, chlorophyll content, photochemical efficiency, and cell membrane stability of the two cultivars during hot summer months of 2022 and 2023. The results indicate that the appropriate dose of VDAL plays a positive role in photosynthetic performance and antioxidant capacity for thermotolerance of creeping bentgrass, and foliar application of VDAL could be considered an effective approach for alleviating SBD. [ABSTRACT FROM AUTHOR]

Introduction: Although drought resistance of a plant may be achieved through morphological, structural, physiological, cellular, and molecular adaptations, most studies remain limited to quantifying the effect of drought on biomass. Methods: Using a highthroughput phenotypic imaging system, we evaluated the drought resistance of 151 bean accessions (Phaseolinae; Fabaceae) in an explorative approach, by quantifying five different traits simultaneously: biomass, water use efficiency (WUE), relative water content (RWC), chlorophyll content (NDVI), and root/shoot ratio. Since crop wild relatives are important resources for breeding programs, we analyzed both wild and cultivated accessions, most of which have never been evaluated for drought resistance before. Results: We demonstrate that the five traits are affected very differently by drought in the studied accessions, with significant correlations existing only between the biomass and WUE indicators (r=0.39), and between the RWC and NDVI indicators (r=0.40). When grouping accessions by subgenus or by species, large intraspecific and withinsubgenus variation was found. For this reason, we performed a cluster analysis, which grouped the accessions into five distinct clusters with similar response profiles. We also correlated the drought resistance for each accession to local climate variables at their original collection sites. The biomass, WUE, and RWC indicators were significantly correlated to annual precipitation (r=0.40, r=0.20, r=0.22, respectively), confirming that accessions from arid environments are generally more drought resistant. Discussion: Our results demonstrate that the drought resistance of Phaseolinae beans is a multifaceted characteristic and cannot be simply quantified through biomass. Furthermore, the broader knowledge of the drought resistance of the accessions studied here may prove an invaluable resource for future crop production. [ABSTRACT FROM AUTHOR]

Introduction: Plastic film mulching has been widely used to enhance soil hydrothermal conditions and increase crop yields in cool, semi-arid areas. However, its impact on soil microbial carbon metabolic activity and functional diversity during plant growth remains unclear despite their important roles in nutrient cycling and soil quality evaluation. Methods: This study used the Biolog EcoPlate technique to investigate the dynamics and driving factors of soil microbial carbon metabolic activity and functional diversity at different maize growth stages following plastic film mulching. Results and discussion: The results revealed that film mulching significantly increased microbial carbon metabolic activities [represented by average well color development (AWCD)] by 300% at the seedling stage and by 26.8% at maturity but decreased it by 47.4% at the flowering stage compared to the control (without mulching). A similar trend was observed for the microbial functional diversity index. Redundancy analysis identified soil moisture (SM), soil temperature (ST), dissolved organic carbon (DOC), microbial biomass carbon (MBC), and bacteria amounts as the primary factors influencing changes in soil microbial carbon source utilization. The mulch treatment significantly increased SM at all growth stages, while its warming effect disappeared at the flowering stage. Soil DOC, MBC, and bacterial populations were notably higher under mulching at the seedling and maturity stages but lower at the flowering stage. Pearson correlation analysis showed that changes in SM, ST, DOC, MBC, and bacterial populations positively correlated with the utilization of all carbon source classes, AWCD, and functional diversity indexes after film mulching. Furthermore, maize grain yield and water use efficiency increased by 142 and 129%, respectively, following film mulching. In conclusion, plastic film mulching enhanced soil microbial carbon metabolic activity and functional diversity at the seedling and maturity stages, improving crop yields in cool, semi-arid areas. Furthermore, the decrease in soil carbon metabolic capacity at flowering stage highlights that supplementing soil carbon sources should be considered after continuous film mulching to sustain or enhance farmland productivity and soil quality. [ABSTRACT FROM AUTHOR]

Knowledge on the variation of yield and water use efficiency under different mulching methods is important for guiding rained maize production in the Loess Plateau area. In this study, eight different plastic film mulching methods was established to analyze the maize growth, soil water content and soil temperature changes of dryland maize, and increase yield and water use efficiency (WUE). The field experiment was conducted in 2019, and eight treatments were set up, including a traditional flat planting without mulching (CK), ridge-furrow with ridges mulching black plastic film and furrows mulching straw (HJ), ridge-furrow with ridges mulching black plastic film and furrows bare (HL), ridge-furrow with ridges mulching liquid plastic film and furrows mulching straw (YJ), ridge-furrow with ridges mulching liquid plastic film and furrows bare (YL), ridge-furrow with ridges mulching biodegradable plastic film and furrows mulching straw (SJ), ridge-furrow with ridges mulching biodegradable plastic film and furrows bare (SL) and ridge-furrow with ridges bare and furrows mulching straw (NJ). Furthermore, the AHP-TOPSIS was employed to evaluate the optimal mulching method for maize. The results showed that compared with CK and NJ treatment, the soil water content and soil storage were significantly changes with other treatments in the reproductive period of maize. Among the six mulching methods, maize yield in HJ, HL, YJ, YL, SJ, and SL treatments were 46.28%, 61.95%, 70.30%, 51.02%, 52.02% and 53.53% significantly greater than CK treatment. In addition, dryland maize WUE was 66.53% and 84.01% higher in the YJ and YL treatments with ridges mulching liquid plastic film than in the CK treatment, respectively. The optimal treatments of economic benefits were YL and HJ. Through AHP-TOPSIS comprehensive analysis, the optimal mulching methods were YL and HJ treatment. Current field trials indicate that YL treatment could serve as a promising option to improve dryland maize yield, WUE, and reducing environmental risks in the Loess Plateau of China. [ABSTRACT FROM AUTHOR]

Introduction: Peanut production is being increasingly threatened by water stress with the context of global climate change. Film mulching have been reported to alleviate the adverse impact of drought on peanut. Lower phosphorus use efficiency is another key factor limiting peanut yield. Application of iron-modified and phosphorus-loaded biochar (BIP) has been validated to enhance phosphorus utilization efficiency in crops. However, whether combined effect of film mulching and BIP could increase water use efficiency and enhance peanut production through regulating soil properties and root morphologies needs further investigation. Methods: A two-year (2021-2022) pot experiment using a split-plot design was conducted to investigate the effects of phosphorus fertilizer substitution using BIP on soil properties, root morphology, pod yield, and water use of peanut under film mulching. The main plots were two mulching methods, including no mulching (M0) and film mulching (M1). The subplots were four combined applications of phosphorus fertilizer with BIP, including conventional phosphorus fertilizer rates (PCR) without BIP, P1C0; 3/4 PCR with 7.5 t ha-1 BIP, P2C1; 3/4 PCR with 15 t ha-1 BIP, P2C2; 2/3 PCR with 7.5 t ha-1 BIP, P3C1; 2/3 PCR with 15 t ha-1 BIP, P3C2. Results and discussion: The results indicated that regardless of biochar amendments, compared with M0, M1 increased soil organic matter and root morphology of peanut at different growth stages in both years. In addition, M1 increased peanut yield and water use efficiency (WUE) by 18.8% and 51.6%, respectively, but decreased water consumption by 25.0%, compared to M0 (two-year average). Irrespective of film mulching, P2C1 increased length, surface area, and volume of peanut root at seedling by 16.7%, 17.7%, and 18.6%, at flowering by 6.6%, 19.9%, and 29.5%, at pod setting by 22.9%, 33.8%, and 37.3%, and at pod filling by 48.3%, 9.5%, and 38.2%, respectively (two-year average), increased soil pH and organic matter content during peanut growing season, and increased soil CEC at harvest. In general, the M1P2C1 treatment obtained the optimal root morphology, soil chemical properties, WUE, and peanut yield, which increased peanut yield by 33.2% compared to M0P1C0. In conclusion, the combination of film mulching with 7.5 t ha-1 BIP (M1P2C1) effectively improved soil chemical properties, enhanced root morphology of peanut, and ultimately increased peanut yield and WUE. [ABSTRACT FROM AUTHOR]

Drought poses a significant challenge to global crop productivity, necessitating innovative approaches to bolster plant resilience. Leveraging transgenic technology to bolster drought tolerance in crops emerges as a promising strategy for addressing the demands of a rapidly growing global populace. AtZAT10/STZ1, a C2H2-type zinc finger protein transcription factor has shown to significantly improve Arabidopsis' tolerance to various abiotic stresses. In this study, we reports that AtSTZ1 confers notable drought resistance in upland cotton (Gossypium hirsutum), amplifying cotton fiber yield under varying conditions, including irrigated and water-limited environments, in field trials. Notably, AtSTZ1-overexpressing transgenic cotton showcases enhanced drought resilience across critical growth stages, including seed germination, seedling establishment, and reproductive phases. Morphological analysis reveals an expanded root system characterized by an elongated taproot system, increased lateral roots, augmented root biomass, and enlarged cell dimensions from transgenic cotton plants. Additionally, higher contents of proline, chlorophyll, soluble sugars, and enhanced ROS-scavenging enzyme activities are observed in leaves of transgenic plants subjected to drought, underscoring improved physiological adaptations. Furthermore, transgenic lines exhibit heightened photosynthetic rate, increased water use efficiency, and larger stomatal and epidermal cell sizes, coupled with a decline in leaf stomatal conductance and density, as well as diminished transpiration rates compared to the wild type counterparts. Transcriptome profiling unveils 106 differentially expressed genes in transgenic cotton leaves post-drought treatment, including protein kinases, transcription factors, aquaporins, and heat shock proteins, indicative of an orchestrated stress response. Collectively, these findings underscore the capacity of AtSTZ1 to augment the expression of abiotic stressrelated genes in cotton following drought conditions, thus presenting a compelling candidate for genetic manipulation aimed at enhancing crop resilience. [ABSTRACT FROM AUTHOR]

The Chinese government has been using water efficiency targets to manage commercial, institutional, and industrial water use across the country. This paper argues that water efficiency targets may influence provincial administrators' preferences in tightening water regulation in cities with higher water use while disproportionately overregulating water use in productive cities to satisfy their efficiency goals. I develop a city‐level production model with water regulation preferences and show that the unintended distortion of water regulation in response to water efficiency targets leads to efficiency loss of resource allocation and further reshapes regional output across cities, especially for productive cities. Using a sample of city‐level water data from 2006 to 2016 in China, this paper empirically investigates the impact of the Three Red Lines (TRL) policy on provincial administrators' preferences in water use regulation. The results indicate that the elasticity of water regulation in response to the policy is approximately −0.64 to −0.8 and has resulted in tighter water regulations for cities with higher economic outputs. Quantitatively, eliminating water distortions would reshape water use across cities and increase the aggregate output of an entire province by up to 0.069%. The results imply that possible consequences of the political consideration of provincial administrators in satisfying water efficiency targets include inefficiency and inequality in water allocation. [ABSTRACT FROM AUTHOR]

Leaf hydraulic traits are considered the key determinants of gas exchange and therefore affect species distributions along environmental gradients, but the patterns of leaf hydraulic traits and their associations with gas exchange across altitudinal gradients remain largely unknown.Here, we measured leaf hydraulic traits, gas exchange, leaf anatomical traits and plant size traits in two dominant alpine shrubs (Caragana jubata and Salix gilashanica) across an altitudinal gradient from 3100 to 3700 m.The findings indicated that with increasing altitude, both shrub species exhibited an increase in leaf hydraulic safety (more negative KleafP50), a decrease in leaf hydraulic efficiency (Kleaf‐max) and an increase in intrinsic water use efficiency (WUEi), thus allowing them to adapt to higher altitude habitats. The more negative KleafP50 was associated with a greater ratio of major to minor vein density (VLAmaj/VLAmin), the lower Kleaf‐max was associated with a lower minor vein density (VLAmin) and greater increase in WUEi arose from the small decrease in the photosynthetic rate relative to the stomatal conductance. However, C. jubata was consistent with the 'hydraulic safety strategy' with a great decrease in KleafP50, a small decrease in Kleaf‐max and a small increase in WUEi along with decreasing plant height and leaf area with increasing altitude. Whereas S. gilashanica was consistent with the 'photosynthetic efficiency strategy' with a small decrease in KleafP50, a greater decrease in Kleaf‐max and a greater increase in WUEi along with an increasing plant height and unchanged leaf area with increasing altitude.Overall, these findings provide new insights to improve understanding how shift in leaf hydraulic traits and their associations with gas exchange and plant size allow plants to adapt to high‐altitude habitats. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

• Carbon isotope composition (δ13C) variation among J. curcas genotypes is discrete. • Drought-induced changes in δ13C is remarkable in J. curcas. • δ13C may be used as a tool for screening water-use efficient genotypes in J. curcas. Jatropha curcas L. is a non-food crop quoted as a promising natural feedstock for biodiesel production in tropical and subtropical regions. Although an efficient mechanism of drought avoidance through stomatal control of transpiration has been demonstrated in this species, low carbon assimilation and growth rates preclude any advantage of such strategy under water limitation. Two greenhouse experiments were conducted with the objective of investigating varietal differences in water use as the trade-off between carbon isotope composition (δ13C) in different tissues and water use efficiency, in young plants of J. curcas. The first experiment was a survey with seven provenances of J. curcas under non-limiting water availability. There were no significant differences among provenances for leaf gas exchange rates, growth and whole-plant transpiration (T). However, significant effects of provenance and tissue (stem bark or leaf) in δ13C were demonstrated. The provenances CNPAE183 and CNPAE222 were selected for the second experiment, as variations in water use traits and δ13C between the two provenances were observed. Soil water deficit, imposed for 18 days, led to significant physiological, biochemical, and morphological changes. An early and sharp response to water deficit in CNPAE183 as compared to CNPAE222 was observed, as indicated by a 44% higher rate of decrease of T in the former. In addition, water deficit led to increase of δ13C, which was more pronounced in CNPAE222 (13% in young leaves) when compared to CNPAE183 (11% in young leaves). In both provenances, δ13C was less negative in young as compared to mature tissues. Significant and direct correlations between stem bark and leaf δ13C and leaf-level intrinsic water use efficiency were observed. Contrasting results, particularly on T and δ13C, suggest the existence of genetic diversity for water relations and metabolic traits linked to drought tolerance in J. curcas. Using stem bark or leaf δ13C measurements as the basis for large-scale screening of water-use efficient genotypes should be considered. [ABSTRACT FROM AUTHOR]

• This work assessed the physiological properties of dark-colored caladium (dark green, pinkish-dark green, dark maroon, maroon, and green lime) and light-colored caladium (yellow, white, young pinkish green, pink, and red). • A higher rate of photosynthesis was positively correlated to the higher stomatal conductance and lower RGB in the dark-colored caladium group rather than the light-colored ones. • The main characteristics of the group of light-colored leaves were a high RGB, LUE, and leaf temperature. This work aims to analyze the physiological characteristics of caladium ornamental plants with different leaf colors. Ten leaf colors, i.e., dark maroon, maroon, red, pink, white, pinkish young green, yellow, lime green, pinkish dark green, and dark green, were arranged in a completely randomized design and subjected to colorimetric red–green–blue (RGB) and portable photosynthesis measurement. Caladium leaf color, defined by the colorimetric RGB value, significantly impacted leaf physiological properties. Heatmap analysis apparently clustered caladiums into dark-colored group and light-colored ones. Dark-colored caladiums, as indicated by lower RGB values, exhibited higher photosynthesis rate, stomatal conductance, and water use efficiency (WUE). In contrast, light-colored caladium show a higher RGB, leaf temperature and light use efficiency (LUE) than the dark ones. By considering their leaf color-based physiological adaptability, this work recommends moderate sunlight and adequate water conditions for growing light-colored caladiums, while dark caladiums potentially tolerate excess light and water scarcity. Further research, including quantitative pigment analysis, is necessary to verify this hypothesis. [ABSTRACT FROM AUTHOR]

Leaf traits are known as indicative of species functional properties in angiosperms. Fern fronds are little studied in this concern, especially ex situ. We studied leaf mesophyll structure, pigments and gas exchange in four fern species grown in a glasshouse—Sphaeropteris cooperi (terrestrial tree fern), Phlebodium aureum (semi‐epiphytic herbaceous), Asplenium australasicum (epiphytic shrubby) and Platycerium bifurcatum (epiphytic herbaceous). Saturated assimilation rate (Asat) decreased and intrinsic water use efficiency (iWUE) increased from a terrestrial tree fern to epiphytic ferns. Asat positively correlated with chloroplast number (Nchl/A) and their surface area per leaf area (Achl/A). iWUE negatively related to Nchl/A and chlorophyll/carotenoid ratio. Most differences between species were found in the mesophyll thickness (MT) and mesophyll cell volume (Vcell) with the smallest values in S. cooperi and the largest ones in P. bifurcatum. We found that photosynthetic limitations in ferns were related to the chloroplast photosynthetic activity rather than to Nchl/A or pigment content which did not differ from most angiosperms. Epiphytic ferns showed larger values of Vcell per cell and per chloroplast compared to angiosperms and tree ferns. We concluded that an increase in MT and Vcell in the studied ferns was not associated with photosynthetic performance, but was related to volumetric cytoplasm–chloroplast ratio meaningful to light absorption and the water‐storage function of fern fronds. [ABSTRACT FROM AUTHOR]

Fimbristylis complanata is an aquatic halophytic sedge that thrives in salt-affected land, marshes, and water channels. Two ecotypes (HR-Rasool headworks ECe 19.45; SH- Sahianwala 47.49 dS m−1) of F. complanata were collected from two salt-affected wetlands of Punjab, Pakistan. Five rhizomes of each ecotype were grown in plastic pots in the Botanical garden research area and treated with three intensities of salt [0 mM (control), 200 mM (moderate), 400 mM (high) NaCl for three durations (0, 15 and 30 days). The pots were arranged using a completely randomized block design (CRD) with three replications. After each duration, sampling was done. The HR ecotype optimally performed better under moderate salt incubation and moderate to higher salt exposure. This ecotype had improved growth traits, including shoot fresh weight (SFW), shoot dry weight (SDW), leaf area (LA), root length (RL), leaf mass fraction (LMF), relative growth rate (RGR), and unit leaf area (ULA) at higher NaCl (400 mM) in comparison with control NaCl (0 mM). This improvement in growth occurs due to the accumulation of photosynthetic pigments, better photosynthesis, and water use efficiency (A/E). The leaf microstructure increased in HR ecotype as midrib (MrT), leaf blade (LTh), bulliform cells (BTh), and cortical cells (CcT) thicknesses to prevent water loss under salinity, increase aerenchymatous area (ArA) for efficient gas movements at moderate salt levels and less exposure time concerning absolute control (0 mM NaCl). The SH ecotype affirmed more tolerance to salt by securing higher biomass (SFW, SDW), increased growth traits (LA, RL, LMF, ULA), photosynthetic pigments (Chl a, b, Car), and maximum photosynthetic performance at high salt regimes and prolonged duration in comparison to control (0 mM NaCl). Additionally, increased MrT, LTh, BTh, ECA, abaxial and adaxial stomatal area, and density, broadened metaxylem and phloem area, large aerenchyma, more cortical cell thickness under moderate to high salt regimes under moderate to high salt levels and time. Overall, changes in morpho-physiological traits and leaf microstructures in both ecotypes are linked to salt tolerance under temporal salt regimes. Our findings suggest that both ecotypes of F. complanata can potentially rehabilitate the salt-affected wetlands. [ABSTRACT FROM AUTHOR]

Cereal crops are frequently rotated with broadleaf crops to achieve the benefits associated with crop diversification. However, broadleaf crops often fail in Mediterranean drylands due to their lower adaptation to drought. Alternative cereal crops such as triticale (×Triticosecale Wittmack) and oat (Avena sativa L.) can help diversify drylands in the Ebro valley, dominated by barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) cultivation. A 6‐year field experiment was conducted with five crop sequences under no‐tillage: triticale–wheat–barley (TWB), oat–wheat–barley (OWB), fallow–wheat–barley, monocrop wheat, and monocrop barley. Wheat and barley grain yield, N use efficiency, and water use efficiency responses were evaluated, and economic analyses of the whole sequences were performed. Oat increased subsequent wheat yields by 15% and barley yields by 12% (p < 0.001) compared to monocropping. Similar water and N availability at sowing suggest additional synergies in an OWB rotation (possibly pest reduction), contributing to the yield increase of both crops. However, this rotation was less profitable than a TWB rotation (p = 0.002) due to the limited adaptation of oat to Mediterranean settings. Long fallowing lacked consistent benefits in water and N availability for subsequent crops. This practice protects farmers from economic losses in low‐yielding seasons, but there is an associated opportunity cost in favorable years. The introduction of alternative cereal crops has demonstrated benefits for wheat and barley production, although greater understanding of the synergistic mechanisms involved is essential to ascertain whether resource efficiency is maintained beyond the studied timeframe. Core Ideas: Crop diversification with winter cereal crop rotations is viable in Mediterranean dryland areas.Wheat and barley tend to more efficiently use water and N in cereal rotations than as monocrop.The performance of a fallow–crop rotation is inconsistent with no clear economic benefits. [ABSTRACT FROM AUTHOR]

The increasing urbanization and growing urban population present significant challenges for urban water resources. Inadequate management has led to a decline in water quality and a mismatch between the availability and usage of city water resources. In this period of significant growth, improving urban water efficiency and reinforcing water resource protection are especially important. Leadership is essential in developing and carrying out urban water resource policies. This research investigates how leadership influences the operational efficiency of water resources protection policies. The study seeks to fill the gap in understanding the relationship between leadership, member trust, and policy effectiveness in water resource management by constructing a theoretical model and conducting empirical analysis through questionnaire surveys. The findings of this study are expected to provide valuable insights into the significance of leadership in driving improvements in water conservation policies. By establishing a link between leadership, member trust, and operational efficiency, the research contributes to both theoretical knowledge and practical implications for enhancing water resource management strategies. Recommendations for Resource Managers: In this big development background, it is particularly important to improve urban water efficiency and strengthen water resources protection.Leadership, as a key factor in the formulation and implementation of urban water resources policy, also plays an important role.Based on this, this paper studies the impact of leadership on the operational efficiency of water resources policies by proposing hypotheses, conducting questionnaire surveys, analyzing data, and verifying construction. [ABSTRACT FROM AUTHOR]

We had assembled a synthetic bacterial community (SynComH) from the rhizosphere microbiota of Haloxylon ammodendron, which enhance drought tolerance in Arabidopsis thaliana under laboratory conditions. Here we assessed the efficacy of SynComH, alone or in combination with SynComS, a consortium of previously identified growth-promoting bacteria from Crocus sativus, in increasing maize plants' fitness under optimal and water-deficit conditions. We were also interested in unveiling the mechanisms by which the bacteria confer drought tolerance. We first performed detailed greenhouse experiments on maize plants that were artificially inoculated with SynComS, SynComH, and SynComH+S, and measured 22 different plant morphological, physiological, biochemical, and histological traits under optimal and water-deficit conditions. Data were analyzed by different univariate and multivariate statistical methods. Lastly, we tested the effects of the SynComs on maize in field in a split-plot experiment with two irrigation regimes as main plots and SynComs as subplots. Results from both greenhouse and field experiments showed that all three SynComs had growth-promoting properties and improved growth-related traits, but only SynComH and SynComH+S were effective in ameliorating the drought stress. SynComH substantially enhanced drought tolerance by increasing stomatal conductance, photosynthesis rate, and proline content, while decreasing transpiration rate, leading to up to 700% increase of water use efficiency. Morphological and histological investigations suggested that these positive effects are probably attributed to modulation of plant stomatal density and xylem structure by SynComH. Besides the significance for practical agronomic use, our results suggest unprecedented capabilities of non-pathogenic bacteria in modulation of plant stomatal density. [ABSTRACT FROM AUTHOR]

Karst landscape, characterised by drought-prone areas, limited water retention and nutrient-poor soils, pose significant challenges for the sustainability of small-scale agricultural systems. This study investigated the impact of smart precision irrigation (SPI) technology, which integrates drip irrigation (DI) and organic fertilisation, on the growth, physiological performance and water use efficiency of chilli plants cultivated in a karst landscape in Gunungkidul District, Yogyakarta, Indonesia. This experiment involved a combination of drip irrigation (D), non-drip irrigation (ND), organic fertiliser (F), and no fertiliser (NF), with a semi-automatically installed SPI system to monitor and adjust soil moisture and watering requirements. The results showed that the combination of drip irrigation and organic fertiliser (D + F) significantly increased plant growth parameters, including plant height, leaf area, and chlorophyll content, and improved physiological traits such as photosynthetic rate, stomatal conductance, and leaf water use efficiency (LWUE). These improvements were attributed to the optimised water distribution and nutrient availability provided by the DI system, which minimised water loss and reduced drought stress, as evidenced by lower proline accumulation and reduced antioxidant enzyme activity in plants. In addition, the D+F treatment resulted in the highest biomass production, fruit yield and water use efficiency, underlining its potential as a sustainable agricultural practice in waterscarce karst environments. The study concludes that adopting organic matter irrigation and fertilisation strategies can improve the productivity and resilience of horticultural crops in areas facing similar environmental constraints. [ABSTRACT FROM AUTHOR]

Extreme weather events are expected to increase in frequency and intensity in South America, likely causing decreased plant productivity and altering species distributions. Yerba mate (Ilex paraguariensis) is a tree species native to South America and has an ecological, social, and economic importance in several countries. Natural forests and cultivated areas of yerba mate will be endangered by climate change because of the expected reduction in water availability. Here we determined how clonal genotypes of yerba mate (BRS BLD Yari, BRS BLD Aupaba, BRS 408, and EC40) respond to four levels of soil water holding capacity (100%, 80%, 60%, and 40% WHC) over 60 days, by evaluating the plants' morphophysiological and biochemical characteristics. We observed a reduction in plant height and biomass accumulation related to the decrease in water availability; physiological and biochemical parameters indicated that water-deficit stress reduced the plants' C assimilation and increased their production of bioactive compounds. BRS BLD Yari had a higher tolerance to low water availability, with greater biomass accumulation and photosynthetic rates that indicate greater water use efficiency. Understanding how different yerba mate genotypes respond to water deficit is essential for species conservation and developing climate-adapted breeding programs. [ABSTRACT FROM AUTHOR]

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Background: Precision phenotyping of short-term transpiration response to environmental conditions and transpiration patterns throughout wheat development enables a better understanding of specific trait compositions that lead to improved transpiration efficiency. Transpiration and related traits were evaluated in a set of 79 winter wheat lines using the custom-built "DroughtSpotter XXL" facility. The 120 l plant growth containers implemented in this phenotyping platform enable gravimetric quantification of water use in real-time under semi-controlled, yet field-like conditions across the entire crop life cycle. Results: The resulting high-resolution data enabled identification of significant developmental stage-specific variation for genotype rankings in transpiration efficiency. In addition, for all examined genotypes we identified the genotype-specific breakpoint in transpiration in response to increasing vapour pressure deficit, with breakpoints ranging between 2.75 and 4.1 kPa. Conclusion: Continuous monitoring of transpiration efficiency and diurnal transpiration patterns enables identification of hidden, heritable genotypic variation for transpiration traits relevant for wheat under drought stress. Since the unique experimental setup mimics field-like growth conditions, the results of this study have good transferability to field conditions. [ABSTRACT FROM AUTHOR]

The article discusses the importance of understanding photoprotection mechanisms in high-light tolerant organisms to enhance crop productivity. It highlights the unique photoprotection mechanisms of Chlorella ohadii, an extremely high-light tolerant green microalga, which lacks traditional photoprotection components found in model organisms. The study suggests that exploring specialized organisms like C. ohadii can reveal novel targets for improving photoprotection and photosynthesis in crops, potentially increasing growth and yield. The research emphasizes the need to expand studies to include highly light-tolerant organisms to uncover unique mechanisms for enhancing crop productivity. [Extracted from the article]

ABSTRACT Identifying the physiological mechanisms by which plants are adapted to drought is critical to predict species responses to climate change. We measured the responses of leaf hydraulic and stomatal conductances (Kleaf and gs, respectively) to dehydration, and their association with anatomy, in seven species of California Ceanothus grown in a common garden, including some of the most drought‐tolerant species in the semi‐arid flora. We tested for matching of maximum hydraulic supply and demand and quantified the role of decline of Kleaf in driving stomatal closure. Across Ceanothus species, maximum Kleaf and gs were negatively correlated, and both Kleaf and gs showed steep declines with decreasing leaf water potential (i.e., a high sensitivity to dehydration). The leaf water potential at 50% decline in gs was linked with a low ratio of maximum hydraulic supply to demand (i.e., maximum Kleaf:gs). This sensitivity of gs, combined with low minimum epidermal conductance and water storage, could contribute to prolonged leaf survival under drought. The specialized anatomy of subg. Cerastes includes trichomous stomatal crypts and pronounced hypodermis, and was associated with higher water use efficiency and water storage. Combining our data with comparative literature of other California species, species of subg. Cerastes show traits associated with greater drought tolerance and reliance on leaf water storage relative to other California species. In addition to drought resistance mechanisms such as mechanical protection and resistance to embolism, drought avoidance mechanisms such as sensitive stomatal closure could contribute importantly to drought tolerance in dry‐climate adapted species. [ABSTRACT FROM AUTHOR]

ABSTRACT Soybean (Glycine max) is the single most important global source of vegetable protein. Yield improvements per unit land area are needed to avoid further expansion onto natural systems. Mesophyll conductance (gm) quantifies the ease with which CO2 can diffuse from the sub‐stomatal cavity to Rubisco. Increasing gm is attractive since it increases photosynthesis without increasing water use. Most measurements of gm have been made during steady‐state light saturated photosynthesis. In field crop canopies, light fluctuations are frequent and the speed with which gm can increase following shade to sun transitions affects crop carbon gain. Is there variability in gm within soybean germplasm? If so, indirect selection may have indirectly increased gm during domestication and subsequent breeding for sustainability and yield. A modern elite cultivar (LD11) was compared with four ancestor accessions of Glycine soja from the assumed area of domestication by concurrent measurements of gas exchange and carbon isotope discrimination (∆13C). gm was a significant limitation to soybean photosynthesis both at steady state and through light induction but was twice the value of the ancestors in LD11. This corresponded to a substantial increase in leaf photosynthetic CO2 uptake and water use efficiency. [ABSTRACT FROM AUTHOR]

Summary In the face of anthropogenic warming, drought poses an escalating threat to food production. C4 plants offer promise in addressing this threat. C4 leaves operate a biochemical CO2 concentrating mechanism that exchanges metabolites between two partially isolated compartments (mesophyll and bundle sheath), which confers high‐productivity potential in hot climates boosting water use efficiency. However, when C4 leaves experience dehydration, photosynthesis plummets. This paper explores the physiological mechanisms behind this decline. In a fast dehydration experiment, we measured the fluxes and isotopic composition of water and CO2 in the gas exchanged by leaves, and we interpreted results using a novel biochemical model and analysis of elasticity. Our findings show that, while CO2 supply to the mesophyll and to the bundle sheath persisted during dehydration, there was a decrease in CO2 conductance at the bundle sheath‐mesophyll interface. We interpret this as causing a slowdown of intercellular metabolite exchange – an essential feature of C4 photosynthesis. This would impede the supply of reducing power to the bundle sheath, leading to phosphoglycerate accumulation and feedback inhibition of Rubisco carboxylation. The interplay between this rapid sensitivity and the effectiveness of coping strategies that C4 plants deploy may be an overlooked driver of their competitive performance. [ABSTRACT FROM AUTHOR]

Background: The pervasively imprudent practices of irrigation and nitrogen (N) application within Oasis Cool Irrigation zones have led to significant soil nitrogen loss and a marked decrease in water and nitrogen use efficiency. Methods: To address this concern, a comprehensive field experiment was conducted from April to September in 2023 to investigate the impact of varying degrees of water and fertilization regulation strategies on pivotal parameters including potato yield, quality, nitrogen balance, and water-nitrogen use efficiency. The experimental design incorporated two water deficit degrees at potato seedling (W1, 55%-65% of Field Capacity (FC); W2, 45%-55% of FC), and four distinct nitrogen application gradients (N0, 0 kg ha-1 of N; N1, 130 kg ha-1 of N; N2, 185 kg ha-1 of N; N3, 240 kg ha-1 of N). A control was also included, comprising N0 nitrogen application and full irrigation (W0, 65%-75% of FC), totally eight treatments and one check. Results: The results indicated that the tuber yield, plant dry matter accumulation, plant height, plant stem, and leaf area index increased with higher nitrogen fertilizer application and irrigation volume. However, tuber starch content, vitamin C, and protein content initially increased and then decreased, while reducing sugar content consistently decreased. Except for W1N2 treatment, the irrigation water use efficiency increased as the N application rate rose, while the nitrogen partial factor productivity, crop nitrogen use efficiency and soil nitrogen use efficiency decreased with an increase in N fertilizer application. The W1N2 treatment resulted in a higher yield (43.16 t ha-1), highest crop nitrogen use efficiency (0.95) and systematic nitrogen use efficiency (0.72),while maintaining moderate levels of soil nitrate and ammonium nitrogen. Conclusion: Therefore, through the construction of an integrated evaluation index (IEI), the W1N2 treatment of mild water deficit (55%-65% of FC) at potato seedling combined with the medium nitrogen application (185 kg ha-1 of N) has the highest IEI (0.978), it was recommended as the optimal water-nitrogen regulation and management strategies to facilitate high-yield, high-efficiency, and environmentally sustainable potato production in the cold and arid oasis areas of northwest China. [ABSTRACT FROM AUTHOR]

Introduction: Water and salt conditions are key factors influencing vegetation growth on shell island in the Yellow River Delta. However, the effects of the depth of underground brine on the photosynthetic characteristics and antioxidant system of halophytes remain unclear. Methods: The laboratory simulation experiment was carried out to investigate the effect of the changes of underground brine depth on Suaeda salsa using four levels of groundwater: 0 cm, 15 cm, 30 cm and 45 cm. Results: The results showed that different underground brine depths had significant impacts on the photosynthetic characteristics and antioxidant system of S. salsa, and 0-30 cm underground brine depth was suitable for S. salsa growth. The net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), light utilization efficiency (LUE) and carboxylation efficiency (CE) of S. salsa increased first and then decreased with increasing depth of underground brine. The stomatal limitation value (Ls) and WUE of S. salsa reached the peak value at the groundwater depth of 0 cm, and water use efficiency was reduced by 19.4%, 8.0% and 8.6% at 15 cm, 30 cm, and 45 cm, respectively, compared to the 0 cm treatment. With the deepening of underground brine depth, the value of LUE and CE firstly increased and then decreased, and reached the peak value when the depth was 30 cm. The antioxidant enzyme (SOD, POD and CAT) activities of S. salsa decreased and then increasedwith the increase of underground brine depth. The enzyme activitieswere the lowest when the underground brine depth was 30 cm. As the groundwater depth increased, MDA content decreased and then increased. The highest degree of membrane peroxidation in S. salsa leaves was observed at the depth of 45 cm. Discussion: Our study reveals that the antioxidant capacity of S. salsa wasweakened at the underground brine depth of 45 cm and the growth of S. salsa was inhibited. [ABSTRACT FROM AUTHOR]

This study investigated the use of an intelligent irrigation system for greenhouse cucumber cultivation, aiming to manage water consumption efficiently. During the initial phase, irrigation was tested at four levels: 80%, 90%, and 100% of Field Capacity (FC), and Conventional Flood Irrigation (CFI). Data on environmental conditions and water usage were meticulously recorded. Optimal yields and crop quality (measured by size and firmness) were achieved at CFI and 100% FC, with CFI consuming the most water (0.148 m3/m2) Consequently, 100% FC was identified as the best practice, informing the intelligent system's calibration in the subsequent phase. This adjustment resulted in reduced water consumption and a 15.6% improvement in Water Use Efficiency (WUE) over CFI. Additionally, by examining the product performance and the color characteristics, chlorophyll content, and photosynthesis of the leaves, it was observed that the quality and optimal water supply and the product performance were maintained in the smart irrigation system. The study concludes that, considering long-term outcomes, the intelligent irrigation system is preferable to CFI, offering significant water savings and enhanced WUE without compromising crop quality. [ABSTRACT FROM AUTHOR]

Aims: This study aimed to evaluate the impact of subsurface drip fertigation (SDF) on soil moisture content, potato growth, and tuber yield in loam soils, and compare these results with conventional surface drip fertigation (CF). The focus was on determining whether SDF could improve water use efficiency and yield quality, particularly in water-scarce regions. Methods: The experiment was conducted during the 2022 spring growing season in Xunyang, Ankang, Shaanxi Province, China. A randomized complete block design (RCBD) was used with three treatments: subsurface drip fertigation (SDF), conventional surface drip fertigation (CF), and a no-fertilization control (NF), with four replications per treatment. Soil moisture content at a 20 cm depth was monitored, and plant growth parameters such as plant height, stem diameter, leaf color index, and chlorophyll fluorescence index were measured during the flowering and harvest stages. Tuber yield characteristics, including tuber diameter, number of tubers per plant, total yield, and marketable yield, were also assessed. Important findings: The results indicated that subsurface drip fertigation significantly improved soil moisture content, with up to 45.5% higher moisture retention compared to conventional fertigation, particularly in the early stages of fertilization. This improved moisture availability led to enhanced plant growth and tuber development. Tuber diameter increased by 6.9 mm, and the number of tubers per plant increased by 18.1% under SDF. Marketable tuber yield was approximately 10% higher in the SDF treatment compared to CF. However, the study found that soil texture plays a critical role in the effectiveness of SDF, and further research is needed to explore its application in other soil types. [ABSTRACT FROM AUTHOR]

A long-term study was conducted to assess the effect of tillage (conventional, CT and minimum, MT) and residue retention treatments on crop yields, sustainable yield index (SYI), rain water use efficiency (RWUE) and soil properties under sorghum – black gram system in resource poor Semi-Arid Tropical (SAT) Alfisol at Hyderabad, India. The results revealed that when averaged over residue retention treatments, MT recorded 12.32 and 5.21% higher sorghum and black gram grain yield, 19.61 and 25.93% higher sustainability yield Index (SYI), and 12.27 and 5.15% rain water use efficiency (RWUE), respectively, over conventional tillage. Residue retention treatments (averaged over tillage treatments) S2 (cutting at 60 cm height for sorghum and 100% retention for black gram) and S1 (cutting at 35 cm height for sorghum and 50% retention for black gram) recorded 33.16 and 16.16, and 32.18 and 14.88% higher sorghum and black gram yield, respectively, over S0 (no residue) and also recorded 26.0 and 9.0, and 48.0 and 22.0% higher SYI over S0 in sorghum and black gram, respectively. Increase in RWUE under S2 and S1 over S0 was 33.19 and 16.23% in sorghum and was 31.4 and 14.53% in black gram. Higher residue retention maintained significantly higher soil organic carbon (SOC), significantly lower bulk density (BD) and significantly influenced potential of hydrogen (pH) and electrical conductivity (EC) at all the depths and also increased available nitrogen (N), phosphorus (P), potassium (K), manganese (Mn), iron (Fe), zinc (Zn) and copper (Cu) by 35.43, 24.55, 12.12, 57.6, 53.99, 51.46 and 13.76%, respectively. Thus, the results of the present study are highly useful in improving the crop yields, yield sustainability and soil properties. Therefore, the conservation agriculture practices can be a resource saving and higher crop production technology in the rainfed Alfisols. [ABSTRACT FROM AUTHOR]

Summary Cis‐regulatory element editing can generate quantitative trait variation that mitigates extreme phenotypes and harmful pleiotropy associated with coding sequence mutations. Here, we applied a multiplexed CRISPR/Cas9 approach, informed by bioinformatic datasets, to generate genotypic variation in the promoter of OsSTOMAGEN, a positive regulator of rice stomatal density. Engineered genotypic variation corresponded to broad and continuous variation in stomatal density, ranging from 70% to 120% of wild‐type stomatal density. This panel of stomatal variants was leveraged in physiological assays to establish discrete relationships between stomatal morphological variation and stomatal conductance, carbon assimilation and intrinsic water use efficiency in steady‐state and fluctuating light conditions. Additionally, promoter alleles were subjected to vegetative drought regimes to assay the effects of the edited alleles on developmental response to drought. Notably, the capacity for drought‐responsive stomatal density reprogramming in stomagen and two cis‐regulatory edited alleles was reduced. Collectively our data demonstrate that cis‐regulatory element editing can generate near‐isogenic trait variation that can be leveraged for establishing relationships between anatomy and physiology, providing a basis for optimizing traits across diverse environments. [ABSTRACT FROM AUTHOR]

In the context of global warming, rising air temperatures are increasing evapotranspiration ( ET c ) in all agricultural crops, including rice, a staple food worldwide. Simultaneously, the occurrence of droughts is reducing water availability, affecting traditional irrigation methods for rice cultivation (flood irrigation). The objective of this study was to determine ET c (water use) and yield performance in rice crop under different irrigation regimes: treatments with continuous flood irrigation (CF) and irrigations with alternating wetting and drying ( A W D 5 , A W D 10 , and A W D 20 ) in an experimental area in INIA–Vista Florida. Water balance, rice physiological data, and yield were measured in the field, and local weather data and thermal and multispectral images were collected with a meteorological station and a UAV (a total of 13 flights). ET c values obtained by applying the METRICTM (Mapping Evapotranspiration at High Resolution using Internalized Calibration) energy balance model ranged from 2.4 to 8.9 mm d−1 for the AWD and CF irrigation regimes. In addition, ET c was estimated by a water balance using the AquaCrop model, previously parameterized with RGB image data and field weather data, soil, irrigation water, and crops, obtaining values between 4.3 and 7.1 mm d−1 for the AWD and CF irrigation regimes. The results indicated that AWD irrigation allows for water savings of 27 to 28%, although it entails a yield reduction of from 2 to 15%, which translates into an increase in water use efficiency (WUE) of from 18 to 36%, allowing for optimizing water use and improving irrigation management. [ABSTRACT FROM AUTHOR]

Guar is a typical legume cash crop native to India. Guar beans are ever-rising in the market share at present. Among them, the guar gum of its seed endosperm has been mainly used in the oil exploration industry. Water-based fracturing fluid can be formulated to increase the permeability of oil-bearing strata during oil production. In addition, guar gum is also widely used in paper making, textiles, food, spices, drugs, as well as mining and metallurgical industries. The nutrient-rich green seeds of guar beans are edible for food vegetables, due to a large amount of protein and a small amount of fat. The plant can be used as fodder and green manure. However, the low supply of guar gum on the market cannot fully meet the broad market space. Only a small number of planting areas of guar beans are suitable for the cultivation of guar beans in the food industry. Among them, Xinjiang located in the northwestern inland arid zone is very similar to the unique geographic conditions for the production and cultivation of guar beans. The temperature and heat conditions are suitable for the origin of guar, rich in the light and heat resources under the soil and water environment, with the high temperature difference between day and night, due to the scarce rainfall and high evaporation. But the relatively small region of guar bean planting still remains so far. Therefore a broad prospect can be expected to optimize the water and nitrogen management for the high crop yield and efficient use of water and nitrogen. This study aims to explore the water and nitrogen mode suitable for drip irrigation of guar beans under film in the Xinjiang area of China. Four irrigation levels were set: W1:1170 m³/hm², W2:1 530 m³/hm², W3:1 890 m³/hm², W4: 2 250 m³/hm²; Two levels of nitrogen application were: N1:30 kg/hm², N2:50 kg/hm². A systematic investigation was made to clarify the effects of water and nitrogen interaction on the growth index, yield, water, and nitrogen use efficiency, as well as the quality of guar bean during drip irrigation under film. The results showed that the coupling effect of water and nitrogen shared a significant effect on the yield, irrigation water use efficiency, and partial factor productivity of nitrogen fertilizer (W3>W4>W2>W1). There was an increase in the plant height, stem diameter, dry matter accumulation, yield, water use efficiency, galactomannan, soluble sugar, and polysaccharide content of Guar bean under the N2 level, compared with the N1 level. Only the partial productivity of nitrogen fertilizer decreased slightly. Principal component and membership function analysis showed that the optimal treatment was achieved in the irrigation amount of 1 890 m³/hm² and the nitrogen application rate of 50 kg/hm²(W3N2). The finding can also provide a theoretical basis to promote the yield, water, and nitrogen use efficiency of Guar bean under mulched drip irrigation. [ABSTRACT FROM AUTHOR]

Groundwater recharge can greatly contribute to the crop growth in farmland for the sustainable development of regional production in modern agriculture. It is crucial to precisely quantify the rational utilization of groundwater sources. Among them, groundwater recharge can be broadly classified into empirical and mechanistic models in recent years. However, some limitations are still remained in practical application, due to the complexity and highly nonlinear of groundwater recharge. In this study, a series of experiments were conducted on the winter wheat under different groundwater levels and irrigation treatments using 24 clustered large-scale lysimeters. The AquaCrop model was calibrated and validated using the soil moisture content, canopy coverage, biomass, and grain yield of winter wheat as evaluation indicators. The calibrated AquaCrop model was then utilized to simulate the growth and development of winter wheat, as well as the soil water dynamics under varying irrigation treatments and groundwater depths. An estimation model was proposed for the groundwater recharge in the period of winter wheat growth. Thereby, the critical groundwater levels were determined for the different growth stages, and the threshold depth of water table suitable for winter wheat growth. Results showed that: 1) The AquaCrop model was performed best on the growth and development of winter wheat under different irrigation treatments and groundwater levels. Simultaneously, the better performance was achieved in the statistical parameters between the simulated and measured values of soil water content, canopy coverage, biomass, and grain yield during the growth period, with the determination coefficient (R²)≥0.8, the relative error (RE) and the normalized root mean square error (NRMSE) are both＜16%. 2) The validated AquaCrop model was employed to simulate the growth of winter wheat under 52 scenarios of groundwater depth and irrigation treatments. Subsequently, the nonlinear regressions of soil water storage - groundwater recharge intensity and groundwater depth - soil water storage were fitted during the growth period of winter wheat. The groundwater recharge intensity was calculated to compare with the measured values for verification. The statistical parameters fell well within the acceptable error range of the model, such as R²≥0.873, RE≤9.22%, RMSE≤0.316 mm/d and NRMSE≤11.89%. 3) The critical tables of groundwater were calculated in different growth stages of winter wheat under various irrigation treatments. The critical tables of groundwater were 3.28, 3.36 and 3.54m, respectively, for the winter wheat during the seedling, frozen and reviving-jointing stages under irrigation. Furthermore, the critical table of groundwater was 3.38 m under the sufficient irrigation treatment in the whole growth period. There was the various behavior in the different growth periods of winter wheat under the insufficient irrigation treatments. In general, the critical table of groundwater decreased with the increasing irrigation amount. The optimal threshold water table was ranged from 2.0 to 2.5 m for the winter wheat, according to the relationship between grain yields and groundwater levels under 52 simulated scenarios. Therefore, the yield and water use efficiency (WUE) of winter wheat were simultaneously reached their optimal levels under the insufficient irrigation treatment (at reviving and filling stages), which were 8.848 t/hm² and 2.17 to 2.43 kg/m³, respectively. The findings can also provide the technical support for the accurate assessments of groundwater contribution for the precision irrigation and decision-making management. making management. [ABSTRACT FROM AUTHOR]

The green fodder deficit is the biggest bottleneck for livestock productivity in semi-arid regions, especially for resource-poor farmers. Low-cost climate-smart hydroponic chamber (CSHC) based hydroponic fodder production provides a viable solution under such an environment. A CSHC equipped with a fan pad-based evaporative cooling system, controlled drip watering system and smart air exhaust system was designed and developed at ICAR-IGFRI, Jhansi, India with the aim of modifying the inside growth environment of the chamber for improved production of quality fodder. The developed CSHC was capable of maintaining daily average temperature and relative humidity in the range of 23-280C and 87-90%, respectively, with an average cooling efficiency of 78.3%. This efficient cooling was an outcome of specialized CSHC designed with an effective covering material (UV stabilized 200 µm LDPE), shade net with 70% shading efficiency, fan pad-based evaporative cooling system, controlled drip watering system, and smart air exhaust system; which enabled ambient environment conducive for optimum plant growth. Among the different treatment combinations of seed loading rates and soaking hours, the highest maize biomass yield of 2.58 kg/ft2 was achieved after seven days with a seed loading rate of 300 g/ft2 when the seed was soaked for 12 h. At the highest productivity of biomass, the values of dry matter, crude protein, and crude fiber contents were found as 13.51%, 13.71%, and 15.12% respectively. The benefit-cost ratio of the developed CSHC was 1.32 with a payback period of 3.12 years. The developed CSHC was found productive and profitable; hence, it can create a great impact in achieving feed security under resource deficit conditions of climate-change-affected semi-arid regions across the globe. [ABSTRACT FROM AUTHOR]

Silicon (Si) is a versatile nutrient that plays an instrumental role in mitigating biotic and abiotic stresses besides improving growth and yield of graminaceous crops. We hypothesized that application Si would significantly improve productivity and resilience of wheat. Hence, the objectives were a) to assess the impact of Si application on wheat growth, productivity, nutrient uptake, water use efficiency, and b) to determine the potentiality of Si in mitigating lodging and aphid density. Therefore, we conducted a field experiment with five levels of Si (0, 2, 4, 6, and 8 g Si liter−1) at three growth stages (crown root initiation, tillering, and jointing stage) using a factorial randomized block design replicated three times. The results showed that increasing Si doses positively influenced plant height, dry matter accumulation (DMA), leaf area index (LAI), yield, and nutrient uptake. The highest grain and straw yield were observed with 8 g Si liter−1, followed by 6 g Si liter−1, while the control had the lowest yields. With 8 g Si liter−1, grain yield, straw yield, and Si uptake increased by 10.5%, 13.5%, and 26.3%, respectively, compared to the control. Additionally, Si application at 8 g Si liter−1 significantly reduced the density of S. avenae (aphids) by 81.4% and lodging by 75.1% compared to the control. Overall, the study demonstrated that increasing Si doses enhanced various growth and yield parameters, with 8 g Si liter−1 and 6 g Si liter−1 showing superior results. Among the growth stages, foliar application of Si during the tillering stage exhibited better performance in terms of growth, yield, and nutrient uptake in wheat. Therefore, the study concludes that Si fertilization at a rate of 8 g Si liter−1 during the tillering stage can effectively improve growth, productivity, and nutrient uptake in wheat in the southern region of Rajasthan. [ABSTRACT FROM AUTHOR]

Climate change-caused water deficiency is a major threat to crop production. Different strategies such as biochar and mycorrhiza are suggested as a solution to improve water storage in the soil and increase plant tolerance to moisture deficiency. This study tested the hypothesis that under deficit irrigation conditions, the combined application of biochar and mycorrhiza can increase maize photosynthesis activity, growth, and water use efficiency (WUE). A greenhouse experiment was established to understand the effect of biochar and mycorrhizal inoculation with deficit irrigation on maize (Zea mays L.) growth, photosynthesis activity, and WUE. A factorial randomized pot experiment was designed using three biochars (B) doses from three different feedstock (DF) and three mycorrhizae (M) species (without mycorrhizae, Rhizophagus clarus and indigenous mycorrhiza), with three different irrigation (I) levels, namely, I100, I75, and I50 respectively 100%, 75%, and 50% of field capacity. For each biochar application, of 0%, 1%, and 2% rates of soil weight were applied. Maize plant dry matter (DM), photosynthesis activities, and leaf water use efficiency (WUEL) were measured. The results showed that deficit irrigation levels, such as I75 and I50 can be used for maize plant growth. Mycorrhizal inoculation increased maize plant growth between 8.2% and 8.9%, whereas biochar increased growth. In addition, mycorrhizal inoculation increased the photosynthesis activity by 9.3%. All the biochars increased maize growth and photosynthesis activity compared to the control, however, poultry manure biochar had the highest growth, photosynthesis activity, and WUE. In addition, statistically, there were no significant differences between B0*M0*I100 and B*M*I50 applications in terms of photosynthesis activity, WUE, and DM. Combined application of biochar and mycorrhiza statistically reduced irrigation water use by 50% without affecting plant DM production. [ABSTRACT FROM AUTHOR]

Over the past three decades, China has implemented extensive reforestation programs, primarily utilizing Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) in southern China, to mitigate greenhouse gas emissions and counter extreme climate events. However, the effects of drought on the carbon sequestration capacity of these forests, particularly during the trunk wood stage, remain unclear. This study, conducted in Huitong, Hunan, China, from 2008 to 2013, employed the eddy covariance method to measure carbon dioxide (CO2) and water fluxes in Chinese fir forests, covering a severe drought year in 2011. The purpose was to elucidate the dynamics of carbon and water fluxes during a drought year and across multi-normal year averages. The results showed that changes in soil water content (−8.00%), precipitation (−18.45%), and relative humidity (−5.10%), decreases in air temperature (−0.09 °C) and soil temperature (−0.79 °C), and increases in vapor pressure deficit (19.18%) and net radiation (8.39%) were found in the drought year compared to the normal years. These changes in environmental factors led to considerable decreases in net ecosystem exchange (−40.00%), ecosystem respiration (−13.09%), and gross ecosystem productivity (−18.52%), evapotranspiration (−12.50%), and water use efficiency (−5.83%) in the studied forests in the drought year. In this study, the occurrence of seasonal drought due to uneven precipitation distribution led to a decrease in gross ecosystem productivity (GEP) and evapotranspiration (ET). However, the impact of drought on GEP was greater than its effect on ET, resulting in a reduced water use efficiency (WUE). This study emphasized the crucial role of water availability in determining forest productivity and suggested the need for adjusting vegetation management strategies under severe drought conditions. Our results contributed to improving management practices for Chinese fir plantations in response to changing climate conditions. [ABSTRACT FROM AUTHOR]

The olive tree is well adapted to the Mediterranean climate, but how orchards based on intensive practices will respond to increasing drought is unknown. This study aimed to determine if the application of a commercial biostimulant improves olive tolerance to drought. Potted plants (cultivars Arbequina and Galega) were pre-treated with an extract of Ascophyllum nodosum (four applications, 200 mL of 0.50 g/L extract per plant), and were then well irrigated (100% field capacity) or exposed to water deficit (50% field capacity) for 69 days. Plant height, photosynthesis, water status, pigments, lipophilic compounds, and the expression of stress protective genes (OeDHN1—protective proteins' dehydrin; OePIP1.1—aquaporin; and OeHSP18.3—heat shock proteins) were analyzed. Water deficit negatively affected olive physiology, but the biostimulant mitigated these damages through the modulation of molecular and physiological processes according to the cultivar and irrigation. A. nodosum benefits were more expressive under water deficit, particularly in Galega, promoting height (increase of 15%) and photosynthesis (increase of 34%), modulating the stomatal aperture through the regulation of OePIP1.1 expression, and keeping OeDHN1 and OeHSP18.3 upregulated to strengthen stress protection. In both cultivars, biostimulant promoted carbohydrate accumulation and intrinsic water-use efficiency (iWUE). Under good irrigation, biostimulant increased energy availability and iWUE in Galega. These data highlight the potential of this biostimulant to improve olive performance, providing higher tolerance to overcome climate change scenarios. The use of this biostimulant can improve the establishment of younger olive trees in the field, strengthen the plant's capacity to withstand field stresses, and lead to higher growth and crop productivity. [ABSTRACT FROM AUTHOR]

In general, young plants in the establishment phase demonstrate sensitivity to changes in environmental conditions, especially regarding water availability. The effects of the seasonality of biophysical processes on plant physiology can trigger differential responses, even within the same region, making it necessary to conduct studies that characterize the physiological performance of the species at different spatial and temporal scales, making it possible to understand their needs and growth limits under water stress conditions. This paper aimed to evaluate the growth, gas exchange and Chl a fluorescence in ipê-rosa seedlings subjected to levels of water replacement (LWRs) of 100, 75, 50 and 25% in a greenhouse. The morphometric variables of plant height, diameter at stem height, numbers of leaves and leaflets, root length and volume, plant dry mass and leaf area were evaluated. The potential evapotranspiration of seedlings (ETc) was obtained using direct weighing, considering the water replacement of 100% of the mass variation between subsequent days as a reference; the cultivation coefficients (kc) were obtained using the ratio between ETc and the reference evapotranspiration (ETo) obtained by the Penman–Monteith FAO-56 method. Biomass and evapotranspiration data were combined to determine water sensitivity. Diurnal fluxes of gas exchange (net photosynthesis rate, transpiration rate, stomatal conductance, internal and atmospheric carbon ratio, water use efficiency and leaf temperature) and Chl a fluorescence (Fv/Fm, ΦPSII, ETR, Fv′/Fm′, NPQ and qL) were evaluated. Water restriction caused reductions of 90.9 and 84.7% in the increase in height and diameter of seedlings subjected to 25% water replacement when compared to seedlings with 100% water replacement. In comparison, biomass accumulation was reduced by 96.9%. The kc values increased throughout the seedling production cycle, ranging from 0.59 to 2.86. Maximum water sensitivity occurred at 50% water replacement, with Ky = 1.62. Maximum carbon assimilation rates occurred in the morning, ranging from 6.11 to 12.50 µmol m−2 s−1. Ipê-rosa seedlings regulate the physiology of growth, gas exchange and Chl a fluorescence depending on the amount of water available, and only 25% of the water replacement in the substrate allows the seedlings to survive. [ABSTRACT FROM AUTHOR]

Glycyrrhiza uralensis is an important plant in desert ecology, where low rainfall and water scarcity limit its growth. In order to explore harvested rainwater and use for Glycyrrhiza uralensis growth and to reduce water scarcity in Northwest China's arid area, this study was conducted in April and July of 2023. Five types of slope micro rainwater collection measures, including horizontal terraces, square ridges, and contour ridges, were utilized to monitor rainfall and runoff. Glycyrrhiza uralensis seedlings were utilized as test subjects for supplementary irrigation in pots utilizing the natural drought method. The results show that supplemental irrigation boosts Glycyrrhiza uralensis root growth and water uptake capacity in short-term drought conditions. Irrigation with 42.97 mm enhanced Glycyrrhiza uralensis root length, belowground dry weight, and water use efficiency by 104.5%, 39.54%, and 4.18%. Supplemental irrigation under prolonged drought stress shifted Glycyrrhiza uralensis development from below- to aboveground, resulting in decreased activity of osmotic adjustment material activity in leaves. After 31 days of continuous drought following supplemental irrigation, plant height and aboveground fresh weight increased by 58.16% and 20.03%, respectively, whereas the superoxide dismutase activity was reduced by 63.16% in the 42.97 mm irrigated treatment. Furthermore, under short-term drought stress following supplemental irrigation, leaf water use efficiency was primarily influenced by osmoregulatory substances and plant growth characteristics. Under long-term drought stress, it was influenced by osmoregulatory substances and photosynthetic properties. This research is critical for preventing soil erosion and restoring grassland ecological health in the Ili River Valley. [ABSTRACT FROM AUTHOR]

Drought is one of the abiotic stresses that can reduce crop yields. It has a major impact on crop yield reduction. For crops under stress, organic modifiers such as biochar can be useful. Guar (Cyamopsis tetragonoloba L.), an annual legume from the Fabaceae Family, is highly adaptable to arid and semi-arid regions, with many applications in various industries. Field experiments were carried out in a randomized complete block design with three replications using a split-split plots arrangement. The aim was to evaluate the influence of irrigation levels (Ir1 = 10, Ir2 = 14, and Ir3 = 17 days irrigation cycle) and biochar (B1 = 0, B2 = 5, and B3 = 10 tons ha−1) application on physiological traits [(chlorophyll a and b, chlorophyll index (SPAD), relative leaf water content (RWC), electrolyte leakage (EL), canopy temperature, leaf area, water use efficiency (WUE)], morphological parameters (length and diameter of the stem, pod length, fresh weight of root and plant, root length), yield components (seed yield, number of branch plant−1, number of clusters plant−1, pod plant−1, seed pod−1, seed plant−1, 1000-seed weight, and gum contents), and leaf nutrient uptake (Ca, Mg, P, Na, and K) of two commercial and local cultivars (cv1 = RGC-936 and cv2 = Saravan) of the guar plant. It was observed that the Ir3 irrigation treatment produced the highest seed yield (1921.8 kg ha−1) in terms of water stress. However, the maximum pod plant−1 (75.5), seed plant−1 (454.2), seed yield (1871.1 kg ha−1), leaf area (861.8 mm2), SPAD (92.2), Mg (49.8 mg g−1), Na (43.3 mg g−1) and P (0.49 mg g−1) were observed in RGC-936. The results also revealed that biochar was more effective than cultivars in terms of morphological traits. While yield and yield components were affected by cultivar, irrigation at different levels also had a significant effect on functional traits, physiology, and morphology. The addition of biochar appeared to have a positive effect on water stress alleviation and guar growth and leaf nutrient uptake. According to Pearson's correlation analysis, plant weight and length, root weight and length, stem diameter, seed pod−1, branches plant−1, and 1000-seed weight are moderately correlated with seed yield, while pod plant−1 and seed plant−1 are strongly associated with seed yield. On the other hand, the pod length, branches plant−1, and gum content showed a positive but not significant relationship. [ABSTRACT FROM AUTHOR]

In sub-Saharan Africa, cattle feedlots face a significant challenge in dealing with heat stress. However, there is a lack of inclusive strategies for resilience in these situations. The aim of this systematic review is to investigate the strategies, challenges, and outcomes related to heat stress resilience in community-based cattle feedlots in sub-Saharan Africa. The PRISMA approach, which is a method for reporting systematic reviews and meta-analyses, was used to identify, screen, and analyze 30 peer-reviewed articles published over the last 20 years from Google Scholar and Scopus. The review found that key strategies to mitigate heat stress include providing shade through natural and artificial means, ensuring constant access to cool, clean water using water spraying systems and cooling ponds, and implementing nutritional adjustments such as high-energy feeds and electrolyte supplements. Additionally, genetic selection for heat-tolerant breeds and management practices like adjusting feeding times and improving ventilation were found to be effective in dealing with heat stress. In particular, local germplasm and genetic traits of cattle in sub-Saharan Africa play a crucial role in heat stress resilience. Indigenous breeds, which have adapted to the region’s harsh climate over centuries, exhibit traits such as higher heat tolerance, better water-use efficiency, and improved feed conversion rates under heat stress conditions. This genetic resilience can be enhanced through targeted breeding programs aimed at amplifying these beneficial traits. Implementing these strategies resulted in improved cattle health and productivity, as evidenced by enhanced weight gain, better reproductive performance, and lower mortality rates. The socio-economic benefits of these strategies included reduced economic losses and increased farmer incomes, which in turn contributed to improved community health and nutrition. However, the review also identified significant challenges, including financial constraints, limited access to knowledge and training, and cultural resistance. To address these barriers, the review recommends increased investment in affordable cooling technologies, farmer education, and community-based initiatives. Additionally, leveraging the genetic strengths of local cattle breeds should be prioritized to maximize the effectiveness of heat stress resilience strategies. [ABSTRACT FROM AUTHOR]

This study extends our prior research on drought responses in three date palm cultivars (Khalas, Reziz, and Sheshi) under controlled conditions. Here, we investigated their drought stress adaptive strategies under ambient environment. Under natural field drought conditions, three date palm cultivars experienced significantly (p ≤ 0.05) varying regulations in their physiological attributes. Specifically, chlorophyll content, leaf RWC, photosynthesis, stomatal conductance, and transpiration reduced significantly, while intercellular CO2 concentration and water use efficiency increased. Through suppression subtraction hybridization (SSH), a rich repertoire (1026) of drought-responsive expressed sequence tags (ESTs) were identified: 300 in Khalas, 343 in Reziz, and 383 in Sheshi. Functional analysis of ESTs, including gene annotation and KEGG pathways elucidation, unveiled that these cultivars withstand drought by leveraging indigenous and multifaceted pathways. While some pathways aligned with previously reported drought resilience mechanism observed under controlled conditions, several new indigenous pathways were noted, pinpointing cultivar-specific adaptations. ESTs identified in three date palm cultivars were enriched through GSEA analysis. Khalas exhibited enrichment in cellular and metabolic processes, catalytic activity, and metal ion binding. Reziz showed enrichment in biological regulation, metabolic processes, signaling, and nuclear functions. Conversely, Sheshi displayed enrichment in organelle, photosynthetic, and ribosomal components. Notably, ca. 50% of the ESTs were unique and novel, underlining the complexity of their adaptive genetic toolkit. Overall, Khalas displayed superior drought tolerance, followed by Reziz and Sheshi, highlighting cultivar-specific variability in adaptation. Conclusively, date palm cultivars exhibited diverse genetic and physiological strategies to cope with drought, demonstrating greater complexity in their resilience compared to controlled settings. [ABSTRACT FROM AUTHOR]

The combination of biochar and nitrogen (N) fertilization in agricultural salt-affected soils is an effective strategy for amending the soil and promoting production. To investigate the effect of nitrogen reduction combined with biochar application on a soda saline soil and soybean growth in black soil areas, a pot experiment was set up with two biochar application levels, 0 (B0) and 4.5 t/hm2 (B1); two biochar application depths, 0-20 cm (H1) and 0-40 cm (H2); and two nitrogen application levels, conventional nitrogen application (N0) and nitrogen reduction of 15% (N1). The results showed that the application of biochar improved the saline soil status and significantly increased soybean yield under lower nitrogen application. Moreover, increasing the depth of biochar application enhanced the effectiveness of biochar in reducing saline soil barriers to crop growth, which promoted soybean growth. Increasing the depth of biochar application increased the K+ and Ca2+ contents, soil nitrogen content, N fertilizer agronomic efficiency, leaf total nitrogen, N use efficiency, AN, Tr, gs, SPAD, leaf water potential, water content and soybean yield and its components. However, the Na+ content, SAR, ESP, Na+/K+, Ci and water use efficiency decreased with increasing biochar depth. Among the treatments with low nitrogen input and biochar, B1H1N1 resulted in the greatest soil improvement in the 0-20 cm soil layer compared with B0N0; for example, K+ content increased by 61.87%, Na+ content decreased by 44.80%, SAR decreased by 46.68%, and nitrate nitrogen increased by 26.61%. However, in the 20-40 cm soil layer, B1H2N1 had the greatest effect on improving the soil physicochemical properties, K+ content increased by 62.54%, Na+ content decreased by 29.76%, SAR decreased by 32.85%, and nitrate nitrogen content increased by 30.77%. In addition, compared with B0N0, total leaf nitrogen increased in B1H2N1 by 25.07%, N use efficiency increased by 6.7%, N fertilizer agronomic efficiency increased by 32.79%, partial factor productivity of nitrogen increased by 28.37%, gs increased by 22.10%, leaf water potential increased by 27.33% and water content increased by 6.44%. In conclusion, B1H2N1 had the greatest effect on improving the condition of saline soil; it not only effectively regulated the distribution of salt in soda saline soil and provided a low-salt environment for crop growth but also activated deep soil resources. Therefore, among all treatments investigated in this study, B1H2N1 was considered most suitable for improving the condition of soda saline soil in black soil areas and enhancing the growth of soybean plants. [ABSTRACT FROM AUTHOR]

Background: Understanding the complex relationship between soil characteristics and crop production is crucial for sustainable agriculture practices. Soil physicochemical properties such as pH, electrical conductivity (EC), organic matter (OM) and nutrient content (e.g., NPK) significantly influence crop yield. Additionally, the application of straw mulch can impact soil moisture retention, there by affecting crop growth and productivity. Intercropping system offers potential advantages in terms of water use efficiency (WUE) and productivity compared to monoculture system. Methods: The experiment was conducted using a randomised block design (RBD) with three replications. The study included six treatments with different cropping system: T1 = Monoculture soybean(planting size 30×10 cm), T2 = Monoculture maize (planting size 45×15 cm),T3 = Maize + soybean (2:2) line sown,T4 = Maize intercropping with soybean (2:2) + wheat straw (5 tha-1), T5 = Maize intercropping with soybean (2:2) + maize straw (5 tha-1), T6 = Maize intercropping with soybean (2:2) + mustard straw (5 tha-1). Result: Water use efficiency (WUE) varied among treatments, with the highest WUE (9.44) observed in application of maize straw mulch 5t ha-1, indicating 42.57% increases compared to monoculture maize and 42.17% increases compared to monoculture soybean cultivation. Similarly, superior grain yield (19.30 q ha-1), pod yield (16.29 q ha-1), intercrop yield (35.59 q ha-1), maximum maize equivalent yield (54.33 q ha-1) when comparing the results with and without straw mulch applied to maize and soybean crops. Maize and soybean intercropping system demonstrated superior land utilization efficiency (LER:1.04 to 1.24) and productivity metrics. [ABSTRACT FROM AUTHOR]

Predicting how plants respond to drought requires an understanding of how physiological mechanisms and drought response strategies occur, as these strategies underlie rates of gas exchange and productivity. We assessed the response of 11 plant traits to repeated experimental droughts in four co-occurring species of central Australia. The main goals of this study were to: (i) compare the response to drought between species; (ii) evaluate whether plants acclimated to repeated drought; and (iii) examine the degree of recovery in leaf gas exchange after cessation of drought. Our four species of study were two tree species and two shrub species, which field studies have shown to occupy different ecohydrological niches. The two tree species (Eucalyptus camaldulensis Dehnh. and Corymbia opaca (D.J.Carr & S.G.M.Carr) K.D.Hill & L.A.S.Johnson) had large reductions in stomatal conductance (g s) values, declining by 90% in the second drought. By contrast, the shrub species (Acacia aptaneura Maslin & J.E.Reid and Hakea macrocarpa A.Cunn. ex R.Br.) had smaller reductions g s in the second drought of 52 and 65%, respectively. Only A. aptaneura showed a physiological acclimatation to drought due to small declines in g s versus ᴪpd (0.08 slope) during repeated droughts, meaning they maintained higher rates of g s compared with plants that only experienced one final drought (0.19 slope). All species in all treatments rapidly recovered leaf gas exchange and leaf mass per area following drought, displaying physiological plasticity to drought exposure. This research refines our understanding of plant physiological responses to recurrent water stress, which has implications for modelling of vegetation, carbon assimilation and water use in semi-arid environments under drought. [ABSTRACT FROM AUTHOR]

The growth of root system directly affects the absorption and utilization of soil water and nitrogen, and understanding the responses of root characteristics to water and nitrogen regimes is thus crucial for optimizing water and nitrogen management. The root characteristics of each soil layer, i.e., root length, root surface area, and root volume, as well as fruit yield and water use efficiency of greenhouse tomato under drip fertigation in response to different irrigation levels and nitrogen rates were explored in northwest China. There were four irrigation levels, i.e., 50% ETC (W1), 75% ETC (W2), 100% ETC (W3), and 125% ETC (W4), where ETC is the crop evapotranspiration, and four nitrogen rates, i.e., 0 kg ha−1 (N1), 150 kg ha−1 (N2), 250 kg ha−1 (N3), and 350 kg ha−1 (N4). The results showed that reasonable irrigation and nitrogen regimes (W3N3) significantly increased fruit yield by 31.64% and root length, root surface area, and root volume by 45.03%, 61.24%, and 148.21% compare to W3N1, respectively. The promoting effect of increasing irrigation level on root characteristics increased with soil depth and had the greatest increases in root volume by 27.07%, 123.43%, and 211.47% for the 0–10, 10–20, and 20–30 cm soil layers, respectively. In addition, reducing irrigation level significantly increased the percentages of roots in the top soil by 29.71%, 26.77%, and 18.53% for root length, root surface area, and root volume, respectively. The reasonable nitrogen rate (N3) significantly increased fruit yield by 41.11%, water use efficiency by 34.42%, and root length, root surface area, and root volume by 40.42%, 41.44%, and 112.76%, respectively. The over-application of nitrogen (N4) reduced root characteristics of all soil layers, fruit yield, and water use efficiency. The promoting effect of increasing nitrogen rate on root length of each soil layer decreased with soil depth, by 71.01%, 48.96%, and 15.71% for 0–10, 10–20, and 20–30 cm soil layers, respectively. Irrigation level was the main factor dominating the root growth of each soil layer. The correlation analysis showed that fruit yield had significantly positive correlations with root characteristics in all soil layers, while water use efficiency had significantly positive correlations with the percentages of root length and root surface area in the 0–10 cm soil layer. In conclusion, rational water and nitrogen regimes achieved better fruit yield by promoting root growth of greenhouse tomato, and the water use efficiency of greenhouse tomato was improved by increasing the root percentage in the topsoil layer to alleviate the adverse effects under water stress conditions. This study reveals how irrigation volume and nitrogen application can enhance tomato yield and water use efficiency by regulating root characteristics and vertical root distribution, providing support for understanding the response of root systems to changes in soil water and nitrogen conditions. [ABSTRACT FROM AUTHOR]

In saline conditions, establishing healthy seedlings is crucial for the productivity of sunflowers (Helianthus annuus L.). Excessive potassium (K+) from irrigation water or overfertilization, similar to sodium (Na+), could adversely affect sunflower growth. However, the effects of salt stress caused by varying K/Na ratios on the establishment of sunflower seedlings have not been widely studied. We conducted a pot experiment in a greenhouse, altering the K/Na ratio of a soil solution to grow sunflower seedlings. We tested three saline solutions with K/Na ratios of 0:1 (P0S1), 1:1 (P1S1), and 1:0 (P1S0) at a constant concentration of 4 dS m−1, along with a control (CK, no salt added), with five replicates. The solutions were applied to the pots via capillary rise through small holes at the bottom. The results indicate that different K/Na ratios significantly influenced ion-selective uptake and transport in crop organs. With an increasing K/Na ratio, the K+ concentration in the roots, stems, and leaves increased, while the Na+ concentration decreased in the roots and stems, with no significant differences in the leaves. Furthermore, an excessive K/Na ratio (P1S0) suppressed the absorption and transportation of Mg2+, significantly reducing the Mg2+ concentration in the stems and leaves. A lower leaf Mg2+ concentration reduced chlorophyll concentration, impairing photosynthetic performance. The lowest plant height, leaf area, dry matter, and shoot/root ratio were observed in P1S0, with reductions of 27%, 48%, 48%, and 13% compared to CK, respectively. Compared with CK, light use efficiency and CO2 use efficiency in P1S0 were significantly reduced by 13% and 10%, respectively, while water use efficiency was significantly increased by 9%. Additionally, improved crop morphological and photosynthetic performance was observed in P1S1 and P0S1 compared with P1S0. These findings underscore the critical role of optimizing ion composition in soil solutions, especially during the sensitive seedling stage, to enhance photosynthesis and ultimately to improve the plant's establishment. We recommend that agricultural practices in saline regions incorporate tailored irrigation and fertilization strategies that prioritize optimal K/Na ratios to maximize crop performance and sustainability. [ABSTRACT FROM AUTHOR]