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991.
Mariana García-Bolaños Cecilia Borgia Noemí Poblador Mamadou DiaOuld Mohamed Vadel Seyid Luciano Mateos 《Agricultural Water Management》2011,98(7):1141-1152
Irrigation plays a fundamental role in world food provision but, to date, it has performed below expectations in Sub-Saharan Africa. The present study assesses and diagnoses the performance of 22 small and medium size community-managed irrigation schemes, mainly devoted to rice production, in different locations along the Mauritanian banks of the Lower Senegal River. The evaluations followed the Rapid Appraisal Process in which semi-structured interviews were held with representatives of the Cooperatives’ Boards in charge of each scheme to obtain information about the organisation of the cooperative, land tenure, irrigation system and organization, cropping pattern and soils. Additionally, for each irrigation scheme, the water-delivery service was characterized by making qualitative and comparative observations during field inspections; the pumping station's performance was diagnosed by a local specialist; the discharge at the head of the system was measured; daily irrigation time was recorded; and crop yields were determined by plot sampling. Then a set of performance indicators was computed. Water delivery capacity referred to irrigated areas was insufficient in a third of the schemes, and this insufficiency was exacerbated by poor maintenance. Irrigation intensity in habilitated areas was rather low being less than 0.66 in 50% of the schemes. The average productivity of land, irrigation water, and fuel (3.38 t ha−1, 0.30 kg m−3 and 2.37 kg kWh−1, respectively) were well below potential. 相似文献
992.
Evaluation of fertigation scheduling for sugarcane using a vadose zone flow and transport model 总被引:1,自引:0,他引:1
V. Ravikumar G. VijayakumarJ. Šim?nek S. ChellamuthuR. Santhi K. Appavu 《Agricultural Water Management》2011,98(9):1431-1440
Micro-irrigation has become an optimal means for providing water and nutrients to crops. There is an ample space for improving fertilizer use efficiency with micro-irrigation, if the movement and reactions of fertilizers in the soil are well understood. However, the rhizosphere dynamics of nutrients is very complex, depending on many factors such as soil temperature, pH, water content, and soil and plant characteristics. Many factors cannot be easily accurately quantified. However, using state-of-the-art modelling techniques, useful and reliable information can be derived.An attempt was made to evaluate the reactive transport of urea in the root zone of a sugarcane crop under drip irrigation, and to quantify the fluxes of urea, ammonium, and nitrate into the crop roots, volatilization fluxes, and deep drainage using a numerical model. This quantification helped in designing an optimal fertigation schedule. Various parameters used in the model were taken from either the literature or the field study. A typical scenario, based on the recommended total quantity of urea for sugar cane crop under drip irrigation in India, was tested using HYDRUS-2D. The total amount of urea was divided into fortnightly doses, depending on the stage of crop growth. For this scenario, the modelled crop uptake was found to be 30% higher than the crop demand. Consequently, an optimal fertigation schedule was developed that reduced the use of urea by 30% while at the same time providing enough N for its assimilation at all stages of crop growth. This type of modelling study should be used before planning field experiments for designing optimal fertigation schedules. 相似文献
993.
Although ‘sewage farming’ or wastewater irrigation started in Australia in the latter parts of the 19th century, it was in the late 1960s that a considerable interest was revived in arid and semi-arid parts of the world due to scarcity of alternative water sources and the urgency to increase local food production. The practice has manifold benefits in the form of water conservation, nutrient recycling, surface and ground water pollution prevention. But for arid and semi-arid regions like many parts of Australia, while wastewater irrigation can be an attractive solution to irrigation water problems, it might not be the ideal solution for the common soil types encountered in these regions. Due to characteristic low rainfall, high evaporation and low leaching, these soils tend to have higher salt accumulations. This paper examines the soil salinity and sodicity effects of wastewater irrigation in soil types typical to South Eastern Australia and takes the soils of Western Treatment Plant (WTP) as a case study to highlight these issues. 相似文献
994.
Rob M. Stevens Gordon Harvey Scott Norton William Frahn 《Agricultural Water Management》2011,101(1):62-70
Wetting plant foliage with saline irrigation increases the uptake of toxic ions Na+ and Cl−. Over three consecutive seasons, Colombard vines grafted on Ramsey rootstock were irrigated with saline water (EC 3.5 dS/m) by over-canopy sprinklers during any one of the first three of the four annual growth stages: bud burst to full bloom (treatment BB-FB), full bloom to veraison (treatment FB-V), and veraison to harvest (treatment V-H). At other times, vines received non-saline water (EC 0.5 dS/m) as did the control. Seasonal average soil salinities remained relatively constant over the trial. In contrast, the concentrations of Na+ and Cl− in one-year old wood and grape juice more than doubled. In treatments FB-V and V-H the average yield over the three seasons was reduced by up to 15%. Results were compared with those obtained in an earlier study which was undertaken in the same vineyard with the same treatments applied via dripper. With drippers, the maximum reduction in the average yield over three seasons was 2%. Saline sprinkling caused rises in Na+ and Cl− concentrations of fruit, leaf lamina and one-year-old wood that were at least 7-fold, 5-fold and 2-fold greater, respectively, than the rises caused by application of the same treatments with drip. Progressive seasonal rises in the concentrations of Na+ and Cl− in these tissues were due in part to carryover of salt added in previous seasons; with saline sprinkling the magnitude of these carryovers was 4-fold greater than those with saline drip irrigation. With saline water, vignerons can reduce losses by using irrigation systems which do not wet the foliage. 相似文献
995.
基于无线传感器网络的丘陵果园灌溉控制系统 总被引:1,自引:0,他引:1
为解决目前丘陵地区果树灌溉技术中存在的过度灌溉、浪费水资源等问题,以实现丘陵果园节水灌溉,结合无线传感器网络技术,设计开发了一种基于无线传感器网络的丘陵果园灌溉控制系统.系统以ATmega128L单片机为控制核心,由上位机、汇聚节点、无线传感器节点、土壤水分传感器和电磁阀等组成,其中土壤水分传感器和电磁阀连接到无线传感器节点上,汇聚节点与传感器节点之间数据采用无线方式进行传输,汇聚节点通过RS-232串口线与上位机相连.系统能实时监测葡萄土壤含水率的变化,根据土壤含水率来判断葡萄是否缺水,并发出灌溉指令实施对葡萄精确灌溉,系统实现了葡萄园灌溉的自动化控制.通过试验,选定25 cm深度的土壤含水率为灌溉启动监测量,启动灌溉的监测阈值设定为26.8%;选定50 cm深度的土壤含水率为灌溉停止监测量,系统停止灌溉的监测阈值为45.5%.试验表明:系统可以达到精确灌溉要求,结合葡萄的生存阈值可以实现节水灌溉. 相似文献
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