论文部分内容阅读
蔬菜田土质肥、施氮肥多,灌溉条件好,杂草种类就多,尤其是繁缕等喜氮杂草危害严重,部分直播蔬菜田(如胡萝卜、原地白菜、菠菜、芹菜田),不能中耕除草,每亩拔草需用30～50人工。近年来随着乡镇企业和农副业的发展,劳动力大量转移,迫切需要化学除草。为制订防除杂草策略,选择适当除草剂种类和数量,开展了菜田草害调查。一、调查方法调查分春夏和秋季两个时期进行,选择面积大的菜田如大豆、马铃薯、原地白菜等,另外还选择了各种类型的田块,如移栽茄子、番茄等。在上海、嘉定、宝山、川沙等县选点,每调查点为50～100块田。调查方法采用5级目测法。分级标准:杂草的相对高度为作物的二分之一以上,但不超过作物,
Soil fertility of vegetables, fertilizers and more irrigation conditions are good, more types of weeds, especially sophorae and other hi nitrogen weeds seriously endangering, part of the live vegetable fields (such as carrots, cabbage native, spinach, celery fields), can not Cultivation weeding, detoxification required per acre 30 to 50 artificial. In recent years, along with the development of township enterprises and agricultural and sideline businesses, a large amount of labor force has been transferred and there is an urgent need for chemical weeding. To develop strategies to control weeds, select the appropriate number and type of herbicides, vegetable field grass damage investigation carried out. First, the investigation methods Survey carried out in two periods of spring and autumn, choose a large area of vegetable fields such as soybeans, potatoes, cabbage and other places, in addition also chose various types of plots, such as transplanting eggplant, tomato and so on. In Shanghai, Jiading, Baoshan, Chuansha counties and other points, each survey point is 50 to 100 fields. Survey method using five visual methods. Grading standards: the relative height of weeds more than half of the crop, but not more than crops,