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A root system is an important factor to increase soil resistance to detachment of soil particles. However, due to the large number of species, there is a need for studying the impacts of native plant species on soil quality and soil erodibility. This investigation did flume experiments at various soil slopes (9.2%, 18.1%, 25.1%, and 32.5%) and different water flow rates (0.56, 0.67, 0.74, 0.81, and 0.94 L/(m·s)), to evaluate sediment detachment capacity caused by rills (D c) and rill erodibility (K r) as well as the soil quality of hillslopes with three common species including Carpinus betulus (as a natural tree species), Alnus glutinosa (as a planted tree species) and Mespilus germanica (as a shrub species) in forestland of northern Iran. The variability of D c has been associated with soil properties and root characteristics of Carpinus betulus. D c was significantly lower (average, −45%) for soils under Carpinus betulus compared to soils with the two other plant species (p < 0.01). This was due to the higher values of soil properties including medium weight diameter of soil aggregates (MWD), organic carbon (OC), total nitrogen (TN), total phosphorous (TP), potassium (K), calcium (Ca), magnesium (Mg) as well as to the more extended root system, as confirmed by the negative correlations between D c and the studied variables. K r also was different among the studied soils and plant species. The root system of Carpinus betulus also played a useful role for increasing soil resistance to rill erosion yielding a safety factor (1.61) in the studied forest ecosystem. Overall, the current study supports a broader use of native species (such as Carpinus betulus) in areas exposed to surface erosion and instability, as an effective eco-engineering conservation technique and an alternative technology instead of utilizing artificial and expensive management practices. [Display omitted] • Sediment detachment capacity (D c) has been estimated by flume experiments for vegetated soils. • A natural species had lower D c compared to the planted and shrub species. • This reduction was due to higher soil quality and more extended plant roots. • Carpinus betulus species played a beneficial role for increasing slope stability. • The rill erodibility (K r) was the lowest in soils under Carpinus betulus species. [ABSTRACT FROM AUTHOR]

The optimized sowing method and appropriate seed rate can improve wheat N use efficiency. However, the interactive effect of the sowing method and seed rate on N use efficiency, particularly N uptake and root length density, are unclear. A field experiment was conducted for two growing seasons in southern Shanxi province, China, using a split-plot design with the sowing method as the main plot (wide-belt sowing, WBS, and conventional narrow-drill sowing, NDS) and seed rate as the sub-plot (100–700 m−2). Our results showed that WBS had a significant and positive effect on N use efficiency (yield per unit of available N from the fertilizer and soil, by 4.7–15.4%), and the relatively higher seed rates (>300 or 400 m−2) enlarged the effects. The N use efficiency increases under WBS were mainly attributed to the increases in N uptake before anthesis, resulting from the promoted nodal roots per plant and per unit area, and root length density in the top layer(s). WBS promoted N translocation and the N harvest index, resulting in equivalent grain protein concentration and processing quality compared to NDS. Thus, adopting higher seed rates (>300 m−2) combined with WBS is recommended for achieving greater N efficiencies while maintaining the grain protein concentration and processing quality of winter wheat. [ABSTRACT FROM AUTHOR]

Soil aggregation, an important indicator of soil restoration in degraded ecosystems, is a fundamental unit of soil structure. However, research on the influence of grass–shrub composites on the distribution of >0.25 mm soil water-stable aggregates (macroaggregates) is scarce. Therefore, this study focuses on the hill and gully region of the Loess Plateau, where vegetation has been well restored since the return of farmland to forests and grasslands. The study investigated the root and macroaggregate distribution characteristics and interrelationships of three widely distributed mixed vegetation types of Caragana korshinskii and Agropyron cristatum (C-AC), C. korshinskii and Bothriochloa ischaemum (C-BI), and C. korshinskii and Artemisia gmelinii (C-AG) in this area. The results indicate that soil macroaggregates decrease with increasing depth. Due to the spatial differences in the distribution of shrub root, the content of macroaggregates at 50 cm from the shrub base was higher than that at the shrub base, with an increase of 25.98%–34.27% in different vegetation associations. In this study, the root length density and root diameter better reflected the influence of roots on the distribution of macroaggregates, and the product of the two had a good power function relationship with the content of macroaggregates (R2 ≥ 0.82, p < 0.01). Grey correlation analysis showed that the influence of root length density on the distribution of large aggregates was greater than that of root diameter. The content of macroaggregates in the vegetation association of taproot herbaceous plants and shrubs was higher than that of fibrous root herbaceous plants. The average soil macroaggregate content in the C-AG was 15.79%–248.6% higher than that in the C-BI and C-AC. In this study, the spatial distribution differences in root caused by shrub growth were the main reason for the spatial heterogeneity of soil macroaggregate content distribution. The improvement ability of soil macroaggregates was higher in the combination of taproot herbaceous plants and shrubs than in the combination of fibrous root herbaceous plants and shrubs. The results of this study can, to some extent, reveal the influence and mechanisms of plant roots on soil aggregates in grass–shrub vegetation association. [ABSTRACT FROM AUTHOR]

This study examined the relationship between the decline in sugarcane productivity and the distribution of macropores and depth of root penetration in sugarcane plantations in Takalar during one planting period (October 2021-September 2022). There were five observation points (P1, P2, P3, P4, and P5) in one hectare of land to measure the distribution of soil macropores using methylene blue solution. Cross-sections of the soil were made to observe the presence of plant roots at a depth of 0-40 cm with a width of 60 cm. In each plot, disturbed soil samples were collected to measure soil texture, soil organic matter (SOM), nitrogen (N), phosphorus (P), and potassium (K) contents. Other measurement parameters were the infiltration rate and plant productivity. The results indicated that SOM and NPK levels at the research location were deficient, serving as the first indicators of problematic soil. Macropore observations revealed that macropores were distributed only at a less than 10 cm soil depth. This distribution limited the penetration of plant roots to a depth of 0-40 cm. The root length density (RLD) value indicated the absence of roots at depths of 30-40 cm in plots P2 and P3. The field findings explained why sugarcane production in Takalar only achieved 50%, around 40 t ha-1 from the first ratoon sugarcane harvest, instead of the expected 70-80 t ha-1.

[Objective] The aims of this study are to reveal the effects of different herb roots on soil permeability in local dump sites, to clarify the optimal index for predicting the improvement of soil permeability by herbaceous plant roots, to obtain the optimal diameter grade of herbaceous plant roots to improve soil permeability, so as to provide an important basis for the selection of ecological restoration plants in the dump. [Methods] Haizhou open pit dump was taken as the study site. The axial root type of Viola philippica, the tiller root type of Izeris polycephala and the rhizome root type of Triglochin palustris were the objects of the study. The root distribution characteristics of three kinds of roots in different soil depths were quantified by image pixel conversion method. Combined with the penetration test, the permeability parameters of the undisturbed root-soil complex of three herbaceous plants were obtained. The relationship between root distribution parameters and permeability parameters of the root-soil complex was explored. [Results] All three herbs can improve soil permeability. Compared with plain soil the initial infiltration rate, steady infiltration rate. average infiltration rate and total infiltration rate of axial, rhizoid and tillering root soil composites increase by 82.23%~254.99%, 85.59%~307.63%, 72.02%~325.91% and 62.93%~ 246.98%, respectively. The root length density and root surface area density of the three herbaceous roots are linearly correlated with the permeability parameters of the root soil complex, and the correlation of root surface area density is stronger than that of root length density. The enhancement effect of three kinds of roots on soil permeability is mainly attributed to the diameter class of 0.5 mm

Mine tailings storage poses significant environmental risks such as the formation of acid mine drainage. Engineered covers offer a solution by controlling water ingress. Their performance is based on specific soil hydrogeological properties (SHPs). They must support vegetation which can impact saturated hydraulic conductivity (ksat) and water retention curve (WRC). This study assesses the impact of 4-year-old willow root colonization on silty soil covers using flexible wall parameters and water retention tests. The obtained SHPs were compared with root traits. The results suggested that the hydrogeological properties of the studied in situ samples were not significantly affected by roots. The variation of measured and predicted ksat values spanned an order of magnitude, regardless of the root colonization intensity, up to a root length density (RLD) of 2.98 cm/cm3. RLD showed a significant and positive linear relationship with measured ksat values (R2 = 0.54). However, when root colonization was low (RLD < 1 cm/cm3), RLD was negatively correlated with the nvG (R2 = 0.44) parameter of the van Genuchten WRC model, while the opposite relationship was observed for samples with RLD > 1 cm/cm3 (R2 = 0.61). Additionally, RLD and the coarse root (diameter > 1 mm) volume to fine root volume (C/F ratio) influenced WRCs. Over time, coarser roots may have a more pronounced impact on SHPs; further research is needed. [ABSTRACT FROM AUTHOR]

Background: Border row effects impact the ecosystem functions of intercropping systems, with high direct interactions between neighboring row crops in light, water, and nutrients. However, previous studies have mostly focused on aboveground, whereas the effects of intercropping on the spatial distribution of the root system are poorly understood. Field experiments and planting box experiments were combined to explore the yield, dry matter accumulation, and spatial distribution of root morphological indexes, such as root length density (RLD), root surface area density (RSAD), specific root length (SRL), and root diameter (RD), of maize and peanut and interspecific interactions at different soil depths in an intercropping system. Results: In the field experiments, the yield of intercropped maize significantly increased by 33.45%; however, the yield of intercropped peanut significantly decreased by 13.40%. The land equivalent ratio (LER) of the maize–peanut intercropping system was greater than 1, and the advantage of intercropping was significant. Maize was highly competitive (A = 0.94, CR=1.54), and the yield advantage is mainly attributed to maize. Intercropped maize had higher RLD, RSAD, and SRL than sole maize, and intercropped peanut had lower RLD, RSAD, and SRL than sole peanut. In the interspecific interaction zone, the increase in RLD, RSAD, SRL, and RD of intercropped maize was greater than that of intercropped peanut, and maize showed greater root morphological plasticity than peanut. A random forest model determined that RSAD significantly impacted yield at 15–60 cm, while SRL had a significant impact at 30–60 cm. Structural equation modeling revealed that root morphology indicators had a greater effect on yield at 30–45 cm, with interactions between indicators being more pronounced at this depth. Conclusion: These results show that border-row effects mediate the plasticity of root morphology, which could enhance resource use and increase productivity. Therefore, selecting optimal intercropping species and developing sustainable intercropping production systems is of great significance. [ABSTRACT FROM AUTHOR]

Plants respond to their environment through adaptations; for example, earthworms that create heterogeneity can lead to local adaptation of roots. This research identifies a mechanism to explain plant responses to earthworms and how these mechanisms are related. Our results show that tillage intensity has a negative effect on earthworms and root volume. The mean root volume and earthworm biomass under conventional tillage were lower than in reduced tillage and no-tillage. The root volume and the root diameter in the field with residues were higher than in the field without residues, while the root length density and earthworm biomass in the field with residues were lower than in the field without residues. This study demonstrates that the mean of the root length density and biomass of the earthworms were higher in sandy loam than in loam. Therefore, sand content had a positive effect on root length density (R2 = 0.72, p < 0.01) and earthworm biomass (R2 = 0.74, p < 0.01). Earthworm biomass had a positive effect on root volume (R2 = 0.54, p < 0.05) and length density (R2 = 0.88, p < 0.01). This confirms our hypothesis on the effect of earthworms on root systems. [ABSTRACT FROM AUTHOR]

This study examined the relationship between the decline in sugarcane productivity and the distribution of macropores and depth of root penetration in sugarcane plantations in Takalar during one planting period (October 2021-September 2022). There were five observation points (P1, P2, P3, P4, and P5) in one hectare of land to measure the distribution of soil macropores using methylene blue solution. Cross-sections of the soil were made to observe the presence of plant roots at a depth of 0-40 cm with a width of 60 cm. In each plot, disturbed soil samples were collected to measure soil texture, soil organic matter (SOM), nitrogen (N), phosphorus (P), and potassium (K) contents. Other measurement parameters were the infiltration rate and plant productivity. The results indicated that SOM and NPK levels at the research location were deficient, serving as the first indicators of problematic soil. Macropore observations revealed that macropores were distributed only at a less than 10 cm soil depth. This distribution limited the penetration of plant roots to a depth of 0-40 cm. The root length density (RLD) value indicated the absence of roots at depths of 30-40 cm in plots P2 and P3. The field findings explained why sugarcane production in Takalar only achieved 50%, around 40 t ha-1 from the first ratoon sugarcane harvest, instead of the expected 70-80 t ha-1. [ABSTRACT FROM AUTHOR]

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Given the low water and fertiliser use efficiency and the extensive distribution of sand interlayered soil in the Hetao irrigation district (HID), this study aimed to investigate the effects of different irrigation and fertilisation regimes on root parameters and yield in spring maize grown in sand interlayered soil. A two-year field plot experiment was conducted using the spring maize "Ximeng 3358" under three irrigation and nitrogen levels. Root length (RL), surface area (RS), diameter (RD), volume (RV), and length density (RLD), grain yield, and water use efficiency (WUE) were examined. Root growth was inhibited at the sand layer, with approximately 72.46–87.37% of the roots concentrated in the 0–40 cm soil layer. Notably, the proportion of roots in the bottom layer was 24.61–87.37% higher than that in the sub-bottom layer. Moreover, RL, RS, RD, and RV peaked in the medium irrigation and nitrogen fertilisation (I2F2) treatment. Furthermore, correlation analysis showed that the root parameters were significantly positively correlated with yield and WUE, with RS being most correlated to yield and WUE. Roots at a narrow row spacing of 20 cm (NR20) and at a depth of 10–20 cm were strongly correlated with yield and WUE. Conclusively, the I2F2 treatment can be used as the optimal combination of water and nitrogen for sand interlayered soil farmlands. [ABSTRACT FROM AUTHOR]

Understanding changes in root traits of high-yielding genotypes that consistently perform during different drought periods is crucial for improving wheat production and yield stability. A 2-year field trial and a pot experiment were conducted to determine the response of root growth and grain yield to early and terminal droughts in old and modern cultivars (FC3: 1960s and CH1: 2010s) under rainfed and irrigated conditions in the field. Rainfed wheat faced terminal drought in 2015–2016 and early drought in 2016–2017. Plants in the pot experiment were exposed to terminal drought, early drought, and well-watered. Both field and pot experiments showed higher grain yield in modern cultivar CH1 compared to FC3. Early and terminal droughts reduced grain yield in both cultivars, with a greater reduction in FC3. CH1 exhibited higher yield stability under drought conditions and experienced less reduction in early drought. Compared to FC3, CH1 produced more root biomass in the early growth stage. At anthesis, CH1 had significantly lower root biomass and root length density in the topsoil layer (00.2 m) and higher in the subsoil layer (0.21.0 m) than FC3, respectively. At maturity, the retention rate of subsoil root biomass in CH1 was higher, especially under early drought (80.2 % in field and 93.9 % in pot experiments). Both cultivars consumed similar seasonal water use, but CH1 reduced pre-anthesis water use and consumed more water after anthesis. This study indicates that modern cultivar had vigorous root growth at early stage. A higher proportion of root biomass preserved in deep soil after anthesis enhanced post-anthesis water use and photosynthetic rate, improved post-anthesis dry matter accumulation, and thus resulted in higher thousand kernel weight. These factors ensure higher yield and yield stability under both early and terminal drought stress.

The optimized sowing method and appropriate seed rate can improve wheat N use efficiency. However, the interactive effect of the sowing method and seed rate on N use efficiency, particularly N uptake and root length density, are unclear. A field experiment was conducted for two growing seasons in southern Shanxi province, China, using a split-plot design with the sowing method as the main plot (wide-belt sowing, WBS, and conventional narrow-drill sowing, NDS) and seed rate as the sub-plot (100–700 m−2). Our results showed that WBS had a significant and positive effect on N use efficiency (yield per unit of available N from the fertilizer and soil, by 4.7–15.4%), and the relatively higher seed rates (>300 or 400 m−2) enlarged the effects. The N use efficiency increases under WBS were mainly attributed to the increases in N uptake before anthesis, resulting from the promoted nodal roots per plant and per unit area, and root length density in the top layer(s). WBS promoted N translocation and the N harvest index, resulting in equivalent grain protein concentration and processing quality compared to NDS. Thus, adopting higher seed rates (>300 m−2) combined with WBS is recommended for achieving greater N efficiencies while maintaining the grain protein concentration and processing quality of winter wheat.

Introduction: While no tillage (NT) can significantly influence soil structure stratification compared to conventional tillage (CT), a comprehensive understanding of the degree of root trait plasticity and trade-offs of lateral roots of crops at various growth stages along a deep soil profile in response to NT remains elusive. This knowledge gap is important for understanding soil resource acquisition strategies and yield of crops. Methods: We systematically investigated the traits of lateral roots at jointing and flowering stages in a long-term (12 years) experiment in Northeast China where maize (Zea mays) has been continuously planted under CT and NT with or without maize residue mulch on soil surface. We also measured soil penetration resistance and bulk density. Results: Soil penetration resistance was reduced at the jointing stage, and was increased at the flowering stage under NT especially at a depth of 10 - 40 cm. Root length density decreased under NT across the two growth stages by on average 22%. In contrast, specific root length and diameter showed greater plasticity, ranging from -14% to 20% and from -11% to 8%, respectively, relative to those under CT. Discussion: These responses could be attributed to changes in root length proportions with different diameters associated with differences in soil penetration resistance between tillage practices. The negative relationships between root traits were stronger under CT than NT, and became weaker from the jointing stage to the flowering stage. To the best of our knowledge, for the first time, our study provides empirical evidence for pivotal root trait plasticity and trade-offs across growth stages as key indicators of changes in soil structure and resources in response to NT. These insights contribute to a better understanding of soil resource acquisition strategies of crops under NT. [ABSTRACT FROM AUTHOR]

Purpose: Cover crops (CC) may increase root growth of the following main crop by improving the soil structure, however, the extent of this effect might depend on the CC species. This study aims at quantifying the effects of different CCs on sugar beet (SB; Beta vulgaris L.) fibrous roots and plant growth. Methods: Two field trials were conducted near Göttingen, Central Germany, with SB after four CC treatments: fallow, oil radish, saia oat, and spring vetch, differing in biomass. SB root length density and biomass was analyzed to 60 cm soil depth in July, around 100 days after sowing. From June on, plants were sampled monthly to determine leaf and taproot biomass. CC biomass and SB residues were further analyzed for carbon content. Results: SB root length density in 0–20 cm soil depth was increased by the CCs, particularly radish and oat, while in lower depths only non-significant differences were found. Differences between the CC treatments regarding SB leaf and taproot biomass were site-specific with increases in SB biomass after CCs at a site with high N supply, yet no effects on sugar yield were found for either site. Carbon input into the soil was significantly increased through CC cultivation by 47 to 85%. Conclusion: CCs with different properties improved fibrous root and overall plant growth of SB to a different extent at sites with contrasting conditions. Future studies under diverse environmental conditions are needed to fully assess the potential benefits of CCs on following SB growth. [ABSTRACT FROM AUTHOR]

The high stalk weight sugarcane cultivar has a special mechanism to obtain greater growth, which was inherited from its parents. Thus far, comparisons of the high stalk weight sugarcane cultivar growth with its parents and cultivars with a low stalk weight have never been reported. The purpose of this research was to reveal the growth mechanism of the high stalk dry weight cultivar KK3 by comparing its physiological, anatomical, and morphological traits to those of a low stalk dry weight cultivar (UT12) and their four parental cultivars under hydroponic conditions. Their growth characteristics were evaluated at 15-day intervals from 30 to 90 days after planting. The root traits were measured at 2 months after planting (MAP), whereas the anatomical and physiological parameters were collected at 3 MAP. Biomass was recorded at 1, 2, and 3 MAP. KK3 had similar anatomical root traits to its female parent, whereas it had similar aboveground morphological traits to its male parent. The comparison between UT12 and its parents revealed that almost all its root anatomical traits were similar to the female parent, but it did not differ in leaf anatomy and root system size. Some physiological traits of KK3 were not different from those of its parents. In contrast, the net photosynthesis rate (PN), height, tiller number, stem dry weight, and stomatal density of UT12 were lower than those of its parent. For KK3, its small root stele and vessel size and high root length, surface area, and volume supported water uptake. The increase in stomatal density and decreased stomatal pore length may be appropriate characteristics for reducing water loss in this drought-resistant cultivar. Furthermore, KK3 exhibited a high water use efficiency (WUE) to promote biomass accumulation and growth despite its low transpiration and photosynthesis rates. This basic knowledge will be useful for selecting the parents based on their characteristics to create new sugarcane cultivars with a high stalk dry weight for drought stress during the early-growth-stage breeding programs and predicting their performance. [ABSTRACT FROM AUTHOR]

Enhancing the spatial and temporal coordination between soil water and roots is very important for crop growth. The vertical distribution and relationship between soil water and root are however poorly understood during maize growth under different soil water conditions. In this study, two maize hybrids ZD958 and FM985 were treated with drip irrigation (DI), flood irrigation (FI), and rainfed (RF) in two–year field experiment as well as with irrigation at 0–30 (TI), 30–60 (MI), 60–90 (BI), 0–90 cm soil layers (AI) and no irrigation in three–year tube experiment. In field experiment, DI and FI both increased root dry weight, root length density (RLD), and the proportion of coarse root length at different soil layers relative to RF. DI increased grain yield by 10.0% in FM985 and by 10.8% in ZD958 compared with FI. Both total root and fine root length were greater in DI than in FI, which increased the nitrogen and water use efficiency and yield. In the tube experiment, irrigation at different soil layers increased root dry weight, RLD and the proportion of coarse root length compared with no irrigation, with AI increasing the most. FM985 distributed more roots at the 0–30 cm soil layer than ZD958. Grain yields were positively correlated with the RLD in each soil layer and coarse root proportion at the upper layer (r=0.493** in field experiment and r=426** in tube experiment) but negatively correlated with root–shoot ratio (r=−0.793** in field experiment and r=−670** in tube experiment) at maturity stage. In conclusion, there is a large potential to improve maize yield by enhancing the spatial coordination between root distribution and soil water movement.

Plants respond to their environment through adaptations; for example, earthworms that create heterogeneity can lead to local adaptation of roots. This research identifies a mechanism to explain plant responses to earthworms and how these mechanisms are related. Our results show that tillage intensity has a negative effect on earthworms and root volume. The mean root volume and earthworm biomass under conventional tillage were lower than in reduced tillage and no-tillage. The root volume and the root diameter in the field with residues were higher than in the field without residues, while the root length density and earthworm biomass in the field with residues were lower than in the field without residues. This study demonstrates that the mean of the root length density and biomass of the earthworms were higher in sandy loam than in loam. Therefore, sand content had a positive effect on root length density (R2 = 0.72, p < 0.01) and earthworm biomass (R2 = 0.74, p < 0.01). Earthworm biomass had a positive effect on root volume (R2 = 0.54, p < 0.05) and length density (R2 = 0.88, p < 0.01). This confirms our hypothesis on the effect of earthworms on root systems.

[Objective] The impacts on soil saturated hydraulic conductivity that occur because of differences in root and soil properties between combinations of grasses and shrubs having different root configurations were studied, and an empirical equation for estimating soil saturated hydraulic conductivity was established by comprehensively considering root and soil properties in order to provide a theoretical reference for the establishment of hydrological models appropriate for conditions following vegetation restoration on the Loess Plateau. [Methods] Plots of grass-shrub mixtures having different root system configurations were used: Agropyron cristatum and Caragana korshinskii, and Artemisia gmelinii and Caragana korshinskii. Saturated hydraulic conductivity was measured by the double-ring knife method. [Results] The influence of sample grass-shrub mixture type and soil depth on soil saturated hydraulic conductivity was significant, and their factor contribution rates on soil saturated hydraulic conductivity were 26% and 52%, respectively. The soil saturated hydraulic conductivity of the tap-root grass Artemisia gmelinii and Caragana korshinskii mixture was greater than that of the fibrous root grass Agropyron cristatum and Caragana korshinskii mixture. Soil saturated hydraulic conductivity of different plots declined with increasing soil depth. Root length density, soil aggregates, and soil bulk density better simulated soil saturated hydraulic conductivity, with a fitting accuracy (R2) reaching 0.86. [Conclusion] The combination of a taproot grass and a shrub had a higher saturated hydraulic conductivity than observed for the combination of fibrous root grasses and shrubs. Root length density, soil aggregates, and soil bulk density were the main factors affecting saturated hydraulic conductivity.

The use of earthworms in bio-composting (vermicomposting) is gaining popularity as a bio-waste management approach for producing nutrient-rich organic fertilizer. Furthermore, the use of seaweed extracts as biostimulants changes the physical, biochemical, and biological aspects of the soil, as well as the architecture of plant roots, allowing for more effective nutrient uptake and increasing plant development and yields. This study aimed to evaluate the combined effect of biocompost and biostimulant on the development of the root system of cannabis (Cannabis sativa L.) plant. An outdoor pot experiment was set up a completely randomized design, with four treatments including vermicompost, vermicompost amended with seaweed-based biostimulant, vermicompost mixed with spent mushroom substrate (SMS) and cattle manure (CM) compost, and vermicompost mixed with SMS+CM compost and amended with seaweed-based biostimulant. The results revealed that the highest values of root length density, root diameter, and nitrogen content in roots (1.36 cm cm-3, 1.29 mm, and 1.23%, respectively) were found in plants grown in the substrate of vermicompost mixed with SMS+CM compost and amended with seaweed-based biostimulant, pointed this out as a recommended treatment for increased biomass production, which is important in the processing of cannabis for medicinal purposes.

The lower yield of wheat grown after wheat (second wheat) compared with the first wheat after a break crop is frequently attributed to fungal disease occurrence, but has also been found without visible disease infection; thus, other factors might be responsible for the lower yield of the second wheat. The aims of this study were to analyze the effects of growing wheat as first and second wheat after oilseed rape, as well as monoculture in a long-term field experiment over three years on (i) aboveground biomass formation, root development and nutrient acquisition during the growing season, (ii) take-all occurrence, and (iii) grain yield and yield components. Subsoil root length density of winter wheat was significantly higher after oilseed rape as pre-crop than after wheat, which was independent of take-all occurrence. Differences in wheat aboveground biomass occurred at early growth stages and were persistent until harvest. Grain yield loss correlated well with take-all disease severity in a wet year but yield differences among crop rotational positions occurred also in a dry year without visible fungal infection. Thus, an effect of the crop rotational position of wheat beyond take-all disease pressure can be assumed. Overall, wheat root length density might be the key to understand wheat biomass formation and grain yield in different crop rotational positions. [ABSTRACT FROM AUTHOR]

While not classified as an essential plant nutrient, silicon (Si) assimilation following exogenous Si application has enhanced the wear resistance of cool-season turfgrass. Given this beneficial supplementation of lignin by Si reported in epidermal tissue of monocotyledonous plants, our research objective was to quantify root morphology, vegetative nutrition and vigor, soil chemistry, and putting green performance in response to split applications of pelletized liming agents rich in Si and/or Ca and Mg. Field evaluation of granular liming agent treatment, 2441 kg (ha year)−1, was conducted on creeping bentgrass (Agrostis stolonifera L. cv. Penn G-2) putting green maintained in the Mid-Atlantic US. Pelletized Ca/Mg-SiO3 slag or dolomitic limestone treatments were conducted in frequent split applications and incorporated into the upper 5 cm of the rootzone. Measurements of canopy color and density, shoot growth as clipping yield, soil pH, Si and nutrient content of clippings, and soil extractable Si were performed each season. Cumulative Ca/Mg-SiO3 application (kg ha−1) increased mean acetic acid (HOAc) extractable Si by 35 to 60 mg kg−1 and leaf Si content by 1.0 to 1.5 mg g−1. However, neither putting green canopy quality, shoot nutrient concentration, 5 to 15 cm depth root length density nor ball roll distance was improved by liming agent treatment. Liming agent-treated or untreated plots showed statistical, yet inconsistent, differences in clipping yield 4, 14, 15, 16, and 17 months from initiation (MFI). This thorough shuffling of treatment rank, resulting in identical experiment-wide means precludes the expectation of dependably superior vigor by any. [ABSTRACT FROM AUTHOR]

The pattern of root distribution in layered soils is one of the significant issues in the calculations of soil water and irrigation management and planning. The objective of this study was to determine the pattern of root distribution of soybean in layered soils and its effect on water uptake. The research was conducted in a completely randomized design with 15 treatments consisting of three different textures of soil (light, heavy, and medium) in four replications. The pattern of root distribution was monitored by the sampling of columns at the end of the growth period of the soybean. It was observed that the presence of the layer with medium texture has led to better plant development and growth after comparing the treatments in terms of plant growth. In general, root length density decreased with increasing soil depth, except in cases where there were different layers of soil, and root length density takes place in the following order: root length density in layers with medium texture≥ heavy texture≥ light texture. The rate of root water uptake rate was highest in the sandy layers, intermediate in clay, and lowest in loamy texture. Also, the rate of root water uptake rate increased significantly with increasing depth regardless of treatments. It can be concluded that the pattern of root distribution and plant growth is significantly affected by soil texture and its stratification.

The lower yield of wheat grown after wheat (second wheat) compared with the first wheat after a break crop is frequently attributed to fungal disease occurrence, but has also been found without visible disease infection; thus, other factors might be responsible for the lower yield of the second wheat. The aims of this study were to analyze the effects of growing wheat as first and second wheat after oilseed rape, as well as monoculture in a long-term field experiment over three years on (i) aboveground biomass formation, root development and nutrient acquisition during the growing season, (ii) take-all occurrence, and (iii) grain yield and yield components. Subsoil root length density of winter wheat was significantly higher after oilseed rape as pre-crop than after wheat, which was independent of take-all occurrence. Differences in wheat aboveground biomass occurred at early growth stages and were persistent until harvest. Grain yield loss correlated well with take-all disease severity in a wet year but yield differences among crop rotational positions occurred also in a dry year without visible fungal infection. Thus, an effect of the crop rotational position of wheat beyond take-all disease pressure can be assumed. Overall, wheat root length density might be the key to understand wheat biomass formation and grain yield in different crop rotational positions.

Crop modeling is an effective tool for simulating crop growth under various agricultural water and salinity management practices. However, most crop models fail to describe the root dynamics in response to soil stresses adequately. To address this issue, field experiments were conducted by planting sunflowers in saline soils. Three machine learning (ML) models of random forest (RF), gaussian process regression (GPR), and extreme gradient boosting (XGBoost) were initially introduced for predicting root length density (RLD). Then, by coupling with a crop model SWAP, the soil salt content (SSC), soil water content (SWC), and crop growth indicators of leaf area index (LAI) and dry matter (DM) were simulated. Results show that RF and XGBoost models could predict RLD more accurately than the GPR model, with root mean square error (RMSE) lower than 0.473 cm cm-3. Compared to using a typical cubic polynomial function (CPF) of RLD in the SWAP model, similar SWC and SSC simulation results were obtained based on the ML models. However, for the crop growth simulation, the performances of ML models were significantly better than the CPF. Especially for LAI simulation in the high salinity fields, the relative root mean square error (RRMSE) in the RF model was 0.222–0.282 lower than in the CPF. Moreover, compared to the XGBoost model of RLD, more accurate and stable simulation results of SWC, SSC, and LAI were obtained based on the RF model. These results illustrate that ML models, especially the RF model, can be used to quantify RLD dynamics and improve crop modeling performances.

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In order to evaluate the effect of mycorrhizal fungi and phosphorous fertilizer on some root growth traits and activity of enzyme and nonenzyme antioxidants of durum wheat in rainfed conditions, an experiment was carried out as factorial based on a randomized complete block design with three replications at Sarableh Agricultural Research station during growing season 2018-2019. Four cultivars of durum wheat (Dehdasht, Zahab, Savarz and Saji) as the first factor and five levels of fertilizer source (control, 25 and 50 kg.ha-1 P, mycorrhizal fungi (GM), mycorrhizal fungi + 25 kg.ha-1 P) as the second factor were considered. The average comparison results of simple effects indicated that Zahab and Saji cultivars among cultivars and combination treatment of mycorrhizal + 25 kg / ha P and then 50 kg / ha P had the greatest effect on improving the studied traits. The interaction effect of cultivars and fertilizer sources revealed that the combined use of phosphorous fertilizer and mycorrhizal fungi had better results compared to their use alone. So that, the highest fresh and dry weight, length density, and root water content and activity of ascorbate peroxidase, peroxidase, catalase, superoxide dismutase and glutathione synthetase was obtained in combined treatment of mycorrhizal and phosphorus fertilizer at Zahab and Saji cultivars. However, the lowest specific root length, and malondialdehyde and hydrogen peroxide activity were obtained in the same treatment and cultivars. In general, the results showed that inoculation with mycorrhizal fungi in rainfed conditions, especially in Zahab and Saji cultivars, in addition to reducing the application of phosphorus fertilizer can improve root growth characteristics and activity of enzyme and nonenzyme antioxidants. As a result, it reduces the peroxidation of membrane lipids (the decline in production of malondialdehyde and hydrogen peroxide) and increases drought stress tolerance.

In maize (Zea mays L.), rational root structure promotes high grain yield under dense sowing conditions. This study was conducted at Qitai Farm in Xinjiang, China, in 2019 and 2021. A traditional wide and narrow row planting method was adopted, with wide rows of 0.7 m and narrow rows of 0.4 m. The cultivars DH618 and SC704, which have grain yield potentials of 22.5 and 15 Mg ha−1, respectively, were selected for study of the root structure and distribution characteristics under high-yield and high-density planting conditions. The highest yield (20.24 Mg ha−1) was achieved by DH618 under a planting density of 12 × 104 plants ha−1. The root structure of DH618 was well developed at that planting density, and the root dry weight (RDW) was 17.49 g plant−1 and 14.65 g plant−1 at the silking and maturity stages, respectively; these values were 7.56% and 11.86% higher, respectively, than those of SC704. At the silking stage, the proportions of RDW at soil depths of 0–10, 10–20, 20–40, and 40–60 cm were 66.29%, 11.83%, 16.51%, and 5.38%, respectively, for DH618; over the 20–60 cm soil layer, this was an average of 4.04% higher than the RDW of SC704. At maturity, the proportions of RDW at soil depths of 0–10, 10–20, 20–40, and 40–60 cm were 61.40%, 11.19%, 17.19%, and 10.21%, respectively, for DH618, which was an average of 9.59% higher than that of SC704 over the 20–60 cm soil layer. At maturity, DH618 roots were mainly distributed in the narrow rows, accounting for 72.03% of the root structure; this was 9.53% higher than the roots of SC704. At silking and maturity, the root weight densities of DH618 were 471.98 g m−3 and 382.98 g m−3, respectively (5.18% and 5.97% higher, respectively, than the root weight densities of SC704). The root lengths of DH618 were 239.72 m plant−1 and 199.04 m plant−1 at the silking and maturity stages, respectively; these were 16.45% and 25.39% higher, respectively, than the root lengths of SC704. The root length densities were 0.58 cm cm−3 and 0.46 cm cm−3 at the silking and maturity stages, respectively, and these were 16.86% and 17.08% higher, respectively, than the root length densities of SC704. This study indicated that the maize hybrid DH618 had a more developed root structure with increased root distribution in the deep soil and narrow rows under high-density planting compared to cultivar SC704, contributing to high grain yield under dense planting. [ABSTRACT FROM AUTHOR]

Given the low water and fertiliser use efficiency and the extensive distribution of sand interlayered soil in the Hetao irrigation district (HID), this study aimed to investigate the effects of different irrigation and fertilisation regimes on root parameters and yield in spring maize grown in sand interlayered soil. A two-year field plot experiment was conducted using the spring maize “Ximeng 3358” under three irrigation and nitrogen levels. Root length (RL), surface area (RS), diameter (RD), volume (RV), and length density (RLD), grain yield, and water use efficiency (WUE) were examined. Root growth was inhibited at the sand layer, with approximately 72.46–87.37% of the roots concentrated in the 0–40 cm soil layer. Notably, the proportion of roots in the bottom layer was 24.61–87.37% higher than that in the sub-bottom layer. Moreover, RL, RS, RD, and RV peaked in the medium irrigation and nitrogen fertilisation (I2F2) treatment. Furthermore, correlation analysis showed that the root parameters were significantly positively correlated with yield and WUE, with RS being most correlated to yield and WUE. Roots at a narrow row spacing of 20 cm (NR20) and at a depth of 10–20 cm were strongly correlated with yield and WUE. Conclusively, the I2F2 treatment can be used as the optimal combination of water and nitrogen for sand interlayered soil farmlands.

The high stalk weight sugarcane cultivar has a special mechanism to obtain greater growth, which was inherited from its parents. Thus far, comparisons of the high stalk weight sugarcane cultivar growth with its parents and cultivars with a low stalk weight have never been reported. The purpose of this research was to reveal the growth mechanism of the high stalk dry weight cultivar KK3 by comparing its physiological, anatomical, and morphological traits to those of a low stalk dry weight cultivar (UT12) and their four parental cultivars under hydroponic conditions. Their growth characteristics were evaluated at 15-day intervals from 30 to 90 days after planting. The root traits were measured at 2 months after planting (MAP), whereas the anatomical and physiological parameters were collected at 3 MAP. Biomass was recorded at 1, 2, and 3 MAP. KK3 had similar anatomical root traits to its female parent, whereas it had similar aboveground morphological traits to its male parent. The comparison between UT12 and its parents revealed that almost all its root anatomical traits were similar to the female parent, but it did not differ in leaf anatomy and root system size. Some physiological traits of KK3 were not different from those of its parents. In contrast, the net photosynthesis rate (PN), height, tiller number, stem dry weight, and stomatal density of UT12 were lower than those of its parent. For KK3, its small root stele and vessel size and high root length, surface area, and volume supported water uptake. The increase in stomatal density and decreased stomatal pore length may be appropriate characteristics for reducing water loss in this drought-resistant cultivar. Furthermore, KK3 exhibited a high water use efficiency (WUE) to promote biomass accumulation and growth despite its low transpiration and photosynthesis rates. This basic knowledge will be useful for selecting the parents based on their characteristics to create new sugarcane cultivars with a high stalk dry weight for drought stress during the early-growth-stage breeding programs and predicting their performance.

Legume cultivars affect N uptake, component crop growth, and soil physical and chemical characteristics in maize–legume intercropping systems. However, how belowground interactions mediate root growth, N fixation, and nodulation of different legumes to affect N uptake is still unclear. Hence, a two-year experiment was conducted with five planting patterns, i.e., maize–soybean strip intercropping (IMS), maize–peanut strip intercropping (IMP), and corresponding monocultures (monoculture maize (MM), monoculture soybean (MS), and monoculture peanut (MP)), and two N application rates, i.e., no N fertilizer (N–) and conventional N fertilizer (N+), to examine relationships between N uptake and root distribution of crops, legume nodulation and soil N availability. Results showed that the averaged N uptake per unit area of intercrops was significantly lower than the corresponding monocultures. Compared with the monoculture system, the N uptake of the intercropping systems increased by 31.7–45.4% in IMS and by 7.4–12.2% in IMP, respectively. The N uptake per plant of intercropped maize and soybean significantly increased by 61.6 and 31.8%, and that of intercropped peanuts significantly decreased by 46.6% compared with the corresponding monocultures. Maize and soybean showed asymmetrical distribution of roots in strip intercropping systems. The root length density (RLD) and root surface area density (RSAD) of intercropped maize and soybean were significantly greater than that of the corresponding monocultures. The roots of intercropped peanuts were confined, which resulted in decreased RLD and RSAD compared with the monoculture. The nodule number and nodule fresh weight of soybean were significantly greater in IMS than in MS, and those of peanut were significantly lower in IMP than in MP. The soil protease, urease, and nitrate reductase activities of maize and soybean were significantly greater in IMS and IMP than in the corresponding monoculture, while the enzyme activities of peanut were significantly lower in IMP than in MP. The soil available N of maize and soybean was significantly greater increased in IMS and IMP than in the corresponding monocultures, while that of IMP was significantly lower than in MP. In summary, the IMS system was more beneficial to N uptake than the IMP system. The intercropping of maize and legumes can promote the N uptake of maize, thus reducing the need for N application and improving agricultural sustainability.

Automating dynamic fine root data collection in the field is a longstanding challenge with multiple applications for cointerpretation and synthesis for ecosystem understanding. High frequency root data are only achievable with paired automated sampling and processing. However, automatic minirhizotron (root camera) instruments are still rare and data are often not collected in natural soils or analysed at high temporal resolution. Instruments must also be affordable for replication and robust under variable natural conditions. Here, we show a system built with off-the-shelf parts which samples at sub-daily resolution. We paired this with a neural network to analyse all images collected. We performed two mesocosm studies and two field trials alongside ancillary data collection (soil CO2 efflux, temperature, and moisture content, and ‘PhenoCam’-derived above-ground dynamics). We produce robust and replicated daily time series of root dynamics under all conditions. Temporal root changes were a stronger driver than absolute biomass on soil CO2 efflux in the mesocosm. Proximal sensed above-ground dynamics and below-ground dynamics from minirhizotron data were not synchronized. Root properties extracted were sensitive to soil moisture and occasionally to time of day (potentially relating to soil moisture). This may only affect high frequency imagery and should be considered in interpreting such data. [ABSTRACT FROM AUTHOR]

Root growth and development of maize (Zea mays L.) is an important process in determining grain yield. The effects of combined fulvic acid (FA, potassium humate as FA source) and super absorbent polymer (SAP) uses on maize root growth and yield were studied. A 2×3 factorial field experiment was applied by combining two SAP doses (0, 45 kg ha-1) and three FA rates (0, 1, and 2 g L-1) over 2 yr. Super absorbent polymer was applied to upper 20 cm soil layer at sowing, and FA solutions (1 or 2 g L-1, corresponding to FA1 and FA2) were sprayed onto the canopy three times during growing season. Root parameters, including root biomass, root length density (RLD), root surface-area density (RSD), and root diameter, were determined in the top 40 cm soil layer. Relative to control plants, both chemicals significantly increased root biomass, but these effects were not significantly different from their combined use. Compared to individual FA or SAP treatment, combined applications increased RLD and RSD in 0-20 cm depth. The combined SAP and FA2 improved RLD at 0-10 cm by 32% compared to FA2 treatment alone and by 82% compared to non-chemicals control plots over 2 yr. Averaged root diameters also significantly increased in the 40 cm soil layer in FA and SAP treatments alone compared to control, but they were not significantly different with the combined treatment. Similar patterns were found for maize yield each year. The combined application of SAP (45 kg ha-1) and FA2 (2 g L-1) greatly increased root length density and biomass than their individual application, and it could be suitable for high production of maize grown under low rainfall conditions. [ABSTRACT FROM AUTHOR]

Understanding the spatial distributions of soil water, temperature and nutrients as well as their effects on maize growth and grain yield is vital for optimizing drip fertigation regimes. In this study, a 2 year field experiment was conducted on drip-fertigated spring maize with plastic mulching in arid northwestern China in 2015 and 2016. Four irrigation levels were set: as I60 (60% ETc; ETc is crop evapotranspiration), I75 (75% ETc), I90 (90% ETc) and I105 (105% ETc) in 2015; and as I60 (60% ETc), I80 (80% ETc), I100 (100% ETc) and I120 (120% ETc) in 2016. Two fertilization rates of N-P2O5-K2O were set: as F180 (180-90-90) and F240 (240-120-120). The results showed that the average soil water content in the deeper soil layer (80–120 cm) increased with the increase in irrigation level, and the lowest average soil water content in the 0–80 cm soil layer occurred under I95 in 2015 and under I100 in 2016. The irrigation level more significantly influenced the soil temperature at 5 cm than at the other depths. With the decrease in the irrigation level and progression of the growth period, the soil temperature increased. The soil nitrate nitrogen content in the root zone decreased with increasing irrigation level. The largest soil nitrate nitrogen content at the 0–100 cm depth occurred under I60 in both 2015 and 2016. Significant differences were observed for root length density in the 0–20 cm soil layer at various lateral locations. In deeper (60–100 cm) soil layers, the root length density under I75 (2015) and I80 (2016) was greater than at other depths. Grain yield, water use efficiency (WUE) and partial factor productivity (PFP) increased with the increase in irrigation level in 2015, while it increased and then decreased in 2016. I105F180 achieved the maximum grain yield (18.81 t ha−1), WUE (3.32 kg m−3), and PFP (52.26 kg kg−1) in 2015, while I100F180 achieved the maximum grain yield (20.51 t ha−1), WUE (3.99 kg m−3), and PFP (57.02 kg kg−1) in 2016. The optimal drip fertigation regimes for spring maize in arid northwest China were recommended as 90–100% ETc and 180-90-90 (N-P2O5-K2O) kg hm−2. [ABSTRACT FROM AUTHOR]

The pattern of root distribution in layered soils is one of the significant issues in the calculations of soil water and irrigation management and planning. The objective of this study was to determine the pattern of root distribution of soybean in layered soils and its effect on water uptake. The research was conducted in a completely randomized design with 15 treatments consisting of three different textures of soil (light, heavy, and medium) in four replications. The pattern of root distribution was monitored by the sampling of columns at the end of the growth period of the soybean. It was observed that the presence of the layer with medium texture has led to better plant development and growth after comparing the treatments in terms of plant growth. In general, root length density decreased with increasing soil depth, except in cases where there were different layers of soil, and root length density takes place in the following order: root length density in layers with medium texture≥ heavy texture≥ light texture. The rate of root water uptake rate was highest in the sandy layers, intermediate in clay, and lowest in loamy texture. Also, the rate of root water uptake rate increased significantly with increasing depth regardless of treatments. It can be concluded that the pattern of root distribution and plant growth is significantly affected by soil texture and its stratification. [ABSTRACT FROM AUTHOR]

In order to evaluate the effect of mycorrhizal fungi and phosphorous fertilizer on some root growth traits and activity of enzyme and nonenzyme antioxidants of durum wheat in rainfed conditions, an experiment was carried out as factorial based on a randomized complete block design with three replications at Sarableh Agricultural Research station during growing season 2018-2019. Four cultivars of durum wheat (Dehdasht, Zahab, Savarz and Saji) as the first factor and five levels of fertilizer source (control, 25 and 50 kg.ha-1 P, mycorrhizal fungi (GM), mycorrhizal fungi + 25 kg.ha-1 P) as the second factor were considered. The average comparison results of simple effects indicated that Zahab and Saji cultivars among cultivars and combination treatment of mycorrhizal + 25 kg / ha P and then 50 kg / ha P had the greatest effect on improving the studied traits. The interaction effect of cultivars and fertilizer sources revealed that the combined use of phosphorous fertilizer and mycorrhizal fungi had better results compared to their use alone. So that, the highest fresh and dry weight, length density, and root water content and activity of ascorbate peroxidase, peroxidase, catalase, superoxide dismutase and glutathione synthetase was obtained in combined treatment of mycorrhizal and phosphorus fertilizer at Zahab and Saji cultivars. However, the lowest specific root length, and malondialdehyde and hydrogen peroxide activity were obtained in the same treatment and cultivars. In general, the results showed that inoculation with mycorrhizal fungi in rainfed conditions, especially in Zahab and Saji cultivars, in addition to reducing the application of phosphorus fertilizer can improve root growth characteristics and activity of enzyme and nonenzyme antioxidants. As a result, it reduces the peroxidation of membrane lipids (the decline in production of malondialdehyde and hydrogen peroxide) and increases drought stress tolerance. [ABSTRACT FROM AUTHOR]

【Objective】 Facility vegetable production in China relies on drip irrigation with the seedbed mulched. How roots grow and its consequence for water uptake is an issue that is not fully understood. The aim of this paper is to investigate the change in root traits and water uptake of tomato under deficit irrigation, as well as the effect of initial soil water on demand of the crop for water. 【Method】 The experiment was conducted in a solar greenhouse, and the irrigation amount in each treatment was calculated based on the cumulative evaporation (EP) measured from a 20 cm standard evaporation pan installed inside the greenhouse. There were three treatments: irrigating 90% of EP with the soil mulched (FM-0.9) and not mulched (WM-0.9) by plastic film, and irrigating 50% of EP with the soil mulched (FM-0.5). In each treatment, we measured root distribution and change in soil water content. The root water uptake was calculated inversely using HYDRUS-1D, from which we analyzed the factors which impacted root water uptake as well as the consequence for fruit yield. 【Result】 Root length in the top 20 cm soil in WM-0.9, FM-0.9 and FM-0.5 accounted for 58.6%, 56.2% and 78.9% of their total root length, respectively. The mean root square error of the soil moisture content simulated by HYDRUS-1D was less than 0.010 cm3/cm3, and the regression coefficient between the measured and simulated soil water content was in the range of 0.867~1.076. The mean root square error of the measured transpiration and the simulated total root water uptake was less than 0.581 mm/d, and the regression coefficient between them was higher than 0.890. The largest root water uptake was in FM-0.9, totaling 240.9 mm, 24.4% and 26.7% more than that in WM-0.9 and FM-0.5, respectively. Roots took most of the water the crop transpired from the 0~40 cm of soil, accounting for 84.2%, 85.7% and 83.2% of the total transpiration for WM-0.9, FM-0.9 and FM-0.5, respectively. Water use efficiency and irrigation water use efficiency of FM-0.5 were 59.0 and 70.3 kg/m3, 34.4% and 55.5% above that of WM-0.9, and 11.3% and 30.4% higher than that of FM-0.9, respectively. FM-0.9 gave the highest fruit yield at 147.7 t/hm2, 19.3% and 23.6% higher that of WM-0.9 and FM-0.5, respectively. 【Conclusion】 Our experimental results showed that irrigating 90% of EP combined with film mulching is optimal to increase the use of deep soil water for greenhouse tomato production.

[Display omitted] • We confirmed herbaceous plants effectively control debris-flow erosion on banks. • We revealed the mechanism of leaves and roots in preventing the debris-flow erosion. • We found a link between the erosion efficiency and leaf area and root length. The importance of implementing vegetation measures to mitigate debris-flow disasters is widely recognized. However, the specific role of herbaceous plants, especially those flourishing on the banks of debris-flow channels, in mitigating lateral erosion remains insufficiently understood. This study aims to elucidate the impact of herbaceous plants on bank erosion during debris-flow surges. In the experiment, Cymbopogon citratus (DC.) Stapf growing on the channel banks was cultivated for 20 to 100 days. Accordingly, the leaf area index (LAI) of plants ranged from 0.10 to 3.21, and the root length density (RLD) in the topsoil varied from 2.5 to 135.5 km/m3. In addition, the banks with plants were subjected to scouring by multiple debris-flow surges in a specially designed flume. The findings demonstrated a significant reduction in the erosion efficiency of debris flow on grassland banks, with reductions ranging from 70.84 % to 92.49 %, in comparison to bare soil banks. This reduction is attributed to the combined influence of two parts: leaves and roots. On one hand, the leaves partially shielded the shear stress of the debris flows. Under the impact of the debris flows, plants quickly fell down, with their leaves covering the soil. Lodging plants absorbed a portion of the shear stress from debris flow and transmitting it to the deeper soil through stems and roots. This process mitigated erosion on the topsoil. The erosion efficiency exhibited an exponential decline with increasing LAI. On the other hand, the roots altered the pattern of the soil erosion. Debris flows eroded soil from the gaps in the root systems with rarely cutting roots off, which means the layered shear failure of soil was suppressed. Additionally, the erosion efficiency exponentially decreased with the increase in RLD. [ABSTRACT FROM AUTHOR]

This study was carried out to investigate effects of subsoiling on the diversity and composition of the bacterial community in a wheat–maize rotation field in the Guanzhong area of Shaanxi Province, China. After the wheat harvest, surface soil samples were collected under two tillage methods (single rotary tillage (RT) and subsoiling + rotary tillage (ST)) to perform high-throughput sequencing and bioinformatics analysis. Soil properties and root length density (RLD) of winter wheat at booting and flowering stages were also studied. Results showed that ST treatment significantly raised the water storage, organic carbon and total nitrogen contents of deep soil (>40 cm), and notably increased the total soil pH, ammonium nitrogen content and RLD in the tillage layer from 0–70 cm at booting stage and 0~100 cm at flowering stage, but the residual nitrate nitrogen significantly decreased by 17.74%. Compared with RT, soil bacterial richness and diversity in the 10~20 cm layer of ST treatment showed a significantly decreased trend. The relative abundances of GAL15, Actinobacteria, Nitrospirae, Rhizobiales, Burkholderiales, Pseudomonas and Serratia in the 10–20 cm layer were remarkably increased in ST. Principal Component Analysis (PCA) and Redundancy Analysis (RDA) results showed that surface soil pH, ammonium nitrogen and nitrate nitrogen contents have the strongest effect on the bacterial structure. In addition, there were positive correlations between the RLD and the relative abundances of Rhizobiales, Burkholderiales, Pseudomonas and the ammonium nitrogen content. In conclusion, although subsoiling was not conducive to improving soil bacterial community richness and diversity, it significantly increased soil beneficial bacteria (biological nitrogen-fixing bacteria, ammonifying bacteria, nitrobacteria) abundances, reduced the nitrogen loss caused by denitrifying bacteria, promoted earlier root development and improved the plant utilization ratio of soil nutrients. [ABSTRACT FROM AUTHOR]

Aims: Root hairs are important for uptake, especially for nutrients with low mobility in soils with high sorption capacity. Mutants with defective root hairs are expected to have lower nutrient uptake, unless they compensate with more root growth. Since root hairs can also contribute to the plant's water uptake their importance could change over the course of a growing season. It was our objective to investigate the role of root hairs under field conditions. Methods: The root hair mutant rth3 of Zea mays and the corresponding wild-type were grown for two years under field conditions on sand and loam. Results: Shoot growth and P and K uptake of the plants were promoted by the presence of hairs at all growth stages. Differences between genotypes were greater on loam than on sand until tassel emergence, presumably as additional exploitation by hairs is more relevant in loam. Compensation for the absence of root hairs by increased root growth was not observed in absolute terms. The root to shoot ratio was higher for rth3 than for wild-type. Root traits showed high plasticity in response to texture, the most salient being a greater mean root diameter in sand, irrespective of genotype. The mechanism causing the increase in mean root diameter is still unknown. Root length density was higher in sand, which can be explained by a greater need for exploration than exploitation in this substrate. Conclusion: The role of hairs for nutrient uptake could be confirmed under field conditions. The large impact of texture on root growth and consequences for carbon balance require further investigations. [ABSTRACT FROM AUTHOR]

Biochar, as a soil amendment, improves soil fertility and enhances crops productivity under water or salinity stresses. This study aimed to investigate the effects of biochar application rates (zero, 40, and 80 Mg ha-1) under three irrigation regimes (50, 75, and 100% of plant water requirement) and salinity levels (0.6, 6, and 12 dS m-1) on physiological parameters, evapotranspiration, and growth of wheat grown under greenhouse condition. The experiment was performed in a complete randomized design with a factorial arrangement in four replications. Application of a high level of salinity (12 dS m-1) declined wheat grain yield by 28%, 57%, and 75% in comparison with that at 0.6 dS m-1 under zero, 40, and 80 Mg ha-1 biochar application, respectively. The results showed that application of 80 Mg ha-1 biochar decreased wheat evapotranspiration by 24.4% in comparison with that at no biochar application. In addition, the application of biochar improved wheat stomatal conductance and canopy temperature under both abiotic stress conditions. Salinity (12 dS m-1) and deficit irrigation (50 %), respectively declined wheat evapotranspiration by 19% and 15% in comparison with that at 0.6 dS m-1 and full irrigation. Also, the application of biochar and salinity both declined the root length density due to the accumulation of salt around the root. It is concluded that 40 Mg ha-1 of biochar can be applied as a soil amendment to improve wheat yield and reduce evapotranspiration under applied deficit irrigation and salinity stress. [ABSTRACT FROM AUTHOR]

Water scarcity is increasing in the world, which is limiting crop production, especially in water-limited areas such as Southern High Plains of the United States. There is a need to adopt the irrigation management practices that can help to conserve water and sustain crop production in such water-limited areas. A 2-year field study was conducted during the summers of 2019 and 2020 to evaluate the effect of deficit irrigation levels and cultivars on root distribution pattern, soil water depletion, and water use efficiency (WUE) of cucumber (Cucumis sativus). The experiment was conducted in a split-plot design with four irrigation levels [100%, 80%, 60%, and 40% crop evapotranspiration (ETc)] as main plot factor and two cultivars (Poinsett 76 and Marketmore 76) as subplot factor with three replications. Results showed that root length density (RLD) was unaffected by the irrigation levels in 2019. In 2020, the RLD was comparable between 100% and 80% ETc, and it was significantly higher in 100% ETc than both 60% Eand 40% ETc. Root surface area density (RSAD) was not significantly different between 100% and 80% ETc, and it was significantly lower in both 60% and 40% ETc than 100% ETc in both years. Soil water depletion was the highest in 40% ETc followed by 60% and 80% ETc, and it was least in 100% ETc in both years. Evapotranspiration (ET) was the highest in 100% ETc followed by 80%, 60%, and 40% ETc. The WUE was not statistically different among the irrigation treatments. However, numerically, WUE was observed in the following order: 80% ETc > 100% ETc > 60% ETc > 40% ETc. The RLD, RSAD, soil water depletion, and ET were not significantly different between ‘Poinsett 76’ and ‘Marketmore 76’. However, fruit yield was significantly higher in ‘Poinsett 76’ than ‘Marketmore 76’, which resulted in higher WUE in Poinsett 76. It can be concluded that 80% ETc and Poinsett 76 cultivar can be adopted for higher crop water productivity and successful cucumber production in SHP.

While not classified as an essential plant nutrient, silicon (Si) assimilation following exogenous Si application has enhanced the wear resistance of cool-season turfgrass. Given this beneficial supplementation of lignin by Si reported in epidermal tissue of monocotyledonous plants, our research objective was to quantify root morphology, vegetative nutrition and vigor, soil chemistry, and putting green performance in response to split applications of pelletized liming agents rich in Si and/or Ca and Mg. Field evaluation of granular liming agent treatment, 2441 kg (ha year)−1, was conducted on creeping bentgrass (Agrostis stolonifera L. cv. Penn G-2) putting green maintained in the Mid-Atlantic US. Pelletized Ca/Mg-SiO3 slag or dolomitic limestone treatments were conducted in frequent split applications and incorporated into the upper 5 cm of the rootzone. Measurements of canopy color and density, shoot growth as clipping yield, soil pH, Si and nutrient content of clippings, and soil extractable Si were performed each season. Cumulative Ca/Mg-SiO3 application (kg ha−1) increased mean acetic acid (HOAc) extractable Si by 35 to 60 mg kg−1 and leaf Si content by 1.0 to 1.5 mg g−1. However, neither putting green canopy quality, shoot nutrient concentration, 5 to 15 cm depth root length density nor ball roll distance was improved by liming agent treatment. Liming agent-treated or untreated plots showed statistical, yet inconsistent, differences in clipping yield 4, 14, 15, 16, and 17 months from initiation (MFI). This thorough shuffling of treatment rank, resulting in identical experiment-wide means precludes the expectation of dependably superior vigor by any.

Intercropping is a breakthrough in land-use optimization. This work aimed to study the effects of intercropping patterns on the growth, yield, root morphological characteristics, and interspecific competition of maize and soybean, as well as provide a reference for the development of intercropping patterns of maize and soybean in Northwest China. Three different cropping patterns were designed: monocropping maize, monocropping soybean, and maize-soybean intercropping. Agronomic traits, intercropping indicators such as land equivalent ratio (LER), aggressivity (A), competition ratio (CR), and actual yield loss (AYL), as well as root morphological characteristics were assessed. The results showed that, compared with monocropping, the intercropping maize plant height increased by 6.07–8.40%, and the intercropping soybean plant height increased by 35.27–38.94%; the root length density (RLD) of intercropping maize was higher than that of monocropping maize, the RLD of intercropping soybean was lower than that of monocropping soybean, in the 0–40 cm soil layer the intercropping increased maize RLD by 1.79–7.44% while the soybean RLD was reduced by 3.06–9.46%; the aggressivity of maize was greater than 0 and the competition ratio was greater than 1, which was the dominant species; the maize/soybean land equivalent ratio was 1.18–1.26, which improved the land utilization rate. Therefore, the effect of increasing yield can be achieved by changing the maize and soybean planting method, which is beneficial to the ecological strategy of sustainable development in the northwest region. [ABSTRACT FROM AUTHOR]

Nutrients are vital for plant growth, development, and aid in disease control because nutrients affect host plant and pathogen interactions. Once a citrus tree is infected with the phloem-limited, Gram-negative bacteria, Candidatus Liberibacter asiaticus (CLas), huanglongbing (HLB; citrus greening), it would fall under threat of survival as the disease has no known control mechanism discovered thus far. The objective of this study was to determine if split soil applications of essential nutrients improve the availability and accumulation, reduce leaching of these nutrients beyond the root zone, and promote root growth and water dynamics of HLB-affected citrus trees in the soil–plant–atmosphere continuum. Split soil applications of three N rates (168, 224, and 280 kg ha−1 year−1) were the main blocks. Micronutrients were randomly applied to the sub-blocks assigned in a split-split plot design, applied in three splits annually. The micronutrients were applied to foliage and soil as follows: foliar only 1× (1×), foliar 1× and soil-applied 1× (2×), and foliar 1× and soil-applied 2× (3×)× (1× = 9 kg ha−1 year−1 of Mn and Zn to each foliar and soil along with 2.3 kg ha−1 year−1 of B). Significant soil NH4-N and NO3-N, Zn, and Mn were retained within the active soil root zone (0–30 cm). Higher soil acidity was detected when trees received the highest micronutrient rate in the upper soil layers (0–15 cm) as compared with the middle (15–30 cm) and the lowest (30–45 cm) soil layers. Fine root length density (FRLD) was significantly lower at the highest micronutrient rates, manifesting root growth negatively associated with high Mn and low soil pH. Invariably, the water dynamics: stem water potential (ψstem), stomata conductance (gs), and sap flow were also negatively affected when trees received foliar 1× and soil 2× (3×) treatment as compared with the other treatments. Split application of nutrients had a significant effect on FRLD growth, retaining soil-applied nutrients within the active root zone, and improved water use efficiency. [ABSTRACT FROM AUTHOR]