一年生杂草正规块状分布的生态场模拟分析

大田杂草多呈块状或斑块分布。精准农业是现代农业的发展方向,它要求对作物-杂草生态系统进行定量描述并按照杂草斑块的性质(大小、密度等)进行定量的控制。本文对杂草正规型斑块进行了定量描述,即呈正规分布的杂草斑块可用同一的模型来描述,其形状在细胞空间中可以从条形变化到圆形。并将个体生态场概念(Wu,etal.,1985)扩展到群体(种群)。应用作者发展的细胞自动机(Wangetal.,2003)方法对杂草正规型斑块进行了模拟,结果表明:在一定范围内,(1)杂草的生态场随(圆形)斑块的增大而增大;(2)杂草的生态场随正规分布杂草斑块的形状变化而变化;(3)正规分布的圆形斑块其生态场随密度增加而增加;(4)通过模拟证实密度较高的杂草斑块,或者较大的杂草斑块需要更大的控制力(除草剂);(5)通过模拟证实杂草斑块的形状影响控制力,因此杂草的精确控制应该考虑杂草的形状。

An Eco-Field Simulation Analysis on Normal Patch Distribution of Annual Weed

The distribution of weed in farmland often displays in patch. Precision agriculture, which is a trend of modem agriculture, requires a quantitative crop-weed system to control weed based on characters of weed patches, such as size or density. In this paper, normal patches were defined and described quantitatively, i.e. normal weed patches could be described by the same model. Their shapes may change from strip to round type. The individual eco-field concept （Wu, et al. , 1985 ） was extended to population eco-field. The normal patches were simulated by using CA method （ Wang et al. , 2003 ）. The simulation results showed that, to some extent, （ 1 ） the size of the eco-field became larger, with the increment of a normal weed （round） patch; （2） the eeo-field varied with the shape of a normal weed patch ; （3） the eco-fields became larger with the increasing density of the normal （round） patches ; （4） it was proved by the simulation that a larger control power （herbicide） was needed for a higher densi- ty; and （5） the weed patch shape influenced the control power, thus the weed patch shape should be taken into account when a precision weed control was applied.