冬小麦-夏玉米两熟农田节水效应的可行性

Feasible study on water-saving effect of wheat-maize rotation pattern

2001-2003年在中国科学院禹城综合试验站研究了冬小麦一夏玉米两熟农Kt节水效应的可行性。结果表明，本地区降雨量主要集中在夏玉米生育时期，月蒸散量呈“M”型变化，双峰一般出现在冬小麦与夏玉米的抽穗开花时期，而且两年的蒸散积累趋势纵向比较均显示出其一致性的特点，这是研究耗水规律的基础环节。土壤水分从时间分布来看，在灌溉降雨的水分供应下，冬小麦期间土壤水分呈下降的趋势，而夏玉米期间土壤水分却有所升高。土壤水分从空间分布来看，土壤水分变化趋势较一致，呈“Z”型变化，0～60cm层次的土壤水分动态变化幅度较大。实验证明夏玉米产量与前季冬小麦产量有一定的互补作用，全年WUE与灌水量成负相关。冬小麦-夏玉米两熟农田实行冬小麦灌溉而夏玉米不灌的灌水措施可行。

Wheat-maize rotation planting pattern is an important farming system in the North-western Plain of Shandong Province. It is critical to know how save water in the wheat-maize rotation pattern. The experiment was carried out from 2001 to 2003 at Yucheng Experimental Station and included eight treatments that were based on irrigations at different winter wheat stages and no irrigations at maize stage, however, due to heavy drought at maize stage, all treatments irrigated 60mm water on July 8 and 90mm water on August 20, 2002. The eight treatments were made up of irrigations at Jointing stage （March 26, 2002）, Hag stage （April 15, 2002）, Grain filling stage （May 11, 2002） in the 2001 - 2002 season, and irrigations at Jointing stage （April 8, 2003）, Heading stage （May 1, 2003） and Grain filling stage （May 17, 2003） in the 2002 - 2003 season. Every irrigation water value was 60mm controlled by a water supply meter. Wheat plant density was 2250000 plants per hectare and maize density was 60000 plants per hectare. The rainfall in Yueheng City is mainly distributed on the summer when summer maize was growing. Rainfall, evapotranspiration （ET） and irrigation are the basic factors to study the rules of water consumption. The ET per month changed as a ＂M＂ curve which two peaks were located, respectively, in the tassel and anthesis stages of wheat and maize. Furthermore, changes of the accumulation of ET were identical between the two years. With the supplement of irrigation or rainfall, water in soil declined gradually with the crop growth in the winter, but increased in the summer. The water content in 0 - 130em soil fluctuated as a ＂Z＂ trend and the changes were very significant in the 0 - 60cm soil profile. The results showed that summer maize and winter wheat had the mutual compensation on the yield and the water use efficiency of the whole year had a negative correlation with irrigation quantity. Results showed that it was feasible to practice irrigations during the winter wheat stage, but no irrigation during the summer maize stage in the field of wheat-maize rotation.