水分处理对冬小麦生育期耗水分配及产量影响

【目的】探索冬小麦产量及水分利用效率对灌溉水在生育期运筹的响应过程。【方法】通过人工控水试验开展了6个生长季(2012—2018年)的测坑冬小麦灌溉试验,试验设置不同灌溉水时间和不同次灌水定额,3个处理分别为拔节90 mm(I90)、拔节45 mm+抽穗45 mm(I45*2)、拔节30 mm+抽穗30 mm+灌浆30 mm(I30*3),总灌溉额均为90 mm,重点研究了灌溉水在生育期分配对冬小麦产量和水分利用效率(WUE)的影响。【结果】6个生长季的试验数据统计分析表明,I90、I45*2和I30*3处理的平均产量分别为6 878.3、7 249.1和7 568.6 kg/hm^2;与I90处理相比,I45*2和I30*3处理的产量分别提高了4.4%和10.0%;在灌溉定额一定条件下,不同灌溉处理对生育期总耗水没有显著影响,但I45*2处理比I90处理生殖生长阶段的耗水增加了23.7%,且生育期水分利用效率提高了14.8%。【结论】有限供水条件下,小定额多次灌溉可以有效改善生育后期麦田水分状况,有利于光合产物向籽粒的转化,进一步提高冬小麦千粒质量和收获指数,最终提高了冬小麦经济产量和水分利用效率。     

The impact of small-scale irrigation on household food security: The case of Filtino and Godino irrigation schemes in Ethiopia

Ethiopia’s irrigation potential is estimated at 3.7 million hectare, of which only about 190,000 ha (4.3% of the potential) is actually irrigated. There is little information on the extent to which the so far developed irrigation schemes have been effective in meeting their stated objectives of attaining food self-sufficiency and eradicating poverty. Therefore, the aim of this paper is to identify the impact of small-scale irrigation on household food security based on data obtained from 200 farmers in Ada Liben district of Ethiopia in 2006. The resulting data was analyzed using Heckman’s Two-step Estimation procedure. Studies elsewhere revealed that access to reliable irrigation water can enable farmers to adopt new technologies and intensify cultivation, leading to increased productivity, overall higher production, and greater returns from farming. Our study findings confirm some of these claims. In the study area about 70% of the irrigation users are food secure while only 20% of the non-users are found to be food secure. Access to small scale irrigation enabled the sample households to grow crops more than once a year; to insure increased and stable production, income and consumption; and improve their food security status. The study concludes that small-scale irrigation significantly contributed to household food security.

Economic impacts on farm households due to water reallocation in China's Chaobai watershed

Our study area in the Chaobai watershed, upstream of Miyun Reservoir, has been undergoing agricultural water transfers to downstream municipal uses in Beijing. We examine the impacts of water reallocation on crop production and farmers’ income and discuss issues relating to current compensation mechanisms. We use data from a survey of 349 farm households and their farm plots in the upper Chaobai watershed within Hebei province. Water reallocation from upstream to downstream areas has reduced agricultural water supply and the area irrigated. Regression results show that in plots deprived of irrigation, maize yields decrease by 21% and crop revenues decline by 32%. On average, losing irrigation on one hectare of cultivated land reduces net crop income by 2422 yuan. We examine compensation arrangements and social equity for the major policies implemented in the region and we identify gaps between current compensation levels and farmers’ income and production losses. The current compensation received by farmers is generally lower than the losses incurred due to reduced irrigation. A more appropriate compensation mechanism is called for in future water transfers.     

甘肃景泰提水灌区田间灌水技术评价与改进

通过田间灌溉试验和计算机模拟，对景泰提水灌区现行地面灌水技术进行了评价，研究对比了地面灌溉田间灌水效率的2种计算方法，用模拟地面灌水流运动的计算机模型模拟灌溉试验，得到平均灌水均匀度和田间灌水效率，并针对灌区田间灌水技术存在的问题，提出了改进建议。     

Access to groundwater and agricultural production in China

Although the ways in which farmers access irrigation services in areas that rely on groundwater have changed over the past decade, little empirical work has measured the impact of these changes. This is surprising given the potential effects—both positive and negative. In this paper we explore the impacts of the emergence of the markets for irrigation services from groundwater on agricultural production - including crop water use and crop yields - and farmer income in northern China. From a survey of 35 randomly sampled villages and 338 households in two provinces (Hebei and Henan Provinces) in 2001 and 2004, we show that when farmers access water from markets for irrigation services, they significantly reduce water use, compared with farmers who have their own tubewells. However, there is no significant difference between the volume of water used by farmers who access irrigation services provided by the village, and the volume used by farmers who access water from markets for irrigation services. Importantly, although water use decreases, we find little effect on either agricultural productivity (yields) or income.     

Policies to support economic and environmental goals at farm and regional scales: Outcomes for rice farmers in Southern India depend on their resource endowment

Improving water use and nitrogen efficiencies is of overall importance to society at large - to conserve scarce water resources and prevent environmental pollution. Efficient cultivation practices for rice which had no yield penalty were not adopted by farmers because of the open access to water free of charge. Well-chosen combinations of policy measures are thus needed to stimulate adoption of new cultivation practices. We developed a multi-objective linear programming (MGLP) model to explore the impact of: (i) modified rice cultivation including water-saving irrigation on farm profit; (ii) water pricing and water quota government policies on adoption of modified rice cultivation by farmers; (iii) a combination of (i) and (ii) to achieve the objectives of both farmers and society at large, and (iv) to study the trade-offs between income, water and nitrogen use. The analysis was carried out on four rice-based farm types for the state of Tamil Nadu, South India. Model results showed that observed farm profit of all four farm types could be increased using current practices simply by optimizing land use for specific crops. Adoption of modified rice cultivation further increased farm profit. Water-saving practices were selected only when water pricing was introduced. Farm profits were reduced even at low water prices but were compensated by farmers through adoption of modified rice cultivation. The combination of policies that stimulate adoption of modified rice cultivation was effective in achieving both increased farm income and water savings. The required water prices differed across farm types and seasons and impacted poor resource-endowed farmers the most. Providing water quotas could protect the poor resource-endowed farmers. The model helped to identify the optimal water price and water quota for each farm type to achieve both the objectives of farmers and society at large. Opportunities for reducing water use and avoiding environmental pollution at acceptable profits are available for all farm types, but need to be tailored to the farmers’ resource endowments.     

Bio-economic evaluation of farmers’ perceptions of viable farms in western Kenya

Arable land in western Kenya is under considerable pressure from increasing human population. Rural households depend on farming for at least part of their livelihood, and poverty rates are among the highest in Kenya. Land is often depleted of nutrients, and for most farmers, access to inputs and markets is poor. There is a need to identify options that are manageable within the context of the farmer’s resource base and the household’s objectives that could improve farm household well-being. In this study we integrated qualitative informal participatory approaches with quantitative mathematical programming and biophysical simulation modelling. Households in four sub-locations in Vihiga District were clustered and pilot cases identified. Meetings were held with farmers to elicit their perceptions of what their ideal farm would look like, and how its performance might compare with their own farm’s performance. With farmers’ help, a range of scenarios was analysed, relating to changes in current enterprise mixes, changes in current farm sizes, and changes in prices of staples foods and cash crops. A considerable mismatch was found between farmers’ estimates of their own farm’s performance, and what was actually produced. There seems to be a threshold in farm size of 0.4 ha, below which it is very difficult for households to satisfy their income and food security objectives. Even for larger farms whose households are largely dependent on agriculture, the importance of a cash crop in the system is critical. There is a crucial role for extension services in making farmers aware of the potential impacts on farm revenue of modest changes in their farm management systems. We are monitoring nine households in the district, whose farmers have made some changes to their system in an attempt to increase household income and enhance food security.     

涌泉根灌技术研究与应用

提出了一种新型涌泉根灌灌水方法,研究设计了一种灌水器,实现了直接将灌溉水输送到植物根系部位的研究目标,研制的涌泉根灌灌水器流态指数小于0.5,属紊流范畴.为了测得不同节水灌溉方式的应用效果,在陕北山地5年生枣树实施了管灌、滴灌和涌泉根灌等工程38.67hm^2,对3种不同灌水方法的经济效益作了分析.结果表明,与不灌溉相比,管灌、滴灌和涌泉根灌的净增收入分别为4707.70,8446.00和10926.00元/hm^2;管灌、滴灌和涌泉根灌每方灌溉水产值分别为1.90,11.30和14.60元/m3.涌泉根灌与滴灌相比,年成本降低2030元/hm^2,净收入增加2480元/hm^2,每方灌溉水产值提高3.30元/m3;涌泉根灌与管灌相比,年成本降低743.30元/hm^2,净收入增加6218.30元/hm^2,每方灌溉水产值提高12.70元/m3.不同节水灌溉方式均使得枣园净收入大幅度提高,尤其是涌泉根灌方式,净增值率高达235.0%.建议在山地经济林果中大面积推广应用涌泉根灌技术.     

温室滴灌条件下辣椒耗水特性的研究

针对现代化玻璃温室地表和地下滴灌方式,选择灌水周期和灌水定额为试验因素,开展了辣椒耗水特性试验研究。结果表明,温室条件下,地下滴灌较地表滴灌能节水5%~18%;为了减少辣椒耗水,地表滴灌方式宜缩短灌水周期,地下滴灌方式则宜适当延长灌水周期。温室滴灌条件下,辣椒耗水量组成中,棵间蒸发占主导,棵间蒸发量是日均蒸腾量的1.7~3.0倍,且辣椒日均耗水量可以用日均棵间蒸发量很好地线性表达,同时,辣椒棵间蒸发量也可以用温室内同期水面蒸发量进行线性预估。     

Managing the water balance of The Fayoum Depression,Egypt

A study of the water balances of The Fayoum irrigated lands and Lake Qarun was made to investigate the management of the irrigation system and the efficiency of irrigation water use. The two water balances are strongly interrelated. The drainage flow to Lake Qarun and the water level of the Lake are in delicate balance. A rise in Lake level causes the inundation of adjacent land. Management of The Fayoum water balance assumes control over irrigation water flows, but this control has technical and organizational limitations. Also discussed is the influence of irrigation practices in The Fayoum on the water balance (e.g., the autumn flushing of fields and farmers' preference for not irrigating at night in winter). Notwithstanding a high overall efficiency, irrigation efficiency during the winter is low. The reasons for this are given, together with the constraints against improving system management. Improved uniformity of the division and application of irrigation water will enable a better technical control of flows and will result in better water management in The Fayoum. Abbreviations: FID — Fayoum Irrigation Department, 1 feddan (fe) — 0.4 ha, 1 mcm — 1 million cubic metres: an average annual flow of 3.17 m³/s gives 100 mcm, m³/fe.year — supplied volume (m³) per surface area (fe) per year: 1000 m³/fe.year equals 240 mm/year, MSL — Mean Sea Level     

膜孔灌溉技术要素试验研究

根据膜孔灌溉大田灌水试验资料 ,分析了膜孔灌溉特点和灌水技术要素对膜孔灌灌水定额的影响 ,研究了单宽流量与开孔率与膜孔灌灌水定额的关系。研究成果为膜孔灌溉理论与技术的进一步研究奠定了基础     

不同滴灌灌溉制度对绿洲棉田土壤水热分布及产量的影响

【目的】探究不同滴灌灌溉制度对绿洲棉田土壤水热分布状况及对产量的影响。【方法】于2017年在策勒地区开展田间试验,设置了2种灌水模式:基于计算机模型的预报灌溉与基于土壤墒情的灌溉,每种灌水模式设置2种灌溉梯度:充分灌溉(100%)和非充分灌溉(75%的充分灌溉)。【结果】预报灌溉的土壤含水率和贮水量在花蕾与花铃期显著高于墒情灌溉;不同灌溉制度各剖面的土壤温度变化趋势一致,整个生育期的表层土壤平均温度表现为墒情亏缺最高,预报充分最低。作物产量在一定范围内随灌溉量的增加而增加,预报充分的产量较预报亏缺,墒情充分,墒情亏缺分别提高13.7%、12.1%、47.6%。水分利用效率表现为预报亏缺最高,且产量与预报充分的产量无显著差异。【结论】在策勒绿洲地区,预报亏缺灌溉可达到节水增产的目的。     

规模化牛场废水灌溉对冬小麦土壤速效氮迁移的影响

研究了牛场废水灌溉冬小麦土壤速效氮迁移特征。结果表明,冬小麦全生育期灌溉2次或3次牛场废水是较优灌溉模式,小麦收获后不会造成土壤硝态氮过量积累。在小麦生育期内,1m土壤剖面上含硝态氮量整体呈"哑铃"形,含铵态氮量随土壤深度增加逐渐降低;牛场废水灌溉下部土层含硝态氮量比正常施肥处理低,说明牛场废水灌溉土壤硝态氮淋溶下渗强度小;但因牛场废水中铵态氮质量浓度较高,牛场废水灌溉处理土壤含铵态氮量在1m土壤剖面高于正常施肥处理。     

磁化水渗灌装置

渗灌就是采用地下供水方式对农田进行灌溉。其基本特点是工作压力低,供水流量小,次数频繁,能精确控制灌溉用水量,只湿润作物根系附近的土壤,具有节水、节能、增产的效果。而在农业上用磁化水灌田,可使土质疏松,加快有机肥分解,刺激农作物生长。为此,全面、系统地介绍了磁化水渗灌装置的组成和磁化水渗灌的优点。     

Minimisation or remediation: A cost benefit comparison of two approaches for managing irrigation-induced deep percolation

We compare the net present costs of two approaches for managing irrigation-induced deep percolation under border-check irrigated pasture: (1) conversion from border-check irrigation to sprinkler irrigation to minimise deep percolation and (2) installation of a subsurface drainage system to extract excess deep percolation under the existing border-check system. Results for a dairy farm in northern Victoria, Australia, show that conversion to sprinkler irrigation is the more cost-effective approach. The net present cost of the second approach varies across an irrigation landscape, depending on the most suitable subsurface drainage and disposal system that can be used for a particular location. Where an aquifer is high yielding and of low salinity and thus drainage water is suitable for reuse on farm, tubewell drainage and farm reuse of drainage water provides a viable alternative to conversion from border-check irrigation to sprinkler irrigation. Where tubewell drainage or farm reuse is not feasible, sprinkler irrigation is more cost-effective than border-check irrigation with subsurface drainage.     

玛纳斯河灌区农户农业灌溉水价承受能力研究

从玛纳斯河灌区农户种植棉花平均生产成本和收入情况、水费占成本、收入的比例情况、农户可接受的灌溉水费占单位面积投入比例、农户对现行灌溉水价的评价及对水价构成的认识等方面进行了抽样调查.在此基础上对灌区农户灌溉水价的承受能力进行了分析,给出了该灌区农户水费承受能力指标及2006年该灌区农户可承受的平均终端灌溉水价为0.110 9元/m 3 .为该灌区制定农业灌溉水价改革政策、提高农业水资源利用效率等提供基础资料.     

蘑菇湖水库水环境容量总量控制研究

为逐渐恢复蘑菇湖水库的农业灌溉及养殖功能,介绍了按灌溉期划分的夏秋、非灌、春灌3个不同时段及不同的水质目标,定量计算蘑菇湖水库主要污染物水环境容量总量,得到水库不同时段的最大日负荷(TMDL)。根据TMDL对蘑菇湖水库的污染来源实施总量控制研究,得出了以下结论:同一水质目标下,在夏秋、非灌、春灌不同时段的水环境容量成递增趋势;扣除水库污染物本底值的环境容量多数为负值;扣除水库污染物本底值的环境容量春灌时段大于夏秋时段,夏秋时段大于非灌时段。最后阐述了对蘑菇湖水库水环境容量实施总量控制的效果。     

山区灌溉技术及应用研究

解决干旱、半干旱山地的农用灌溉用水问题，是帮助干旱山区农民脱贫致富的关键。采用YD型移动式高扬程灌溉及SYD型移动式滴灌技术，具有投资少、转移快捷方便、灌溉效率高及增产增效等优势，通过典型干旱山区的应用研究，该灌溉技术具有推广使用价值。     

Agricultural water management and poverty linkages

Water is critically important to the livelihoods of more than 1 billion people living on less than $1 a day, particularly for the 850 million rural poor primarily engaged in agriculture. In many developing countries, water is a major factor constraining agricultural output, and income of the world's rural poor. Improved agricultural water management can contribute to poverty reduction through several pathways. First, access to reliable water improves production and productivity, enhances employment opportunities and stabilizes income and consumption. Secondly, it encourages the utilization of other yield-enhancing inputs and allows diversification into high-value products, enhances nonfarm outputs and employment, and fulfils multiple needs of households. Third, it may contribute either negatively or positively to nutritional status, health, societal equity and environment. The net impact of agricultural water management interventions on poverty may depend individually and/or synergistically on the working of these pathways. Improved access to water is essential, but not sufficient for sustained poverty reduction. Investments are needed in agricultural science and technology, policies and institutions, economic reform, addressing global agricultural trade inequities, etc. But how best to match the agricultural water management technologies, institutions and policies to the needs of the heterogeneous poor living in diverse agro-ecological settings remains unclear. This article provides a menu of promising pathways through which agricultural water management can contribute to sustained poverty reduction.     

Pathways to breaking the poverty trap in Ethiopia: Investments in agricultural water, education, and markets

Investments in agricultural water management should complement or strengthen the livelihood and coping systems of the rural poor, and should thus be instrumental for breaking the poverty trap in Ethiopia. Underdeveloped water resources constrain progress towards poverty reduction. We examine linkages and complementarities between agricultural water, education, markets and rural poverty through an empirical study using household level data from selected villages in southern Ethiopia. We show that investments in irrigation can contribute to poverty reduction, but the poverty reducing impacts of irrigation water are greater when human capital and rural markets are well developed. The size of landholding, access to irrigation water, on-farm land and water conservation practices, literacy of the household head, and years of education of adults are all significant determinants of household welfare, and thus potential pathways for reducing poverty. Expansion of cultivated land, particularly irrigated land, universal literacy, and an extra school year for adults all reduce poverty, but reductions in poverty are greater when irrigation is combined with universal literacy. These findings call for simultaneous investments in agricultural water, education, markets and related policy support measures for reducing poverty in smallholder agriculture in Ethiopia.