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2 0 0 1～ 2 0 0 3年在甘肃庆阳黄土高原连续 3 a研究了紫花苜蓿 -冬小麦轮作系统中土壤 0～ 3 0 0 cm剖面水分动态特征 ,作物产量及其含 N量。处理包括 4龄苜蓿草地 (L C)、4龄苜蓿草地后茬持续休闲 (L F)、4龄苜蓿草地休闲 4个月后种植冬小麦(L Fl W) ,和 4龄苜蓿草地休闲 1个月后种植冬小麦 (L Fs W)。结果表明 ,种植 4a苜蓿后春季翻挖实施休闲至冬小麦播种(L Fl W)的 4个月期间 ,降雨的入渗深度为 150 cm,而苜蓿秋季翻挖休闲至小麦播种 (L Fs W)的一个月间 ,降雨在土壤内的入渗深度为 90 cm,不同休闲长度对头茬冬小麦土壤 0～ 90 cm水分贮存量无显著影响 ,亦不影响头茬冬小麦的出苗和出苗数。苜蓿后茬完全休闲 (L F)一个生长季后 ,60～ 90 cm土壤水分含量达田间最大重力持水量 (Drainage U pper L imit DU L )的 93 % ,0～ 3 0 0cm剖面土壤贮水量达 670 mm ,是剖面田间最大重力持水量 (DUL )的 78% ;L Fl W和 L Fs W处理下头茬小麦籽粒产量之间差异显著 (P<0 .0 5) ,收获指数和千粒重等指数无显著差异 ;L Fl W和 L Fs W处理中获得的二茬小麦产量无显著差异 ;连续种植苜蓿与种植小麦有接近的生物量 ,但苜蓿地植物总 N的输出量较小麦田高 2～ 3倍。由于黄土高原降雨变率大 ,因此预测土壤含水量动态有?
The dynamic characteristics of soil moisture, crop yield and N content in the 0 ~ 300 cm soil profile of alfalfa-winter wheat rotation system were studied in the Qingyang loess plateau of Gansu Province from 2003 to 2003. After four months of alfalfa grass (LC), four years of alfalfa grass continuous cropping (LF), four years of alfalfa grass recreation four months after planting winter wheat (L Fl W), and four years old alfalfa grass leisure one month after planting Winter wheat (L Fs W). The results showed that the infiltration depth of rainfall was 150 cm during the four months of spring digging from spring to winter wheat planting (L F1 W) after planting alfalfa, while alfalfa was cut open for leisure to wheat planting (L Fs W) In one month, the infiltration depth of rainfall in the soil was 90 cm. The different leisure length had no significant effect on the water storage of 0-90 cm soil layer of winter wheat, but also did not affect the emergence and emergence of winter wheat in the first crop. After one growing season of alfalfa after complete fallow (LF), the soil water content of 60-90 cm reached 93% of the maximum soil water content in field (Drainage U pper L imitation DU L), and the soil water storage of 0 ~ 300 cm soil profile reached 670 mm, which is 78% of the maximum gravimetric water holding capacity (DUL) in the cross-section field. There was a significant difference (P <0.05) in grain yield between the treatments of L Fl W and L Fs W with no significant difference in harvest index and 1000-grain weight There was no significant difference in the yield of the second crop of wheat between the treatments of L Fl W and L Fs W; the continuous planting of alfalfa and wheat had the similar biomass, but the output of total N of alfalfa plant was 2-3 times higher than that of the wheat . Due to the large rainfall variability in the Loess Plateau, the dynamic of soil moisture is predicted.