Drainage: An annotated guide to books and journals : G. Naber. Bibliography 18, International Institute for Land Reclamation and Improvement (ILRI), Wageningen, The Netherlands, 1984. 37 pp., Dfl. 15.00/US $6.00. ISBN 90-70260-93-X     

W. Dierickx 《Agricultural Water Management》1985,10(4)

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Farmers' irrigation practices in a high rainfall area     

K. S. Yoon  K. H. Yoo  T. W. Tyson  L. M. Curtis 《Irrigation and Drainage Systems》1993,7(3):221-229

Recent droughts in the humid southeastern United States have focused attention on the need for and use of supplemental irrigation. Total annual rainfall amounts are sufficient for most crops in the region. However, erratic distribution of rainfall and the low water-holding capacities of most soils in the region cause frequent drought stresses in many crops. An on-farm study was conducted in southeastern Alabama to evaluate the effects of farmers' irrigation scheduling decisions on soil moisture variations in peanut fields irrigated with center-pivot irrigation systems. The study showed that the way irrigation was practiced in this high rainfall area often caused soil moisture deficit (SMD) level higher than the desired SMD limit during over 20% of the 140-day growing season. This is partially due to farmers' tendency to delay irrigation in anticipation of rainfall which may or may not occur, as rainfall during the growing season is often erratic and local. In contrast SMD in non-irrigated fields was higher than the SMD limit for half of the growing season.Abbreviations SMD soil moisture deficit - ET evapotranspiration - R_eff effective rainfall - WHC water holding capacity  相似文献   

Water use estimates for various rice production systems in Mississippi and Arkansas     

M. C. Smith  J. H. Massey  J. Branson  J. W. Epting  D. Pennington  P. L. Tacker  J. Thomas  E. D. Vories  C. Wilson 《Irrigation Science》2007,25(2):141-147

Rice irrigation-water use was estimated in Mississippi (MS) and Arkansas (AR) in 2003 and 2004. Irrigation inputs were compared on naturally sloping (i.e. contour-levee system) and mechanically graded fields. In MS, rice production consumed, on average, 895 mm water, but irrigation inputs were greatly affected by production system. Contour-levee systems accounted for 35% of the production area and consumed 1,034 mm irrigation. Fields mechanically graded to a consistent slope of approximately 0.1% (i.e. straight-levee systems) consumed 856 mm irrigation and accounted for 60% of the production area. Fields devoid of slope (i.e. zero-grade system) accounted for 5% of the production area and consumed 382 mm irrigation. In AR, contour-levee rice production consumed 789 mm compared to 653 mm with a straight-levee system. Using low pressure, thin wall (9–10 mil) disposable irrigation tubing to deliver water to each paddy independently reduced irrigation inputs by 28% in MS and 11% in AR when compared to a single-point (levee-gate) distribution system.  相似文献   

The growth and nitrogen economy of rice under sprinkler and flood irrigation in South East Australia     

E. Humphreys  W. A. Muirhead  F. M. Melhuish  R. J. G. White  J. Blackwell 《Irrigation Science》1989,10(3):201-213

Summary Dry-seeded rice (Oryza sativa L., cv. Calrose) was subjected to 4 irrigation treatments — continuous flood (CF) and sprinkler irrigation at frequencies of one (S1 W), two (S2W) and three (S3W) applications per week — commencing 37 d after 50% emergence (DAE). The amount of water applied was calculated to replace water lost by pan evaporation. Urea (120 kg N ha^–1) was applied in a 1:1 split 36 and 84 DAE, and there were also unfertilized controls for each irrigation treatment. Amounts of nitrate (NO ₃ ^– ) in the soil were very low throughout the growing season in all treatments, despite regular periods of draining which lasted for up to 7 d in SlW. In all irrigation treatments, the majority of the fertilizer nitrogen (N) was located in the top 20 mm of soil. After each application of fertilizer, levels of mineral N in CF declined rapidly, while levels in S3W and S1W remained high for 1–2 weeks longer. The poor growth of sprinkler-irrigated rice was not due to lower amounts of mineral N in the soil. The greater persistence of fertilizer N in the sprinkler-irrigated treatments was probably due to reduced root activity near the soil surface because of frequent periods of soil drying in between irrigations. Net mineralization of soil N in the unfertilized sprinkler-irrigated treatments was reduced by about half compared with CF.On average, the quantity of water applied (1.2–1.4 × EP) to the sprinkler-irrigated treatments appeared to be sufficient to meet the evapotranspiration demands of the crop, except possibly around flowering time. However, the plants may have suffered from moisture stress in between irrigations. Soil matric potential data at 100 mm suggested little water stress in the sprinkler-irrigated treatments during the vegetative stage, consistent with the similar tiller and panicle densities in all irrigation treatments. However, the crop was stunted and yellow and leaf rolling was observed in the sprinkler-irrigated treatments during this period. Soil matric potential data at 100 mm indicated considerable water stress in S1W beyond the commencement of anthesis, and in S2W during grain filling, consistent with the reduced floret fertility and grain weight in those treatments.  相似文献   

Crop water requirements for rainfed and irrigated grain corn in China   总被引：1，自引：0，他引：1  

W.H. Terjung  H-Y. Ji  J.T. Hayes  P.A. O&#x;Rourke  P.E. Todhunter 《Agricultural Water Management》1983,6(1):43-64

A basic parametric crop water use model (WATER) that employes climatic and environmental data to calculate temporal and spatial water consumption for a variety of major corps was applied specifically for grain corn to the region of China and Korea to investigate the evapotranspiration (ET) demand on grain corn and the associated irrigation water applications necessary for optimal crop production. A network of 241 stations provided the seasonal climatic input. The climatic input consisted of data averaged over approximately a 20 year period. Among the results, highest ET under full irrigation (first harvest) occurred in the northwestern inland sections of China, whereas least ET was found for the southeast. Under rainfed conditions, the relationship became nearly inverse. In order to achieve optimum crop yields, about 1000 mm of irrigation water was needed in the northwest, contrasted with none required in the south and east of China. A sensitivity analysis was applied to determine the degree of error introduced by faulty or uncertain environmental input data.  相似文献   

Salinity,water management and fertility interactions on yield and nitrogen fixation in snap-beans     

W. F. Campbell  R. J. Wagenet  R. R. Rodriguez 《Irrigation Science》1986,7(3):195-204

Summary Salinity, a common environmental constraint in arid and semiarid regions, causes substantial reduction in yield and nitrogen fixation in sensitive edible seed legumes. Greenhouse experiments were designed to determine whether irrigation and fertilizer supplements could reduce the adverse effects of soluble salts on yield and nitrogen fixation in a sensitive seed legume. Snapbeans, Phaseolus vulgaris L. cv Early Gallatin, inoculated with Rhizobium phaseoli L., were given 3 levels of irrigation salinity, 3 frequencies of irrigation and 2 N levels, and 3 P levels, on a P-deficient Argixeroll. Yield components, percent plant N, and acetylene reduction were reduced significantly as salinity and the interval between water applications increased. Fertilizer application had no effect on any plant component. Two- and three-way interactions confirmed the strong effects of the individual variables of salinity and irrigation frequency. Increasing irrigation frequency increased yield at all of the water salinities studied. Application of N, P, K fertilizers helped maintain yields at low to moderate levels of soil salinity, but not at high salt levels. Snap-bean plants harvested at seed maturity, however, did not show a significantly substantial benefit of fertilizer for Rhizobium in the stressed rhizosphere.  相似文献   

Irrigated land retirement     

W. Wallender  J. Rhoades  M. Weinberg  S. Lee  C. Uptain  D. Purkey 《Irrigation and Drainage Systems》2002,16(4):311-326

Land retirement is ceasing irrigation withthe goal of reducing load, in general, ofdissolved constituents and, in particular,of trace elements, present in subsurfacedrainage generated from irrigated lands. Retirement is achieved through a process ofgoal setting, strategy development anddetermining effects, developing landselection criteria, implementation, andmonitoring. In this study, effects of landretirement are evaluated using hydrologic,soil and economic models as well as resultsfrom a field demonstration study. From themodeling and field monitoring, a process isdeveloped to meet the goals of a landretirement program in the San JoaquinValley of California.Potential negative effects listed for landretirement included loss of agriculturalproductivity, perhaps permanently, and lossof revenue to surrounding communities. Uncertainties included those associatedwith reuse of retired lands as wildlifehabitat, with retired-land maintenanceincluding dust control, with potentialpreservation of retired lands in reservefor future re-introduction to irrigated ordry-land agriculture, and withinstitutional changes concerning repaymentof federal and state water contracts. Benefits would accrue from economic returnto the landowner from the sale of property,the sale or lease of irrigation watersupply, the reduced cost of handlingdrainage, and allocation of freed-up waterto beneficial uses, and the reduced risk ofselenium exposure to fish and wildlife.A recommended sequential approach to selectand manage retired land is to identifyprimary objectives; formulate and implementarea-specific land retirement scenarios;measure biologic, hydrologic, soils andeconomic consequences in the short term andthe long term and manage and monitorretired lands based on dynamic biologic,hydrologic and soil conditions.  相似文献   

Cover crop evapotranspiration under semi-arid conditions using FAO dual crop coefficient method with water stress compensation     

G. Bodner  W. Loiskandl 《Agricultural Water Management》2007,93(3):85-98

Cover cropping is a common agro-environmental tool for soil and groundwater protection. In water limited environments, knowledge about additional water extraction by cover crop plants compared to a bare soil is required for a sustainable management strategy. Estimates obtained by the FAO dual crop coefficient method, compared to water balance-based data of actual evapotranspiration, were used to assess the risk of soil water depletion by four cover crop species (phacelia, hairy vetch, rye, mustard) compared to a fallow control. A water stress compensation function was developed for this model to account for additional water uptake from deeper soil layers under dry conditions. The average deviation of modelled cumulative evapotranspiration from the measured values was 1.4% under wet conditions in 2004 and 6.7% under dry conditions in 2005. Water stress compensation was suggested for rye and mustard, improving substantially the model estimates. Dry conditions during full cover crop growth resulted in water losses exceeding fallow by a maximum of +15.8% for rye, while no substantially higher water losses to the atmosphere were found in case of evenly distributed rainfall during the plant vegetation period with evaporation and transpiration concentrated in the upper soil layer. Generally the potential of cover crop induced water storage depletion was limited due to the low evaporative demand when plants achieved maximum growth. These results in a transpiration efficiency being highest for phacelia (5.1 g m⁻² mm⁻¹) and vetch (5.4 g m⁻² mm⁻¹) and substantially lower for rye (2.9 g m⁻² mm⁻¹) and mustard (2.8 g m⁻² mm⁻¹). Taking into account total evapotranspiration losses, mustard performed substantially better. The integration of stress compensation into the FAO crop coefficient approach provided reliable estimates of water losses under dry conditions. Cover crop species reducing the high evaporation potential from a bare soil surface in late summer by a fast canopy coverage during early development stages were considered most suitable in a sustainable cover crop management for water limited environments.  相似文献   

黄河流域典型灌区灌溉节水管理模型研究   总被引：2，自引：0，他引：2  

崔远来  李远华  顾炜  谢崇宝 《中国农村水利水电》2002,(4):14-17

以黄河流域上下游2个典型灌区为背景，针对灌区有其农业水管理现状，开发了灌溉节水策略分析决策支持系统（DSS）原型。DSS是一个规划工具，通过对不同策略下田间配水及供水系统的模拟分析及综合决策，寻求最优的策略集合，以达到节约灌溉用水量、提高农业用水效率及维持农业可持续发展的目的。该DSS系统主要用于黄河流域灌区提高农业水管理水平的策略分析，也可用于评估灌区续建配套及土地最佳利用方案等方面。  相似文献   

“层流型”分草曲面用于覆盖免耕播种机的研究   总被引：8，自引：3，他引：8  

谷谒白  张云文 《农业机械学报》1994,25(1):46-51

运用流体力学基本原理对分草曲面的工作流场、秸秆覆盖层的连续介质属性，以及曲面用于分草、防堵的机理进行了研究。采用“环槽试验方法”测定秸秆层的“相当粘度”，将分草曲面视为绕流物体，提出“层流型”曲面分草器最具良好的绕流性能，宜用作覆盖免耕播种机的防堵装置。本文并对５种流线的流速变化特征及其绕流特性进行了分析研究，提出抛物线与双曲线最宜用作分草曲面的流线。  相似文献