摘要
对苏北沿海平原海安县稻麦免耕土壤的研究表明,持续免耕土壤肥力呈先下降后回升趋势.通过对20项原始变量的标准化处理,建立了免耕土壤肥力消长模型,并从中分解出人工耕作调控作用衰减函数和自调作用增长函数,提出免耕后土壤肥力调控机制有一个从人工调控机制为主逐步向自调机制为主转变的过程.在此过程中,自调机制的发育尚不足以弥补耕作后效作用的衰减,引起土壤肥力的暂时失调而形成肥力的“低谷”.分析了江苏沿海平原稻麦两熟制条件下轻壤土免耕后的肥力失调期、主导调控机制的转换期、调控作用补偿点和自调作用的功效.通过免耕土壤肥力的动态模拟,提出该地区轻壤土稻麦免耕对策和轮耕的年限。
Experiments of no-tillage(NT)on light loamy were conducted in Haian County,Jiangsu Province,from 1986 to 1989.The models of soil fertility variance of NT were proposed,fromwhich the attenuation function of tillage control and the incrcase function of soil autoregulation were re-solved.In the process of no tillage there is a conversion course of leading control mcchanism from tillage con-trol to autoregulation,in which soil fertility control system falls into“low status region”and results in re-duction of soil fertility.Some concepts about critical stages including fertility imbalance stage(FIS),time of leading control mechanism conversion(TLCMC)and control compensation point(CCP)were presented,and the specific values of which,on light loamy under wheat-rice double cropping innorthern Jiangsu Province,was given.
出处
《南京农业大学学报》
CAS
CSCD
北大核心
1992年第2期1-9,共9页
Journal of Nanjing Agricultural University
关键词
免耕
肥力消长模型
两熟
土壤
no-tillage
model of fertility variance of no-tillage
autorcgulation
light loamy
