一.什么是杂草凡田间不是人们有意识栽培的植物,都算是杂草。田间杂草是从周围草地传布到栽培地中的;久而久之,一部分草类脱离了它们原来的生长地,习惯于栽培植物出生长环境,经过长期自然选择,它们便成为具有特殊生物学性能而难以防除的一些植物。二.杂草的生物学分类及其为害季节杂草大致可以分为一年生与多年生两类。根据苏联植物学家的研究,一年生杂草又分为春性、冬性、越冬性和二年生四类,后三者在植物学上统称 What is a weed Where the field is not consciously cultivated plants, are regarded as weeds. As weeds pass from the surrounding grasslands to the cultivation fields, as time passes, some of the grass species break away from their original habitats and become accustomed to growing plants in their habitats. After long-term natural selection, they become difficult to be identified as having special biological properties Some plants to control. Second, the biological classification of weeds and its damage season weeds can be roughly divided into annual and perennial two categories. According to the study of Soviet botanists, annual weeds are divided into spring, winter, winter and biennial four, the latter three collectively referred to as botany