Water

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11 pages, 1551 KiB

Open AccessArticle

Monitoring of Soil Water Content in Maize Rotated with Pigeonpea Fallows in South Africa

by Misheck Musokwa, Paramu L. Mafongoya and Paxie W. Chirwa

Water 2020, 12(10), 2761; https://doi.org/10.3390/w12102761 - 4 Oct 2020

Cited by 7 | Viewed by 2235

Maize production under smallholder systems in South Africa (RSA) depends on rainfall. Incidences of dry spells throughout the growing season have affected maize yields negatively. The study examined water distribution and water use efficiency (WUE) of maize rotated with two-year pigeonpea fallows as [...] Read more.

Maize production under smallholder systems in South Africa (RSA) depends on rainfall. Incidences of dry spells throughout the growing season have affected maize yields negatively. The study examined water distribution and water use efficiency (WUE) of maize rotated with two-year pigeonpea fallows as compared to continuous maize without fertilizer. A randomized complete block design, replicated three times, was used with four treatments, which included continuous unfertilized maize, natural fallow-maize, pigeonpea + grass-pigeonpea-maize, and two-year pigeonpea fallow-maize. Soil water mark sensors were installed 0.2; 0.5; and 1.2 m on each plot to monitor soil water tension (kPa). Soil samples were analyzed using pressure plates to determine water retention curves which were used to convert soil water tension to volumetric water content. Maize rotated with two-year pigeonpea fallows had higher dry matter yield (11,661 kg ha⁻¹) and WUE (20.78 kg mm⁻¹) than continuous maize (5314 kg ha⁻¹ and 9.48 kg mm⁻¹). In this era of water scarcity and drought incidences caused by climate change, maize rotated with pigeonpea fallows is recommended among smallholder farmers in RSA because of its higher WUE, hence food security will be guaranteed. Full article

(This article belongs to the Special Issue Agriculture Water Management and Water Saving Strategies)

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10 pages, 5869 KiB

Open AccessArticle

Moving beyond the Mirage: Water Scarcity and Agricultural Use Inefficiency in USA

by Jenny Kehl

Water 2020, 12(8), 2290; https://doi.org/10.3390/w12082290 - 14 Aug 2020

Cited by 15 | Viewed by 6810

Abstract

The purpose of this article is to examine water scarcity and food security in the United States, the world’s largest grain producer, and to provide empirical evidence that high volumes of water-intensive crops are grown in water-scarce regions. The primary methodology is to [...] Read more.

The purpose of this article is to examine water scarcity and food security in the United States, the world’s largest grain producer, and to provide empirical evidence that high volumes of water-intensive crops are grown in water-scarce regions. The primary methodology is to analyze data using Geographic Information System (GIS) and to visually represent the results through statistical mapping of water stress overlaid with the amount of production of different commodities. The article concludes by discussing strategies to restructure agriculture to improve water efficiency and to maintain regional agricultural economies that depend on the sustainability of water resources. Full article

(This article belongs to the Special Issue Agriculture Water Management and Water Saving Strategies)

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24 pages, 8076 KiB

Open AccessArticle

Identifying Optimal Sites for a Rainwater-Harvesting Agricultural Scheme in Iran Using the Best-Worst Method and Fuzzy Logic in a GIS-Based Decision Support System

by Kamaleddin Aghaloo and Yie-Ru Chiu

Water 2020, 12(7), 1913; https://doi.org/10.3390/w12071913 - 4 Jul 2020

Cited by 27 | Viewed by 4900

Abstract

Rainwater-harvesting (RWH) agriculture has been accepted as an effective approach to easing the overexploitation of groundwater and the associated socioeconomic impacts in arid and semiarid areas. However, the stability and reliability of the traditional methods for selecting optimal sites for RWH agriculture need [...] Read more.

Rainwater-harvesting (RWH) agriculture has been accepted as an effective approach to easing the overexploitation of groundwater and the associated socioeconomic impacts in arid and semiarid areas. However, the stability and reliability of the traditional methods for selecting optimal sites for RWH agriculture need to be further enhanced. Based on a case study in Tehran Province, Iran, this study proposed a new decision support system (DSS) that incorporates the Best-Worst Method (BWM) and Fuzzy logic into a geographic information system (GIS) environment. The probabilistic analysis of the rainfall pattern using Monte Carlo simulation was conducted and adopted in the DSS. The results have been demonstrated using suitability maps based on three types of RWH systems, i.e., pans and ponds, percolation tanks, and check dams. Compared with traditional methods, the sensitivity analysis has verified that the proposed DSS is more stable and reliable than the traditional methods. Based on the results, a phase-wise strategy that shifts the current unsustainable agriculture to a new paradigm based on RWH agriculture has been discussed. Therefore, this DSS has enhanced the information value and thus can be accepted as a useful tool to ease the dilemma resulting from unsustainable agriculture in arid and semiarid areas. Full article

(This article belongs to the Special Issue Agriculture Water Management and Water Saving Strategies)

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20 pages, 6853 KiB

Open AccessFeature PaperArticle

Remote-Sensing-Based Water Balance for Monitoring of Evapotranspiration and Water Stress of a Mediterranean Oak–Grass Savanna

by Elisabet Carpintero, Ana Andreu, Pedro J. Gómez-Giráldez, Ángel Blázquez and María P. González-Dugo

Water 2020, 12(5), 1418; https://doi.org/10.3390/w12051418 - 16 May 2020

Cited by 14 | Viewed by 3670

Abstract

Mediterranean oak savannas (known as dehesas in Spain) are exposed to numerous threats from natural and economic causes. A close monitoring of the use of water resources and the status of the vegetation in these ecosystems can be useful tools for maintaining the [...] Read more.

Mediterranean oak savannas (known as dehesas in Spain) are exposed to numerous threats from natural and economic causes. A close monitoring of the use of water resources and the status of the vegetation in these ecosystems can be useful tools for maintaining the production of ecological services. This study explores the estimation of evapotranspiration (ET) and water stress over a dehesa by integrating remotely sensed data into a water balance using the FAO-56 approach (VI-ET_o model). Special attention is paid to the different phenology and contribution to the system’s hydrology of the two main canopy layers of the system (tree + grass). The results showed that the model accurately reproduced the dynamics of the water consumed by the vegetation, with RMSE of 0.47 mm day⁻¹ and low biases for both, the whole system and the grass layer, when compared with flux tower measurements. The ET/ET_o ratio helped to identify periods of water stress, confirmed for the grassland by measured soil water content. The modeling scheme and Sentinel-2 temporal resolution allowed the reproduction of fast and isolated ET pulses, important for understanding the hydrologic behavior of the system, confirming the adequacy of this sensor for monitoring grasslands water dynamics. Full article

(This article belongs to the Special Issue Agriculture Water Management and Water Saving Strategies)

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23 pages, 3143 KiB

Open AccessArticle

Modeling Soil Water–Heat Dynamic Changes in Seed-Maize Fields under Film Mulching and Deficit Irrigation Conditions

by Yin Zhao, Xiaomin Mao, Manoj K. Shukla and Sien Li

Water 2020, 12(5), 1330; https://doi.org/10.3390/w12051330 - 8 May 2020

Cited by 16 | Viewed by 2880

Abstract

The Soil–Water–Atmosphere–Plant (SWAP) model does not have a mulching module to simulate the effect of film mulching on soil water, heat dynamics and crop growth. In this study, SWAP model parameters were selected to simulate the soil water–heat process and crop growth, taking [...] Read more.

The Soil–Water–Atmosphere–Plant (SWAP) model does not have a mulching module to simulate the effect of film mulching on soil water, heat dynamics and crop growth. In this study, SWAP model parameters were selected to simulate the soil water–heat process and crop growth, taking into account the effect of film mulching on soil evaporation, temperature, and crop growth, in order to predict the influence of future climate change on crop growth and evapotranspiration (ET). A most suitable scheme for high yield and water use efficiency (WUE) was studied by an experiment conducted in the Shiyang River Basin of Northwest China during 2017 and 2018. The experiment included mulching (M1) and non-mulching (M0) under three drip irrigation treatments, including full (WF), medium (WM), low (WL) water irrigation. Results demonstrated that SWAP simulated soil water storage (SWS) well, soil temperature at various depths, leaf area index (LAI) and aboveground dry biomass (ADB) with the normalized root mean square error (NRMSE) of 16.2%, 7.5%, 16.1% and 16.4%, respectively; and yield, ET, and WUE with the mean relative error (MRE) of 10.5%, 12.4% and 14.8%, respectively, under different treatments on average. The measured and simulated results showed film mulching could increase soil temperature, promote LAI during the early growth period, and ultimately improve ADB, yield and WUE. Among the treatments, M1WM treatment with moderate water deficit and film mulching could achieve the target of more WUE, higher yield, less irrigation water. Changes in atmospheric temperature, precipitation, and CO₂ concentration are of worldwide concern. Three Representative Concentration Pathway (RCP) scenarios (RCP2.6, RCP4.5, RCP8.5) showed a negative effect on LAI, ADB and yield of seed-maize. The yield of seed-maize on an average decreased by 33.2%, 13.9% under the three RCPs scenarios for film mulching and non-mulching, respectively. Predicted yields under film mulching were lower than that under non-mulching for the next 30 years demonstrating that current film mulching management might not be suitable for this area to improve crop production under the future climate scenarios. Full article

(This article belongs to the Special Issue Agriculture Water Management and Water Saving Strategies)

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13 pages, 1802 KiB

Open AccessArticle

Vegetable Crops Grown under High Soil Water Availability in Mediterranean Greenhouses

by Santiago Bonachela, Alicia M. González, María D. Fernández and Francisco J. Cabrera-Corral

Water 2020, 12(4), 1110; https://doi.org/10.3390/w12041110 - 14 Apr 2020

Cited by 4 | Viewed by 2105

Abstract

The soil water availability of six vegetable crop cycles, irrigated with water of 0.4 dS m⁻¹ electrical conductivity, was modified by varying the irrigation frequency in typical Mediterranean greenhouses at SE Spain. The soil matric water potential (SMP) in the middle of [...] Read more.

The soil water availability of six vegetable crop cycles, irrigated with water of 0.4 dS m⁻¹ electrical conductivity, was modified by varying the irrigation frequency in typical Mediterranean greenhouses at SE Spain. The soil matric water potential (SMP) in the middle of the loamy soil layer where most roots usually grow was maintained between −10 and −20 kPa (H), −20 and −30 kPa (C), and −30 and −50 kPa (L) for the crops grown under high, conventional and low soil water availability, respectively, while the total irrigation water applied was similar for the three treatments. The high soil water availability (H) did not improve the fresh weight of total, marketable and first class fruits, or the shoot biomass and partitioning. The irrigation frequency did not affect the total root biomass at the end of the autumn–winter cucumber, but the crop under L distributed its root biomass more homogenously throughout the soil profile than the crop under H. Regulating the soil water availability (maintaining the SMP higher than or close to the level at which crop water stress may occur) over the cycle as a function of crop conditions or farmers’ requirements appears to be a useful management practice for controlling soil root distribution or shoot partitioning. Full article

(This article belongs to the Special Issue Agriculture Water Management and Water Saving Strategies)

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13 pages, 2669 KiB

Open AccessArticle

Water Conservation Methods and Cropping Systems for Increased Productivity and Economic Resilience in Burkina Faso

by Hamidou Traoré, Albert Barro, Djibril Yonli, Zachary Stewart and Vara Prasad

Water 2020, 12(4), 976; https://doi.org/10.3390/w12040976 - 30 Mar 2020

Cited by 9 | Viewed by 4077

Abstract

Resilience of smallholder farmers in their ability to bounce-back and overcome shocks, such as drought, is critical to ensure a pathway out of hunger and poverty. Efficient water conservation methods that increase rainwater capture and reduce soil erosion such as stone lines and [...] Read more.

Resilience of smallholder farmers in their ability to bounce-back and overcome shocks, such as drought, is critical to ensure a pathway out of hunger and poverty. Efficient water conservation methods that increase rainwater capture and reduce soil erosion such as stone lines and grass bands are two technologies that have been proposed to increase the resilience in Sudano–Sahelian farming systems. In Burkina Faso, we show that stone lines, grass bands, and crop rotation are effective resilience strategies individually and in combination. During years when rainfall is well-distributed over time, differences are minimal between fields with water conservation methods and fields without. However, when there are periods of prolonged drought, water conservation methods are effective for increasing soil water, yield, revenue, and resilience. During drought conditions, sorghum (Sorghum bicolor (L.) Moench) grain yield and revenue with stone lines and grass bands were over 50% greater than that of the control, by an average of 450 kg ha⁻¹, which amounted to an increase of 58,500 West African CFA franc (CFA) ha⁻¹ (i.e., 98 USD ha⁻¹). The results also suggest that the combination of water conservation method and crop rotation additionally improves cropping system productivity and revenue. Growing cowpea (Vigna unguiculata (L.) Walp.) in rotation with sorghum production provided more options for farmers to increase their income and access to nutrition. This study also sheds light on the limited productivity gains due to improved crop varieties. The local sorghum landrace, Nongomsoba, and the local cowpea variety in rotation resulted in the highest yields as compared to the improved varieties of Sariaso 14 sorghum and KVX 396-4-4 cowpea. Under similar low input/degraded conditions, improved crop varieties likely are not a suitable resilience strategy alone. We conclude that during erratic rainy seasons with frequent periods of drought (i.e., water stress) in rain-fed conditions in Burkina Faso, stone lines or grass bands in combination with sorghum and cowpea rotation are effective practices for increasing resilience of smallholder farmers to maintain crop productivity and revenue. With future and present increases in climate variability due to climate change, stone lines, grass bands, and crop rotation will have growing importance as resilience strategies to buffer crop productivity and revenue during periods of drought. Full article

(This article belongs to the Special Issue Agriculture Water Management and Water Saving Strategies)

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18 pages, 1628 KiB

Open AccessArticle

Evaluation of Hydroclimatic Variability and Prospective Irrigation Strategies in the U.S. Corn Belt

by María Elena Orduña Alegría, Niels Schütze and Dev Niyogi

Water 2019, 11(12), 2447; https://doi.org/10.3390/w11122447 - 21 Nov 2019

Cited by 11 | Viewed by 3697

Abstract

Changes in climate, land use, and population growth has put immense pressure on the use of water resources in agriculture. Non-irrigated fields suffer from variable water stress, leading to an increase in the implementation of irrigation technologies, thus stressing the need to analyze [...] Read more.

Changes in climate, land use, and population growth has put immense pressure on the use of water resources in agriculture. Non-irrigated fields suffer from variable water stress, leading to an increase in the implementation of irrigation technologies, thus stressing the need to analyze diverse irrigation practices. An evaluation of 17 sites in the U.S. Corn Belt for two temporal climatic conditions was carried out. It consisted of the analysis of critical hydroclimatic parameters, and the evaluation of seven diverse irrigation strategies using the Deficit Irrigation Toolbox. The strategies included rainfed, full irrigation, and several optimizations of deficit irrigation. The results show a significant change in the hydroclimatic parameters mainly by increased temperature and potential evapotranspiration, and a decrease in precipitation with an increase in intense short rainfall events. Consequently, the simulations indicated the potential of deficit irrigation optimization strategies to increase water productivity above full irrigation and rainfed conditions. In particular, GET-OPTIS for wet soil conditions and the Decision Tables for dry soil conditions seasons. The present study highlights the contributions of atypical weather to crop production and the implications for future management options, and allows specialized regionalization studies with the optimal irrigation strategy. Full article

(This article belongs to the Special Issue Agriculture Water Management and Water Saving Strategies)

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18 pages, 1436 KiB

Open AccessEditor’s ChoiceArticle

Irrigation-Advisor—A Decision Support System for Irrigation of Vegetable Crops

by José M. Mirás-Avalos, José S. Rubio-Asensio, Juan M. Ramírez-Cuesta, José F. Maestre-Valero and Diego S. Intrigliolo

Water 2019, 11(11), 2245; https://doi.org/10.3390/w11112245 - 26 Oct 2019

Cited by 21 | Viewed by 4934

Abstract

Climate change will intensify water scarcity, and therefore irrigation must be adapted to save water. Operational tools that provide watering recommendations to end-users are needed. This work presents a new tool, Irrigation-Advisor (IA), which is based on weather forecasts and is able to [...] Read more.

Climate change will intensify water scarcity, and therefore irrigation must be adapted to save water. Operational tools that provide watering recommendations to end-users are needed. This work presents a new tool, Irrigation-Advisor (IA), which is based on weather forecasts and is able to separately determine soil evaporation and crop transpiration, and thus is adaptable to a broad range of agricultural situations. By calculating several statistical indicators, IA was tested against the FAO-56 crop evapotranspiration (ET_cFAO) methodology using local crop coefficients. Additionally, IA recommendations were compared with current standard practices by experienced farmers (F). Six field experiments with four widely cultivated species (endive, lettuce, muskmelon and potato) were performed in Southeast Spain. Irrigation water applied, crop yield, aboveground biomass and water productivity were determined. Crop water needs underestimations (5%–20%) were detected when comparing IA against ET_cFAO, although the index of agreement proved reasonable adjustments. The IA recommendations led to water savings up to 13% when compared to F, except for lettuce, with a 31% surplus in irrigation when using IA. Crop yield was not compromised and water productivity was increased by IA. Therefore, IA mimicked the farmers′ irrigation strategies fairly well without deploying sensors on-site. Nevertheless, improvements are needed for increasing the accuracy of IA estimations. Full article

(This article belongs to the Special Issue Agriculture Water Management and Water Saving Strategies)

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24 pages, 7132 KiB

Open AccessArticle

Detecting the Response of Irrigation Water Management to Climate by Remote Sensing Monitoring of Evapotranspiration

by Fatima-Ezzahra El Ghandour, Silvia Maria Alfieri, Youssef Houali, Adnane Habib, Nadia Akdim, Kamal Labbassi and Massimo Menenti

Water 2019, 11(10), 2045; https://doi.org/10.3390/w11102045 - 30 Sep 2019

Cited by 5 | Viewed by 3711

Abstract

This study on a large irrigation scheme in Morocco addressed a two-fold question: (a) does the local water management authority adapt water releases to atmospheric water demand ET₀-P? and (b) does crop actual evapotranspiration respond to inter- and intra-annual variability in [...] Read more.

This study on a large irrigation scheme in Morocco addressed a two-fold question: (a) does the local water management authority adapt water releases to atmospheric water demand ET₀-P? and (b) does crop actual evapotranspiration respond to inter- and intra-annual variability in water releases? We have evaluated the inter-annual variability of ET₀-P during the period 1992–2017 and compared its anomalies (i.e., deviations from average) with anomalies in annual water release. Overall, it appeared that anomalies in water release were consistent with anomalies in ET₀-P. The actual evapotranspiration (ET_a) was estimated using a time series of multi-spectral satellite image data by applying the Surface Energy Balance (SEBAL) algorithm in a dry, wet, and reference year. We have determined the quartiles of the distribution of the ET₀-P time series to identify these three years. The dry year was 2015–2016, the wet year was 2014–2015, and the reference (median of ET₀-P) was 2013–2014. Finally, we compared seasonal and annual anomalies in ET₀-P, ET_a and release, W_d of irrigation water. In the period 1992–2017, the relative anomalies in ET₀-P and W_d were similar only in 2000–2001 and 2015–2016. The analysis of anomalies in water inflow and stocks confirmed the response in increased W_d following wet years with higher inflow and replenishment of the reservoir. The response of crop water use to the irrigation water supply was evaluated by comparing anomalies in the ratio of actual to maximum ET, i.e., ET_a/ET_c with anomalies in W_d. As regards the Sidi Bennour, Faregh, and Gharbia districts, the relative anomalies in ET_a/ET_c and W_d were consistent, i.e., they had the same sign and comparable magnitude. Overall, the study shows that water delivery W_d responds to inter-annual variability in the pre-irrigation season water inflows into the reservoirs, rather than in ET₀-P. On the other hand, actual crop water use, i.e., ET_a/ET_c, does respond to inter- and intra-annual variability in W_d. This evidence suggests that there is scope for adaptive water management based on a flexible adaptation of water release to inter- and intra-annual variability in water demand. Full article

(This article belongs to the Special Issue Agriculture Water Management and Water Saving Strategies)

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19 pages, 4747 KiB

Open AccessArticle

Study on the Optimization of Dry Land Irrigation Schedule in the Downstream Songhua River Basin Based on the SWAT Model

by Qiang Fu, Liyan Yang, Heng Li, Tianxiao Li, Dong Liu, Yi Ji, Mo Li and Yan Zhang

Water 2019, 11(6), 1147; https://doi.org/10.3390/w11061147 - 31 May 2019

Cited by 16 | Viewed by 4007

Abstract

The optimization of irrigation schedules is of great significance for saving water resources and ensuring food security. For the downstream of the Songhua River Basin, the key growth stages of crops were determined by the coupling degree between the effective precipitation and crop [...] Read more.

The optimization of irrigation schedules is of great significance for saving water resources and ensuring food security. For the downstream of the Songhua River Basin, the key growth stages of crops were determined by the coupling degree between the effective precipitation and crop water requirement and the sensitivity indexes of the crop water production function. A Soil and Water Assessment Tool (SWAT) model was used to simulate 16 irrigation schedules in different scenarios. Taking four factors into consideration, Analytic Hierarchy Process (AHP)-Gray Interconnect Degree Analysis (GIDA) was used to establish the optimal irrigation schedule. The results showed that the key growth stages of corn and soybean were vegetative, reproductive and pod formation, seed enlargement. Deficit treatments were beneficial to improving crop yield and WUE. The optimal schedules were: the corn was irrigated with four times in key growth stages, and the irrigation quota was 21 mm; irrigation occurred six times in both normal and dry year, with quotas of 84 mm and 134 mm, respectively; the soybean was filled with six times in key growth stages, and the irrigation quotas were 10 mm, 28 mm and 89 mm in wet, normal and dry year, respectively. The evaluation method of irrigation schedule provided a theoretical basis for agricultural management and planting in the basin. Full article

(This article belongs to the Special Issue Agriculture Water Management and Water Saving Strategies)

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19 pages, 2829 KiB

Open AccessArticle

Evaluation and Optimization of Agricultural Water Resources Carrying Capacity in Haihe River Basin, China

by Jian Kang, Xin Zi, Sufen Wang and Liuyue He

Water 2019, 11(5), 999; https://doi.org/10.3390/w11050999 - 13 May 2019

Cited by 25 | Viewed by 3626

Abstract

The shortage and uneven spatial and distribution of agricultural water resources has greatly restricted the sustainable development of regional society and economy. In this study, an improved five-element connection number set pair analysis model, which subdivides the same–different–opposite connection number in the set [...] Read more.

The shortage and uneven spatial and distribution of agricultural water resources has greatly restricted the sustainable development of regional society and economy. In this study, an improved five-element connection number set pair analysis model, which subdivides the same–different–opposite connection number in the set pair analysis theory to enhance the integrity and effectiveness of the original ternary connection numbers is constructed to evaluate the agricultural water resources carrying capacity (AWRCC) in the Haihe River Basin. Based on this evaluation result, an optimization model (AROL model) is proposed to optimize the effective irrigation area and groundwater exploitation to achieve a “better level” of AWRCC. The evaluation result shows that the current AWRCC of the Haihe River Basin is relatively low. The AWRCC in Shanxi, Inner Mongolia, and Liaoning is Level III and the current agricultural water resources are not overloaded but have little carrying potential. The AWRCC of Beijing, Tianjin, Hebei, Henan, and Shandong are rated IV and overloaded, among which Shandong has the lowest comprehensive score and the most serious overload. The optimization result shows that the extraction and conservation of groundwater in most areas of the Haihe River Basin is unbalanced and the effective irrigation area needs to be increased. With different current conditions in different areas, the groundwater exploitation and the effective irrigation area is adjusted correspondingly. Among the areas, the adjustment of groundwater exploitation and the effective irrigation area in Hebei are the most significant. Full article

(This article belongs to the Special Issue Agriculture Water Management and Water Saving Strategies)

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14 pages, 3218 KiB

Open AccessArticle

Improving Water Use Efficiency of Spring Maize by Adopting Limited Supplemental Irrigation Following Sufficient Pre-Sowing Irrigation in Northwest China

by Shiwei Zhou, Xiaotao Hu, Zhenjiang Zhou, Wen’e Wang and Hui Ran

Water 2019, 11(4), 802; https://doi.org/10.3390/w11040802 - 17 Apr 2019

Cited by 7 | Viewed by 3495

Abstract

In order to improve the water use efficiency (WUE) of spring maize in northwest China, the irrigation strategy of adopting limited supplemental irrigation following a high quota pre-sowing irrigation was evaluated under field conditions in 2016 and 2018. There were three treatments (W1, [...] Read more.

In order to improve the water use efficiency (WUE) of spring maize in northwest China, the irrigation strategy of adopting limited supplemental irrigation following a high quota pre-sowing irrigation was evaluated under field conditions in 2016 and 2018. There were three treatments (W1, W2 and W3) differing in designed wetting depth (D_h) where soil water was replenished. D_h in W1, W2 and W3 were 0–40, 0–50 and 0–60 cm, respectively. The limited supplemental irrigation was adopted to improve soil water content (SWC) within D_h to field capacity (θ_FC) when SWC within 0–40 cm layer decreased to 60%θ_FC following a high rate of pre-sowing irrigation. Results showed that the smaller D_h was beneficial for improving root length density and enhance the utilization of water in subsoil. In both seasons, different D_h led to similar grain yields, which were comparable to the typical regional yield (14.3 t ha⁻¹). The highest WUE (2.79 kg m⁻³) was achieved in W1 and was 13% more than the typical regional level of 2.46 kg m⁻³, implying it was adequate for achieving high yield and WUE to maintain SWC in 0–40 cm above 60% θ_FC with not replenishing soil water in 40–100 cm during the growth season after pre-sowing irrigation. Full article

(This article belongs to the Special Issue Agriculture Water Management and Water Saving Strategies)

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