大豆重迎茬减产的原因及农艺对策研究——大豆重迎茬减产的原因与机理(上)

Reasons of soybean yield reduction by continuous and alternate cropping and corresponding agronomic countermeasures—reasons and mechanism of yield reduction by continuous soybean

通过连续8年在黑龙江省6个生态区9个固定轮作场圃综合试验,试验区专项研究,框区、盆栽试验,实验室分析,以及大量的大面积生产调查,发现影响重迎茬大豆产量的主要因素有土壤病虫危害、根系分泌物、根茬腐解物、根际微生物及其分泌物、土壤养分以及植株对于养分的吸收利用,其中土壤病虫危害是最主要的影响因素。各种影响因素间有相互推进的作用,其中主要的起因是根茬腐解物的积累改变了根际土壤的微生态环境,进一步影响了重迎茬大豆根际土壤微生物区系的组成、加剧了病虫危害、降低了土壤养分的可利用性、减弱了植株对于土壤养分的吸收利用,影响了植株的生长发育,导致减产。

In order to examine the reasons of yield reduction by continuous soybean and soybeans planted alternatively and thus corresponding practices to get more yield,an eight-year series of research were implemented since 1993.Nine rotations were established in 6 different ecological regions of Heilongjiang Province,and a great deal of field experiments,case study,pot experiment,and laboratory analysis were carried out.The result showed that the main reasons of yield reduction of continuous soybean and alternate soybean were soil-born diseases,root exu dates,stubble rotten,rhizosphere microorganism and its secretions,and soil nutrients.Among them,pests and pathogens in the soil were the most important factor.Various factors promoted each other,the accumulation of stubble rotten was the main reason which changed the micro-ecological environment of rhizosphere,affected the composition of microorganism system,aggravated the occurence of diseases and pests,reduced the availability of soil nutrients,weakened the absorbing and utilizing ability of plants,affected the growth and development of soybean,and thus resulted in yield reduction.