دانلود رایگان مقاله انگلیسی ارزیابی عملکرد و زیان های اقتصادی در کشاورزی ناشی از علف های هرز در هند - نشریه الزویر

ABSTRACT

Weeds are notorious yield reducers that are, in many situations, economically more harmful than insects, fungi or other crop pests. Assessment of crop yield and economic losses due to weeds in agriculture is an important aspect of study which helps in devising appropriate management strategies against weeds. A study was conducted to estimate the yield and economic losses due to weeds using the data from 1581 On-Farm Research trials conducted by All India Coordinated Research Project on Weed Management between 2003 and 14 in major field crops in different districts of 18 states of India. The study revealed that potential yield losses were high in case of soybean (50–76%) and groundnut (45–71%). Greater variability in potential yield losses were observed among the different locations (states) in case of direct-seeded rice (15–66%) and maize (18–65%). Three factors viz. location (state), crop, and soil type significantly (p < .0001) explained the variability in actual yield losses due to weeds at farmers’ fields. Significant differences were also observed between different locations, crops and soil types. Actual economic losses were high in the case of rice (USD 4420 million) followed by wheat (USD 3376 million) and soybean (USD 1559 million). Thus, total actual economic loss of about USD 11 billion was estimated due to weeds alone in 10 major crops of India viz. groundnut (35.8%), soybean (31.4%), greengram (30.8%), pearlmillet (27.6%), maize (25.3%), sorghum (25.1%), sesame (23.7%), mustard (21.4%), direct-seeded rice (21.4%), wheat (18.6%) and transplanted rice (13.8%).

4. Conclusion

Yield losses due to weeds are very important figures for assessment of effectiveness of current plant protection measures (Oerke and Dehne, 2004). These data provide a basis for making decisions on the relative importance of weeds with respect to agriculture and the environment (Walker, 1983). Economic losses due to weeds are also very important statistics for policy makers and others including researchers to understand the impact of weeds as far as economic loss is concerned. Total economic loss of about USD 11 billion was estimated due to weeds alone in 10 major field crops in 18 states of India. In economic terms, the greatest loss of approximately USD 347/ha was observed in groundnut with average loss of about 36% followed by maize (USD 136/ha) and soybean (USD 117/ha). Further losses in wheat and rice were calculated as USD 116 and 89/ha, respectively.

Study conducted includes the direct losses in crop yield due to weed competition. However, there are some other indirect losses including the weed control measures that contribute to increased cost of production and also contribute in increasing economic loss due to weeds (Oliveira et al., 2014). Use of herbicides has been escalated during past decades and is still going up (Choudhury et al., 2016) for controlling weeds at farmers’ fields due to shortage of labourers and high cost involved in the manual weeding. At the same time, herbicides are able to control the weeds up to certain time but further flushes of weeds pose new challenges to the farmers during cropping season. Further, high cost of herbicides, their timely unavailability and lack of technica know-how also make weed control difficult for marginal farmers despite its harmful effects on environment. So, there is need to integrate several methods including cultural, mechanical and chemical under integrated weed management (IWM) strategy.

The present study included data of 10 crops from 18 states for the assessment of yield and economic losses due to weeds. However, if more number of crops and locations are included, the losses may be much greater than what is actually estimated from the available data. Also, under changing climate scenario, weeds may get favourable environment against crops and may inflict higher loss in crop production (Peters et al., 2014; Ramesh et al., 2017).