Wheat Water Use Research Articles

Effects of different cycocel doses and irrigation levels on grain production, quality characteristics and water use in bread wheat

Cycocel (CCC) is a synthetic substance widely used as a growth retardant in grain crops. The importance of CCC is greater under different stress conditions. In this study, the effects of different CCC doses (D0 = 0, D1 = 750, D2 = 1500, and D3 = 2250 g ha−1) and different irrigation levels (I0 = 100% as control, I1 = 75%, I2 = 50%, and I3 = 25%) on some agro-morphological characteristics, yield and quality parameters, and crop water use characteristics in a semi-dwarf bread wheat variety were investigated. The internode length, number of grains, grain weight per spike, biological yield and grain yield values showed significant reductions, especially under I3, regardless of CCC applications. Grain yields varied between 2.31-6.14 and 2.28-4.43 kg ha−1 in 2019-2020 and 2020-2021, respectively. There was no significant difference in crop water consumption among different CCC doses under the same irrigation level. The effects of increasing water stress on the decrease in plant height were greater than that of increasing CCC application. Under I3 and increasing CCC applications, the spike length was significantly reduced. The protein content, sedimentation, wet gluten ratio, and gluten index values increased significantly, especially under I2 and I3. Plant yield response factors for both biological (0.85-0.90 in 2019-2020 and 0.74-0.99 in 2020-2021) and grain yields (0.77-0.90 in 2019-2020 and 0.77-0.1.12 in 2020-2021) varied between years depending on CCC applications and climatic conditions. The foliar CCC application for the purpose of increasing crop yield during drought season might not be recommendable.

Long‐term effects of management practices on soil water, yield and water use of dryland wheat: A global meta‐analysis

AbstractSoil water conservation in dryland agriculture mainly depends on precipitation. We chose 35 long‐term experiments and analysed the data by using meta‐analysis to check how fallow management methods affect soil water storage of dryland winter wheat planting (SWS), precipitation storage efficiency (PSE), crop yield and water use efficiency (WUE). No‐tillage (NT), compared to conventional tillage (CT) in the fallow period, increased PSE, SWS, grain yield and WUE by 32.9%, 27.1%, 30.5% and 22.6%, respectively. Reduced tillage (RT) and subsoil tillage (ST) increased PSE by 15.2% and 11.7%, SWS by 17.4% and 15.0% and grain yield by 15.5 and 13.8%, respectively, but these had a non‐significant effect on WUE. The conservation tillage methods interacted significantly with the residue management and fallow mulching practices. Compared to CT, the conservation tillage methods with fallow mulching increased PSE, SWS, grain yield and WUE, but the growing of cover crops (designated as biological mulching) decreased PSE, SWS and grain yield by 17.3%, 13.0% and 32.0%, and had a non‐significant impact on WUE. Under the condition of straw mulching, NT increased PSE, SWS, grain yield and WUE by 43.7%, 38.1%, 40.6% and 42.9%, respectively, compared to CT. NT and RT increased the PSE, SWS and WUE, under normal mean annual precipitation (MAP), however, ST increased these observations under wet MAP, compared to CT. The effects of tillage methods varied with soil texture, and they were highly interrelated with water conservation, wheat yield and water use. We conclude that compared to conventional tillage, the conservation tillage methods increased soil water conservation during the fallow period, which increased wheat yield and water use. Moreover, NT with or without residue retention increased the fallow water conservation and wheat yield. Crop residues should be retained while applying RT and ST to grow winter wheat in dryland regions.

The Synergistic Production Effect of Water and Nitrogen on Winter Wheat in Southern Xinjiang.

Water and nitrogen management are crucial for food security and the efficient use of water and fertilizer, especially in arid regions. Three irrigation levels, namely, 80% crop water requirement (ETC) (W1), 100% ETC (W2), and 120% ETC (W3), and three nitrogen application levels, namely, 0 kg/ha (N1), 207 kg/ha (N2), and 276 kg/ha (N3), were used as the experimental treatments, and a control group, denoted as CK, was created. The results show that the maximum height achieved was 82.16 cm under W3N3. There was a single-peak variation trend throughout the growth stages of SPAD. It peaked at 58.44 under W3N3 and then at 27.9 under W2N2. The net photosynthetic and transpiration rates displayed bimodal peaks and the phenomenon of a "photosynthetic midday depression". And the prominent peaks in leaf water use efficiency occurred at 14:00 and 18:00, alongside noteworthy enhancements observed under the W3 treatment. Water and nitrogen and their interactions significantly affected the dry matter (DM) of winter wheat, with the spike accounting for the highest percentage. The W2N2 treatment demonstrated superior effectiveness in enhancing winter wheat water use efficiency, offering the potential to decrease irrigation requirements by 20% and nitrogen application by 25%. Moreover, the maximum PFPN attained under W2N2 reached 60.13, representing a noteworthy 35.25% increase compared to the control group (CK), but the HI of the W2N2 treatment only reached 0.56. The highest HI was achieved with W3N2 (0.73), and the nitrogen application of 207 kg/ha was more conducive to obtaining a higher HI. The highest yield was achieved under W3N3 (13.599 t/ha), followed by W2N2 (12.447 t/ha), and the spike proportion exceeded 60% with W2N2, and its production cost and economic benefit ratio of under 0.31 were superior to those for other treatments. Multiple regression analysis revealed that the maximum yield reached 12.944 t/ha with an irrigation amount of 3420.1 m3/ha and a nitrogen application of 251.92 kg/ha. Overall, our study suggests using an optimal water-nitrogen combination, specifically an irrigation level of 2829 m3/ha and a nitrogen application rate of 207 kg/ha, leading to increased winter wheat yields and economic benefits. These research results provide a pragmatic technique for improving winter wheat production in southern Xinjiang.

No-tillage enhances soil water storage, grain yield and water use efficiency in dryland wheat (Triticum aestivum) and maize (Zea mays) cropping systems: a global meta-analysis.

Climate change significantly affects crop production and is a threat to global food security. Conventional tillage (CT) is the primary tillage practice in rain-fed areas to conserve soil moisture. Despite previous research on the effect of tillage methods on different cropping systems, a comparison of tillage methods on soil water storage, crop yield and crop water use in wheat (Triticum aestivum ) and maize (Zea mays ) under different soil textures, precipitation and temperature patterns is needed. We reviewed 119 published articles and used meta-analysis to assess the effects of three conservation tillage practices (NT, no-tillage; RT, reduced tillage; ST, subsoil tillage), on precipitation storage efficiency (PSE), soil water storage at crop planting (SWSp), grain yield, evapotranspiration (ET) and water use efficiency (WUE) under varying precipitation and temperature patterns and soil textures in dryland wheat and maize, with CT as the control treatment. Conservation tillage methods increased PSE, SWSp, grain yield, ET and WUE in both winter wheat-fallow and spring maize cropping systems. More precipitation water was conserved in fine-textured soils than in medium-textured and coarse-textured soils, which improved ET. Conservation tillage increased soil water conservation and yield under high mean annual precipitation (MAP) and moderate mean annual temperature (MAT) conditions in winter wheat. However, soil water conservation and yield were greater under MAP <400mm and moderate MAT. We conclude that conservation tillage could be promising for increasing precipitation storage, soil water conservation and crop yield in regions with medium to low MAPs and medium to high MATs.

The grain Food-Energy-Water nexus in China: Benchmarking sustainability with generalized data envelopment analysis

Food insecurity can be considered as a significant cause to instability in some regions around the world. Grain production utilizes a multiple of inputs, such as: water resources, fertilizers, pesticides, energy, machinery, and labor. In China, grain production has led to huge irrigation water use, non-point source pollution, and greenhouse gas emissions. It is necessary to emphasize the synergy between food production and ecological environment. In this study, a grain Food-Energy-Water nexus is delivered and an eco-efficiency sustainability evaluation metric is introduced, Sustainability of Grain Inputs (SGI), for investigating the sustainability of water and energy use in grain production across China. SGI is constructed by using generalized data envelopment analysis to comprehensively incorporate differences of water and energy inputs (including indirect energy use contained in agricultural chemicals such as fertilizers, pesticides, agricultural film, and direct energy use such as the electricity and diesel used for irrigation and agricultural machinery) in different regions across China. Both water and energy are considered by the new metric at the same time, which is built on the single resources metrices that are often used in the sustainability literature. This study evaluates the water and energy use of wheat and corn production in China. Wheat production uses water and energy sustainably in Sichuan, Shandong, and Henan; Corn production has the highest combined sustainability index in Shandong, Jilin, Liaoning, and Henan. In these areas, the grain sown area could be increased. However, wheat production in Inner Mongolia and corn production in Xinjiang rely on unsustainable water and energy inputs, and their grain sown areas could be reduced. The SGI is a tool that researchers and policy makers can use to better quantify the sustainability of water and energy inputs to grain production. It facilitates formulating policies about water saving and carbon emission reduce of grain production.

Time to Onset of Flowering, Water Use, and Yield in Wheat

Crop breeding has been successful in increasing crop grain yield (GY; reproductive biomass) largely through reduced vegetative size, increased reproductive effort (RE = reproductive biomass/total biomass) and increased water-use efficiency (WUE) in grain production. Flowering time is an important life history trait that signifies the switch from vegetative to reproductive growth. The relationship between GY and time from sowing to flowering (Tsf) is unclear. We fit the relationships between GY and RE vs. Tsf to the logistic model using data from 18 spring wheat genotypes grown under simulated rainfed conditions. Tsf accounted for water use before and after flowering, root length density, total leaf area, and the time from flowering to harvest. Early flowering meant decreased water use before flowering and increased water use afterward. Soil water remaining at harvest was positively correlated with yield. Early flowering genotypes have a higher WUE of grain production, but there was no significant difference in the WUE of total biomass production. The relationship between grain yield and Tsf is described as a unimodal curve, as is the relationship between RE and Tsf. Higher yields and a higher RE have been achieved through earlier flowering, and both RE and Tsf reached their optimal values for maximizing GY. Crop breeding is unlikely to achieve further increases in GY through this route in the future. The results suggest that breeding does not improve biomass’s water-use efficiency, but causes changes in biomass allocation strategy, and this could be a new direction for genetically improving grain yield.

Nitrogen and potassium in biomass production and water use efficiency of irrigated wheat cv. BRS 394 in Cerrado

The objective of this study was to evaluate the influence of nitrogen and potassium levels in biomass production and efficiency in water consumption of wheat BRS 394 in brazilian Cerrado. The experiment consisted of fractioned factorial combination of five levels of (N): (0, 70, 140, 210 and 280 kg ha−1) and five levels of potassium (K): (0, 50, 100, 150 and 200 kg ha−1), randomized block design and four replications. The shoot biomass, the number of spikelets per ear and the efficiency of water use for biomass production were evaluated as a function of the N and K levels used in the present study. Analysis of variance at 5% and 10% was performed using F test for the surface response model and when not significant to the first and second degree regression using the R software. The combination of N(238 kg ha−1) and K(97 kg ha−1) increased spikelet yield per spike (15.5), during 2019 harvest. The fertilization with N(115 and 125 kg ha−1) in an isolated way guaranteed maximum shoot biomass yield(5827 kg ha−1) and wheat water use efficiency (32.9 g L−1), during 2018 harvest, respectively. The N provided isolated increases in number of spikelets per spike in 2018 harvest, as well as for shoot biomass and water use efficiency in 2019. The main use of nitrogen fertilization and its combination with potassium provide gains in the production of shoot biomass and water use efficiency of wheat BRS 394 in brazilian Cerrado.

Plant Architecture Influences the Population Transpiration and Canopy Temperature in Winter Wheat Genotypes

To study how plant architecture affects the canopy traits and water use of wheat, the Triticum aestivum L. population is expected to provide important information for cultivar improvement and the ideal population structure establishment for conserving water without causing an enormous grain yield loss. This study was conducted for three consecutive growing seasons using two genotypes with contrasting plant architectures as the materials, the upright-leafed compact type Jing 411 and the flat-leafed loose type Jinmai 47. The population-scale transpiration (PT) and soil evaporation (E) were partitioned from the evapotranspiration (ET) using micro-lysimeters, and the canopy traits population density and the canopy temperature depression (CTD) were also monitored during the period from the jointing to early grain filling stage—the largest water requirement period of wheat crops. Jinmai 47 showed a lower E than Jing 411, but a similar PT and ET, though it had a higher population density at the sowing density. The total evapotranspiration (TET) for the whole growing season was also similar in the two genotypes. This indicated that Jinmai 47 performed better in water conservation than Jing 411. With a similar PT and TET, however, Jinmai 47 showed a rather larger CTD and a significantly higher grain yield than Jing 411. If the higher population density and higher leaf net photosynthetic rate could explain its higher grain yield, the higher leaf stomotal conductance and transpiration rate and the higher population density could not explain the similar PT, ET and TET to Jing 411. Presumably, the involvement of the plant architecture disrupted the original higher transpiration–larger CTD relation, and broke up the prevailing saving water-losing yield concept. Thus, the study might suggest the important water saving value of the flat-leafed loose architecture in wheat crops and demonstrate the possibility of conserving irrigation water without causing serious grain yield loss by taking advantage of the distinct plant architecture to establish an appropriate population structure.

Moisture- and period-dependent interactive effects of plant growth-promoting rhizobacteria and AM fungus on water use and yield formation in dryland wheat

PurposeIn drought-prone soils, plant growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungus (AMF) might positively affect water uptake and crop yield via rhizosphere interactions.MethodsSole and combined additions of Bacillus amyloliquefaciens producing 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase and Rhizophagus irregularis into rhizospheric soils were performed under well-watered (WW; 80% field water capacity), moderate water stress (MWS; 50% FWC) and severe water stress (SWS; 35% FWC) in pot-cultured wheat (Triticum aestivum L.).ResultsIn moderate and severe drought stress, water use efficiency (WUEB) was increased by 27.9–34.3% in PGPR and 20–22.1% in AMF treatments, respectively, and grain yield was improved by 20.03–30.77% in PGPR and 12.13–34.34% in AMF treatments, respectively, compared with control (CK). Importantly, the co-inoculation of AMF and PGPR significantly promoted WUEB by 11.12–27.77% and grain yield by 18.26–21.68% compared to the average value of two sole inoculations in MWS and SWS treatments, respectively. WUEY and biomass production followed a similar trend as WUEB and yield. Particularly, the above parameters were significantly enhanced with the prolonged developmental stages (p < 0.05). ACC deaminase significantly reduced ACC accumulation in MWS and SWS, enhanced AMF root colonization, and promoted rhizosphere microbial biomass carbon and nitrogen levels across all three developing stages. Furthermore, AMF-PGPR co-inoculation enhanced chlorophyll and carotenoid contents during anthesis while reducing them during pre-harvesting. Enhanced water uptake and root activities upsurged photosynthetic traits throughout the growing season.ConclusionAMF-PGPR co-inoculation acted as a promising solution to cope with the droughted environment via root activities for stronger water capture.

Development of an irrigation regime for winter wheat to save water resources by avoiding irrigation at anthesis stage

AbstractLatest published information is limited on agronomic responses of winter wheat to irrigation quantity and the necessity of irrigation at the anthesis stage. This study was conducted to (1) evaluate winter wheat yield, water use, assimilate redistribution and economic benefit with respect to water input and (2) quantify relationship between water input and yield to develop a standard for withholding irrigation at anthesis. A 4‐year long field experiment was conducted to evaluate winter wheat water use, yield formation pathway and farmers' income under three irrigation regimes: rainfed, irrigation at sowing and jointing (SJ‐W) and irrigation at sowing, jointing and anthesis (SJA‐W). The yield formation pathway was correlated with the water‐induced variation in assimilate redistribution and accumulation. Throughout the experimental period, wheat yield was 19–38% lower in rainfed than that under other irrigation treatments. Moreover, SJ‐W treatment substantially increased biomass accumulation at anthesis, accelerated assimilate redistribution in vegetative organs and eventually resulted in a similar wheat yield to that of SJA‐W. Simultaneously, the SJ‐W treatment had lower irrigation water, reduced additional irrigation cost, suppressed yield loss and obtained a similar farmer's net income to the SJA‐W treatment. Water‐induced variations in yield were determined by irrigation, rainfall and soil water storage. SJ‐W plots receiving 204–331 mm water input (rainfall + irrigation) before anthesis and holding 549–587 mm soil water during anthesis stage achieved higher irrigation water use efficiency and yield relative to the rainfed and SJA‐W plots. In contrast, water input under rainfed plots exceeded 200 mm before anthesis, limiting yield substantially even when seasonal soil water consumption exceeded 160 mm. Developing a standard for withholding irrigation at the anthesis stage should incorporate 204–331 mm of water input (rainfall + irrigation) before anthesis and 549–587 mm soil water storage at anthesis, which could achieve a high wheat yield and save water resources.

Seeding and NP Fertilizer Rates’ Effect on Irrigated Wheat Yield and Water Use Efficiency in Midland Tropical Environment

Seeding and NP Fertilizer Rates’ Effect on Irrigated Wheat Yield and Water Use Efficiency in Midland Tropical Environment

Productivity and water use in forage-winter wheat cropping systems across variable precipitation gradients on the Loess Plateau of China

Fallow-winter wheat (Triticum aestivum L.) (F-W) is the major cropping system for wheat production on the Loess Plateau of China. Integrating forage crops into the summer fallow season could improve crop yield, water productivity, and rainwater use efficiency, but this process is limited by the inter- and intra- annual variable precipitation. A 3-year (2016–2019) field experiment was conducted on the Loess Plateau to investigate the effects of fallow-winter wheat, oat (Avena sativa)-winter wheat (O-W), soybean (Glycine max)-winter wheat (S-W), and vetch (Vicia sativa)-winter wheat (V-W) systems on dry matter yield, water use, water productivity, and precipitation use efficiency under three interannual rainfall scenarios: a 30% decrease in rainfall (R-30%), normal rainfall (CK), and a 30% increase in rainfall (R+30%) by a rainfall-collection-redistribution device. In 2017–2018, under the CK scenario, the F-W, O-W, S-W, and V-W system wheat yields were 3.39, 3.63, 4.30, and 3.24 t ha−1, respectively, and the system yield values were 11.28, 16.72, 16.40, and 14.27 t ha−1, respectively. Compared to the CK scenario, the F-W, O-W, S-W, and V-W system yields increased by 22.9%, 34.5%, 20.4%, and 33.8% in 2016–2017 under the R+ 30% scenario, but the system water productivity decreased by 19.9%, 41.8%, 19.6%, and 32.4% in 2017–2018 under the R-30% scenario. Compared to those of the F-W system, the O-W, S-W, and V-W system yields significantly increased by 48.2%, 45.4%, and 26.5%, respectively, and the system water productivity increased by 51.5%, 47.3%, and 25.17%, respectively, in 2017–2018 under the CK scenario. The system precipitation use efficiency also increased by 29.3%, 42.9%, and 28.9% in 2018–2019 under the R+ 30% scenario. Across the three growing seasons, the F-W system had the highest wheat yield in the dry growing season. The S-W system had the highest dry matter yield, water productivity, and precipitation use efficiency in the normal and wet growing seasons. Therefore, we recommend the F-W system for local farmers when considering saving more soil water and maintaining wheat yield in the dry growing season. In normal and wet growing seasons, we recommend the S-W system for local farmers considering that the system increases productivity and improves environmental sustainability.

Climate Change Effect on Irrigation Water Requirement of Wheat and Maize in Northern Part of Bangladesh

Bangladesh is one of the most vulnerable countries for climate change in agricultural water management. A research had been done to assess climate change effects on irrigation water use of wheat and maize in the northern part of Bangladesh. The twenty nine years of data (1990-2018) were analyzed with Mann-Kendall test as well as Sen’s slope for climate change impact and the responsible weather parameters due to climate change were identified with correlation coefficients. The crop water requirement of wheat in Bogura and Rangpur was declining at the rate of 3.3mm and 2.3mm per decade respectively. Net irrigation water requirement of wheat at both Bogura and Rangpur was inclining at the rate of 1mm and 10mm per decade respectively because the effective rainfall of these regions was decreasing at 5mm and 11mm per decade respectively. The crop water requirement of maize for similar districts was increasing at the rate of 3.2mm and 2.5mm per decade respectively although net irrigation water requirement had statistically non-significance for climate change effect. The weather parameter, which was mainly responsible for climatic change in irrigation water requirement, was increasing temperature. Therefore, wheat cultivation might be coped with climate change in the northern part of Bangladesh rather than maize on the basis of irrigation and water management.

Short- and Long-Term Straw Mulching and Subsoiling Affect Soil Water, Photosynthesis, and Water Use of Wheat and Maize

Water shortages and rainfall variability lead to a decrease in grain yield. Straw mulching (SM), subsoiling (S), and combined amendments (subsoiling + straw mulching, SS) are potential solutions for maintaining crop productivity and water resource sustainability. However, short- and long-term applications of these methods appear to result in different yield and water use efficiency outcomes. In this study, we, therefore, compared short- and long-term applications of SM, S, and SS, with a control. We analyzed field experimental data of wheat and maize cultivation with control (conventional tillage), SM, S, and SS treatments to assess the impact on yield and water use efficiency, resulting from short- and long-term applications of these practices. The results show that SS treatment led to higher soil water storage (SWS) compared with other treatments during the regreening, jointing, and booting stages of wheat, and the big bellmouth and filling stages of maize in the short- and long-term experiments. However, long-term SS treatment also led to higher SWS in the growth stage of wheat in 2015–2016 and in the growth stage of maize in 2015. Additionally, SS treatment was conducive to raising the net photosynthetic rate (Pn) and leaf water use efficiency (LWUE) of wheat compared with other treatments in 2015 and 2016. Conversely, Pn and LWUE of maize under S and SS treatments were higher (P &amp;lt; 0.05) compared with other treatments in the two studied years. Short-term treatment led to higher wheat yield compared with long term in 2014–2015 (ample rainfall) and of maize in 2016 (low rainfall). The yield of wheat under long-term S treatment in 2015 was 9625.-kg hm−2, which was the highest (P &amp;lt; 0.05) in 2 years, with a 17.7% increase compared with the control, followed by short-term S treatment. However, the water use efficiency (WUE) of wheat under long-term SS treatment in 2016 was the highest (P &amp;lt; 0.05) compared with other treatments. The yield of maize under SM and S treatments was higher than other treatments, whereas the WUE of maize under long-term SS treatment in 2016 was still the highest (P &amp;lt; 0.05). Our findings provide evidence that S and SS treatments improve both crop productivity and water resource sustainability, and long-term application resulted in higher productivity than short-term application.

Quantitative response of wheat to sowing dates and irrigation regimes using CERES-Wheat model.

An experiment was conducted at Punjab Agricultural University, Ludhiana during 2014–15 and 2015–16, keeping four sowing dates {25th Oct (D1), 10th Nov (D2), 25th Nov (D3) and 10th Dec (D4)} in main plots and five irrigation schedules {irrigation at 15 (FC15), 25 (FC25), 35 (FC35) and 45 (FC45) % depletion of soil moisture from field capacity (FC) and a conventional practice} in sub plots. The objective of the study was to evaluate the performance of CERES-Wheat model for simulating yield and water use under varying planting and soil moisture regimes. The simulated and observed grain yield was higher in D1, with irrigation applied at FC15 as compared to all other sowing date and irrigation regime combinations. Simulated grain yield decreased by 19% with delay in sowing from 25th October to 10th December because of 8% reduction in simulated crop evapotranspiration. Simulated evapotranspiration decreased by 16%, wheat grain yield by 23% and water productivity by 15% in drip irrigation at 45% depletion from field capacity as compared to drip irrigation at 15% of field capacity. It was further revealed that the model performed well in simulating the phenology, water use and yield of wheat.

Growth and Yield Performance of Selected Wheat Genotypes at Variable Irrigation Management

Growth and Yield Performance of Selected Wheat Genotypes at Variable Irrigation Management

Improving estimation of in-season crop water use and health of wheat genotypes on sodic soils using spatial interpolation techniques and multi-component metrics

Crop water use can be a useful indicator of in-season crop conditions including health and greenness on sodic soils. However, in-field manual measurements of crop water use can be tedious, time and labour-intensive and may also exhibit large spatial variability, and inefficient for surveying large areas. Here we propose a novel approach to estimate in-field crop water use of wheat using spatial interpolation techniques at critical crop development stages (tillering and close to flowering) on a moderately sodic and a highly sodic site in southern Queensland, Australia. The six spatial interpolation techniques; ordinary kriging, empirical Bayes kriging, inverse distance weighting, spline, local polynomial interpolation, and radial basis function were employed on ground-measured crop water use data and compared to accurately estimate the spatial distribution of crop water use. Initially, the comparison was made using root mean square error, mean absolute error, and coefficient of determination values using cross-validation. For a more clear comparison and to account for complexities of site-specific crop water use distribution, the standardized, multi-component model performance efficiency metrics, i.e. Kling-Gupta efficiency and spatial efficiency were adopted and tested over cross-validation techniques. Results showed that Kling-Gupta efficiency was slightly better at selecting the optimum interpolation models for crop water use estimation at a field scale than the spatial efficiency metric. Spline and local polynomial interpolation were relatively better estimators of crop water use for both the sites at tillering, while the radial basis function and spline were superior close to flowering. The estimated crop water use was positively and closely associated with seasonal GreenSeeker® normalized difference vegetation index data (R2 = 0.49 and 0.39 at tillering; and R2 = 0.71 and 0.62 at close to flowering, for the moderately sodic and highly sodic sites, respectively). The research improves our understanding of selecting appropriate spatial interpolation methods for in-season crop water use estimation that could help detect changes in crop health due to in-field and seasonal variations of crop water use in a sodic soil environment.

Cover‐crop water use and productivity in the high plains wheat–fallow crop rotation

AbstractA long fallow period (∼15 mo) in a winter wheat (Triticum aestivum L.)–fallow rotation (W‐F) cropping system is meant to store soil water for the following crop but loss of soil quality, low precipitation use‐efficiency, and increased cost of fallow management are among its drawbacks. Replacing a portion of the fallow period with a short‐season cover crop may alleviate these drawbacks. The objectives of this study were to evaluate available soil water at planting (ASWPcc), performance, management, and post‐cover‐crop fallow efficiency, and available soil water at winter wheat planting (ASWPww) of 12 short‐season cover crops. This field study was conducted from 2008 through 2011 at Garden City, KS. The experimental design was a randomized complete block with split‐split‐plot arrangement. Crop phases were main plot, cover‐crop species was the subplot, and cover‐crop management method (cover crop left standing or hayed) was the split‐split‐plot treatment. Results showed ASWPcc was greater at spring cover‐crop planting than in the fall or winter cover crops. However, water use, productivity, and post‐cover‐crop fallow efficiency were greatest for sole winter triticale (×Triticosecale spp.) or winter legume–triticale mixtures. In addition, ASWPww was 4–27% more for cover crop left standing than hayed cover crops. Post‐cover‐crop precipitation storage was positively related to ASWPww but cover‐crop biomass had a negative linear relationship with ASWPww. We concluded that cover crops left standing stored more soil water than those hayed; however, forage use of the cover crop could provide a dual purpose and economic benefit to improve overall system profitability.

Climate change impact on yields and water use of wheat and maize in the North China Plain under future climate change scenarios

Climate change has already and will continue to exert a vital impact on crop yield and water use in the North China Plain (NCP). Currently, this plain is facing a dilemma between groundwater depletion and grain production demand. It is urgent to identify the impact of future climate change on crop yield and water consumption and then develop efficient adaptation strategies in the region. In this study, we used statistically downscaled daily climate data from 33 global climate models (GCMs) and two Representative Concentration Pathways (RCP4.5 and RCP8.5) for 61 stations distributed across the NCP and drove the well-validated APSIM model to simulate crop yield and water use for two future periods of 2031–2060 (2040s) and 2071–2100 (2080s). Data from all 33 GCMs show an increase in annual mean temperature and almost all the GCMs also show increases in annual mean solar radiation and annual total precipitation across the NCP. Future climate warming led to an advance in phenology for both winter wheat and summer maize, two typical crops in the NCP. However, the length of the reproductive growth period (RGP) of winter wheat was prolonged while that of summer maize was shortened under future climate scenarios across the NCP. Our simulated results show that future climate change had negative impacts on maize yield but positive impacts on wheat yield across the NCP. Mainly due to the shortening of the whole growth period, crop water consumption was largely decreased under future climate scenarios. The amount of irrigation required was also reduced mainly due to increased precipitation and decreased ET. Although future climate change would likely mitigate groundwater overdraft in most part of NCP, some areas in the northern NCP still had groundwater over-pumping in the future. Therefore, we suggest that it might be a good choice to change cropping system for reducing planting area of water-consuming crop (e.g. winter wheat) in those over-pumping areas to balance groundwater use and crop yield.

Effects of plastic film mulching on soil water use efficiency and wheat yield in the Loess Plateau of China

Increasing water use efficiency is indispensable for attaining high yields and achieving sustainable development in arid and semiarid areas. A two-year field experiment was conducted to explore the effects of plastic film mulching on soil water storage, consumption, water use efficiency, and wheat yield. Three treatments, including no fertilizer or mulching (CK), chemical fertilizer (F) and combined chemical fertilizer and plastic film mulching (FM), were applied. The results showed that compared with CK and F, FM increased soil water storage in the 0–200 cm layer by 0.90–1.35% and 0.57–1.23% in 2016–2017 and 2017–2018, respectively. In addition, mulching was conducive to increasing soil water storage in the 0–100 cm soil layer, especially in the 0–40 cm soil layer, while reducing water storage in the deeper soil layers. Furthermore, in the normal year, mulching could reduce soil water consumption and increase the rainfall utilization ratio. In addition, mulching increased wheat yield and water use efficiency.