Farmers' irrigation practices in a high rainfall area

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     

南方易渍农田水稻节水增产灌溉方式试验研究

针对我国南方易渍稻田土壤粘重、地下水位高、通透性差等特点，提出不同的灌水方法，并通过对大量的试验结果分析，得出了适宜的灌水方法及地下水埋深。     

井灌水稻区渠道增温效果与其影响因素关系试验研究

通过田间试验 ,探求了三江平原井灌水稻区渠道内井水增温与其几个影响因素的函数关系 ,建立了经验模型 ,可供灌溉管理者及有关人士参考。     

Impacts of Institutional Reforms on Irrigated Agriculture in Pakistan

Poor functioning of theirrigation system in Pakistan has been asource of concern for the last few decades,during which time it has been the subject ofconsiderable external assistance andinternal policy reforms. Consequently, thegovernment of Pakistan introducedinstitutional restructuring in irrigationand drainage subsectors to impartnecessary improvements. Under thesereforms, management at secondary canallevel has recently been handed over to theFarmers Organizations (FOs) of selecteddistributaries in pilot areas. This studywas designed to evaluate a farmer-manageddistributary in southern Punjab. Fieldmeasurements revealed that hydraulicaspects of the irrigation service deliveredby the FO management has been significantlyimproved and as a result highlyproportionate and equitable waterdistribution was observed, particularly atthe tail reaches of the distributary. Dueto effective FO management farmers'interventions to increase the outletdischarge by illegal means has been almosteradicated. As a result of theseimprovements imparted by the FO in systemmanagement, the extent of irrigated area hasincreased on average by 6 to 7%, evenunder severe drought-like conditionsprevailing in the country during recentyears. Further cost recoveries haveincreased by an amount of 14% for summerand 23% for winter growing seasons,respectively, from the irrigated area of thedistributary. Thus experience from Hakra4-R distributary has shown that even underundesirable natural circumstancesIrrigation Management Transfer (IMT) wasquite effective in achieving the keytargets of the institutional reformslaunched at pilot scale in the country.     

制动气室有效承压面积的研究

我国拖拉机挂车气制动系统执行机构主要采用膜片式制动气室，对其有效承压面积进行理论分析和试验研究后．得出膜片式制动气室有效承压面积不仅与几何尺寸和气压有关。还与工作行程有关，找到了膜片式制动气室有效承压面积的变化规律，指出了不同型式的膜片式制动气室推杆有效工作行程范围。     

试论丘陵地区灌溉机械化发展对策

本文通过四川省射洪县的事例，分析了丘陵地区机械灌溉在发展农业和农村经济中的地位和作用，以及目前存在的困难和问题，提出了发展对策建议。     

灌区灌溉自动化监控系统的设计与研究

介绍了 1种灌区灌溉自动化监控系统的组成、功能和实现方法。系统利用田间传感器实时测量田间参数 ,通过网络传送给控制计算机 ,由控制计算机根据决策模型自动控泵房电机起停、渠首闸门启闭实现灌区内农田自动灌溉 ,系统具有实时控制、实时数据采集与保存 ,现场实时视频监视等功能。     

基于Landsat数据的条件植被温度指数升尺度转换方法

以陕西省关中平原为研究区域,应用点扩散函数、混合像素面积权重法和中值像素变异权重法将基于Landsat卫星遥感数据反演的分辨率为30 m的条件植被温度指数(VTCI)干旱监测结果上推至930 m的干旱监测结果,并与Aqua MODIS数据反演的分辨率为930 m的VTCI干旱监测结果进行对比分析,以期为两种空间尺度的干旱监测结果的综合应用提供技术支持。以MODIS数据反演的VTCI为参考,应用相关系数、均方根误差、半变异函数的估计值和图像纹理特征等对尺度上推的VTCI进行评价。结果表明,点扩散函数和混合像素面积权重法的尺度上推效果均较好,而中值像素变异权重法的尺度上推效果较差,说明点扩散函数和混合像素面积权重法均适用于研究区域VTCI干旱监测结果的尺度转换,且点扩散函数的数据处理过程更为简单。典型样点VTCI的尺度上推结果表明,空间异质性越小,尺度上推的结果越好。     

东北地区种植业机械化水平的灰色关联辨识

发展农业机械化是东北老工业基地振兴的重要内容.为此,对现阶段东北地区种植业机械化装备水平、生产经济系统的投入产出状况以及环境状况进行了科学的分析,运用灰色关联分析方法对其进行系统的辨识,这对于东北农业的发展、增加农民收入、加快农村富余劳动力转移,优化农业和农村经济结构具有重要意义.     

干旱缺水灌区节水灌溉评价标准及其分析

在分析节水灌溉定义内涵的基础上，提出了评价干旱缺水灌区农田节水灌溉的目标标准和技术标准，并对这些评价标准的运用进行了讨论。