半干旱黄土丘陵区梯田集水增产效应研究

Research on Rainwater Harvesting and Yield Increasing Effect of Terrace in Semiarid Area of Loess Hilly Region

研究表明，半干旱区梯田平均可拦蓄入渗92．4％的雨水径流及泥沙，正常年份2m土层有效贮水量比坡地多112～184mm，可基本满足当地春小麦160．7mm的亏缺水分的补给；增加土壤水分的高峰期主要在3～5月和7月份，增加量为9．15～46．41mm，对本区土壤水分的快速补充恢复和缓解5，6月份的“卡脖早”具有极其显著的作用；建成3年以上的梯田较10°以上的坡地增产幅度可达27．07％～52．78％，水分利用效率也高1．01～3．38kg／（mm·hm^2）。在限量供水条件下，相应的水分利用效率平均达17．9kg／（mm·hm^2），比早作提高14．42％。因此，是半干旱区聚水增产的重要措施之一。

Research results shown that terrace has a significant rainwater harvesting, water and soil conservation and yield increasing effects. It can intercept 92.4% of the rainfall runoff and bed load averagely, which may increase 2-meter＇s soil layer water holding capacity by 112-184 mm and meet the 160.7 mm water supplying demand of wheat in dryland. The peak time period of soil water content increment is during March to May and July with 9.15-46.41 mm water increased, which can rapidly renew soil water losing during the dry-season and decrease the ravages of the ＂neck-blocking＂ drought during May to June in the semiarid area in Loess Plateau. The yield increasing range of three-year and above terrace is 27.07 % - 52.78 % with corresponding WUE 1.01 - 3.38 kg/（mm·hm^2） higher than that of dry-slope land. Under the condition of limited water supply, the WUE of terrace may reach 17.9 kg/（mm·hm^2）, which is 14.42% more than that of dry-slope land. Therefore, terrace is one of the most important farming practices for rainwater harvesting and yield increasing in semiarid region.