稻田轮作系统的生态学分析

针对目前稻田单一化的连作耕作制度对农田环境造成的不利因素,通过5a田间定位试验,从土壤理化性状、作物产量变化、病虫害发生发展规律、能流及养分平衡状况等角度对稻田连作耕作制度和轮作系统进行生态学分析.结果表明,与连作耕作制度相比较,在试验设计范围内,稻田轮作系统明显改善了土壤的理化性状,使得土壤随着耕种年限增加,容重下降,而孔隙度增加,固相比率下降,气相比率上升,气液比值增大,土壤通透性大大增强,有效阻止土壤次生潜育化和土壤酸化,提高土壤pH值.轮作系统不但提高了作物产量,而且总初级生产力、光能利用率、辅助能利用率分别比连作系统高17.47%、9.87%和5.0%.N、P、K的养分利用率也同样明显高于连作系统.提出了合理轮作的优化模式和复种模式.

Ecological analysis on crop rotation systems of paddy field

At present, environment of cultivated land has been influenced unfavorably by single continuous cropping in paddy field. In the field experiment of five years in this paper, ecological analysis based on paddy-field rotate system and continuous cropping was studied in the view of soil physical and chemical characteristics, crop output variety, occurring and developing rule of plant diseases and insect pests of farmland, power-flow and state of equilibrium nutrient. The results show that, compare with single continuous cropping, firstly, paddy-field rotate system has improved soil physical and chemical characteristics apparently. Secondly, yield of the rotate system was increased . Moreover, the overall initiative productivity, light energy using rate and assistant energy using rate was increased by 17.47%, 9.87%, 5.0% respectively. Nutrient using rate of N, P, K was also improved in the rotate system. Thereby, optimizing pattern and complex cultivating pattern have been suggested about rational crop rotation.