春播苜蓿地田间杂草生态经济阈值模型的研究

A Study on Eco一economic Threshhold and Weeding Eco一economic Threshold of Modelling in Weed Populations in Alfalfa Spring一sowing Fields

本文研究了春播苜蓿地田间杂草的生态经济阈值、生态经济除草阈值，建立了田间杂草密度与苜蓿干草损失率之间的关系；Ｐ＝１．９２６３＋０．８５３８ＬｏｇＸ。通过试验，建立了田间杂草的生态经济阈值和生态经济除草阈值模型。研究结果指出当春播苜蓿地中田间杂草密度低于其生态经济阈值时，不需要防除。

We have studied on both eco一economic threshold and weeding eco一economic threshold modelling inweed populations in alfalfa spring一sowing fields. The relative formula between weed density and yield lossof alfalfa(on DM basis)was calculated in the study as p=1. 9263+0. 8538Logx, Through our experimen-tation, the weeding eco一economic threshold and its control eco一economic threshold have also been estab-lished.The computed results indicated that when the weed densitv was lower than its eco一economic thresh-old in alfalfa fields,hence no weed controlling measures should be taken。