Determination of critical period of crop-weed competition in sesame

Abstract

A field experiment was conducted during summer season of 2006 and 2007 under irrigated condition in a sandy loam soil at Sriniketan, West Bengal to determine the critical period of crop-weed competition in sesame. Results revealed that weed-free condition between 15 and 45 days after sowing (DAS) significantly increased the yield of sesame, whereas the lower yield of was recorded when weeds were allowed to grow during this period. The maximum competition between crop and weed was between 15 and 45 DAS, which can be considered as critical period of crop-weed competition. However, the extrapolated critical period was determined from 19-42 DAS. To avoid the yield loss, weed management should be done in such a time so that minimum weed infestation is achieved in summer sesame. Sesame ranks third in terms of total oilseed area and fourth in terms of total oilseed production in India. The average yield of sesame is very low (274 kg/ha) (Anonymous 2012a). It is one of the important oilseed crops in West Bengal mainly grown on marginal lands with minimum care. Sesame is cultivated in summer, Kharif and post- Kharif season on an area of about 0.18 m ha (Anonymous 2012b). The area, production and productivity of sesame are higher in summer season than other seasons. Out of several factors, weed competition is considered to be the most important responsible for low productivity of the crop. Prevalence of high temperature with high relative humidity and frequent rainfall during the crop season coupled with slow early growth favour luxuriant weed growth since seedling emergence, resulting in about 5075% reduction in seed yield (Bhadauria et al. 2012). Determination of exact critical period of weed competition in sesame is essential for timely and effective weed management and higher productivity and profitability. The present investigation was carried out to determine the critical period of weed competition in summer sesame of West Bengal.