大豆连作减产主要障碍因素的研究 Ⅱ.连作大豆土壤有害生物的障碍效应

A STUDY OF MAIN FACTORS CAUSING YIELD DECREASE OF CONTINUOUS CROPPING SOYBEAN Ⅱ.Effects of Harmful Organisms in Soil on Continuous Cropping Soybean

在田间条件下对土壤进行灭菌，施肥和灌水试验，其结果表明：土壤中所存在的以大豆生长为最佳生存条件的有害生物，对大豆生长发育有重大不良影响，连作较非连作土壤生长的大豆生物量减少了７．２６％－１４．５２％，株高降低了１１．６％－１７．２６％，茎粗减少了１４．６３％－２１．９５％，叶面积减少了１０．４２％－１８．７０％，最终导致收获期减产１２．１９％－１４．５９％，用一个大气压湿热灭菌法对大豆连作土壤进行灭菌后，生育期的各项指标和收获期产量都和非连作土壤相一致，差异不显著。大豆病虫害是土壤有害生物主要表现形式。肥水不能直接消除有害生物的障碍效应，但可使连作大豆相对生长健壮，能抵御有害生物的危害，降低了减产幅度。

The soil for field trial was disinfected, fertilized and irrigated in this study. The result shows that, the harmful organisms related to soybean optimum growth soil affect the development of continuous cropping soybean greatly; Compared with control, the soybean biomass reduces 7.2%-14.52%, plant height goes down 11.6%-17.26%, stem thickness decreases 14.63%-21.95%,LA declines 10.42%-18.67%, and finall yield falls 12.19%-14.59%. By using steaming disinfection to the soil of continuous cropping soybean, there are no significant differences on development and final yield between treatments and control. Soybean pests and diseases are reflected by harmful organisms in soil. Fertilizer and water can not kill harmful organisms in soil, but can make soybean plant stronger and stablize final yield.