水分生产率指标随空间尺度变化规律

Variation of water productivity in different spatial scales

根据漳河灌区4年田间及中等尺度的水量平衡试验,以及同步的灌溉系统及灌区尺度的水量观测,结合利用遥感信息估算的灌溉系统及灌区尺度的腾发量获得不同年份不同尺度的水量平衡要素。根据实测或统计资料获得不同尺度的水稻产量资料。计算分析了各种水分生产率指标及水量消耗比例指标随不同空间尺度及不同水文年度的变化规律。结果表明:灌溉水分生产率及毛入流量水分生产率总体上随空间尺度的增大而增大,但于某些年份在中等尺度上有降低的现象;水稻腾发量水分生产率则随时空尺度变化不大;采用节水灌溉技术不仅可以提高田间尺度的灌溉水分生产率,也促进了灌区灌溉水分生产率的整体上升,达到了真实节水;水分生产率指标受降雨及其年内分配的影响,另外,水管理措施的好坏显著影响水分生产率指标的高低。

The water budget components of different spatial scales in different hydrological yeas were obtained according to 4 years water accounting experiment of Zhanghe Irrigation System in micro/farm and meso-scale together with the estimated evapotranspiration from remote sensing data of irrigation system and irrigation district scale. Rice yields were measured or obtained from the statistic data of irrigation management bureau. Based on these data, the water productivity and water consumption ratio indices for different spatial scales and different years were calculated and its spatial and temporal variation laws were investigated. The results indicate that in general, the irrigation water productivity and gross inflow water productivity increase with the scale except in meso scale it were decrease in some years. The evapotranspiration water productivity does not change remarkably with the scale. It is concluded that the adopted water saving technique not only promote the water productivity of micro/farm scale but also the water productivity of the whole irrigation system. Thus, the objective of real water saving can be achieved. Water productivity indices were also influenced by rainfall and its distribution during rice growing season and water management strategies affected water productivity indices apparently.