Weed control through degradable, herbicidal plastics and organic mulches and their effect on crop growth and yield of winter rapeseed (Brassica napus)

Abstract

Field experiments were conducted during winter (rabi) of 2004 and 2005 to control weed intensity in winter rapeseed (Brassica napus) using different types of mulches, viz black polyethylene, transparent polyethylene, herbicidal polyethylene film (herbicide coated), degradable polypropylene, straw mulch and non-mulched control. The results indicated that irrespective of the colours and types, plastic film mulches significantly reduced the weed density and weed dry weight at all stages. In general, the weed density and weed dry weight was lowest with black polyethylene film mulch at all the stages. Similarly, the weed-control efficiency and weed index were also highest with black polyethylene film mulches. However, the weed control efficiency did not differ much between the black and herbicidal polyethylene film mulch in the later stages. Though black polyethylene film mulch excelled the other treatments in weed control, the same was not reflected in the growth and yield parameters due to its poor soil-warming efficiency. Leaf chlorophyll concentration was higher with black polyethylene mulch though it was at par with other plastic mulches at all the stages. The increased number of pods/plant, number of seeds/pod and seed yield with herbicidal plastic mulches indicated that herbicidal plastic mulch could improve the rapeseed production through better weed control.