مقاله انگلیسی رایگان در مورد زیان اقتصادی در کشاورزی ناشی از علف های هرز – الزویر 2018

Reduction in economic losses in agricultural production due to abiotic and biotic factors is of utmost importance in modern day inputintensive agricultural systems. Sustaining the production levels demands devising newer strategies for mitigating the ill-effects of these adverse factors. As with abiotic causes, especially the lack or excess of moisture in the growth season, extreme temperatures, high or low irradiance and nutrient supply, biotic stresses have the potential to reduce yields substantially (Oerke, 2006). Among the major biotic constraints, weeds are considered as the most harmful to agricultural production besides affecting agrobiodiversity and natural water bodies. They also affect the crop production indirectly, by competing with the crop for resources, sheltering crop pests, interfering with water management, reducing the yield and quality, and subsequently increasing the cost of processing (Zimdahl, 2013). Therefore, weed management is the major and important part of crop production. In India, reduction in crop yield was estimated as 31.5% (22.7% in winter and 36.5% in summer and rainy seasons) by weeds (Bhan et al., 1999). Whereas, the economic losses due to weeds in India was estimated as INR 20 to 28 billion about two decades ago (Sahoo and Saraswat, 1988; Sachan, 1989). In another study, it was reported that loss in agricultural production due to weeds amounts to INR 1050 billion per annum (NRCWS, 2007; Varshney and PrasadBabu, 2008). In general, the yield loss due to weeds is almost always caused by a group of different weed species, and these weeds may have substantively different competitive ability (Weaver and Ivany, 1998; Milberg and Hallgren, 2004). Practically, it is very difficult to estimate the yield loss due to single weed species and therefore, it is estimated as the collective efforts by all the weeds. Overall, weeds produced the highest potential loss (34%), with animal pests and pathogens being less important (losses of 18 and 16%) worldwide (Oerke, 2006). As far as studies on yield loss at global level is concerned, Milberg and Hallgren (2004) explored the large-scale patterns in yield loss in cereals due to weeds in Sweden and mentioned that weed biomass explained 31% of the variation in yield loss due to weeds. Whereas, O’Donovan et al. (2005) developed various regression equations in western Canada to estimate the effects of weeds on yield loss of field crops. Oliveira et al. (2014) also presented that insect, pests cause an average annual production loss of 7.7% in Brazil, which is a reduction of approximately 25 million tonnes of food, fibre and biofuels.