【摘要】 土壤肥力水平高低直接影响肥料的增产效果与经济效益。本文总结了1981～1982年在山西晋中平川水地上进行的玉米氮磷肥试验结果。初步结果表明,在亩施农家肥6000～8000斤基础上,中等肥力土壤增施氮磷肥的增产效果大于高肥力土壤,肥料的经济效益也高。所以,在肥料分配上应侧重在中、下等肥力水平的地块上。试验结果还表明,玉米对氮肥反应明显,在高肥力或中等肥力土壤上都有不同程度的增产效果。而磷肥只有在土壤有效磷(P)含量小於5ppm的土壤上才有一定的增产效果;大於10ppm时还表现负效应。因此,在玉米→冬小麦——夏谷子二年三熟制的轮作周期内,当磷肥有限时,对玉米可少施或不施,而重点施用于冬小麦上,以发挥肥料的增产效果。施用肥料都能不同程度地提高土壤养分含量,但在一定农业生产条件下,当土壤养分含量提高到一定水平后,作物产量将趋于稳定,若再继续增加施肥量则对产量影响很小,经济效益很低。因此,在一定农业生产条件下,不应过分强调为提高土壤肥力水平而盲目地、大量地施肥,而应注重提高肥料的经济效益,以期达到增产增收。更多还原

【Abstract】 An experiment of the effect of nitrogen and phosphorous on corn was made in 1981—1982 at different fertility levelsof irrigated lands in the central regions of Shanxi Province. The results show That effect of fertilizers on yield and economic benefit of fertilizers are greater in soil of moderate or low fertility than that of higher one’s under the condition of applying 6000—800 jins of farmyard manure Per mu. Thus, it is suggested that fertilizers should be applied to soil of moderate or low fertlities, whenever farmer’s income is considered. The effect of nitrogen on corn are significant than that of phosphorus, Phosphorus are only effective in soil with available phosphorus contents less than 5p.p.m. In soils which available phosphorus contents are more than 10p.p.m, the effect is negative. Within the rotation system Of corn—wheat—millet, it is emphasized that most phosphorus should be applied to wheat with a little portion to corn. However, yield tend to be stable when the fertility of soil achieve some level, if applcation of fertilizers continually, it will increasiny, the fenancial effect will be decreased.更多还原