Direct Seeded Rice: A New Technology for Enhanced Resource-Use Efficiency

Abstract

Rice (Oryza sativaL.) is a major staple food crop that feeds around 60% of the world’s population. It is a major food crop in terms of production, economy and is grown in all ecological zones of Nepal. In Nepal, traditional method of rice cultivation is widely accepted in which 20-25 days old seedlings are transplanted in the puddled field. Looming water scarcity, water-intensive traditional method of rice cultivation, escalating labour costs pressurize the development of alternative which is highly sustainable and profitable. Direct-seeded rice (DSR) offers a very good opportunity that can cope up the global need and reduces the water use to 50%, labour cost to 60% and increases productivity by 5-10%. It involves sowing of pre-germinated seeds into wet soil surface (wet seeding), dry soil surface (dry seeding) and standing water (water seeding). Weeds are the major constraint in direct-seeded rice (DSR) reducing the crop yield upto 90% and sometimes even crop failure. Enhanced nutrient use efficiency and integrated weed management can produce comparable yields to that of transplanted rice (TPR) encouraging many farmers to switch to DSR. Methane gas emission is significantly lower in DSR than in conventionally tilled puddled transplanted rice mitigating the world’s threat of global warming. Blast disease and root-knot nematode (RKN) are other important problems associated with DSR. Based on the evidences collected, the article reviews integrated package of cultivation technologies associated with DSR, advantages, constraints and likeliness of DSR to be the future of rice cultivation in Nepal.Int. J. Appl. Sci. Biotechnol. Vol 6(3): 181-198

A Review on Weed in Direct-Seeded Rice (Dsr)

“…Mechanical weeding involves the weeding by hands which is called as manual weeding or by mechanical tools like cono-weeder (Devkota & Yadav, 2014). Manual weeding involves the pulling out the weeds from the soil after 25-40 days after sowing (DAS) when weeds are sufficiently large enough to be pulled out leading to losses in soil during initial stage of crop growth (Bista, 2018).So, controlling weeds solely by hand weeding is practically and economically impossible because of labor scarcity and rising of labor wages. To reduce the herbicide application and to prevent the production and accumulation of weed seed, one or two hand weeding is recommended (Devkota & Yadav, 2014).…”

“…Weedy rice (Oryza sativa f.spontanea), also known as red rice, has been a serious threat in the areas where TPR is replaced by DSR which has recorded an yield lose ranging from 15-100% (Kumar & Ladha, 2011). Weedy rice which evolve with DSR establishment method are difficult to control because of its genetic, morphological and phonological similarities with rice and also, herbicide which selectively control weedy rice at a satisfactory level has not achieved (Bista, 2018).…”

“…This is desirable weed management technique which not only reduces weed emergence but also manage large weed seed bank which occur due to weed infestation in the past (Rao et al, 2007). Weeds are allowed to germinate and grow by irrigating field one or two times 2-4 weeks prior to sowing and then grown weeds are killed by either a nonselective herbicide (glyphosate or paraquat) or by tillage (Devkota & Yadav, 2014) which assumed to suppress weeds upto 53% (Bista, 2018). The rice seed should be sown with minimum disturbance for avoiding the germination of seeds buried at deeper depth and also to pevent its exposure to light and other stimuli which may encourage emergence of weedy rice (Singh et al, 2013).…”

“…Rice (Oryza sativa) is a major staple food crop for around 60% of the world population which belongs to family Poaceae (Bista, 2018). It helps to insecure food security and livelihood for millions of people globally (Singh et al, 2016).…”

“…It helps to insecure food security and livelihood for millions of people globally (Singh et al, 2016). More than 90% world's rice is grown in Asia (Bista, 2018), which provides 30-75% of the total calories to more than 3 billion Asians (Khush, 2004). In Nepal, rice is the major food crop in term of production and economy which can be widely adapted in all ecological zones of Nepal, cultivated from terai to hilly region (Marasini et al, 2016).…”