Effect of different mulching materials on weed dynamics and yield of direct seeded rice in Chitwan, Nepal

Abstract

An experiment was carried out at farmers' field to compare the effects of live mulches and herbicide on weed growth and dynamics, yield, and economic performance of direct seeded rice under humid sub-tropical condition at Phulbari, Chitwan in 2009. The experiment was conducted in Randomized Complete Block Design with eight treatments and three replications. The treatments consisted of i) control, ii) three hand weeding, iii) herbicide application (bispyribac sodium @ 80 ml/ha) + one hand weeding, iv) wheat straw mulch @ 5t/ha + one hand weeding, v) Eupatorium mulch @ 5t/ha + one hand weeding, vi) brown manuring with Sesbania aculeata @ 30 kg/ha, vii) brown manuring with Sesamum indicum @ 2kg/ha, and viii) brown manuring with Crotolaria juncea @ 30 kg/ha. Weed dry matter accumulation was significantly lower with herbicide application (1.15 g/m 2 ) than wheat straw mulch (6.75 g/m 2 ). The treatments with brown manuring and Eupatorium mulch were found to be equally effective in suppressing the weed growth by reducing both dry matter content and weed density. Application of Eupatorium mulch one day after sowing produced significantly higher grain yield (3.5 t/ha) than control (1.77 t/ha), Sesamum brown manuring (2.97 t/ha) and wheat straw mulch (2.83 t/ha). Yield attributes like effective tillers/m 2 , panicle length and panicle weight were positively correlated with grain yield (r = 0.540, 0.705, 0.531 and 0.613 respectively). The net profit (Rs. 63.17 x 1000/ha) obtained from the treatment with Eupatorium mulch was higher than other tested treatments. Eupatorium mulch and herbicide application recorded equal benefit cost ratio of 2.4. Cultivation of direct seeded rice with the application of Eupatorium mulch or brown manuring (BM) of Sesamum was found effective for increasing yield and net returns in humid subtropical condition of Chitwan. Live mulching could be an eco-friendly weed control options in DSR. The BM option also provides crop residue for the addition of organic matter. This result suggests that BM is a potential alternative of herbicide application. Either mulching with Eupatorium and wheat straw or growing of Sesbania and Crotolaria as BM with rice up to 30 DAS are advisable to increase productivity with reduced cost of production at Chitwan and similar condition.

Weed management in maize under rainfed organic farming system

“…Long term application of organic amendments were reported to improvement in SOC, available N, P and K in soil, thereby sustaining the soil health (Panwar et al 2010). The use of weed biomass (shrubs) such as Eupatorium adhenophorum as mulching material for soil and moisture conservation and fertility build up in crop production has been also reported by other researchers (Acharya et al 1998 andGaire et al 2013).…”

“…The use of biomass from facultative weed such as Eupatorium as mulch has been reported a good source of organic matter *Corresponding author: jayanta.icar@gmail.com and weed suppressor for several upland crops in Himachal Pradesh (Acharya et al 1998). Application of Eupatorium mulch along with HW gave significantly higher yield of upland rice compared to control in Nepal (Gaire et al 2013). A promising way to use allelopathy in weed control is using extracts of alleloopathic plants as natural herbicides (Ankita and Mittal 2012).…”

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“…An experiment was conducted by Shelar (2014) at Dr. Balasaheb Sawant Konkan Krishi Vidyapeeth, Agronomy farm Dapoli during Kharif 2013 to find out effect of methods of sowing and weed control on the performance of direct seeded rice in Konkan region reported that maximum net returns (Rs.16878.66) and B:C ratio (1.37) was recorded in the treatment of pre emergence application of oxadiargyl @ 120 g/ha + post emergence application of bispyribac sodium @ 25 g/ha. Gaire et al (2013) studied the effect of different mulching materials on weed dynamics and yield of direct seeded rice in Chitwan, Nepal and concluded that three hand weeding gave highest gross return, net return and lowest B:C ratio (1.8) as compared to wheat straw mulch (1.9) and lowest B: C ratio (1.5) recorded under weedy check. Mishra and Dash (2013) found that, the pre-emergence application of Oxadiargyl @ 70 g a.i.…”

Brown manuring, An effective technique for yield sustainability and weed management of cereal crops: A review

“…Brown manuring helps smothering weeds, conserving moisture and adding about 15kg N ha -1 without adding much on cost of production (Gaire et al, 2013). A lower broad-leaved weed density and dry weight were observed with Sesbania spp.…”