大豆肥田机制的研究Ⅲ.大豆对耕层土壤含氮物质影响

大豆生育期间能否丰富和积累土壤含N物质是决定大豆肥田机制之一。试验结果表明，1988年大豆、玉米和休闲对比试验，在降雨正常情况下，大豆和玉米秋后土壤有机质分别增加0.461%和0.341%，全N增加1.1%，而玉米却亏损了5.2%。1990年6个处理试验中在深松条件下，各肥料处理的各土壤含N物质皆亏损，而未深松的，虽有夏早，仍使各土壤含N物富集，尤其是施用有机肥区效果明显，所以大豆肥沃土壤是有条件的。大豆落叶尚可归还土壤11.9-18.9kg/hm^2的N素。

STUDY ON MECHANISM OF SOYBEAN FERTILIZING SOILⅢ.. THE INFLUENCE OF SOYBEAN ON NITROGENOUS COMPOUNDS IN TILTH SOIL

The study probed the influence of soybean on soil nitrogenous in compounds in Heilongjiang province. The experiment indicated that the soil on increased 0.461% and 0.341% after harvesting the soybean and corn respectively. The soil total N increased 1.1% after harvesting the soybean,but it decreased 5.2% for corn under normal rainfall condition in 1988. By different tillage practices the nitrogenous compound contents all reduced in deeply looseed plots of the three fertilizer treatments ,but the contents in undeeply loosened plots slightly surpassed in their basal contents in soil of 1990,especially it was very obvious in soil applied with organic manure. So a certain condition is needed on sowing soybean for fertiling soil. As there were many soybean falling leaves in field,they could return N 11.9-18.9kg/hm 2 to soil.