土壤基质势调控对温室滴灌番茄土壤水分分布和产量的影响

【目的】指导设施蔬菜生产中科学合理地利用滴灌技术进行灌溉。【方法】采用小区试验的方法,以冬春茬番茄为研究对象,布置了7个不同土壤基质势阈值的试验,在番茄开花坐果期和结果期分别控制滴头正下方20 cm深度土壤基质势在-15和-15 kPa(S1)、-15和-30 kPa(S2)、-15和-45 kPa(S3)、-25和-25 kPa(S4)、-30和-15 kPa(S5)、-30和-30 kPa(S6)以及-30和-45 kPa(S7),研究了日光温室滴灌土壤基质势调控下土壤水分随时间变化及空间分布的规律,以及番茄产量、畸形果率和灌溉水利用效率等。【结果】①控制滴头正下方20 cm深度土壤基质势可以明显影响0～100 cm深度土壤水分状况。②在番茄开花坐果期,当土壤基质势阈值控制在-30 kPa或更高时,番茄根系主要吸收利用0～60 cm深度以上范围的土壤水分,70 cm深度以下土壤水分基本不变,0～60 cm深度土壤体积含水率平均为28.6%,为田间持水率的84%,60～100 cm土壤体积含水率平均为36.2%,为田间持水率的90%。③番茄进入结果期后,当土壤基质势阈值控制在-25～-15 kPa时,整个土体土壤含水率基本保持在田间持水率的77%～91%,根系主要吸收利用0～60 cm深度以上范围的土壤水分,70 cm深度以下土壤水分消耗缓慢;当土壤基质势阈值降低到-45～-30 kPa时,根系吸收利用到80～100 cm深度的土壤水分,整个土体土壤含水率不断降低,降低到田间持水率的60%～66%。④不同处理番茄产量、畸形果率和灌溉水利用效率有明显差异,其中S3和S7处理番茄产量高,S5处理产量低;S1、S3和S4处理的畸形果率大,S6和S7处理的畸形果率低;S1处理的灌溉水利用效率最低,S7处理的灌溉水利用效率最高。【结论】日光温室少量高频滴灌条件下,当滴头正下方20 cm深度土壤基质势阈值开花坐果期控制在-30 kPa、结果期控制在-45 kPa时,整个土体土壤水分状况基本良好,番茄的产量高,畸形果率低,灌溉水利用效率高。     

不同土壤基质势对滴灌枸杞生长的影响研究

采用滴头正下方0．2m深处埋设负压计控制土壤基质势下限进行水盐调控,通过田间试验研究了不同土壤基质势对宁夏枸杞生长和产量的影响。试验结果表明,2010年枸杞生长周期内,随着土壤基质势的降低,不同处理的累计灌水量显著减少,不同土壤基质势处理对枸杞生长和产量都没有显著影响。当滴头正下方0．2m处土壤基质势为-20kPa时,...     

The inherent variability of water stress indicators in apple, nectarine and pear orchards, and the validity of a leaf-selection procedure for water potential measurements

The following two topics were examined: (1) The variability in the measurement of leaf water potential (LWP), stem water potential (SWP), maximum daily trunk shrinkage (MDS), and soil water tension (SWT) in apple, nectarine and pear orchards; and (2) The validity of a leaf-selection procedure for SWP measurements in commercial apple orchards. 27 trees were selected in an apple orchard, 27 in a nectarine orchard, and 30 in a pear orchard. The trees were close to each other. The measurements comprised of: midday SWP in apple, nectarine and pear; midday LWP in apple; MDS in apple and nectarine; and SWT in pear. The mean and standard errors (SEs) of each water status indicator in each species were calculated for an increasing sample size. The sample sizes required for stable averages were: SWP – 4, 5, and 8 trees for apple, nectarine and pear, respectively; MDS – 17 and 16 trees for apple and nectarine, respectively; SWT – 21 for pear trees. The relative SEs (i.e. percent of population mean) were 2.4, 6.1 and 10.1% in SWP/LWP, MDS and SWT, respectively. Possible explanations for the differing variability of the various water status indicators are discussed. The results show that smaller samples were sufficient to represent SWP and LWP properly than what was required for MDS and SWT. 9 commercial apple plots were selected and about 25 randomly selected leaves were used for midday SWP measurements in each plot (i.e. experimental sets). About 5 leaves on closely adjacent “representative” trees were selected in each of the commercial plots (i.e. commercial sets) and midday SWP was measured. The average difference in SWP between the experimental and the commercial sets was –0.127 MPa. The choice of closely adjacent trees increased the deviation from the experimental sets. The use of a reasonable sample size (n=7) may enable midday SWP to be measured within ±0.15 MPa in most commercial orchards.     

Model for assessing impact of salinity on soil water availability and crop yield

The salinity condition in the root zone hinders moisture extraction from soil by plants, because of osmotic potential development in soil water due to presence of salts, which ultimately, decreases transpiration of plants and thereby affects crop yield. Therefore, an effort was made in this study to quantify the impact of salinity on soil water availability to plants. The movement of salts under irrigation and evapotranspiration regimes in root zone of soil profile was studied throughout the growing season of wheat crop with adopting exponential pattern of root water uptake. A model was developed to analyze soil water balance to find out moisture deficit because of salinity. A non-linear relationship was formulated between moisture content and salt concentration for simultaneous prediction. The Crank–Nicolson method of Finite Differencing was used to solve the differential equations of soil water and solute transport. The effect of various salt concentrations on transpiration was analyzed to develop a relationship between relative evapotranspiration and relative yield. Relationships among salt concentration, matric potential, moisture deficit and actual transpiration were also established to provide better understanding about impact of salinization and to provide guidelines for obtaining better crop yields in saline soils.     

Drought response of rice at different nitrogen levels using line source sprinkler system

Summary In rainfed rice, the nitrogen status of soil and plant is closely related to the moisture regime in the soil. The lower the soil moisture content, the lower the nitrogen use efficiency in the plants.In this study, the yield and growth responses of four rice cultivars to seven irrigation and three nitrogen levels were evaluated using the line source sprinkler system. Visual observations on the degree of drought reaction and measurement of leaf water potential (LWP) were also made.The effect of drought was least on the traditional variety Kinandang Patong and most on the modern variety IR 20. Increasing nitrogen levels from 0 (no nitrogen fertilizer) to 60 and 120 Kg N/ha increased the degree of water stress. This also resulted in decreased LWP especially when the total water applied was minimal. At all levels of nitrogen, Kinandang Patong had significantly higher LWP than IR 20. There was a curvilinear decrease in the number of days to heading and a linear increase in plant height and dry matter production with increase in total water applied.The yield-water-fertilizer relationships of the four cultivars revealed different production surfaces. The early-maturing IR 52 rice gave the highest grain yield at 120 kg N/ha and with maximum water application of 850 mm. Without nitrogen fertilizer application, Kinandang Patong gave the highest predicted yield with 550 mm of water applied. At 120 kg N/ha and 550 mm of water, IR 36 was superior in yield to other rices tested.Results suggest that in areas of uncertain moisture supply, nitrogen application rate should be reduced from that normally used for irrigated rice.     

Use of saline–sodic waters through phytoremediation of calcareous saline–sodic soils

Use of poor-quality groundwater has become inevitable for irrigation to compensate rapidly increasing water demands in many arid and semiarid regions. Salinity and sodicity are the principal soil and water quality concerns in such areas. Many saline–sodic and sodic soils have saline or saline–sodic subsurface drainage waters. Amelioration of these soils needs a source of calcium (Ca²⁺) that can replace the excess exchangeable sodium (Na⁺). Most of these soils, however, contain calcite (CaCO₃) of extremely low solubility. The native calcite does not supply adequate levels of Ca²⁺ for soil amelioration as do other chemical amendments. Phytoremediation may help ameliorate such soils through cultivation of certain crops tolerant to ambient soil salinity and sodicity. This amelioration strategy works through plant root action to help dissolve CaCO₃ to supply adequate Ca²⁺ without the application of an amendment. During a 3-year field experiment conducted under irrigated conditions, we evaluated phytoremediation against soil application of gypsum and farm manure, and water treatment with sulphuric acid on a calcareous saline–sodic soil (pH_s=8.0–8.4, EC_e=24–32 dS m⁻¹, SAR=57–78, CaCO₃=45–50 g kg⁻¹ for the top 0.15 m depth; Calcic Haplosalids). A saline–sodic water (EC=2.9–3.4 dS m⁻¹, SAR=12.0–19.4, RSC=4.6–10.0 mmol_c l⁻¹, SAR_adj=15.6–18.4) was used to irrigate the rice (Oryza sativa L.) and wheat (Triticum aestivum L.) crops grown in rotation. Active desalinisation and desodication processes were observed in all the treatments. After the final wheat crop, the 1.2 m soil profile EC_e was 7±0.5 dS m⁻¹ and SAR was 15±2 with non-significant treatment differences, indicating comparable soil amelioration effect of phytoremediation with other treatments. Better crop yields were obtained from the manure-treated plots, owing to its annual addition to the soil that possibly improved soil fertility. Phytoremediation needed minimum capital input because no initial investment was made to purchase the amendments.     

水分调控对干旱山地苹果树生长发育和结实的影响

人为灌溉补水是改善干旱山地果园水分供应状况的有效措施。为给山地果树精准灌溉提供科学依据,以陕北米脂山地6年生红富士苹果树为研究对象,以苹果树物候期为时段,以土壤田间持水量为标准进行了水分调控试验,研究分析了水分调控对干旱山地苹果树生长及果实生长发育的影响。结果表明,陕北山地苹果树萌芽期(3月下旬-4月中旬)、开花期(4月下旬-5月初)、新稍生长和幼果发育期(5月初-7月上旬)及果实膨大期(7月中旬-10月上旬)适宜的土壤含水量分别为田间持水量的50%~60%、50%~60%、50%~60%和70%~80%。在一般水文年,陕北山地苹果树萌芽期适宜的灌溉量为56.50mm,开花期为22.20mm,新稍生长和幼果发育期为92.63mm,其中5月初-6月上旬宜灌水75.16mm,6月中旬-7月上旬宜灌水17.47mm,果实膨大期降雨量可满足苹果树的需水量,不需灌溉。     

宁夏南部雨养农业区玉米生育期土壤含水率控制阈值研究

在宁夏南部雨养农业区,设置玉米不同生育期土壤含水率控制下限指标,开展以土壤含水率为灌溉控制指标的精量灌溉技术试验研究。在分析玉米各生育期灌水量、土壤含水率、作物产量、水分利用效率的基础上,推荐在丰水条件下,玉米生育期土壤含水率控制阈值为:种植期80%θf、苗期—拔节期55%θf、拔节期—抽雄期85%θf、抽雄期—灌浆期80%θf,水分生产效率可达3.35kg/m3。宁夏南部雨养农业区推荐土壤含水率控制阈值为:种植期60%θf、苗期45%θf、拔节期50%θf、抽雄前期60%θf,水分生产效率可达3.7kg/m3。     

蓄水坑灌条件下不同灌水下限幼龄苹果树叶片光合特性研究

以3a生矮砧红富士为试验材料,采用LI-6400XT便携式光合仪,对蓄水坑灌条件下不同灌水下限(分别为田间持水率的50%、60%、70%)幼龄苹果树叶片光合特性进行研究,并通过通径分析与多元逐步回归分析量化各影响因子与净光合速率的关系。结果表明:蓄水坑灌条件下不同灌水下限叶片净光合速率、气孔导度、蒸腾速率、胞间CO2浓度变化规律基本一致。当土壤水分不足时,净光合速率主要受土壤含水率影响;当土壤水分充足时,净光合速率主要受光合有效辐射影响。气孔导度主要受光合有效辐射影响,地面灌溉条件下气孔导度对环境变化的响应更积极。蒸腾速率主要受土壤含水率和光合有效辐射的影响,土壤水分充足时,蒸腾速率对光合有效辐射的响应更敏感。相同条件下,土壤含水率越高蒸腾速率越大。     

蓄水坑灌条件下不同灌水下限幼龄苹果树耗水特性及作物系数的试验研究

以三年生矮砧红富士为试验材料,利用水量平衡方程和彭曼-蒙特斯公式(Penman-Monteith)计算幼龄苹果树全生育期的实际耗水量和参考作物蒸发蒸腾量,探明了蓄水坑灌条件下不同灌水下限幼龄苹果树的耗水特性及作物系数变化规律。结果表明:1CK、T_2、T_3处理全生育期耗水量差异不大,分别为327.40、322.60和314.10mm;T_1处理最小为296.40mm。生育期内各处理耗水量均呈中间大,两头小的"纺锤形"分布,生育中期(7-9月)的耗水模数为69.43%~75.44%,此阶段是幼龄苹果树的需水关键期。2CK、T_2、T_3处理幼树作物系数全生育期内呈双峰分布,初始生育期缓慢增长;花芽分化期,略有下降;快速生育期,作物系数持续增长并在生育中期达到峰值;成熟期,作物系数迅速减小;T1处理幼树作物系数全生育期内呈单峰分布,除7月外,其余时期都小于其他处理;不同处理幼树作物系数均在9月达到峰值。3蓄水坑灌比地面灌溉具有更强的蓄水保墒能力。     

苗期土壤水分控制对线辣椒生长和水分利用效率的影响

以我国北方普遍种植的经济作物线辣椒为研究对象,根据线辣椒的生理生长特点,通过盆栽试验,研究了苗期不同土壤水分下限对线辣椒长势、产量和WUE的影响。结果表明,在试验条件下,土壤水分下限控制在田间持水率(θF)的45%～60%时,线辣椒生长状况良好,50%θF时线辣椒的生物量、根冠比最大;各处理按线辣椒单株产量大小排序为:处理4>处理3>处理2>处理1>处理5>处理6;各处理按线辣椒全生育期WUE大小排序为:处理3>处理4>处理2>处理1>处理5>处理6。产量最高时的苗期土壤含水率为50%θF,WUE最高的苗期土壤含水率为55%θF,从而得出线辣椒获得较高产量所对应的苗期土壤水分下限为(50%～55%)θF。     

Water status response of corn and cotton to altered irrigation

Water is a primary limiting factor to crop production and thus crop water status is essential information for management decisions. Corn and cotton were grown in the field under two constant water regimes. The low water level (WL) was 0.662PET (potential evapotranspiration) in corn and rainfall for cotton. The high water level (WH) was 1.02PET for both crops. Two transient water treatments in each crop began as the two constant water level treatments but then the water inputs were reversed and the change in water status was monitored. When the transient water treatments were initiated, corn was at the V14 and V16 growth stages in the WL and WH treatments, respectively, and cotton was 2 weeks past first bloom for both water levels. The purpose of the experiment was to compare the sensitivity of leaf water potential (LWP) and crop canopy temperature to changes in irrigation rate. The transient water treatment of each crop that relieved water stress (TLH) changed from WL to WH and the treatment which induced water stress changed from WH to WL (THL). The LWP values of the transient water treatments reversed 5 and 8 days after reversing water input rates to corn in 1998 and 1999, respectively, and after 3 days in both years for cotton. A reversal in canopy temperatures, expressed as the amount of daily time that the temperature was above 28°C (DST), was not detected between the TLH and THL treatments of corn after 25 days in 1998 or after 13 days in 1999. The DST values of the cotton transient water treatments reversed after 4 days in 1998 and 5 days in 1999, when the values of THL became greater than for TLH. Corn tassels, which apparently transpire less than leaves, were forming at the beginning of the transient water treatments and their presence in the view of the infrared thermocouples may have reduced the apparent radiometric temperature difference between the transient water treatments. During the water status adjustment period following the initiation of the transient water treatments, there were significant linear relationships between LWP and DST in cotton in both years but only in 1998 in corn. Cotton canopy temperature could be used to rapidly monitor an entire field in contrast to LWP which accurately measures plant water status but cannot provide automated measurements across a large area.     

水气互作对温室番茄生长、产量和水分利用效率的影响

[目的]探寻温室番茄适宜水气组合及加气阈值,为温室番茄的高产提供理论基础及技术指导.[方法]采用微纳米气泡水结合地下滴灌系统,设置了3个灌溉水溶解氧质量浓度分别为井水对照3～5 mg/L (O1)、15 mg/L(O2)和25 mg/L (O3),每个溶解氧质量浓度下均设置3种不同灌溉控制水平,土壤含水率分别控制在田间...     

水分调亏对地下滴灌夏玉米田水热动态的影响

通过北京地区地下滴灌夏玉米田间试验,研究了前期不同程度水分亏缺对土壤水热和夏玉米冠层温度、株高、叶面积指数及产量的影响。结果表明:在20～60 cm土层,除重度亏水处理外,其他处理的土壤含水率均在高位平稳变化;在60～100 cm土层,丰水处理的土壤含水率最大;对不同深度的土层,轻度与中度亏水处理两者间的土壤含水率差异较小。受作物覆盖度和亏水程度的影响,拔节期各处理间土壤温度和冠层温度有明显差异;在较浅土层(距地表30 cm和50 cm处)中,拔节期之前丰水处理的土壤温度较低,拔节期之后各处理间差异逐渐减小;在较深土层(距地表80 cm处)中,水分亏缺程度越大,土壤温度越高。轻度亏水处理能获得较高的产量,中度亏水处理能提高水分利用效率。     

Evapotranspiration relationship with pan evaporation and evapotranspiration ratio of corn under different nitrogen levels and moisture regimes

In a field experiment with four moisture regimes and eight nitrogen levels, the ratios between evapotranspiration and pan evaporation ($\text{Et}\text{Eo}$) were low in the initial stages of crop growth and attained maximum values at 70–80% (20 and 40% available soil moisture depletion (ASMD)), 65% (60% ASMD) and 55% (80% ASMD) of the crop growth stage. Amongst nitrogen levels, the evapotranspiration ratio (ETR) was highest (3573) under no nitrogen and lowest (1312) with 180 kg N/ha. The 20% ASMD regime utilised less water (ETR= 1499 to produce a kilogram of grain than did the other moisture regimes. The lowest evapotranspiration ratio (914) was recorded with 20% ASMD and 180 kg N/ha in combination. The highest ETR (3954) was found with 60% ASMD and no nitrogen. An additive effect of nitrogen and moisture was found, in indicating that they can be substituted one for the other, when one of them becomes a constraint.     

不同节水灌溉方式对小麦产量及水分利用效率的影响

为探讨不同节水灌溉方式对小麦产量及水分利用效率的影响,在通许试验基地进行了节水灌溉方式(滴灌、微喷灌、喷灌和小白龙)及灌水量(45、90、135mm)的大田试验,分别于拔节和灌浆前期灌水。结果表明:小麦收获时土壤储水量表现为滴灌微喷灌喷灌小白龙,总耗水量以滴灌和微喷灌方式下较少;小麦千粒重随灌水量增加有降低趋势,且在微喷灌方式下明显高于其他处理,而小麦群体、穗长、小穗数和穗粒数均以滴灌方式下表现较佳;灌水能增加小麦产量,水分利用效率随灌水量的增加而降低;以滴灌135 mm的产量最高,水分利用效率以滴灌45mm处理为最高。4种节水灌溉方式中,滴灌更有利于增产和节水,其次为微喷灌。     

The dual crop coefficient approach using a density factor to simulate the evapotranspiration of a peach orchard: SIMDualKc model versus eddy covariance measurements

The dual crop coefficient approach accounts separately for plant transpiration and soil evaporation by using the basal crop coefficient and the evaporation coefficient, respectively. The SIMDualKc model, which performs the soil water balance simulation with estimation of the actual crop evapotranspiration (ET) with the dual crop coefficient approach, was applied to a drip-irrigated peach orchard under Mediterranean conditions. Orchard ET was obtained with the eddy covariance technique, which was subsequently correlated with tree transpiration estimated from sap flow measurements and soil evaporation determined with microlysimeters, thus providing ET for the whole irrigation season. Two years of field observations were used for model calibration and validation using those ET measurements and taking into account the fraction of ground covered by trees through a density factor which adjusts the basal crop coefficient. Model fitting relative to ET observations during calibration and validation provided indices of agreement averaging 0.90, coefficients of regression close to 1.0, root mean square errors around 0.41 mm and average absolute errors of 0.32 mm. Model fitting relative to transpiration and to soil evaporation produced similar results, so showing the adequateness of modelling.     

干旱区膜下滴灌棉田灌溉制度及土壤水盐运移规律研究

以棉花各生育期适宜土壤含水率上、下限差值为灌水控制指标,设置3水平灌水处理,开展膜下滴灌大田试验,分析研究适宜试验区棉花生长、水分利用效率高的灌溉制度及膜下滴灌棉田土壤水盐运移规律。结果表明:适宜土壤含水率上、下限差值形成的灌溉制度,决定了土壤水盐运移规律、盐分分布和积累特征。总体表现为:空间上土壤水分分布与滴灌带间距呈负相关系,盐分分布则相反,0~40 cm深度土壤水分在灌后重分布,盐分在滴灌水分的淋洗作用下定向运移,至湿润体边缘积聚。综合分析关键点与主根层的土壤水盐时间序列变化,T2处理(385 mm/18次)主根层0~40 cm深度水分处于棉花生长的适宜含水率范围,并形成淡化脱盐区,对盐分的调控最佳。T2处理棉田产量最高,为6 083 kg/hm~2,水分利用效率为1.05 kg/(mm·hm~2),为适宜的灌溉制度。     

不同灌溉控制指标对冬小麦生长及耗水特性的影响

【目的】探究冬小麦适宜的计划湿润层深度和土壤含水率控制下限的组合模式,为冬小麦田间用水管理及自动灌溉控制决策提供理论依据。【方法】以冬小麦为研究对象,采用大田试验,设置3个土壤含水率控制下限(L:40%,M:50%,H:60%)和3个计划湿润层深度(60、80、100 cm),共9个处理(T60L、T60M、T60H、T80L、T80M、T80H、T100L、T100M、T100H),研究了不同计划湿润层深度与土壤含水率控制下限对华北地区冬小麦生长发育和水分利用的影响。【结果】计划湿润层深度及土壤含水率控制下限的不同改变了处理间灌水定额及灌水次数,计划湿润层深度过高或土壤含水率控制下限过低均不利于冬小麦植株的生长发育。随着计划湿润层深度(60~100 cm)和土壤含水率控制下限(40%~60%)的增大,冬小麦花前及花后的干物质累积量呈先增大后减小的趋势。产量随土壤含水率控制下限增高呈增加趋势,当计划湿润层深度为80 cm时,产量相对最高,同时耗水量也越多,而计划湿润层深度为60 cm时耗水量最少。计划湿润层深度越低,土壤含水率控制下限越高,冬小麦水分利用效率则越高。T60H处理的水分利用效率最大,为19.96 kg/(hm²·mm),比最小值T100L大21.0%。【结论】本试验条件下,计划湿润层深度为60 cm,土壤含水率控制下限设置为土壤有效含水率的60%时,冬小麦节水高产效果相对最优。     

沙地喷灌土壤基质势调控对土壤水分分布和马铃薯产量的影响

[目的]制定砂质土壤马铃薯的喷灌灌溉制度。[方法]选择“夏波蒂”(抗旱性弱)和“费乌瑞它”(抗旱性强)2种不同抗旱能力的马铃薯品种,通过2a的田间试验,研究了不同土壤基质势阈值对土壤水分状况、马铃薯产量与灌溉水利用效率等的影响,以确定马铃薯适宜的土壤基质势阈值来指导灌溉。2012年布置了3个处理,在马铃薯定苗后分别控制垄中心20cm深度处土壤基质势阈值为-20、-30和-40kPa,2013年增加了1个-10kPa处理。[结果]大型喷灌机灌溉条件下监控垄中心20cm深度处土壤基质势可较好地调控马铃薯农田的土壤水分状况;①指导灌溉的土壤基质势阈值越高,马铃薯生育期内0~30cm深度平均土壤基质势越高,并且变化幅度越平缓;土壤基质势阈值越低,0~30cm深度平均土壤基质势越低,且变化越剧烈;40cm深度以下土壤水分状况与土壤基质势阈值的关系不明显。②不同抗旱能力马铃薯品种的产量都随着土壤基质势阈值的降低而线性降低,当阈值低于-15.8 kPa时,土壤基质势每降低1kPa,产量降低1.8%,且主要表现在大薯(W≥250g)和中薯(150g≤ W<250g)质量的降低,单株结薯个数基本不受影响。③灌溉水利用效率随着土壤基质势的降低而线性增加,表现为土壤基质势每降低1 kPa,灌溉水利用效率升高1.3%。[结论]砂质土壤大型喷灌机灌溉或类似农业生产条件下,推荐监控垄中心20cm深度处土壤基质势来指导施肥灌溉,并且土壤基质势阈值建议为-15.8 kPa左右,在淀粉积累期之后可考虑适当地降低土壤基质势阈值,以获得高产和较高的灌溉水利用效率。