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Commodity crops, such as wheat and maize, are extremely dependent on chemical fertilizers, a practice contributing greatly to the increase in the contaminants in soil and water. Promising solutions are biofertilizers, i.e., microbial biostimulants that when supplemented with soil stimulate plant growth and production. Moreover, the biofertilizers can be fortified when (i) provided as multifunctional consortia and (ii) combined with biochar with a high cargo capacity. The aim of this work was to determine the molecular effects on the soil microbiome of different biofertilizers and delivery systems, highlight their physiological effects and merge the data with statistical analyses. The measurements of the physiological parameters (i.e., shoot and root biomass), transcriptomic response of genes involved in essential pathways, and characterization of the rhizosphere population were analyzed. The results demonstrated that wheat and maize supplemented with different combinations of selected microbial consortia and biochar have a positive effect on plant growth in terms of shoot and root biomass; the treatments also had a beneficial influence on the biodiversity of the indigenous rhizo-microbial community, reinforcing the connection between microbes and plants without further spreading contaminants. There was also evidence at the transcriptional level of crosstalk between microbiota and plants. [ABSTRACT FROM AUTHOR]

Interspecific interactions and recovery growth play an important role in crop growth, development and ultimately yield in intercropping systems. However, the impact of different water and nitrogen levels on intercropping production, interspecific interactions between intercrops, and the recovery growth of late-maturing crops is still unclear. A two-year field experiment was conducted in Yangling, Shaanxi province, to investigate the dynamics of interspecific interactions, and the effects of interspecific interactions on crop growth and yield. The experiment consisted of three factors, including three cropping systems (wheat/maize intercropping, sole wheat, sole maize), three nitrogen (N) levels and two water applications (supplementary irrigation and rainfed). The results demonstrated that, during the co-growth period, intercropped wheat was more competitive than intercropped maize; so, intercropped wheat showed a yield advantage. Intercropping increased maize yield under irrigated conditions, and this was attributed to the full recovery growth of intercropped maize after wheat harvest. However, rainfed and nil nitrogen aggravated the interspecific competition, and water deficit under maize rows, in turn, limited the recovery growth of intercropped maize, leading to yield reduction. However, compared with sole maize, the yield of intercropped maize decreased, indicating nitrogen deficiency limited the recovery growth of intercropped maize. Among all treatments, the intercropping of medium nitrogen fertilizer with irrigation had the best yield improvement and land use advantages, the total yield of intercropping was 14.8% higher than that of sole cropping, and the land use efficiency increased 16%. These results confirmed that supplementary irrigation and optimal nitrogen application alleviated the interspecific competition, promoted the recovery growth of intercropped maize and improved the yield of wheat/maize intercropping system. [ABSTRACT FROM AUTHOR]

Intercropping increases the grain yield to feed the ever-growing population in the world by cultivating two crop species on the same area of land. It has been proven that N-fertilizer postponed topdressing can boost the productivity of cereal/legume intercropping. However, whether the application of this technology to cereal/cereal intercropping can still increase grain yield is unclear. A field experiment was conducted from 2018 to 2020 in the arid region of northwestern China to investigate the accumulation and distribution of dry matter and yield performance of wheat/maize intercropping in response to N-fertilizer postponed topdressing application. There were three N application treatments (referred as N1, N2, N3) for maize and the total amount were all 360 kg N ha−1. N fertilizer were applied at four time, i.e. prior to sowing, at jointing stage, at pre-tasseling stage, and at 15 days post-silking stage, respectively. The N3 treatment was traditionally used for maize production and allocations subjected to these four stages were 2:3:4:1. The N1 and N2 were postponed topdressing treatments which allocations were 2:1:4:3 and 2:2:4:2, respectively. The results showed that the postponed topdressing N fertilizer treatments boosted the maximum average crop growth rate (CGR) of wheat/maize intercropping. The N1 and N2 treatments increased the average maximum CGR by 32.9% and 16.4% during the co-growth period, respectively, and the second average maximum CGR was increased by 29.8% and 12.6% during the maize recovery growth stage, respectively, compared with the N3 treatment. The N1 treatment was superior to other treatments, since it increased the CGR of intercropped wheat by 44.7% during the co-growth period and accelerated the CGR of intercropped maize by 29.8% after the wheat had been harvested. This treatment also increased the biomass and grain yield of intercropping by 8.6% and 33.7%, respectively, compared with the current N management practice. This yield gain was primarily attributable to the higher total translocation of dry matter. The N1 treatment increased the transfer amount of intercropped wheat by 28.4% from leaf and by 51.6% from stem, as well as increased the intercropped maize by 49.0% of leaf, 36.6% of stem, and 103.6% of husk, compared to N3 treatment, respectively. Integrated the N fertilizer postponed topdressing to the wheat/maize intercropping system have a promotion effect on increasing the translocation of dry matter to grain in vegetative organs. Therefore, the harvest index of intercropped wheat and maize with N1 was 5.9% and 5.3% greater than that of N3, respectively. This demonstrated that optimizing the management of N fertilizer can increase the grain yield from wheat/maize intercropping via the promotion of accumulation and translocation of dry matter. [ABSTRACT FROM AUTHOR]

The use of plant growth‐promoting bacteria (PGPB) to enhance plant growth and protection against heavy metal toxicity has been extensively studied. However, its potentiality to reduce arsenate toxicity, a threat to plant growth and metabolism, has been hardly investigated. Moreover, the toxic effect of arsenic oxide nanoparticles (As‐NPs) on plants and possible mechanisms for its alleviation has not yet been explored. In this study, the impact of the bioactive actinomycete Streptomyces spp. on the growth, physiology and stress‐related metabolites, such as sugars and proline, on As‐NPs‐stressed wheat and maize plants was investigated. Soil amendment with arsenic oxide nanoparticles (As‐NPs) induced the uptake and accumulation of As in the plants of both species, resulting in reduced growth and photosynthesis, but less marked in maize than in wheat plants. Under As‐NPs‐free conditions, Streptomyces spp. treatment markedly improved growth and photosynthesis in wheat only. The application of Streptomyces spp. reduced As accumulation, recovered the As‐NPs‐induced growth, photosynthesis inhibition, and oxidative damage in plants of both species. Wheat plants specifically accumulated soluble sugars, while both species accumulated proline. Under As‐NPs stress, the ornithine pathway of proline biosynthesis was more important in maize than in wheat plants, while the glutamine pathway was dominant in wheat ones. The addition of Streptomyces spp. further induced the accumulation of proline and starch in both plant species. Overall, despite a different response to Streptomyces spp. under nontoxic conditions, the amendment of as‐contaminated soil with Streptomyces spp. induced similar metabolic responses in the two tested species, which trigger stress recovery. [ABSTRACT FROM AUTHOR]

The current noticeable climate change that has a significant impact on the environment and agricultural systems has become a serious concern for human society. Followed by the industrial activities of the global community and increased concentrations of greenhouse gases in the atmosphere, these changes are still considered as a threat to food safety and the environment. Changes in minimum and maximum temperature, rainfall amounts, and precipitation pattern, changes in CO2 concentrations, and complex interactions between these factors and different crops are studied in the form of different probabilistic scenarios to get a glimpse of the future cultivation situation. Agriculture in Qazvin Plain is based on the water transferred from Taleqan Dam and groundwater. Since today these resources are facing issues like restriction on transfer and draw off, which is because of growth of interest in city dwelling, inappropriate water consumption patterns and over-exploitation, agriculture is sensitive to probable changes in water requirements and it is necessary to predict these changes for better management in the future. This study was carried out to investigate the effect of climate change on growth indices for three crops including wheat, barley, and maize in Qazvin Plain with different possible climate change scenarios, in the form of five large-scale climate models and three greenhouse gas emissions scenarios in 30 years' time from 2021 to 2050 as well as from 2051 to 2080. Results showed that biomass production, grain yield, and water use efficiency in three crops of wheat, barley, and maize have increased up to 20–40% in future periods in Qazvin region climate. Growing degree-days (GDD) of these three crops have increased by 20%. Transpiration has risen by 10% in wheat and maize; however, it was stable on average in the first period and slightly decreased in the second period in barley. The transpiration coefficient has reduced by 5% for wheat and barley and has increased by 15% for maize. Results are valid as long as the initial growing conditions of these three plants are done as before, and the irrigation scheduling is performed according to the present period in spite of climate change. [ABSTRACT FROM AUTHOR]

The roles of biochar, melatonin (Me), and P application have been well researched; however, biochar with Me application in helping plants be more drought tolerant are little understood. The aim of this greenhouse study is to evaluate the effects of Me and P in combination with biochar made from date (Phoenix dactylifera L.) and wheat (Triticum aestivum L.) residues on vegetative growth and biochemical impact of maize (Zea mays L.) varieties Azam and Mallika under drought stress. Date residue and wheat straw biochars combined with melatonin (D+W+Me) reduced oxidative stress caused by excessive reactive oxygen species (ROS) the most. Generations of ROS species (malondialdehyde [MDA], H2O2, thiobarbituric acid reactive substances [TBARS], O2−, lipoxygenase [LOX], and electolyte leakage [EL]) was 118 and 700% higher in Azam variety compared to Mallika. The application of D+W+Me maintained osmolyte accumulation, α‐amylase activity, and antioxidant enzyme activities at higher levels in Mallika (2−7, 29, 9−55%, respectively) than in Azam and the rest of the treatments. The D+W+Me treatment also enhanced leaf gas exchange traits in Mallika (3−20%) under drought stress, helping to main better photosynthesis machinery. The D+W+P and D+Me treatments application alleviated a portion of the drought stress. Overall, Me application with date residue and wheat straw biochars enhanced the efficiency of biochar, by better assuaging the adverse drought stress influences. [ABSTRACT FROM AUTHOR]

Background and aims: Previous studies showed that the competition-recovery principle is one of the mechanisms underpinning overyielding in wheat/maize intercropping. However, few studies have focused on the effects of root morphological and physiological changes during the recovery growth of late-maturing species. The present study aimed to determine the mechanism underlying the recovery growth in terms of root distribution and nitrogen (N) uptake in response to different N supplies. Methods: The roots of maize were sampled three times by auger after wheat harvest in the intercropping system with six levels of N application and sole crops at one N-application rate under field condition. Results: Intercropped maize adjusted its root length density (RLD) and root distribution and enhanced its N absorption per unit root length with increasing soil N concentration. Soil inorganic N concentration had a direct influence on RLD of intercropped maize which was related to shoot N concentration. In addition, maize took up 93% more N per unit root length when intercropped with maize compared with sole cropping. Conclusions: Our findings show that the recovery growth of late-maturing species involves phenotypic plasticity of maize root architecture, and the enhanced N uptake resulted from extra soil N acquired from the area where wheat was growing before its harvest. [ABSTRACT FROM AUTHOR]

ABSTRACT The characteristic evolution of El Niño Southern Oscillation ( ENSO) on timescales of months to years means that risks to agriculture have structure between seasons and years. The potential for consecutive ENSO-induced yield anomalies is of particular interest in major food producing areas, where modest changes in yield have significant effects on global markets. In this study, we analyse how multi-year El Niño and La Niña life cycles relate to climate sensitive portions of major crop-growing seasons in North and South America. We analyse the dynamics underlying these life cycles to illustrate which aspects of the system are most important for agriculture. In North America, the same-season teleconnections affecting soybean and maize have been well studied, but we demonstrate the importance of lagged soil moisture teleconnections for wheat in the southern Great Plains. In South America, peak ENSO sea surface temperature ( SST) teleconnections are concurrent with, and therefore critical for, wheat and maize growing seasons while soil moisture memory in Argentina plays an important role during the soybean growing season. Finally, we show that ENSO teleconnection life cycles are consistent with historical yield anomalies. Both El Niño and La Niña life cycles tend to force consecutive seasons of either above or below expected yields. While the magnitude of the yield anomalies forced by ENSO is often modest, they occur in major crop-producing regions. [ABSTRACT FROM AUTHOR]

Estimating plant nitrogen concentrations (PNCs) with remote sensing technology is critical for ensuring precise field nitrogen (N) management. Compared with other remote sensing platforms, low-altitude unmanned aerial vehicles (UAVs) produce images with high spatial resolutions that can be used to clearly identify soil and vegetation. Previously, many spectral indices were designed to remove soil effects to obtain optimal PNC predictions. Herein, we attempt to enhance the PNC prediction accuracy only by removing soil pixels in high-resolution images. Thus, we aimed to collect a dataset containing different crops and image types to investigate whether removing soil pixels to purify crop spectra can improve PNC estimations. For this purpose, N fertilizer experiments were conducted on cotton (Gossypium hirsutum L.), wheat (Triticum aestivum L.) and maize (Zea mays L.), and multispectral and hyperspectral UAV images and PNCs were collected at different growth stages. The multispectral images had actual high spatial resolutions, while the hyperspectral images had virtual high spatial resolutions constructed by fusing high resolution panchromatic images and coarse resolution hyperspectral images. These images represent two typical UAV image types. First, for each crop, the relative changes and driving forces associated with the purified and nonpurified spectra were analyzed under different growth stage, N treatment. Then, three commonly used methods, the spectral index (SI), partial least squares regression (PLSR) and artificial neural network (ANN) methods were used to design PNC prediction model using purified and nonpurified spectra respectively. The results showed the differences between purified and nonpurified spectra were affected by the proportion of crop pixel, sunlit soil pixel and sunshade soil pixel in image. This influence had various trends and magnitudes among different N treatment, growth stages and crop types. It is better to remove soil pixels in imagery, when designing PNC prediction model for plants across growth stages, crop types or even in a single growth stage. The results from actual high spatial resolution images demonstrated this point, with the best PNC prediction model from purified spectra. When considering virtual high spatial resolution image, as the spectrum obtained for each vegetation pixel still represented a mixed vegetation and soil spectrum, removing soil pixels showed no improved performance for PNC estimation. These results provide a reference for others to reasonably choose an optimal data-processing method for constructing PNC prediction models. • Plant nitrogen concentration can be estimated using UAV-based images. • Purified and nonpurified spectra exist significant difference. • Plant nitrogen concentration can be better estimated using purified spectra. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) toxicity in agricultural soils is serious concern these days which needs continuous attention. Little is known about the combined use of berseem and/or maize residues soil applied as a green manure alone or along with foliar dressing of zinc oxide nanoparticles (ZnONPs) on Cd accumulation in wheat (Triticum aestivum L.). A pot experiment under ambient conditions with wheat grown in Cd-contaminated soil was performed after soil applied different green manure amendments and foliar dressing of ZnONPs was done during plant growth and plants were harvested at full maturity. Compared with control, plant growth attributes and biomass of above ground parts substantially increased with applied amendments being maximum with combined use of ZnONPs + B75 (berseem residue, 75 mg/kg) followed by ZnONPs + M75 (maize residue, 75 mg/kg). All the treatments improved the leaf chlorophyll contents and improved the leaf antioxidant enzyme activities thereby reduced the leaf electrolyte leakage. The Cd accumulation in roots and aboveground parts of the wheat was reduced especially in ZnONPs + B75 followed by ZnONPs + M75. The higher rate of soil applied amendments along with NPs minimized the available Cd in soil extracts but soil post-harvest pH was not much affected by the applied amendments. In conclusion, incorporation of berseem and maize residues as a green manure applied in Cd-contaminated soil combined with foliar NPs may decrease Cd phytoavailability and its accumulation in wheat grains. However, substantial field studies are required under various environmental conditions before final recommendations at field levels. [Display omitted] • The highest Cd concentrations were found in plants without any treatments. • ZnONPs and green manure increased growth and biomass of wheat. • ZnONPs and green manure enhanced activities of antioxidants enzymes in leaves. • ZnONPs and green manure decreased Cd contents in grains of wheat. [ABSTRACT FROM AUTHOR]

Pot experiments were carried out in a completely randomized design in the screenhouse of Faculty of Agriculture, South Valley University, Egypt, to evaluate the application effects of different organic wastes (sewage sludge, filter mud cake, compost, filter mud cake-compost mixture and sewage sludge-compost mixture) at different levels (5, 15 and 30 ton/fed. on the release and availability of N, P and K in three different soils (clay, calcareous sandy, and sandy soils). Corn plants followed by wheat plants were grown during two successive seasons of summer 2011 and winter of 2011/2012. Total Nitrogen (N), available phosphorus (P) and available potassium (K) in soils as well as plant dry matter and the uptake of these nutrients by plants were determined to evaluate the N, P and K released in the soil and their uptake by these plants. The application of these organic wastes at different levels showed significant increases in N, P and K that were released in the studied soils as well as plant dry matter yield and the uptake of these nutrients by corn and wheat plants. In general, use of these investigated organic wastes at the level of 30 ton/fed. in these studied soils gave the best results. [ABSTRACT FROM AUTHOR]

Determining the proper rate of wheat residues incorporation into the soil under a wheat–maize double cropping system is an important issue in southern parts of Iran, where these two irrigated crops are consecutively grown. A 2-year experiment (2010–2011) was conducted to evaluate the effect of wheat residue incorporation rates (25%, 50% and 75%) and irrigation intervals (12, 16 and 20 days) on yield and growth of maize under no-tillage system compared to control without residue and under conventional tillage (CT) at the College of Agriculture, Shiraz University, Shiraz, Iran. The experiment was conducted as a split plot arranged in randomized complete block design with three replications. The results showed that increased irrigation intervals reduced the plant height (14.6%), leaf-area index (12.9%), rows (10.1%) and grains per ear (29.8%), thousand grain weight (6.9%), grain (33.8%) and biological yield (24.2) and harvest index (23.2%). Water deficit had no significant effect on soil organic matter and carbon-to-nitrogen ratio. Under 12 and 20 days irrigation intervals, the highest grain yields were obtained with 12.7 and 8.6 t ha−1in CT and 25% residue incorporation into soil, respectively. Therefore, according to the results of this 2-year study, realized incorporation of 25% wheat residue soil covering percentage is recommended for this area with limited water resources. [ABSTRACT FROM PUBLISHER]

Biochar can benefit human society as a carbon-negative material and soil amendment. However, negative biochar impacts on plant germination and growth have been observed, and they have not been fully explained. Therefore, protocols to avoid these risks cannot be proposed. We hypothesized that the free radicals generated during charring may inhibit plant germination and growth. Significant electron paramagnetic resonance (EPR) signals were observed in the biochars derived from several types of common biomass (corn stalk, rice, and wheat straws) and the major biopolymer components of biomass (cellulose and lignin), but not in the original materials, suggesting the ubiquitous presence of free radicals in biochars. EPR signal intensity increased with increasing pyrolysis temperature, and it was dominantly contributed by oxygen centered in the mixture of oxygen- and carbon-centered free radicals as the temperature increased. The free radicals in biochars induced strong ∙OH radicals in the aqueous phase. Significant germination inhibition, root and shoot growth retardation and plasma membrane damage were observed for biochars with abundant free radicals. Germination inhibition and plasma membrane damage were not obvious for biochars containing low free radicals, but they were apparent at comparable concentrations of conventional contaminants, such as heavy metals and polyaromatic hydrocarbons. The potential risk and harm of relatively persistent free radicals in biochars must be addressed to apply them safely. [ABSTRACT FROM AUTHOR]

Abstract: An assessment of contamination of cereals with the Fusarium mycotoxins deoxynivalenol (DON) and zearalenone (ZEA) is difficult because of the complexity and interactions of various driving factors. We study the mycotoxin accumulation in winter wheat growing after maize or oilseed rape at different topographic positions within fields consisting of alternating hilltop and depression positions across a transect in the Uckermark region in the Northeast of German Lowlands. A linear mixed-effects model and censored regression are used to account for spatial autocorrelation and non-detects in determining factors controlling DON content in 304 samples from 19 fields in 2006 and 2007. Environmental factors (actual rainfall during the anthesis, long-term mean annual precipitation), topographic factors (relief position, topographic wetness index TWI) and management factors (tillage, preceding crop, susceptibility ranking of wheat cultivars to Fusarium spp.) as well as the year of investigation were included as explanatory factors in this analysis. The spatial linear mixed-effects model indicates that DON on wheat fields with maize as preceding crop was one order of magnitude higher than in wheat grown after oilseed rape (significant at the 5% level). Tillage had a similar effect: Ploughing significantly reduced DON by more than one order of magnitude. Humid areas (mean annual precipitation >550mm) showed a significantly higher DON contamination (3.7-fold increase) than the drier areas. TWI and topographic position had significant influences on DON levels. Their combined effect lead to a 68% higher DON at depressions with high TWI compared to hilltops with low TWI. The results of the censored regression were very similar to those of the mixed model. The susceptibility ranking score of the wheat cultivars to Fusarium infection did not have a significant influence on DON in these models. Overall, the statistical models revealed a combined influence of climatic, topographic, and crop management factors on DON concentration in winter wheat on different spatial scales for the environmental setting of our study area. [Copyright &y& Elsevier]

Interest in the use of inoculants containing bacteria that promote plant growth is likely to increase in the coming years, due to higher costs of fertilizers, concerns over pollution and emphasis on sustainable agriculture. Although Brazil has a long tradition in research on nitrogen fixation in Azospirillum-grass associations, it has not led to recommendations of strains for use in commercial inoculants. In this study, we report the selection and evaluation of Azospirillum strains for the maize ( Zea mays L.) and wheat ( Triticum aestivum L.) crops, following protocols established by the Brazilian legislature, i.e. field experiments have to be performed in at least two different localities representing the crop growing regions, and for at least two seasons. In a first set of nine trials performed at Londrina and Ponta Grossa, southern Brazil, nine Azospirillum strains were evaluated after application to seeds as peat-based inoculants. A. brasilense strains Ab-V4, Ab-V5, Ab-V6 and Ab-V7 increased grain yields of maize by 662–823 kg ha−1, or 24–30%, in relation to non-inoculated controls. Two A. lipoferum strains were tested in two of these experiments and promising results were also obtained. With wheat, A. brasilense strains Ab-V1, Ab-V5, Ab-V6 and Ab-V8 were the most effective, increasing yields by 312–423 kg ha−1, or 13–18%. In a second trial set with eight field experiments at Londrina an Ponta Grossa, liquid and peat-based inoculants carrying a combination of A. brasilense strains Ab-V5 and Ab-V6 increased maize and wheat yields by 27% and 31%, respectively. Effects of inoculation were attributed to general increases in uptake of several macro and micronutrients and not specifically to biological nitrogen fixation. All experiments received only a low N-fertilizer starter at sowing (24 kg and 20 kg of N ha−1 for the maize and wheat, respectively) and although yields can be globally considered low, they were compatible with Brazilian mean yields. This study resulted in the identification of the first Azospirillum strains authorized for the production of commercial inoculants in Brazil. [ABSTRACT FROM AUTHOR]

Abstract: Wheat (Triticum aestivum L.), rice (Oryza sativa) and maize (Zea mays L.) are the most important cereals worldwide. However, in the last few years, soil has been submitted to both use and handling pressures due to the increase in agricultural practices, which are leading to its degradation. The use of plant growth-promoting rhizobacteria (PGPR) as inoculants constitutes a biological alternative for sustainable production. Pseudomonas aurantiaca SR1 was formulated as an inoculant in order to evaluate its growth promotion effect in the field when applied on maize and wheat seeds at the sowing time. P and N fertilization treatments were also included in the assays. P. aurantiaca SR1 colonized the root system of both crops and it persisted at appropriate population densities. It also showed a significant plant growth-promoting effect that was reflected in the yield. Another relevant finding was that both crops, when inoculated with P. aurantiaca SR1, presented higher yields with fertilization doses lower than those conventionally applied. This indicated its potential use as a reasonable alternative for crop production, with a minimization of the ecological impact. [Copyright &y& Elsevier]

• Microbial communities clearly undergo cyclical patterns within the growing season. • Bacteria cycled at shorter periods, associated with soil physical/weather conditions. • Fungi cycled at longer periods, associated with soil chemical properties. • Fertilizer and tillage may modulate microbial community cycles in the growing season. • Time lags with associated soil conditions was strongly influenced by microtopography. Soil microbial communities maintain many ecosystem functions including decomposition and symbiotic nutrient uptake. Prior field studies have focused on either geospatial or relatively large-time scale trends in these communities. Whereas, their small-time scale (e.g., weekly) dynamics in agricultural fields have largely been overlooked. Our objective was to determine the effects and characteristics of short-time scales on five phospholipid fatty acid (PLFA) microbial groups throughout the whole growing season, while under two soil disturbance levels. The microbial community groups included total microbial abundance (TMA), arbuscular mycorrhizal fungi (AMF), total fungi, actinomycetes, and total bacteria. The fungal to bacterial ratio (F:B) was also determined. Soils were sampled twice per week from planting to harvest during two consecutive growing seasons (N = 62) and analyzed for microbial abundances and chemical and physical properties. The study was conducted at an on-farm site with a corn [ Zea mays ] – soybean [ Glycine max] – wheat [ Triticum aestivum ] rotation and two soil disturbance levels [high (chisel plow) and low (shallow vertical till)] using a randomized complete block design. Data analysis included 1) spatial and temporal coefficients of variations, 2) a mixed linear model to test for time and disturbance level effects, and 3) a Fourier analysis to detect and characterize cyclical patterns via autocorrelation spectral densities. The Fourier analysis also included cross spectral densities and phase lags with a large suite of soil chemical, soil physical, and weather states. Temporal variations of microbial communities were one to threefold greater than their spatial variations. Significant time effects were observed for TMA, AMF, and bacteria, where these communities behaved as sine and consine functions over time. However, strong cyclical patterns were above white noise levels at the experimental plots level for all microbial groups during each growing season. Cross spectral densities indicated that bacteria and actinomycetes tended to cycle at short and long periods (biweekly to whole season) associated with soil physical and weather states, whereas TMA, AMF, fungi, and F:B cycles at long periods (bimonthly to whole season) associated with soil chemical states. These microbial communities in a field setting clearly undergo cyclical patterns over small periods with some modulations from soil disturbance levels, fertilization, and microtopography. Further research on these cyclical and cross-correlated dynamics is warranted to determine the magnitude of influence on ecosystem services and crop productivity. [ABSTRACT FROM AUTHOR]

The cadmium (Cd) activity in soil has been widely studied. However, the interactive effects of soil properties (e.g. soil pH, CEC, and SOM) on Cd transfer from soil to grain are generally overlooked. In total 325 datasets including soil pH, CEC, SOM, and soil Cd content were used in this study. The descriptive statistics indicated that Cd content in wheat and maize soils ranged from 0.05 to 10.31 mg/kg and 0.02–13.68 mg/kg, with mean values of 0.87 and 1.14 mg/kg, respectively. Cd contents in wheat and maize grains were 0.01–1.36 mg/kg and 0.001–1.08 mg/kg with average values of 0.15 and 0.10 mg/kg, respectively. The results of SEM demonstrated that the interactive effects of soil properties contributed more to Cd transfer from soil to wheat grain than the soil Cd content. Subsequently, CITs-MLR indicated that the critical factors, including soil pH and total soil Cd content, could mask the contribution of other soil properties on Cd accumulation in grain; soil CEC may prevent Cd from leaching and therefore improve grain Cd level of wheat especially at acidic soil condition. The result of derived Cd thresholds revealed that current Cd thresholds are not completely suitable to wheat and maize grain at different soil conditions. This study provides a new model for further investigation on relationships between soil properties, soil Cd content and grain Cd level. Image 1 • The interactions of soil properties influence Cd transfer in a higher degree than soil Cd content. • Soil pH may mask other soil properties' contribution on Cd transfer. • Diverse Cd thresholds for different soil conditions are obtained. [ABSTRACT FROM AUTHOR]

summary: The effect of ammonium and nitrate nutrition on maize and wheat grown hydroponically and salinity stressed was assessed from measurements of growth rate and gas exchange. In both maize and wheat the ammonium‐grown plains were much more sensitive to salinity toxicity than nitrate‐grown plants particularly when exposed to 60–80 mM salinity. Shoot growth was retarded to a far greater extent than root growth in salinity‐stressed plants of both wheat and maize with either nitrogen source. There was no significant decrease of photosynthetic rate in salinity‐stressed plants of either species fed nitrate or ammonium, except in severely wilted plants of both species fed nitrate or ammonium at the highest (80 mM) salinity concentration. The same was true for stomatal conductance, transpiration rate and transpiration ratio (water use efficiency). In nitrate‐fed wheat, raising the calcium concentration from 2 to 12 mM in the presence of 60 mM salinity produced an 11% increase in growth. This effect is ascribed to improved nitrate uptake due to calcium protection of the nitrate transporter and was not evident in ammonium‐grown wheat. Possible reasons for the differential effects of ammonium and nitrate nutrition are discussed. [ABSTRACT FROM AUTHOR]

The uptake of the auxin‐type herbicide 2,4‐D and of the non‐auxin‐type atrazine into seedlings of maize (Zea mays L.cv. SZeTC 505) and wheat (Triticum aestivum L.cv. GK Szeged) was investigated, as were their effects on the growth and K+ uptake under different nutrient conditions. A brief incubation of the roots in 0.01 mM 2,4‐D caused a marked herbicide influx only in the absence of Pi. Lowering the Pi concentration of the uptake solution led to an increased 2,4‐D influx into the roots, thereby inhibiting K+ uptake, growth and dry‐matter production of the plants. In the case of 0.01 mM atrazine, Pi‐supply in the external solution influenced neither the herbicide uptake nor the growth of the plants. [ABSTRACT FROM AUTHOR]

The Decision Support System for Agrotechnology Transfer – Cropping System Model was used with an objective to evaluate maize (Zea mays L.), winter wheat (Triticum aestivum L.) and grain sorghum (Sorghum bicolor L. Moench) yield, crop water productivity (CWP) and return after variable cost (RAVC) under different combinations of irrigation interval/capacity and plant available soil water (PASW) thresholds on three soil types in southwestern Kansas. Maize, grain sorghum and winter wheat yields were maximized under irrigation capacity of 4.2–6.3, 3.1–4.2 and 2.5–3.1 mm/d, respectively. The lowest and highest values in the range corresponded to silt loam and fine sand soils, respectively. For maize, maximum RAVC ($630–710/ha) and CWP (25–27 kg/ha/mm) were achieved with a relatively shorter irrigation interval (25 mm/4–8 d). RAVC values for grain sorghum and winter wheat were not substantially affected by irrigation interval. The RAVC for grain sorghum and winter wheat ranged from $150 to $200/ha and $310 to $370/ha, respectively. The CWP of grain sorghum peaked at shorter irrigation interval (25 mm/6–8 d), whereas, high CWP of wheat was simulated even at longer irrigation interval (25 mm/26 d). Overall, for winter wheat and grain sorghum, irrigation strategy for attaining higher RAVC values is different from irrigation strategy for attaining higher yield. Whereas, for maize, irrigation strategy for higher yield is the same as that irrigation strategy for higher RAVC. This study guides producers to identify and prioritize the most suitable irrigation strategy for optimizing yield, CWP and/or income while enhancing sustainability of environment and management of ground water. The present work assumes all factors except water are optimal and findings are sensitive to dynamics of price changes, productivity levels and variations in crop management and climate. • Irrigation scheduling for maize, winter wheat and grain sorghum was evaluated. • Yield, crop water productivity (CWP) and income were used as evaluation criteria. • For maize, maximum income, CWP and yield were met at shorter irrigation interval. • Irrigation strategy for high income in wheat is different from that for high yield. • Grain sorghum and wheat income was not substantially affected by irrigation. [ABSTRACT FROM AUTHOR]

Biophysical simulation models can help to satisfactorily estimate the crop performance for grain production, their stability across years and their impact on components of hydrological balance in diverse areas once those models have been calibrated and validated with field data. The Inner Argentinian Pampas (IAP) region is very susceptible to both frequent flooding and random droughts due to flat landscape, sub-humid to semi-arid climate, coarse- textured soils and shallow water tables. The Soil Water Balance (SWB) model appears to be suitable for the IAP region since it includes most of the necessary requirements for the particular conditions of such an environment. The objectives of this study were: i) to identify the most sensitive crop parameters of the SWB model for a satisfactory estimation of aerial biomass, grain yield and crop evapotranspiration in the IAP region; ii) to parameterise and calibrate the SWB model for simulation of aerial biomass, grain yield and crop evapotranspiration of wheat (Triticum aestivum L.), soybean [ Glycine max L. (Merr.)] and maize (Zea mays L.); iii) to validate the SWB model using an independent dataset over a wide area in the IAP region. We used data from 9 field experiments for calibration and from 116 field experiments for validation. The most critical parameters, as indicated by a sensitivity analysis, were biomass-transpiration coefficient (K b), radiation use efficiency (e), and extinction coefficient (k), suggesting that they should be locally obtained before promoting the use of the SWB model in a given region. The SWB model, after calibration, was able to accurately estimate crop aerial biomass (d = 0.97–0.99, GSD = 9.5–23.9% and RMSE = 786–2,438 kg ha−1), grain yield (d = 0.95–0.96, GSD = 4.5–10.7% and RMSE = 357–637 kg ha−1), crop evapotranspiration (d = 0.97–0.99; GSD = 8.1–16.1%, RMSE = 17–51 mm) and soil water content (d = 0.87–0.96, GSD = 11.2–15.5% and RMSE = 9.6–13.2 mm). The robustness to estimate water balance, aerial biomass and grain yield fluctuations for wheat, soybean, and maize across different soil textures and rainfall variability reflects the potential of SWB model as a valuable tool to face the main challenges of the agricultural systems in our region. [ABSTRACT FROM AUTHOR]

Numerous strategies for mitigating ammonia volatilization (AV) from agricultural land have been investigated with limited evaluation of their efficacy and response to differing field conditions across China. Therefore, this meta-analysis seeks to draw conclusions about AV in China, and assess the effect of crop type (wheat, maize, and rice as staple crops), climatic conditions, and soil properties on AV and variations in responses that can guide selection of appropriate strategies under different conditions. Novel analysis indicates nitrogen (NH 3 –N) losses of 7.62 Tg due to AV from these three crops in China. AV is 12.8 and 18.0% (95% CI) higher from maize than from wheat and rice, respectively, without N application under warm and sub-humid conditions (MM), and 13.8 and 2.8% higher under hot and humid conditions (HH). AV increases notably under HH as compared with cold and sub-arid conditions (LL) by 11.5% and 28.4% under the control treatment and application of 150 kg N ha−1, respectively in rice fields while it is most substantially under maize (52.5%) with application of 150 kg N ha−1. The ratio of change in AV between soil grades 3 and 1 (potential AV >1.0 and < 0 cmol kg−1) is significantly greater for wheat and rice (2.5%) than for maize (1.9%). The strategy of reducing N rate is more effective for maize and rice than wheat, where applying N at a rate of 150–220 kg N ha−1 to them has similar effects to applying 300 kg N ha−1 to wheat. For wheat and maize, urea should be partially substituted with organic amendments, while improved urea is the preferable N source for rice. Subsurface application has competitive efficacy, especially for maize, and higher N rates. Applying inhibitors achieves the highest AV reduction, especially with rice under various conditions, creating more actively options for future research to increase applicability. Image 1 • About 7.62 Tg N–NH 3 from main staple crops in China was indicated using CMA outputs. • Higher AV from maize fields than wheat and rice by (95% CI = 12.8 and 18%) even without N applications. • AV under maize and rice is higher under warm-humid conditions than cold-dry but wheat showed reverse response. • Improved urea and inhibitor usage is optimum strategy in reducing AV especially under rice. • Organic amendments, mulching and subsurface application are efficient strategies in reducing AV for wheat and maize. [ABSTRACT FROM AUTHOR]

• Low-cost biochar was used to ameliorate salt-affected soil. • 12 t ha–1 biochar reduced soil bulk density and increased saturated hydraulic conductivity. • 12 t ha–1 biochar decreased sodium adsorption ratio and increased nitrogen use efficiency. • 6–12 t ha–1 biochar maintained crop yields while fertilizer use was reduced by 25%. Soil salinity and its associated soil compaction and low fertility is a big problem for land management in the arid region or coastal zone. Here, a low-cost and potassium (K)-rich biochar of reed (phragmites communis) was demonstrated effective in alleviating the problem in wheat-maize rotation in the Yellow River Delta region. Adding the biochar at 0, 3, 6, and 12 t ha–1 to a soil with a 2.8‰ salt content via rotary tillage with straw returning, with or without fertilizers, reduced soil bulk density (BD) and increased saturated hydraulic conductivity (K s). At 12 t ha–1 dose and by wheat and maize harvests, respectively, biochar lowered soil BD by 9.1% and 14.5%, increased K s by 82.7% and 91.2%, and reduced sodium adsorption ratio (SAR) by 64.9% and 92.8% in comparison with the control (CK). Further, in comparison with conventional fertilization (CF: 375 kg ha–1 for each crop), biochar use (6 and 12 t ha–1), together with 75% of CF, enhanced the nitrogen use efficiency (NUE) by 20.5%–31.4% for wheat and 15.9%–30.9% for maize. It raised the yields of wheat by 11.3%–17.1% and maize by 9.7%–14.8%. By reducing BD, increasing K s, and decreasing SAR, biochar alleviated soil compaction and salt stress and increased NUE and crop yields. This outcome suggests that the conversion of local bio-waste into biochar as a soil amendment is of agronomic and environmental benefits. [ABSTRACT FROM AUTHOR]

• Water conservation is the best way to increase water management efficiency in agriculture and reduce potential negative environmental impacts. • Residue improves soil tilth and adds organic matter to the soil as it decomposes. • Crop residue can reduce the rate of water evaporation and runoff, increase penetration of water and therefore improve soil water conservation. Wheat (Triticum aestivum L.) residues and water management are major problems in southern part of Iran where irrigated wheat-corn (Zea mays L.)-wheat rotation is a common practice. A 2-year (2015–2016) field experiment was conducted as a split plot design with four replications to determine the influence of different irrigation regimes (50, 70, and 100% of water requirement) and wheat residue rates (0, 25, and 50%) incorporation into the soil on sweet corn (Zea mays L V. Saccharata) growth, grain yield, and some soil properties at School of Agriculture, Shiraz University, Shiraz, Iran. The results showed that the highest plant height (187.12 cm) and leaf area index (3.49) were obtained when the crop was normally irrigated (100% of water requirement) and sown into the 25% incorporated wheat residues. Furthermore, canned yield (68%) and water use efficiency (WUE) increased with normal irrigation and 25% residue incorporation compared to the 50% wheat residue rate. The highest grain protein (14.67%) was achieved under incorporation of either 25 or 50% wheat residue into the soil, while the highest grain sugar (2643.5 mg g−1) was obtained when the crop was moderately irrigated (70% of water requirement) with 25% residue incorporation into the soil. The highest soil nitrogen (N) and soil organic carbon (SOC) were achieved with normal irrigation and 50% residue incorporation in both years.In general, adopting an adequate rate of wheat residue (between 25%–50%) accompanied by decreasing irrigation volume to 70% water requirement of corn is recommended in semi-arid agroecosystems. [ABSTRACT FROM AUTHOR]