我国北方地区农业生态系统水分运行及区域分异规律研究的内涵和研究进展

概述了国家自然科学基金重大项目"我国北方地区农业生态系统水分运行及区域分异规律研究"的内涵及初步研究进展,提出要通过对我国北方地区农业生态中水分运行和转换规律的综合田间试验及联网研究,确立北方地区农业生态系统水平衡、水循环过程的机制,确立北方地区有限水环境下作物生产力模型,对北方地区农业生态系统中水分运行与农业可持续发展及其区域分异规律作出评估,研究给出了我国北方地区主要作物的耗水、需水规律,夏玉米的水肥优化耦合模式和农田生态系统综合模型;获得了近40年来我国北方蒸发潜力自东向西逐渐递增的空间变化和自90年代以来北方部分地区潜在蒸发有明显下降趋势的时间变化特征;得出了黄土高原旱作高产农田土壤干燥化是高产田产量产生波动性的主要原因,比较了森林和草地的水文效应差异,指出在郁闭度相同的情况下,森林小流域较自然牧草小流域有较小的径流量、较大的蒸散量和较低的3 m土层平均含水量。

CONNOTATION AND SOME ADVANCES OF THE RESEARCH ON THE WATER MOVEMENT AND ITS REGIONAL CHANG REGULAR IN AGRO-ECOSYSTEM OF NORTH CHINA

The author discusses the connotation and development of the research on the water movement and its regional change regular in agro-ecosystem of north China in this paper. That is the established the mechanism of water balance and water cycle process in agro-ecosystem, the model of crop productivity in limited water environment condition of north China by means of the combined field experiment and network study of water movement and exchange regular in agro-ecosystem, and gives the evaluation for water movement and productivity sustainable development and its regional change regular in agro-ecosystem of north China.The research results in this project were shown as following: (1) The water consumption and requirement regularity of main crops in different regions of north China and the corn production model under dynamic optimal management of water and fertilizer supply were got. (2) A comprehensive agro-ecosystem management model also was got. (3) The potential evaporation in north China has a regional increasing character from east to west during the period of 1961-2000 and it also has an obvious decreased trend from 1990 years. (4) The soil desiccation happened in the entire soil profile is a direct cause of the yield fluctuation for high-yield field. (5) The comparison of hydrological behaviors of forest and grassland watersheds in gully region of the Loess Plateau pointed out that, the depth of annual runoff in the forest watershed is less than that of the adjacent grassland on condition that cover degree of both is the same, the amount of evapotranspiration in forest watershed is higher than that of grassland, and soil water storage in the three-meter horizon is less than that of grassland.