Evaluierung von wirtschaftlich tragfähigen und umweltfreundlichen Unkrautbekämpfungsmethoden für Weizen (Triticum aestivum L.)

Abstract

During the past few decades, extensive use of herbicides has created ecological and environmental problems such as dominance of minor weeds due to their resistance to herbicides, and human health hazards. Recognising these problems, an experiment was conducted in two consecutive wheat seasons during 2012–2014 in Central Bangladesh to evaluate five weed control methods: (i) control (weedy check), (ii) one hand weeding (one HW) at 25 days after sowing (DAS), (iii) one mechanical weeding by using a BARI dry land weeder (BARI weeder) at 25 DAS, (iv) Mechanical weeding by using a power tiller operated weeder (PTOW) at 25 DAS, and (v) chemical weed control (herbicide) by using carfentrazone + isoproturon (affinity at the rate of 5.75 g a.i. ha−1). Results revealed that one HW at 25 DAS resulted in lowest weed density (numbers m−2) and weed dry biomass (g m−2), but highest weed control efficiency (WCE %), followed by the application of herbicide, using either PTOW or BARI weeder at 25 DAS. Consequently, one HW at 25 DAS produced the highest grain yield of wheat followed by PTOW, herbicide, and BARI weeder, while the weedy check treatment produced the lowest yield. Grain yield increased over weedy check by 28, 24, 18, and 15% in one HW, PTOW, herbicide and BARI weeder, respectively. The weed control treatment PTOW also resulted in the highest benefit-cost ratio (BCR) and marginal benefit-cost ratio (MBCR) (1.5 and 10.4, respectively) followed by the herbicide, hand weeding, and BARI weeder treatments. Considering the negative effect of herbicides on the environment and the labour crisis during the peak period of weed control for manual weeding wheat farmers can use PTOW which would also reduce the weeding costs as well as increase yield and net return. However, manual weeding would still remain an option for the resource-poor farmers with abundant family labour.