毛乌素沙地固定沙丘表层土壤水分时间稳定性特征

土壤水分在干旱半干旱地区的水文过程和植被恢复中具有重要的决定性作用,探究毛乌素沙地固定沙丘表层土壤水分的时间稳定性特征,对该地区水资源调控和生态环境改善具有重要意义.在毛乌素沙地东南缘选取固定沙丘迎风坡、背风坡和坡顶进行网格化布点,于2019年7月至10月使用土壤温湿度记录仪(TMS)对表层(0～5 cm)土壤含水量进行测定,分析表层土壤水分的时空变异性与时间稳定性特征.结果表明:研究期内表层土壤含水量的均值为21.00％,时空变化总体上具有中等变异性特征.表层土壤含水量的空间模式在观测时间上具有较弱的相似性,各日期对之间均具有较低的相关系数.土壤含水量的相对差分平均值(MRD)在-17.24％～18.80％之间,相对差分标准差(SDRD)和时间稳定性指数(ITS)的平均值分别为12.70％和14.20％,表层土壤含水量具有较好的时间稳定性.土壤含水量高于平均值的观测点,SDRD与ITS均较低,较高土壤含水量观测点的时间稳定性优于较低土壤含水量观测点.通过土壤含水量的时间稳定性特征分析判定,观测点77可以较好的代表研究区内表层土壤含水量的平均水平(决定系数为0.8769).     

压砂地土壤盐分演替特征研究

针对西北旱区特有的压砂地,分析了不同种植年限压砂地土壤盐分演替特征,结果表明,裸地及新、中、老压砂地土壤盐分平均相对偏差介于-15.43%~28.14%之间,标准差介于4.44%~31.02%之间,变化范围较小,Spearman秩相关系数较大且显著相关,通过时间稳定性可初步确定研究区土壤盐分均值的代表性测点。盐分均值与代表测点值相关系数的变化范围为0.762~0.952,标准误差及平均偏差均较小,代表测点的土壤盐分与区域平均值相关性较高,差异性较小。对新砂地表层土壤盐分进行时空模拟,各时段土壤盐分累计分布曲线变化规律相似,模拟值与实测值略有差异,其空间分布基本趋势与实测数据相符。各时段土壤盐分均属于中等弱变异性,盐渍化程度表现为裸地老砂地新砂地中砂地,压砂地土壤盐分时刻都在发生着演替,中砂地土壤盐渍化程度最小,但伴随着种植时间的延长和覆盖砂石土砂比的增加,老砂地土壤盐渍化呈加剧趋势。     

覆膜滴灌条件下棉花根层土壤盐分时间稳定性研究

为揭示膜下滴灌棉田主根区土壤盐分的时间变异特性,基于2013—2014年田间实测数据,采用变异系数、平均相对偏差和标准差等方法研究了不同土层土壤盐分的时间稳定性,并进一步确定了可以反映各土层土壤平均含盐量的代表性测点。结果表明,研究区域0~40 cm土层土壤盐分随时间序列的变异性只有少数几个测点属于强变异,其余均属于中等变异;在棉花主根层(40 cm)内,土壤盐分的时间稳定性随土层深度增加呈现先增强后略微减弱趋势,在30 cm土层深度稳定性最强,平均相对偏差浮动范围最小、且其平均标准差最小;反映各土层平均含盐量的代表测点分布较为集中,可选取代表地块对区域土壤含盐量进行估算(决定系数R2为0.791 2~0.917 1)。棉田主根层土壤盐分时间稳定性研究有利于指导田间灌溉;选取少量且具有代表性的测点可为区域合理布设土壤盐分监测点提供理论依据。     

农田土壤含水率空间变异的时变特性研究

农田土壤含水率的空间时变特性对土壤墒情监测及灌溉预报有重要影响。在天津市武清区北靳庄和西吕村两个试区布置两套墒情监测系统,每套系统包括1台基站、3个测点,每个测点连接两个土壤水分传感器(埋设于地表下30和60 cm处)。测得两个深度的土壤含水率数据,利用线性公式计算得0～60 cm平均含水率,利用统计学方法分析土壤含水率的变异系数(C_V)随时间的变化特性,分析试区测点土壤含水率之间的相关关系。结果表明,C_V随时间有显著的变化,C_V变化较大时,相应时段的土壤含水率较小,通常为灌溉时期;C_V较小时,土壤含水率较大,普遍为降雨量较大时期;本试区C_V呈弱变异和中等变异;相关系数在一定程度上能够反映空间变异性大小,随着研究尺度的增大,测点之间土壤含水率的相关系数在减小。     

秸秆还田下土壤水分时间稳定性与玉米穗质量的相关性

为揭示黑土区秸秆还田条件下农田土壤水分时间稳定性与玉米穗质量的相互关系,基于TDR法测得的土壤含水率(2017年6—9月)及称量法测得的玉米穗质量,在确定秸秆还田条件下农田土壤水分时间稳定性特征的基础上,量化分析其时间稳定性与玉米穗质量在单一尺度和多尺度上的相关特征。结果表明:随土层深度增加,土壤水分时间稳定性逐渐增强,且较深土层(40～60 cm、60～80 cm)土壤含水率较高的测点时间稳定性较强;随土层深度变化,土壤水分代表性测点有所不同,利用代表性测点土壤含水率可确定研究区域土壤最低含水率、最高含水率和平均含水率等信息,可为土壤水分估算与调控提供科学指导;时间稳定性与穗粒质量、穗轴质量相关程度随土层深度的变化趋势在单一尺度和多尺度上不同,大部分土层土壤水分时间稳定性与穗粒质量、穗轴质量的多尺度相关程度均大于单一尺度相关程度。多尺度相关分析能更深入地确定土壤水分时间稳定性与穗质量的相互关系,进而为深入揭示土壤水分对作物产量的影响机制提供理论依据。     

小型红壤坡面土壤含水率时空特性研究

为了探索小型红壤坡面土壤含水率的时空分布规律,在桂林市雁山镇平均坡度14°、坡长12 m、宽度5 m的红壤坡面布设14个观测点,分别对0~60 cm土深的6个土层进行了为期1 a的土壤含水率观测,并用统计学方法及时间稳定性概念进行了分析。结果表明,随着土壤深度的增加,各土层平均土壤含水率总体逐步上升,各土层含水率变异系数的均值总体逐步减小,各土层的含水率更加均匀;随着平均含水率的增加,各土层含水率的波动幅度先增大后减小;不同坡位的土壤含水率在干湿2季表现出不同的特点,湿季0~10 cm土层的含水率为下坡位中坡位上坡位,其余土层均表现为上坡位中坡位下坡位,干季0~10 cm土层含水率沿坡位的变化特点与湿季相同,而其余土层未表现出相同的规律。在时间特性上,红壤坡面土壤含水率与降雨量及降雨频次的关系密切,气温和空气湿度也是影响含水率的重要因素;随着土层的加深,土壤含水率的时间稳定性增强;除0~10、40~50 cm土层外,全序列所得时稳最强点对土壤平均含水率的代表性优于其他序列,干季序列所得各点的时间稳定性指数与全序列更为接近,同时干季序列所得时稳最强点对土壤平均含水率的代表性也明显优于湿季序列;植被根系对含水率的时间稳定性有一定影响,40~50 cm土层植被根系最多,使得全序列所得时稳最强点对所在土层平均含水率的代表性较差。     

不同微咸水灌溉方式对压砂地土壤水盐及pH空间变异的影响

掌握不同灌溉方式下压砂地土壤水盐及pH的空间分布规律可以有效提高微咸水的利用效率。利用田间取样、经典统计学、地统计学以及克里格插值法对比分析了滴灌和微喷灌0～40 cm土层土壤含水率、电导率和pH值的空间变异特征。结果表明：微喷灌的土壤含水率略低于滴灌，0～40 cm土层土壤含水率属于中等变异性，且具有中等强度的空间相关性。微喷灌0～20 cm土层土壤平均电导率和离散化程度小于滴灌，同时，2种灌溉方式下0～20 cm和20～40 cm土层电导率的空间分布均表现出中等变异且具有较强的空间相关性；20～40 cm土层的平均电导率小于0～20 cm土层。无论微喷灌还是滴灌，调查地块的土壤电导率表现为中间位置低而地边较高，土壤含水率则在中间位置高而地边低。灌溉方式对土壤pH值的影响不显著，其空间变异性属于弱变异，但微喷灌条件下pH值具有较强的空间相关性。微咸水灌溉条件下压砂地抑制了表层土壤盐分累积，并存在向未覆砂的地块边缘聚积的现象。不同灌水方式下压砂地土壤水分和盐分均存在中等的空间变异性和空间自相关性，而pH值空间变异性较弱。研究结果可以为压砂地的微咸水合理利用提供理论依据。     

土壤水盐信息与容重在垂直方向的空间结构性研究

通过对土样含水率和EC值的测定,运用地质统计学理论研究在垂直方向上土壤水盐的空间结构性及容重的变化情况。统计分析表明,水分的变异性小于盐分的变异性。容重在垂直方向上的离散性和空间变异性都很小。容重在距地表2.0 m深垂直剖面内的均值为1.48 g/cm3。运用OK法估计区域水盐信息,结果表明,试验田内的测点与微咸水试验田外的测点土壤含水率在垂直剖面上的分布,主要区别是干燥层位置明显下移,表层和底层含水率变化范围基本保持一致。试验田内的测点EC分布基本上从0~80 cm深度内为单调递减,80 cm以下EC值基本上为一常数。微咸水试验田外的测点,剖面上存在有明显的变化,在距地面约90 cm深度处有EC峰值。土壤容重在80 cm以下深度土层基本上稳定,大约在1.45 g/cm3左右。与统计分析均值计算结果1.48 g/cm3非常接近。     

不同沟灌方式下夏玉米棵间蒸发试验

采用常规沟灌和交替隔沟灌技术,研究了不同水分处理(水分控制下限为田间持水率的80%、70%、60%)夏玉米的棵间蒸发。结果表明:常规沟灌的灌后蒸发和全生育期棵间蒸发量均大于交替隔沟灌,灌水后短期内由于表层土壤含水率较高,土壤蒸发较大;在满足作物蒸腾耗水的基础上,交替隔沟灌减小了灌溉湿润面积而减小无效蒸发耗水;不同沟灌方式下土壤蒸发与表层土壤含水率呈明显的脉冲波动变化,而深层土壤含水率波动较弱;表层土壤含水率和叶面积指数对棵间蒸发影响明显,二者与相对土面蒸发强度均有良好的指数函数关系。水分下限控制合适,交替隔沟灌棵间蒸发与蒸腾耗水明显降低,是夏玉米适宜的灌水方式。     

膜下滴灌棉田土壤呼吸特征及其影响因素

为探讨膜下滴灌条件下棉田土壤呼吸的动态变化及其影响因子,在棉花生长期采用Li-8100A土壤碳通量自动测定仪连续观测垄上、垄间和裸地土壤呼吸速率及环境因子.结果表明:3种样地的土壤呼吸速率日变化均表现为单峰型曲线,峰值出现在14:30;月变化呈现先升高后降低的趋势,7月中下旬土壤呼吸速率最高.3种样地的土壤呼吸速率和土壤有机碳质量比差异性显著,由高到低依次为垄上、垄间、裸地,且垄上的土壤呼吸总量最大,是垄间和裸地的1.5倍和2.8倍,而土壤温度的差异性由大到小依次为裸地、垄上、垄间.采用相关分析法研究表明,土壤呼吸速率与土壤含水率的相关性较弱,与土壤有机碳质量比呈显著正相关.土壤温度能够解释土壤呼吸速率变异性的75.1%~84.4%,两者表现出较高的指数正相关关系;3种样地的土壤呼吸对温度的敏感系数差异显著,敏感系数由大到小依次为垄上(2.208)、垄间(2.160)、裸地(1.675).     

Field-measured evapotranspiration as a stochastic process

Spatial variability of evapotranspiration (ET) within irrigation intervals and the temporal variability of spatially averaged ET of Yolano pink beans (Phaseolus vulgaris) were measured and statistically modeled to improve irrigation management. Field experiments were conducted at the University of California, Davis, on the Yolo soil series (Typic Xerorthents) during the summer of 1992. Daily soil water measurements were taken at 27 locations along a transect at 10 m intervals with a neutron probe. Changes in soil moisture over the 165 cm profile gave field-measured ET. Neutron probe measured ET was 20% less than the production function estimated ET, but both had similar pattern along the row. The trend of decreasing ET with distance down the row became increasingly steep as the growing season progressed. This trend was caused by a similar trend in soil water imposed by a furrow irrigation. After removing the trend with a first-order difference, ET was not spatially correlated (95% confidence interval) at 10 m. Therefore, each sample taken at a 10 m spacing provided maximum new information because it was not predictable from its neighbor. However, ET was temporally correlated (95%v confidence interval at lag 1) and characterized by an autoregressive moving average (1,1) model. Therefore, ET could be predicted one day in advance. For the field conditions studied, neutron probe measurements can be used to estimate daily ET for about 44 days in the middle of the growing season, when measured crop ET was greater than 1.4 mm, and at an interval of 6 days at the beginning of the cropping season.     

Temporal persistence of spatial soil-water patterns under trickle irrigation

Summary Trickle irrigation of perennial crops results in local wetting near trees and vines. Methods to measure soil-water content or storage within the root zone generally require intensive instrumentation to characterize spatial patterns of soil water adequately. The goals of this research were to determine if spatial patterns of soil-water storage under trickle irrigation are temporally presistent which may make it feasible to use less intense sampling to characterize total storage. Soil-water storage from the 0 to 1.5 m soil depth was measured at 23 sites on one side of trickle-irrigated almond trees using a neutron probe over three years in the San Joaquin Valley of California. Measurements were made on two trees in each of five different irrigation treatments. The persistence of spatial patterns with time was evaluated using Spearman rank correlation and relative differences from mean values. Spatial patterns were different for each tree and irrigation treatment but remained fairly persistent with time during a season. In many cases, temporal changes in soil-water storage were adequately estimated from a single location. Single sampling locations identified during one year gave estimates of mean storage during the following year with some increase in error. However, use of the same sampling locations for more than two years increased the error in storage estimates. Soil-water content or storage in trickle-irrigated orchards may be monitored by intense sampling during the early part of the irrigation season in order to identify locations giving mean soil-water storage. Only these locations may then be sampled to monitor changes in soil water.     

Responses of winter wheat (Triticum aestivum L.) evapotranspiration and yield to sprinkler irrigation regimes

The North China Plain (NCP) is one of the main productive regions for winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) in China. However, water-saving irrigation technologies (WSITs), such as sprinkler irrigation technology and improved surface irrigation technology, and water management practices, such as irrigation scheduling have been adopted to improve field-level water use efficiency especially in winter wheat growing season, due to the water scarcity and continuous increase of water in industry and domestic life in the NCP. As one of the WSITs, sprinkler irrigation has been increasingly used in the NCP during the past 20 years. In this paper, a three-year field experiment was conducted to investigate the responses of volumetric soil water content (SWC), winter wheat yield, evapotranspiration (ET), water use efficiency (WUE) and irrigation water use efficiency (IWUE) to sprinkler irrigation regimes based on the evaporation from an uncovered, 20-cm diameter pan located 0-5 cm above the crop canopy in order to develop an appropriate sprinkler irrigation scheduling for winter wheat in the NCP. Results indicated that the temporal variations in SWC for irrigation treatments in the 0-60-cm soil layer were considerably larger than what occurred at deeper depths, whereas temporal variations in SWC for non-irrigation treatments were large throughout the 0-120-cm soil layer. Crop leaf area index, dry biomass, 1000-grains weight and yield were negatively affected by water stress for those treatments with irrigation depth less than 0.50E, where E is the net evaporation (which includes rainfall) from the 20-cm diameter pan. While irrigation with a depth over 1.0E also had negative effect on 1000-grains weight and yield. The seasonal ET of winter wheat was in a range of 206-499 mm during the three years experiments. Relatively high yield, WUE and IWUE were found for the irrigation depth of 0.63E. Therefore, for winter wheat in the NCP the recommended amount of irrigation to apply for each event is the total 0.63E that occurred after the previous irrigation provided total E is in a range of 30-40 mm.     

Effects of climate change on paddy water use efficiency with temporal change in the transplanting and growing season in South Korea

The aim of this study was to assess the effects of climate change on green and blue water use with temporal change in the transplanting and growing season for paddy fields in South Korea using the representative concentration pathway (RCP) 4.5 and 8.5 scenarios in 2025 (2011–2040), 2055 (2041–2070), and 2085 (2071–2100). The optimal transplant date determined by an accumulated temperature analysis, between 27 April and 21 May in 1995, was delayed until 29 June in 2085, and the average growing period was decreased by about 20 days in 2085. Changes in the transplanting season and growing period could influence the efficiency of future green water use and blue water savings. Approximately 810.5 Mm³ of green water was available during the 1995 transplanting season, but the predicted use of green water was 1524.7 Mm³ in future for the optimal transplanting season. In addition, 923.0 Mm³ of blue water savings can be expected in 2025. This study showed that appropriate change of transplanting season could mitigate the water requirements in paddy fields by optimizing phenology, improving green water efficiency, and blue water savings.     

膜下滴灌棉田土壤水分空间变异规律研究

2009年,在新疆库尔勒包头湖农场智能化棉花膜下滴灌工程示范区,选择典型的一膜一管4行种植的棉花为试验区(共计20个测点),测定了各个采样点以及3个不同深度的土壤含水率。运用地统计学和经典统计学方法,分析了棉花4个生育期内土壤水分的空间变异特性。结果表明,土壤质地为砂壤土时,土壤含水率的空间变异性属于弱变异;随着棉花的生长,土壤水分的分布越来越趋于均匀化;在棉田主要生育期内,研究土壤含水率空间分布最好的半方差函数模型是球形模型;土壤含水率的大小基本上和该点与滴灌带的垂直间距成反比例关系;棉花行对棉田土壤水分的再分布起到了很大的影响,距离棉花行越远,受到的影响就越小。     

Combining an ecological model with remote sensing and GIS techniques to monitor soil water content of croplands with a monsoon climate

Soil water is an important factor affecting photosynthesis, transpiration, growth, and yield of crops. Accurate information on soil water content (SWC) is crucial for practical agricultural water management at various scales. In this study, remotely sensed parameters (leaf area index, land cover type, and albedo) and spatial data manipulated using the geographic information system (GIS) technique were assimilated into the boreal ecosystem productivity simulator (BEPS) model to monitor SWC dynamics of croplands in Jiangsu Province, China. The monsoon climate here is characterized by large interannual and seasonal variability of rainfall causing periods of high and low SWC. Model validation was conducted by comparing simulated SWC with measurements by a gravimetric method in the years 2005 and 2006 at nine agro-meteorological stations. The model-to-measurement R² values ranged from 0.40 to 0.82. Nash-Sutcliffe efficiency values were in the range from 0.10 to 0.80. Root mean square error (RMSE) values ranged from 0.028 to 0.056 m³ m⁻³. Simulated evapotranspiration (ET) was consistent with ET estimated from pan evaporation measurements. The BEPS model successfully tracked the dynamics and extent of the serious soil water deficit that occurred during September-November 2006. These results demonstrate the applicability of combining process-based models with remote sensing and GIS techniques in monitoring SWC of croplands and improving agricultural water management at regional scales in a monsoon climate.     

Use of CERES-Maize to study effect of spatial precipitation variability on yield

The objective of this study was to determine the usefulness of on-farm precipitation measurement, through determining spatial and temporal precipitation variability and its effect on corn yield. CERES-Maize (DSSAT version 3.5) was used with three precipitation data sources, for an Indiana farm—an on-farm National Weather Service (NWS) station, the nearest non-urban NWS station with electronic reporting (27 km from the farm), and a weighted mean of the three nearest such stations (27–35 km away)—to simulate 31 years of crop yield on 1-ha grid cells. Described as a percentage of the mean, spatial precipitation variability among the three data sources by corn phenological phase was 21–104%, while temporal (year-to-year) variability was 20–49%. The difference in simulated yield based on spatial precipitation variability was 15.8%, while year-to-year yield variability was 21.5%. The apparent yield difference based on spatial precipitation variability was of the same order as year-to-year variability, which suggests having on-farm precipitation data may be necessary for accurate yield modeling.     

Potential productivity and water requirements of maize-peanut rotations in Australian semi-arid tropical environments—A crop simulation study

The growing demand for maize (Zea mays L.) in intensive livestock and other industries has opened up fresh opportunities for further expansion of the maize industry in Australia, which could be targeted in relatively water rich semi-arid tropical (SAT) regions of the country. This crop simulation study assessed the potential productivity and water requirements of maize peanut (Arachis hypogaea L.) rotations for the SAT climatic zone of Australia using the Agricultural Production Systems Simulator (APSIM) model. APSIM was configured to simulate maize (Pioneer hybrid 3153) either in the dry (May-October) or wet season (November-April) and peanut (cv. Conder) in the following season for three soils found at Katherine (14.48°S, 132.25°E) from 1957 to 2008. The simulated mean total yield potential of the dry season maize and wet season peanut (DMWP) rotation (15-19.2 t/ha) was about 28% greater than the wet season maize-dry season peanut (WMDP) rotation because of the higher yield potential of maize in the dry season compared to in the wet season. These high yields in the DMWP rotation have been achieved commercially. The overall simulated irrigation water requirement for both rotations, which varied from 11.5 to 13.8 ML/ha on different soils, was similar. The DMWP rotation had 21% higher water use efficiency. Similar yield and water use efficiency advantages of the DMWP rotation were apparent for eight other agriculturally important locations in the Northern Territory, Western Australia and Queensland. The simulations for Katherine also suggested that the irrigation requirement of the two rotations could increase by 17.5% in El-Nino years compared to La-Nina years for only a small gain in yield, which has implications for climate change scenarios.     

Avocado root distribution in fine and coarse-textured soils under drip and microsprinkler irrigation

A common irrigation-scheduling problem in orchards is the proper location of instruments for monitoring soil water content within the active root zone. Given the high spatial variability of soils in the field, and seasonal changes in root distribution and frequency, both within the orchard and around the trees, the accuracy and representativeness of soil water measurements can be strongly affected. Adequate soil water monitoring in orchards thus requires assessment of the variability and location of the active roots in a given location over an extended period of time. We examined the root systems of 12-year-old ‘Hass’ avocado (Persea americana Mill.) trees grafted on ‘Mexicola’ seedling rootstocks, growing in fine or coarse-textured soils, under either drip or microsprinkler irrigation systems in Central Chile. We dug 3 m long and 0.75 m deep trenches within the tree rows in spring, summer and autumn, and counted the active roots (white, diameter ≤2 mm) found on the walls. Over the three growing seasons of our study, season had the most significant effect on root distribution, as autumn root frequencies accounted for about half of the cumulative average. Also, the location of the highest concentration of roots under microsprinklers in autumn clearly differed between the fine soils, at about 200 cm from the trunk and 50–60 cm deep, and coarse soils, where they were found within 30 cm from the trunk, and within the first 25 cm of soil. Trees in fine soil had 25% more roots than those in coarse soil, and drip irrigation produced about 30% more roots than microsprinkler, although both of these figures are mainly due to the high number of roots found in the fine soil-drip irrigation combination. Overall, we found the highest root frequency within the first meter from the tree trunk, for all combinations, with some differences between irrigation types. Throughout the growing season in semi-arid regions, some changes in both the quantity of tree roots and the location of the zones of the greatest root activity should be expected, which will vary according to the seasonal soil temperatures, soil texture, and type of irrigation used.     

Modeling soil water dynamics in a drip-irrigated intercropping field under plastic mulch

Intercropping, drip irrigation, and the use of plastic mulch are important management practices, which can, when utilized simultaneously, increase crop production and save irrigation water. Investigating soil water dynamics in the root zone of the intercropping field under such conditions is essential in order to understand the combined effects of these practices and to promote their wider use. However, not much work has been done to investigate soil water dynamics in the root zone of drip-irrigated, strip intercropping fields under plastic mulch. Three field experiments with different irrigation treatments (high T1, moderate T2, and low T3) were conducted to evaluate soil water contents (SWC) at different locations, for different irrigation treatments, and with respect to dripper lines and plants (corn and tomatoes). Experimental data were then used to calibrate the HYDRUS (2D/3D) model. Comparison between experimental data and model simulations showed that HYDRUS (2D/3D) described different irrigation events and SWC in the root zone well, with average relative errors of 10.8, 9.5, and 11.6 % for irrigation treatments T1, T2, and T3, respectively, and with corresponding root mean square errors of 0.043, 0.035, and 0.040 cm³ cm^?3, respectively. The results showed that the SWC in the shallow root zone (0–40 cm) was lower under non-mulched locations than under mulched locations, irrespective of the irrigation treatment, while no significant differences in the SWC were observed in the deeper root zone (40–100 cm). The SWC in the shallow root zone was significantly higher for the high irrigation treatment (T1) than for the low irrigation treatment, while, again, no differences were observed in the deeper root zone. Simulations of two-dimensional SWC distributions revealed that the low irrigation treatment (T3) produced serious severe water stress (with SWCs near the wilting point) in the 30–40 cm part of the root zone, and that using separate drip emitter lines for each crop is well suited for producing the optimal soil water distribution pattern in the root zone of the intercropping field. The results of this study can be very useful in designing an optimal irrigation plan for intercropped fields.