沟灌条件下灌水沟入渗特性研究

为探明沟灌时灌水沟的水分入渗规律,从沟灌二维入渗过程、入渗湿润锋运移特性、累计入渗水量变化过程、土壤含水量分布等方面研究了沟灌的入渗特征及其影响,研究表明：灌水沟中水深、沟底宽、湿周对沟灌入渗过程均有明显影响。沟中水深增大,有利于加大侧向入渗,垂向入渗减少,而水深减小,会加大垂向入渗,增加深层渗漏。灌水沟底宽不影响灌水沟的侧向入渗,仅影响垂向入渗,底宽减小,垂向入渗深度相应减小,且土壤表面以下40 cm深以内水平向入渗深度平均值与最大垂向入渗深度的比值在沟底宽小时均大于沟底宽大时。合理的断面形式和大小有利于减小垂向入渗,加大水平侧向入渗,灌水沟断面形式为梯形断面时,宽深比近似为2效果最优。研究结果可为改进沟灌灌水技术提供参考。     

Agronomic and economic response to furrow diking tillage in irrigated and non-irrigated cotton (Gossypium hirsutum L.)

The Southeast U.S. receives an average of 1300 mm annual rainfall, however poor seasonal distribution of rainfall often limits production. Irrigation is used during the growing season to supplement rainfall to sustain profitable crop production. Increased water capture would improve water use efficiency and reduce irrigation requirements. Furrow diking has been proposed as a cost effective management practice that is designed to create a series of storage basins in the furrow between crop rows to catch and retain rainfall and irrigation water. Furrow diking has received much attention in arid and semi-arid regions with mixed results, yet has not been adapted for cotton production in the Southeast U.S. Our objectives were to evaluate the agronomic response and economic feasibility of producing cotton with and without furrow diking in conventional tillage over a range of irrigation rates including no irrigation. Studies were conducted at two research sites each year from 2005 to 2007. Irrigation scheduling was based on Irrigator Pro for Cotton software. The use of furrow diking in these studies periodically reduced water consumption and improved yield and net returns. In 2006 and 2007, when irrigation scheduling was based on soil water status, an average of 76 mm ha⁻¹ of irrigation water was saved by furrow diking, producing similar cotton yield and net returns. Furrow diking improved cotton yield an average of 171 kg ha⁻¹ and net return by $245 ha⁻¹ over multiple irrigation rates, in 1 of 3 years. We conclude that furrow diking has the capability to reduce irrigation requirements and the costs associated with irrigation when rainfall is periodic and drought is not severe.     

华北平原滴灌灌溉频率对萝卜生长的影响

研究了华北平原秋萝卜滴灌条件下 ,不同滴灌频率处理对萝卜叶面积系数、叶绿素含量、萝卜周径膨大、萝卜干重积累、根长密度、根干重密度等萝卜生长参数的影响并比较了各处理间萝卜产量的差异 ,发现在华北平原下半年降雨较多的情况下种植秋萝卜 ;1滴灌频率无论是 1 d1次还是 8d1次 ,对萝卜生长发育都没有明显影响 ;2滴灌条件下萝卜的平均重量和产量大大高于地面灌溉     

夏玉米产量与水分关系及其高效用水灌溉制度

依据灌溉试验资料,研究了水分胁迫对夏玉米生长发育和产量形成的影响,建立了产量与水分关系的数学模型,分析给出了大田夏玉米的高效用水灌溉定额,并用动态规划技术优化得出了夏玉米的最优灌水时间和每次的灌水定额。结果表明,各生育时段的水分胁迫对夏玉米的生育和产量均会造成不利影响,其中尤以抽雄～吐丝期前后４０天左右缺水对产量影响最大,其次为拔节期缺水;在１９９７年夏玉米生育期降雨量只有１３７ｍｍ的条件下,得出其最优灌溉定额为１９６６．０８ｍ３／ｈｍ２,３次灌水时间分别为７月４日、７月２８日和８月１６日。     

不同水肥措施下的冬小麦水氮利用和生物效应研究

【目的】寻找合适的冬小麦水肥方案。【方法】采用田间试验方法,在传统畦灌和水肥一体化微喷灌下分别设置不同施氮肥处理,研究了小麦干物质积累、产量、水氮利用和土壤贮水量。【结果】与传统畦灌比,微喷灌各处理灌水量减少50%,干物质积累量、产量、氮肥生产效率、水分利用效率分别增加28.2%～41.1%、0.2%～27.3%、0.8%～76.6%和23.3%～61.7%。其中传统畦灌下,推荐施氮肥与不施氮肥、农民习惯施氮肥和推荐施氮肥减氮20%处理比较,小麦干物质积累量、产量、氮肥生产效率、水分利用效率分别增加4.0%～11.4%、1.8%～26.9%、32.1%～75.3%、0.8%～28.2%。微喷灌下,与推荐施氮肥比,推荐施氮肥减氮20%的小麦干物质积累量、产量、氮肥生产效率、水分利用效率分别提高6.4%、4.5%、0.8%、2.3%。【结论】综合比较,水肥一体化微喷灌下推荐施氮肥减氮20%表现最优,提高冬小麦水氮利用效率,稳定产量,是节水减肥可推荐的有效途径。     

泾惠渠灌区畦长对夏玉米耗水特性和产量影响

泾惠渠灌区中畦田规格参差不齐,灌区由于畦田过长而造成的灌溉水量浪费屡见不鲜,不仅没有形成高产而且极大的造成了水资源的浪费。通过大田与小区试验相结合,以当地农民习惯的灌溉方式为对照,设置3个灌溉畦长处理(80、120、240 m),每个处理设置3次重复,改水为80%。研究了灌溉畦长对夏玉米在生育期内的耗水特性和产量的影响,土壤水分分布与产量及其构成因素的关系等问题,选择出兼顾节水高产可行的最优畦长。研究结果表明:在生育期灌水后,80和120 m处理畦长内畦首、畦中和畦尾的土壤相对含水率较为均匀无显著差异,240 m处理畦长畦首、畦中和畦尾的土壤相对含水率产生显著性差异;80和120 m处理夏玉米在畦首、畦中和畦尾灌水均匀度较为平均且无显著差异,240 m畦长处理差异较为显著,且80 m畦长处理产量分布最为平均、平均水分利用效率最高产量为1.021 839万kg/hm2,水分利用效率为25.12 kg/(hm2·mm)。综合夏玉米产量及其分布、水分利用效率等因素,在泾惠渠灌区80 m的灌溉畦长是兼顾节水高产的最适宜畦长,该结论以期为泾惠渠灌区大田作物高产节水提供一定理论依据。     

Field values of the shape factor for estimating surface storage in furrows on a clay soil

Surface storage of water in furrow irrigation is an important parameter in volume balance analysis for computing different parameters such as infiltration characteristics. Surface storage can be estimated in several ways. A commonly used method is to multiply the cross-sectional area of flow at the inlet of a furrow by a shape factor, whose value is often assumed to vary between 0.7 and 0.8. In this study, field data for 13 furrow irrigation events were collected from a farm in northern New South Wales, Australia. These data were used to investigate the validity of the assumption regarding the value of the shape factor. The soil type at the experimental site has a high clay content (up to 67%) and develops cracks when dry. The values of the shape factor calculated for the irrigation events in the study varied from 0.96 to 1.8, and varied between furrows and from one irrigation to the next in the same furrow. They also varied considerably during a given irrigation event. It is therefore incorrect to assume a constant value of the shape factor between 0.7 and 0.8 in mathematical models of furrow irrigation. Received: 6 May 1996     

交替隔沟灌溉条件下玉米群体水氮利用研究

为探索交替隔沟灌溉条件下玉米优化水氮供给模式,通过遮雨棚内微区试验,研究了沟灌方式、灌水量和施氮量对玉米群体水氮利用的影响.结果表明:交替隔沟灌溉中水低氮处理的籽粒产量最高,是交替隔沟灌溉高水高氮处理的1.06倍.在相同水分和氮肥条件下,交替隔沟灌溉的籽粒产量分别是常规沟灌和固定隔沟灌溉的1.05、1.16倍.各因素对全氮累积总量的影响从大到小依次为:沟灌方式、施氮量、灌水量;灌水量对全氮累积总量影响显著.     

低压管喷及其节水高产机理研究

通过在中国农科院商丘试区实施低压管喷 ,结合麦棉套种作物需水特点、农田小气候相互关系进行了农业高效用水研究与实践 ,揭示出低压管喷麦田较连续畦灌节水 4 5%～ 4 7%,棉田较连续沟灌节水 4 3 %,小麦和棉花水分生产效率达 1 .88～ 1 .95kg/ m3和 0 .3 2 kg/ m3较高水平的节水高产机理     

Impact of water application conditions on nitrogen leaching under furrow irrigation: Experimental and modelling approaches

Local infiltration tests on 1.5 m long blocked furrows were carried out on a loam soil to assess N fertiliser leaching under furrow irrigation where ridging operations entails placing nitrogen on the upper part of the ridge. This article focuses on the impact of flow depths, or water application depth (WAD), on nitrogen movement in seven 1.5-m long blocked furrows. For a first irrigation event, a WAD greater than or equal to 240 mm, significantly reduced the heterogeneity of the N concentration profiles measured at the top of the ridge and beneath the furrow. The virtually homogeneous N soil distribution with depth permitted the determination of the nitrogen balance throughout the season using soil samples obtained at the beginning and end of the season as well as the determination of nitrogen present in the crop tissue. This is not possible when there is a heterogeneous N soil profile at the end of the irrigation season, as observed under moderate WAD conditions. In addition, a substantial WAD delivered during the first irrigation event, and at a period where the plant N requirements are high, does not affect crop yield potential.     

不同灌水方式下基于水面蒸发量的夏玉米灌溉试验研究

为了探索依据水面蒸发量确定灌溉定额的可行性,在防雨棚下测坑中进行了夏玉米灌溉试验。结果表明,从总耗水量看,畦灌略高于沟灌,而沟灌又略高于滴灌,但差别不是很大。畦灌条件下植株发育快,滴灌次之,沟灌最慢。畦灌和滴灌下产量均以中等灌溉定额处理最高,而沟灌下产量以最大灌溉定额处理最高。总体上,滴灌条件下水分利用效率高于其他2种灌溉方式。干旱条件下,畦灌下以E601蒸发皿蒸发量(PE)作为夏玉米灌溉定额,每次灌水60mm;滴灌下以2/3PE作为灌溉定额为宜,灌水定额为20mm。     

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.     

Comparison of flooded and furrow-irrigated rice on clay

In some situations, potential water savings or relatively steep slopes make furrow irrigation a useful management practice for rice (Oryza sativa L.). Furrow-irrigated and flooded rice were compared in a field study conducted during three growing seasons: 1990, 1991, and 1992, at the University of Arkansas Northeast Research and Extension Center, Keiser, Ark., USA on a Sharkey silty clay soil. Excessive levee seepage greatly affected the water-use data for flooded rice production; however, there appeared to be potential for water savings on the Sharkey soil with furrow irrigation. Yields for flooded production consistently exceeded those for furrow-irrigated, with 3-year averages of 7.04, 6.02, and 5.88 Mg ha^-1 for flooded and two furrow-irrigated treatments, respectively. The yield difference appeared due to greater individual grain weight for the flooded treatment. Attempts to compensate for the yield reduction through additional nitrogen applications were unsuccessful. These results are consistent with findings of reduced rice grain yield associated with sprinkler irrigation. Furrow irrigation at an estimated 19 mm soil water deficit had a 3-year average of 11 kg ha^-1 of rice produced per mm of irrigation water applied.     

西瓜微喷试验研究

本文通过西瓜微喷试验,,研究了西瓜的需水规律、灌溉制度以及微喷对西瓜产量和含糖度的影响。试验资料表明;微喷西瓜此沟灌增产45％,省水50％左右,西瓜全生育期可喷水3～4次,灌水定额以15～17m~3/亩为宜。适宜土壤含水率为苗期60～70％,伸蔓期60～75％,结瓜期70～80％,成熟期55～65％(占田持百分数)。西瓜全生育期需水强度高峰值在结瓜期,日平均需水量达5.4mm,此期是灌水关键时期。试验表明,微喷西瓜是一种节水节能、效益高、设备简单、使用方便的灌水方法。     

垄膜沟种涌泉灌溉技术要素的试验研究

在垄膜沟种农田进行了涌泉灌灌水试验，通过对水流推进过程观测，分析了田面水流运动特性，研究了沟宽对田间灌水均匀度的影响，并对垄膜沟种涌泉灌溉技术要素进行了探讨。结果表明，涌泉灌田面水流推进曲线可用幂函数表示。随着沟宽的增大，灌水均匀度呈下降趋势。从灌水质量和管网成本两方面综合考虑，试验条件下灌水技术要素的入沟流量、沟宽和灌水器间距分别以80～100L/h、20-30cm和4～5m为宜。     

土壤入渗特性和田面糙率的变异性对沟灌性能的影响

以杨凌区粘壤土和砂壤土区域进行的大田沟灌试验为基础,在假定各灌水沟内部土壤入渗特性和糙率均一的条件下,重点分析各灌水沟之间土壤入渗参数和田面糙率的不同组合对沟灌水流运动过程和灌水质量的影响,结果表明土壤入渗特性的变异性对沟灌水流推进过程和灌水质量指标影响较大,在模拟时必须充分考虑;而田面糙率的变异性对沟灌水流推进过程和灌水质量指标影响较小,可采用田块糙率均值代替各灌水沟的糙率。经实例验证,水流推进过程相对误差为7.28%,灌水效率、灌水均匀度和储水效率模拟值与实测值误差分别为5.74%、6.18%和4.07%,结果表明其模拟效果较好。     

Wind effects on solid set sprinkler irrigation depth and yield of maize (<Emphasis Type="Italic">Zea mays</Emphasis>)

A field experiment was performed to study the effect of the space and time variability of water application on maize (Zea mays) yield when irrigated by a solid set sprinkler system. A solid set sprinkler irrigation layout, typical of the new irrigation developments in the Ebro basin of Spain, was considered. Analyses were performed (1) to study the variability of the water application depth in each irrigation event and in the seasonal irrigation and (2) to relate the spatial variability in crop yield to the variability of the applied irrigation and to the soil physical properties. The results of this research showed that a significant part of the variability in the Christiansen coefficient of uniformity (CU), and wind drift and evaporation losses were explained by the wind speed alone. Seasonal irrigation uniformity (CU of 88%) was higher than the average uniformity of the individual irrigation events (CU of 80%). The uniformity of soil water recharge was lower than the irrigation uniformity, and the relationship between both variables was statistically significant. Results indicated that grain yield variability was partly dictated by the water deficit resulting from the non-uniformity of water distribution during the crop season. The spatial variability of irrigation water depth when the wind speed was higher than 2 m s^–1 was correlated with the spatial variability of grain yield, indicating that a proper selection of the wind conditions is required in order to attain high yield in sprinkler-irrigated maize.     

Effect of improved cultural practices on crop yield and soil salinity under relatively saline groundwater applications

The salinity in the root zone increases with the application of relatively saline groundwater. Therefore, a limited water supply coupled with high pumping cost and salinity hazards, makes it more important than ever that irrigation water be used efficiently and judiciously. In the present study, farmer's practices of irrigation application methods (Field 1) were compared with the water saving techniques (Field 2) for crop yield and salinization for two years with maize–wheat–dhanicha cropping pattern. For maize crop, regular furrow method of irrigation was used in Field 1 and alternate furrow method of irrigation was used in Field 2. For wheat experiments, basin irrigation method of water application was compared with bed and furrow method. For dhanicha, basin irrigation was applied in both the fields. The results showed that about 36% water was saved by applying irrigation water in alternate furrows in each season without compromising the maize crop yield. The salt accumulation in root zone in alternate furrow field was less than that in regular furrow field. The salinity level near the surface increased substantially in both the fields. The water saving in wheat crop under bed and furrow was 9–12% in both seasons. The salinization process in both fields during wheat crop was almost same except redistribution of salts throughout the root zone in basin field of wheat. The salinity developed in root zone during two major growing seasons was leached in monsoon.     

Effect of small irrigation amounts on the yield of wheat

Yields of dryland crops are governed by the moisture in the soil profile at seeding and by rainfall during the growing season. Occasionally limited amounts of water may also be available for irrigation. Field experiments were conducted over a period of 4 years on loamy sand and 3 years on sandy loam to study the effects of pre-seeding, post-seeding and split application of limited amounts of water on root growth, water use, dry matter accumulation and grain yield of wheat. This article reports the treatment effects on dry matter accumulation and grain yield.Early season water stress decreased the rate of dry matter accumulation. Grain yield responded significantly to irrigation 30 days after seeding irrespective of the amount of water, year and soil type. Yield with post-seeding irrigation averaged 3518 kg ha^?1 against 2317 kg ha^?1 for unirrigated control in loamy sand and 4440 kg ha^?1 against 3391 kg ha^?1 in sandy loam. The increase in yield was manifested by a significant increase in the number of effective tillers per m row length, number of grains per ear and thousand grain weight.     

基于CROPWAT的泾惠渠灌区玉米和棉花灌溉需水量时空分布研究

基于泾惠渠灌区30a的气象资料,采用CROPWAT模型分析了泾惠渠灌区作物蒸发蒸腾量及灌溉需水量的变化,并运用SPSS软件,计算了灌区作物需水量与气象因子的相关系数。分析表明:玉米蒸发蒸腾量平均值为524.33mm,蒸发蒸腾量高峰期出现在7月中旬到8月下旬;棉花蒸发蒸腾量平均值为869.13mm,峰值出现时间与玉米一致;灌区玉米在抽雄-开花期灌溉需水量为130.12mm,籽粒形成-乳熟期灌溉需水量为359.32mm,9月下旬以后,灌溉需水量下降;棉花生育期需水量空间分布比较均匀,平均值为869 mm,整个灌区灌溉需水量平均值为453.6mm,棉花苗床期灌溉需水量开始增加,花铃期达到最大值,吐絮期灌溉需水量减小;灌区作物需水量与气温呈正相关,与降水呈负相关,与风速和相对湿度相关性较小,与日照时数相关性较大。