Integration of mechanical methods and herbicides in controlling weeds of soybean (Glycine max).

Weeds cause problems in soybean crops by reducing yield. While weeds can be controlled in soybeans in a number of ways, the main means of control is through herbicide application. Problems from to the overuse of herbicides have led to an interest in integrated weed management (IWM) approaches. In order to investigate the integration of mechanical and chemical control methods in soybean, a field experiment was conducted during 2003–2004 at the research farm of Agronomy Department, Agriculture Campus of Tehran University, Karaj. Treatments were included in five groups, viz.: 1) herbicides alone; 2) herbicides plus cultivation; 3) pre-plant herbicides followed by post-emergent herbicides; 4) trifluralin (1920 g a.i. ha) applied with irrigation water (herbigation) separately or tank mixed with bentazon or oxyflourfen; and 5) a weed free check. The effects of treatments were significant on 100-seed weight, pods per plant, seed yield, biological yield and harvest index at P ≤0.01. With regard to the weed control efficiency, integration of trifluralin and oxyflourfen, and trifluralin (herbigation) plus oxyflourfen reduced weed dry weight by the greatest amount. However, oxyflourfen also reduced yield of soybeans.