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棉田施用氮肥、磷肥及合理密植是重要的栽培措施。结合栽培措施控制害虫费用很低并有预防性作用,在害虫综合治理中具有重要意义。对棉田这方面的研究国内外侧重于氮肥的效应,一般认为施氮过多有利于棉铃虫类(Heliothis)的发生为害,但缺乏多种栽培因素综合效应的研究。为此我们于1987～1988年在河北省邯郸市,通过田间试验研究了氮肥、磷肥和种植密度对棉花害虫、天敌及产量的综合效应。试验采用三因素、三水平的正交设计
The application of nitrogen fertilizer, phosphate fertilizer and close planting density is an important cultivation measure. The combination of cultivation measures to control pest costs is low and has a preventive effect, and is of great significance in the comprehensive management of pests. The research on cotton field in this area focuses on the effect of nitrogen fertilizer at home and abroad. It is generally considered that excessive nitrogen application is beneficial to the occurrence of Heliothis, but there is a lack of comprehensive effects of various cultivation factors. To this end, we conducted a field experiment in 1987 and 1988 in Handan, Hebei Province to study the combined effect of nitrogen, phosphate and planting density on cotton pests, natural enemies and yield. Test using three factors, three levels of orthogonal design