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作物轮作的增产效应与其水分吸收增加和高效利用有关，假设轮作生长的作物比单一种植生长的同样作物消耗更多土壤水分。因为轮作使单一种植作物的一些因素的负效应被减弱了。轮作亦提高了水分利用效率（MUE）。本研究旨在确定，当玉米（zeamaysL．）和大豆（GlgcinemaxCL．marr）轮作时，是否改变水分吸收或使水分利用效率有所提高。在1987年和1988年，测定了玉米一大豆轮作试验中，至地表下1．5m深处季节性土壤水分状态。被测试内玉米和大豆处理顺序为：连续种植，种植5年一类作物后第一年种另一类作物；种植5年一类作物后第二年种植另一类作物，两种作物每年轮换种植。同单一种植方式相比较，收获玉米后种植大豆，增产30％。收获大豆后种植玉米，增产11％。第一年种植玉米处理中，在其生长种植季节内总的土壤消耗水分是16mm，高于连续种植玉米的耗水量，玉米的土壤水分利用率与种植顺序相关达中等显著水平（P＝0．14）。种植顺序不改变大豆的季节性土壤耗水。但第一年种植大豆的处理的总的水分利用效率比连续种植大豆的要高（P＝0．05）。1988年，降雨稀少，与大豆相比，玉米耗水更多，而且吸收更深层的土壤水分；轮作时，两种作物都表现出耗水量增加。1987年，频繁的降雨量足以湿润地表0．3m以内的土
The yield-enhancing effect of crop rotation is related to its increased water absorption and efficient use, assuming that crop rotation consumes more soil moisture than the same crop grown alone. The negative effect of rotation on the part of the plantation crop was weakened. Crop rotation also increased water use efficiency (MUE). The purpose of this study was to determine whether water absorption or water use efficiency was improved when corn (zeamays L.) and soybean (Glgcinemax L. marr) were rotated. In 1987 and 1988, the seasonal soil moisture status at a depth of 1.5 m below the subsurface was measured in a maize-soybean rotation test. The maize and soybean tested in the order were planted continuously, planted another crop for the first year after planting a five-year crop, planted another crop for the second year after planting a five-year crop, and the two crops were rotated annually Planting. Compared with the single planting method, corn was harvested after planting soybean, an increase of 30%. Corn was planted after harvesting soybeans, yielding an 11% increase. In the first year of maize processing, the total soil water consumption during the growing season was 16 mm, which was higher than that of continuous maize. The soil water use efficiency of maize was significantly correlated with the planting order (P = 0. 14). Planting sequence does not change the seasonal soil water consumption of soybean. However, the total water use efficiency of the first year soybean planting was higher than that of the continuous soybean growing (P = 0.05). In 1988, rains were scarce, corn consumed more water and absorbed deeper soil moisture than soybeans, and both crops showed increased water use during rotation. In 1987, frequent rainfall was enough to moisten the soil within 0.3m above the surface