Salinity and drought affect yield response of bell pepper similarly

Abstract

There is a growing realization that an increasing number of countries are approaching full utilization of their conventional water resources and that the quantity of good-quality water supplies available to agriculture is diminishing. Effects of irrigation regime and irrigation water salinity on bell pepper including yield, fruit number and quality, vegetative and root growth, evapotranspiration and water use efficiency were investigated in this study by conducting two different experiments. Six different salinity levels of irrigation water and four different irrigation regimes were used as treatments. Considering the results from irrigation water salinity experiment, it can be concluded that as soil salinity increases, water consumption, water use efficiency, yield and other vegetative growth parameters of bell pepper were decreased. A polynomial relationship between soil salinity and water consumption was observed. It was found that bell pepper is moderately sensitive to salinity with a 1.2 dS m^?1 threshold and a 10.9% slope value. In the irrigation regime experiment, limited irrigation caused decreases in water consumption, yield and vegetative growth of bell pepper. Yield response factors were close in the cases of irrigation regime (1.50) and irrigation water salinity (1.40). Total soluble solids of bell pepper were increased due to both irrigation water salinity and water application rate but not dry matter ratio. Considerable water consumption decreases because of salinity were determined. Therefore, the effect of irrigation water salinity should be considered in irrigation management to prevent excess saline water application and to protect the environment.     

Effects of deficit irrigation on tomato and eggplant and their infection with the root-knot nematode under controlled environmental conditions

Deficit irrigation has been widely investigated as a valuable strategy for dry regions where water is the limiting factor in crop cultivation. Soil moisture can be one of the important factors that influence root-knot nematode (RKN) disease development. To determine how different levels of irrigation can affect disease development, irrigation regimes ranging from 20% to full field capacity (FC) were applied to tomato and eggplant plants inoculated with Meloidogyne javanica (M. javanica) under controlled conditions. In addition, in vitro bioassays were done to evaluate the effect of water potential and soil moisture content on M. javanica viability in the soil and reproduction on plant hosts. The relative egg hatching percentage decreased significantly with decreasing water potential from –0.1 to –1 MPa. The use of 80% irrigation level caused minor reductions in growth but significantly reduced nematode infection load. Nematode infection was reduced even further at lower levels of irrigation, however this also led to marked reductions in fresh and dry weights of the tomato and eggplants. Therefore, deficit irrigation could be used at a rate of 80% or 60% of FC to increase water use efficiency and reduce the level of RKN (M. javanica) infection without greatly reducing the growth performance of tomato and eggplant crops.     

Effects of Different Irrigation Regimes and Mulches on Yield and Macronutrition Levels of Drip-Irrigated Cucumber Under Open Field Conditions

ABSTRACT

The effectiveness of different mulch types on fruit yield, leaf-nutrient composition, and normal plant growth parameters was investigated in order to maximize water use efficiency (WUE) in cucumber grown under water stress. Treatments were (1) bare soil + water stress (WS), (2) bare soil + unstressed (control, C), (3) black polyethylene mulch + water stress (BPM + WS), (4) wheat straw mulch + water stress (WSM + WS), and (5) wheat straw mulch plus black polyethylene mulch + water stress (WSM + BPM + WS). Seasonal crop evapotranspiration was between 492 and 960 mm. Seasonal irrigation water amounts were 965 and 485 mm for the C and WS treatments, respectively. The WUE ranged from 3.40 to 5.78 kg m^?3, while irrigation water-use efficiency (IWUE) was between 3.39 and 6.08 kg m^?3. IWUE and WUE were increased under WS treatments with mulching compared with the control treatment, as mulching significantly reduced the amount of irrigation water required. Both BPM and WSM improved the fruit yield, fruit size, plant dry matter, total leaf area, and chlorophyll and nutrient concentrations in leaves under the stressed treatments, while these two mulches in combination (BPM + WSM) caused further increases in these parameters. This study confirms that limiting soil evaporation with mulches is a key action to take to save irrigation water and to improve WUE and IWUE. Because use of drip irrigation with mulching can increase WUE, this strategy might be used for vegetable production in semi-arid regions where irrigation water is limited.     

Effect of Drip Fertigation on Yield,Water Use Efficiency,and Nutrients Availability in Banana in West Bengal,India

Field studies were conducted during 2008–2009 and 2009–2010 at the Gangetic alluvial plains of West Bengal, India, to assess the different levels of drip fertigation at variable evaporation replenishment compared to surface irrigation and conventional soil fertilization on yield, water use efficiency, and nutrients availability in plant and ratoon crop of banana. The experiment was laid in an Augmented Factorial Complete Block Design with three replications having three drip irrigation schedules at 50%, 60%, and 70% of cumulative pan evaporation (CPE) and three drip fertigation schedules at 50%, 60%, and 80% of recommended nitrogen, phosphorus, and potassium (NPK) fertilizers with inclusion of conventional surface irrigation at 100% of IW/CPE. The results showed that fruit yield of plant and ratoon crop increased progressively with increasing levels of irrigation water (up to 60% CPE) and NPK fertigation through the drip system. However, maximum fruit yield and water use efficiency of crops was obtained with drip irrigation at 60% CPE with NPK fertigation at 80% of recommended dose. Drip irrigation, as a whole, registered higher fruit yields and water use efficiency with savings of 38.3–41.5% of water compared to surface irrigation. Availability of N, P, and K in soil at vegetative, shooting, and harvesting stages for plant and ratoon crop consistently increased with increasing rate of irrigation water and NPK fertigation through the drip system. Higher availability of macronutrients in soil was recorded with drip irrigation at 70% CPE with 80% of recommended drip NPK fertigation. Overall drip fertigation system improved the available plant nutrients in the soil as compared with traditional surface irrigation.     

基于基因表达式编程的作物水分生产函数构建

作物水分生产函数的确定是农业水资源优化配置的关键。该研究采用农业水文生态系统模型（Agro-Hydrological & Chemical and Crop systems simulator, AHC）与基因表达式编程（Gene Expression Programming, GEP）相结合的方法构建作物水分生产函数。以河套灌区3种主要作物（葵花、玉米、小麦）为研究对象,采用AHC模型模拟作物产量等,构建基于GEP算法的作物水分生产函数,探讨考虑盐分胁迫的作物水分生产函数构建的思路与方法。结果表明：1）作物模拟产量与地下水埋深、地下水矿化度和灌水量等因素有关。2）构建作物水分生产函数的最优输入因子组合为地下水埋深、灌溉量、蒸散发、地下水矿化度、土壤根层盐分对作物胁迫因子、土壤根层含水率。3）应用作物水分生产函数估算不同灌溉定额条件下作物产量（预测产量）,并与AHC模型计算的产量（模拟产量）进行比较,玉米、葵花、小麦预测产量与模拟产量具有很好一致性,其决定系数分别是0.96、0.93、0.96,平均相对误差均小于5%,满足计算精度要求。因此,该研究所构建的作物水分生产函数可以较准确地估算盐分胁迫下作物产量,为农业节水与灌溉水高效利用提供科学参考。     

滴灌模式对棉花根系分布和水分利用效率的影响

理解膜下滴灌参数对土壤盐分运移和作物生长的影响是制定科学滴灌制度、合理利用水资源的重要环节。毛管布置方式和滴灌水质是膜下滴灌的重要参数,为研究其对土壤盐分变化、棉花根系分布及水分利用效率的影响,设计了2种毛管布置方式（一管四行（Ms）和一管两行（Md））和3个滴灌水质水平（淡水0.24?dS/m、微咸水4.68?dS/m、咸水7.42?dS/m）。结果表明,滴管布置方式对土壤盐分变化和根系分布有显著影响。在相同滴灌水质条件下,Ms处理有利于降低棉花根区土壤含盐量。所有处理根系主要分布于0～40?cm土层内,矿质水滴灌时Md中根系受抑制程度明显高于Ms,但其主要影响根系密度δR＞0.5?kg/m3区域的分布范围,对δR＞0.2?kg/m3区域范围分布无明显影响。生育期内棉花总耗水量随滴灌水矿化度的上升而降低,与滴管布置无关。相对淡水滴灌而言,矿质水滴灌时Ms处理产量有所降低,但其水分利用效率随灌水矿化度上升而升高;而Md处理产量和水分利用效率均随灌水矿化度上升而下降。     

Effects of Irrigation Water Salinity and Leaching Fraction on Yield and Evapotranspiration in Spring Wheat

To determine the effects of irrigation water salinity and leaching fraction on crop evapotranspiration (ETc), grain yield, straw yield, shoot sodium (Na), and chloride (Cl) concentrations of spring wheat (Triticum aestivum L.) cultivar ‘Onfarom 9,’ a pot experiment was conducted using saline soil with electrical conductivity of soil paste extract (ECe) of 13.2 dS m^?1. A factorial experiment with a completely randomized design replicated seven times was used with three levels of saline irrigation water (4, 9, and 12 dS m^?1) and four leaching levels (0, 17, 29, and 37%) included as the factors. The results showed that ETc significantly decreased as a result of an increase in irrigation water salinity (ECi) and decrease in leaching level. Crop evapotranspiration deficit and decreasing irrigation and drainage water effectively resulted in grain and straw yield reduction. Increase in ECi increased accumulation of Cl and Na in crop shoot, but application of leaching decreased this accumulation.     

咸水安全利用农田调控技术措施研究进展

淡水资源短缺已经成为全球性的问题,开发利用地下咸水资源,发展农业灌溉已成为各国关注的焦点问题。微咸水或咸水代替部分淡水进行农业灌溉,在一定程度上可缓解淡水资源的不足,但咸水和微咸水灌溉带来的土壤积盐和作物减产等问题始终是研究的重点和难点。本文从咸水或微咸水灌溉带来的潜在土壤盐渍化危害入手,就如何应对咸水和微咸水灌溉带来的次生盐渍化问题,通过总结前人大量的研究成果,分析了减轻土壤盐渍化对作物危害的各种途径,从微咸水灌溉和咸水灌溉两个层面就优化农田管理农艺措施、生物措施、水利工程措施等方面进行概述。重点介绍了咸水或微咸水灌溉对土壤微环境的影响,优化田间管理农业措施(如合理的灌溉制度和灌溉方式、覆盖、深耕等),土壤中施入有机物质(如植物秸秆、有机肥、绿肥、生物质炭等)和无机土壤改良剂(如石膏、沸石等)、施用根际促生菌肥、种植盐土植物和耐盐作物品种等,以及咸水结冰灌溉、暗管排盐等水利工程措施,这些都是降低咸水灌溉带来的土壤盐害行之有效的方法。以微咸水或咸水补灌为核心,结合雨水资源利用,通过种植耐盐植物品种、增施土壤微生物肥、土壤调理剂等措施提高土壤缓冲能力,配套垄作和地膜覆盖等降低土壤蒸发措施,抑制土壤盐分表层积聚,配套秸秆还田和土壤耕作技术,提高土壤蓄雨淋盐和养分快速提升,集成微咸水安全高效灌溉技术模式,制定规范化的技术应用规程,有机地结合各种改良措施,可有效控制咸水和微咸水灌区土壤次生盐渍化,达到咸水资源的高效安全可持续利用,提升水资源保障能力。     

华北平原小麦－玉米两熟制节水潜力与灌溉对策

利用详细校正的农业系统模型可以综合土壤、气候及作物等因素综合评价节水灌溉制度,为农田水分优化调控提供理论和技术支持。该文利用根系水质模型（RZWQM-CERES）模拟分析了华北平原2个代表性站点（禹城和栾城）小麦-玉米两熟制下作物产量、农田蒸散和灌溉需水量多年的变化特征（1961－1999）,结果表明栾城站小麦季农田最大蒸散量与灌溉需水量多年平均分别为632和496 mm,明显高于禹城站,而玉米季最大蒸散量相近,分别为395和384 mm。2个站点灌溉需水量都集中在小麦季（3－5月）,但在栾城站播种期（6、10月）灌溉需水量较高。由于2站点气候和土壤条件的差异,作物产量对水分胁迫的响应特征明显不同,在获得相似目标产量时,禹城站灌溉需水量低于栾城站。以作物水分胁迫指数为基础的节水灌溉制度模拟评价表明2个站点冬小麦水分敏感期为孕穗期,但播前灌溉的产量效应差异明显。综合以上结果初步建立了2个站点高效用水和环境友好型的节水灌溉策略。     

灌溉水盐度和施氮量对棉花产量和水氮利用的影响

淡水资源不足和盐渍化是干旱半干旱地区农业生产的重要限制因素,因此提高水、 肥利用效率和作物产量,减少根区盐分积累和地下水污染风险是这些地区水分养分优化管理的重要目标。通过田间试验研究了滴灌条件下灌溉水盐度和施氮量对棉花产量和水、 氮利用率的影响。试验设置灌溉水盐度和施氮量两个因素,灌溉水盐度（电导率,EC）设3个水平,为0.35（淡水）、 4.61（微咸水）和 8.04（咸水）dS/m,分别用SF、 SM和SH表示;施氮（N）量设4个水平,为0、 240、 360和480 kg/hm2,分别以N0、 N1、 N2和N3表示。研究结果表明,棉花干物质重、 氮素吸收量和氮肥利用率受灌溉水盐度、 施氮量及二者交互作用的影响显著。咸水灌溉处理（SH）棉花干物质重、 氮素吸收量、 产量和氮肥表观利用率均显著降低,而微咸水灌溉（SM）对棉花氮素吸收量和氮肥表观利用率影响不大,但干物质重和产量有所降低。施氮肥可显著促进棉花生长,增加干物质重、 氮素吸收量和产量,但随着灌溉水盐度的增加,其促进效应明显受到抑制。微咸水和咸水灌溉会导致水分渗漏增加、 蒸散量降低,增施氮肥则可显著降低水分渗漏、 增加蒸散量。微咸水灌溉水分利用率最高,其次是淡水灌溉,咸水灌溉最低;增施氮肥则可显著提高水分利用率。因此滴灌条件下,高盐度的咸水不宜用于灌溉。而短期的微咸水灌溉不会对棉花产量和水、 氮利用率产生严重的负面影响;同时,合理的配施氮肥也有助于促进棉花生长,提高棉花产量和水分利用率。     

Impacts of different water salinity levels on salt tolerance,water use,yield, and growth of chives (Allium schoenoprasum)

ABSTRACT

Using saline irrigation water for crop production continues to gain more importance year by year, especially in regions where freshwater resources are very scarce. Therefore, this study was carried out to investigate the effects of six water salinity levels (0.38 (control), 1.0, 2.0, 4.0, 6.0, and 8.0 dSm^?1) on salt tolerance, evapotranspiration, and yield of chives under a rain shelter. The experiment was laid out in pots using a randomized plot design with four replicates of each treatment. Leaf fresh-dry weights, plant height, evapotranspiration, and water use efficiencies of chive plants were significantly affected by increasing levels of salinity. The results revealed that chives can be classified as a salt-sensitive crop with a threshold value of 1.13 dSm^?1 and relative yield decreased by 6.19% per unit increase of soil salinity. In conclusion, with appropriate leaching management practices, irrigation water with 0.38 dSm^?1 salinity level is recommended for chives production.     

苏北滩涂水稻微咸水灌溉模式及土壤盐分动态变化

为研究微咸水灌溉对水稻水分利用效率和土壤盐分动态的影响,利用田间试验资料对SWAP(Soil-Water-Atmosphere-Plant)模型进行了率定和验证。用验证认可的模型模拟并分析了水稻生育期水盐运移规律和水稻水分利用效率,并预测了长期微咸水灌溉对土壤盐分的影响。结果表明:1.5 mg/cm3矿化度微咸水足量灌溉可以获得较高的产量和水分利用效率;各微咸水处理在60~90 cm土层均出现不同程度的盐分累积现象,具体累积深度和土壤盐分浓度与灌水量和灌水矿化度有关;采用1.5 mg/cm3矿化度微咸水进行微咸水长期灌溉研究,10 a的模拟结果显示此灌溉制度不会引起0~100 cm土层土壤次生盐渍化。该研究为滨海地区微咸水合理利用提供了理论依据。     

鲁北地区地膜覆盖对棉花需水量、作物系数及水分利用效率的影响

作物系数和需水量是制定作物灌溉制度和计算区域水资源平衡的重要参数,不同气候和不同栽培条件下作物系数和需水量会发生变化。本文通过大田试验,以水量平衡法计算作物需水量、以Penman-Monteith公式计算参照作物蒸散量和作物系数。结果表明,鲁北地区棉花地膜覆盖栽培比露地栽培生育期内作物需水量减少101.5mm,作物系数降低17.6%,水分利用效率增加29.3%。     

基于负压灌溉系统的温室番茄蒸发蒸腾量自动检测

针对目前关于作物蒸发蒸腾量测量方法中存在测定成本高、工作强度大及精确度差等问题,设计了一种测量作物蒸发蒸腾量的负压灌溉系统(negative pressure irrigation,NI)。为验证测量结果的精确性,以水量平衡法为对照(CK),采用田间小区定位试验,研究了NI条件下日光温室番茄周年土壤水分动态变化,并对比分析了温室番茄蒸发蒸腾量及水分利用效率。结果表明:NI条件下的温室番茄0~20 cm土壤含水率及0~100 cm土体贮水量变化稳定,周年变化幅度分别为21.4%~23.8%和322.2~333.3 mm。负压灌溉系统测量的春茬番茄蒸发蒸腾量呈单峰曲线变化,季节变化幅度为0.46~5.68 mm,最高值出现在5月20日;秋茬番茄的蒸发蒸腾量季节变化幅度小于春茬番茄,仅为0.56~3.43 mm,最高值出现在10月12日。NI测定的番茄周年蒸发蒸腾量为533.4 mm,低于CK计算结果(541.6 mm),但并无显著性差异(P0.05)。2种方法测定的周年蒸发蒸腾量呈极显著线性正相关关系(P0.01),相对误差绝对值的平均仅为3.83%~7.71%,绝对误差绝对值的平均也只有2.14~5.08 mm。2种方法得到的温室番茄水分利用效率也无显著性差异。综合分析,负压灌溉系统能够实现温室番茄蒸发蒸腾量的计算,其结果不仅与水量平衡法无显著差异,而且简便快捷、使用成本低、测定结果可靠,为温室作物的蒸发蒸腾量测量提供了新的技术手段。     

干旱区膜下滴灌条件下洋葱水分生产函数与优化灌溉制度

为探索西北内陆旱区膜下滴灌条件下洋葱节水、高产和高效的灌溉制度,开展了2 a田间试验,分析了洋葱的耗水规律及其影响因素,建立了洋葱的水分生产函数,并对洋葱的灌溉制度进行了优化。结果表明：膜下滴灌条件下洋葱的耗水量为170.1～395.7 mm,产量随灌水量和耗水量的增加而增加,水分利用效率则随灌水量的增加而降低。苗期和成熟期亏水对洋葱产量和水分利用效率无显著影响。洋葱水分敏感指数在鳞茎膨大期最大,发叶期次之,苗期和成熟期较小。膜下滴灌条件下,西北旱区干旱年洋葱全生育期灌水量为375 mm时,可获得较高的产量;其优化灌溉制度为苗期灌水30～40 mm,发叶期灌水130～140 mm,鳞茎膨大期灌水170～190 mm,成熟期灌水25 mm,灌水间隔可采用5 d。该优化灌溉制度对西北内陆旱区洋葱的节水灌溉实践具有一定参考价值。     

膜上灌水技术的生态环境效应研究

该文依据膜上灌水技术室内外试验数据,分析探讨了膜上灌水对作物生长要素中土壤水、肥、气、热环境的影响。研究结果表明：膜上灌水技术与传统的沟畦灌相比,地膜覆盖灌水法在减少地面蒸发,实现节水的同时,可调节土壤温度,减少灌溉水的深层渗漏和保持土壤肥力,提高了水分利用率,增加作物产量。膜上灌水不仅节约用水,同时也为作物的生长发育创造了适宜的根部生态环境。     

有限供水条件下旱地春小麦水分的高效利用

全球气候变化最令人担忧的问题是干旱,而水分又是影响小麦产量的重要因素之一,农田水分的管理与有效利用已经受到人们的高度重视。作者以春小麦为实验材料,采用盆栽和小区试验相结合的方法,针对黄土高原半干旱地区的有限水分环境,研究了有限供水的高效利用问题。盆栽条件下,采用3种肥力水平与拔节期、孕穗期和灌浆期有限供水组合处理。对生长发育、产量构成和水分利用效率等指标测定的结果表明,施肥可以显著增大叶面积,促进根系生长,提高子粒产量;而施肥条件下,拔节期有限供水能够显著增加穗粒数和粒重。小区试验结果表明,满足春小麦最大产量所需的灌水量约为200mm,获得作物水分利用效率最高时的适宜灌水量约为100mm,而拔节期60mm的灌水量可以使灌水利用效率接近最大值。拔节期60mm灌水条件下,耗水量、作物水分利用效率和灌水利用效率同步增长,同时土壤的贮存水也得到了有效利用。根据以上结果可得出:在黄土高原缺水地区,春小麦有限灌溉的适宜灌水量下限应不低于60mm,一次性补充灌溉的最佳时期为拔节期     

华北地区设施茄子蒸散量估算模型及作物系数确定

构建华北地区设施茄子蒸散量估算模型,可为制定其优化灌溉制度提供理论依据。本研究设灌水定额15 mm(W1)、22.5 mm(W2)、30 mm(W3)和37.5 mm(充分灌溉, CK)4个处理,在设施茄子苗期、开花座果期和成熟采摘期土壤含水率分别达田间持水量的70%、80%和70%时进行灌溉,以保证土壤供水充足。基于修正后的Penman-Monteith方程,通过分析CK处理的作物系数与叶面积指数的关系,建立了基于气象数据与叶面积指数的蒸散量估算模型,利用W1、 W2和W3实测蒸散量对其进行验证。结果表明:修正后的Penman-Monteith方程可用于设施参考作物蒸散量的估算,W1、W2和W3蒸散量的实测值与新建模型的模拟值平均相对误差分别为17.81%、18.31%和17.97%。作物系数与叶面积指数呈显著线性关系,可通过叶面积指数确定作物系数。分析W1、W2、W3和CK处理的产量和水分利用效率(WUE)得出, W2与CK产量差异性不显著,而WUE差异性显著,较CK提高31.59%,表明W2兼顾产量和WUE。W2处理下茄子的作物系数,苗期为0.21～0.46,开花座果期为0.62～0.94,成熟采摘期为0.70～0.92。本研究认为,新建模型在估算设施茄子实际蒸散量上具有较好适用性,计算出的作物系数在节水灌溉条件下具有实际应用价值。     

Responses of Tomato Cultivars to Water-Deficit Conditions (Case Study: Moghan Plain,Iran)

A field experiment was arranged in split plot based on randomized complete block design in three replications at Moghan plain, Iran, during the years 2014–2016. Treatments included four irrigation levels, 100%, 80%, 60%, and 40% of water requirements for the main plot, and tomato cultivars included for a subplot. Results indicated that deficit irrigation resulted in a decrease in yield and yield components, morphological characteristics and water use efficiency (WUE), and volumetric soil moisture in different layers of soil, while resulting in an increase in qualitative characteristics. Reductions of tomato fruit yield and other studied traits were different in the first and second agronomic years. But in general, comparison of means showed that, based on the normal irrigation, optimal growth and plant growth were observed for 08 cultivar. Moreover, under deficit irrigation conditions, Superbita cultivar exhibited higher yield and WUE compared to 08 and Matin cultivars.

Abbreviations: WUE = Water use efficiency; IWUE = Irrigation water use efficiency; K = Kelvin; IR = Irrigation water; Cul = Cultivar; ETo = Reference evapotranspiration; Etc = Evapotranspiration; Kc = Crop coefficient; Kp = Pan coefficient; cm = Centimeter; gr = Gram; t = Tone; ha = Hectare; ? = Volumetric water content; kg = kilogram.     

Physiological responses of pepper plant (Capsicum annuum L.) to drought stress

Water shortage is the most important factor constraining agricultural production all over the world. New irrigation strategies must be established to use the limited water resources more efficiently. This study was carried out in a completely randomized design with three replications under the greenhouse condition at Shahrekord University, Shahrekord, Iran. In this study, the physiological responses of pepper plant affected by irrigation water were investigated. Irrigation treatments included control [full irrigation (FI) level] and three deficit irrigation (DI) levels—80, 60, and 40% of the plant's water requirement called DI₈₀, DI₆₀, and DI₄₀, respectively. A no plant cover treatment with three replications was also used to measure evaporation from the soil surface. Daily measurements of volumetric soil moisture (VSM) were made at each 10-cm intervals of the soil column, considered as a layer. The differences between the measured VSM and the VSM in the next day and evaporation rate at the soil surface at the same layer of the bare soil with no plant cover treatment were calculated. Eventually, by considering the applied and collected water in each treatment, evapotranspiration (ET_C) and root water uptake in each layer per day were estimated. Furthermore, fruit number per plant, fresh fruit weight/day, root fresh/dry weights, shoot fresh/dry weights, root zone volume, root length and density, crop yield, and water use efficiency (WUE) were measured under different water treatments. The results showed that the maximum and minimum of all the studied parameters were found in the FI and DI₄₀ treatments, respectively. ET_C in the DI₈₀, DI₆₀, and DI₄₀ treatments were reduced by 14.2, 37.4, and 52.2%, respectively. Furthermore, applying 80, 60, and 40% of the plant's water requirement led to the reduction in crop yield by 29.4, 52.7, and 69.5%, respectively. The averages of root water uptakes in the DI₈₀, DI₆₀, and DI₄₀ treatments reduced by 17.08, 48.72, and 68.25%, respectively. WUE and crop yield also showed no significant difference in the FI and DI₈₀ treatments. Moreover, in the DI₈₀ treatment, the reduced rate of water uptake was less than the reduced rate of plant's applied water. According to these results, it can be concluded that 20% DI had no significant reduction on the yield of pepper, but above this threshold, there was an adverse effect on the growth and yield. Therefore, for water management in the regions with limited water resources, rate of plant's applied water can be decreased by around 20%.