基于遗传投影寻踪模型的黑河中游地区农业节水潜力综合评价

农业节水潜力综合评价是进行节水规划的重要依据。目前,区域农业节水潜力的定量研究和综合评价研究仍存在不足。为此,本研究以地处西北内陆的黑河中游地区为研究单元,以流域统计资料和野外参与式农户调查资料为基础,借鉴层次分析方法原理,考虑区域社会经济发展水平、水文水资源状况、农业水资源开发利用、农业节水水平和生态环境对区域农业节水潜力的影响,建立了区域农业节水潜力综合评价指标体系。并针对各个单项评价指标的不相容问题,提出基于实码加速遗传投影寻踪的区域农业节水潜力综合评价模型,利用最佳投影方向判断各指标对综合评价目标的贡献大小和方向,通过投影指标值大小对黑河中游地区各区县(甘州区、民乐县、临泽县、高台县和山丹县)农业节水潜力实现水平进行评价。结果表明:水利投资占GDP比例、渠道防渗面积比和管道输水面积比等指标对区域农业节水潜力的影响较大,而人均粮食产量、人均水资源拥有量、供水量模数等指标影响较小;2005年,甘州区、民乐县、临泽县、高台县和山丹县的投影值Z(i)=(1.366 5,1.170 4,1.239 1,1.259 6,1.158 6),故甘州区、高台县和临泽县农业节水技术水平较高,山丹县和民乐县农业节水技术水平较低,节水技术应用潜力空间较大。研究结果可为区域节水农业技术持续发展提供科学依据和决策支持。

Comprehensive evaluation of agricultural water-saving potential in the middle reaches of Hei River using genetic projection pursuit model

A comprehensive evaluation of agricultural water-saving potential is the basis for agricultural water planning. Currently, however, insufficiencies of quantitative research have precluded the comprehensive evaluation of regional agricultural water-saving potential. This study therefore focused on agricultural water-saving potential in the middle reaches of Hei River, which is located in the northwest inland of China. Based on the principle of analytical hierarchy, a comprehensive evaluation index system of the regional agricultural water-saving potential was established, which combined a series of statistical data and participatory rural appraisal which took into account the impacts of socio-economic development, hydrology and water resources, agricultural water resources development and utilization, agricultural water-saving level and ecology on regional water-saving potential. Given that the evaluation indexes were incompatible, the projection pursuit model (based on genetic algorithm) was used to evaluate agricultural water-saving potential. The model used the optimum projection vector to evaluate the directional contribution of each index in the comprehensive evaluation system. Projection index value was used to evaluate future achievable agricultural water-saving potential of the district and counties in the study area. The districts/countries included Ganzhou District, Minle County, Linze County, Gaotai County and Shandan County. Results indicated that the index ratios of water conservancy investment to GDP, impermeable channel area and pipeline irrigation area had significant influence on regional agricultural water-saving potential. Then per capita grain yield index, per capita water resources index and water supply modulus index had little influence on regional agricultural water-saving potential. The projected values [Z(i)] for Ganzhou District, Minle County, Linze County, Gaotai County and Shandan County in 2005 were 1.366 5, 1.170 4, 1.239 1, 1.259 6 and 1.158 6, respectively. This showed that agricultural water-saving levels of Ganzhou District, Gaotai and Linze Counties were higher than other counties/districts. These other counties/districts were at a lower level and had large agricultural water-saving potential. This study provided scientific basis and decision-making support for developing regional agricultural water-saving technology.