Effects on production potential and economics of direct seeded rice sowing dates and weed management techniques

Transcription

1 Iian Journal of Weed Science 43 (3&4) : , 011 Effects on production potential a economics of direct seeded rice sowing dates a weed management techniques Devera Maal, D. Singh, Rakesh Kumar, Anupma Kumari a Vinod Kumar Department of Agronomy, Rajera Prasad Agricultural University, Pusa, Samastipur (Bihar) rakeshpusa08@gmail.com ABSTRACT Plant height, tillers/m row leng, leaf area iex (LAI), crop grow rate (CGR), net assimilation rate (NAR) a dry matter accumulation in plants were significantly higher in plots getting weed free environment closely followed by pre-emergence application of butachlor 1.5 kg/ha fb 1 HW. However, yield attributes i.e. panicles/m a fertile grains/panicle a finally yield were significantly higher in weed free check wi butachlor fb 1 HW closely on its heel. Among e nutrient concentration, it was only P in straw which was very marginally higher in weed free check a butachlor fb 1 HW. However, sowing date of June showed significantly higher N, P a K uptake by grain a straw. Weed population a weed dry matter were significantly higher in 1 July sown crop but least weed population, dry matter a good weed control efficiency were accounted wi weed free check a butachlor fb 1 HW ough e nutrient concentration were affected significantly bo due to sowing date a weed management practices. Nutrient uptake due to weed was higher in 1 July sowing date. Amongst e weed management meods, e nutrient uptake of weeds were least in weed free check followed by butacholar fb 1 HW a Sesbania broadcast fb,4-d 0.5 kg/ha at. Similar results were also recorded in e case of gross return, net return a B :C ratio in case of June. Key Words : Direct seeded rice, Herbicides, Nutrient uptake, Yield attributes, Economics, Cultural control. Direct seeded rice (DSR) is becoming popular as it is cheap alternative to transplanting. But crop weed competition in e system is more severe, reducing grain yield by 0-95% (Gogoi 1995). Manual weeding is expensive, laborious a time consuming as well as difficult in early stage of crop grow. To make paddy cultivation cost effective, DSR provide an option which saves labour a water use. The direct seeding could also help to eure e timely sowing in a stipulated time. Use of pre-emergence herbicides has been fou effective in early stage, but e seco flush of weeds at 5 to days after sowing () becomes a problem. Heavy infestation of weeds is one of e major constraints for successful cultivation of DSR. However, success of DSR depes largely on effective weed control especially wi chemical meods. Various herbicides have been used for controlling weeds in DSR but efficacy of chemical meods based on a single herbicide treatment may be unsatisfactory because of eir narrow spectrum weed control. Therefore, application of several herbicides in combination or sequence can be more useful. Agronomic practices can also lower crop-weed competition a yield losses keeping is in view, e present field investigation was carried out to test e response of sowing dates a weed management techniques in DSR. MATERIALS AND METHODS A field experiment was coucted at e farm of Rajera Agricultural University, Pusa, (Samastipur), Bihar during rainy seasons of 007 a 008. The experiment was laid out in split plot design wi two sowing date ( June a 1 July) in e main plots a six weed management meods, viz., pre-emergence (PE) pretilachlor 0.5 kg/ha; PE butachlor 1.5 kg/ha fb 1HW; fenoxaprop g/ha ; Sesbania broadcast fb,4-d 0.5 kg/ha a weedy check a weed free check allocated to e sub-plots having ree replications. The soil of e experimental plot was low in available N, P a K a having soil reaction in e slightly alkaline range (8.). Recommeed dose of N, P, K was applied at e rate of 10, a kg N, P a K/ha rough urea, single super phosphate a muriate of potash. A common 4 dose of 5 kg Zn SO /ha was applied at e time of puddling or sowing. However, one ird nitrogen a whole amount of P a K a Zn were applied after puddling a remaining dose of N was applied in two equal splits at a in direct seeded rice. Rice variety BPT-504 wi e seed rate 80 kg/ha was sown on June a 1 July, respectively a ed in first 139

2 Effects on production potential a economics of direct seeded rice sowing dates a weed management techniques fortnight of November during bo e years. The sowing of DSR was done by broadcasting e pre-sprouted seeds after puddling. The total rainfall received during crop season was 106 a 150 mm in e first a seco years, respectively. The direct seeded rice was kept moist during e first week to ensure its proper germination a water was not allowed to accumulate to avoid seed rotting. Therefore, e irrigation was applied at ree days after disappearance of poed water roughout up to 15 days before ing, whereas in transplanted rice, continuous poing of water was kept for e first 15 days for e better establishment of rice a to improve e efficacy of applied herbicides. The subsequent irrigations were given two days after e poed water was infiltrated into e soil. All e cultural operations like ha weeding was done manually wi e help of shovel as per treatment at 0 a 40 a crop requirements. RESULTS AND DISCUSSION Effects on crop grow The plant height, number of tillers/m row leng, leaf area iex (LAI) a dry matter accumulation in plants were significantly higher in June sowing as compared to ose uer 1 July sowing. Crop grow rate (CGR) a net assimilation rates (NAR) were also higher in June sowing (Table 1). However, e variations in grow parameters were more pronounced uer e impact of weed management practices. Plant height was similar uer e treatments of weed free check, pre-emergence application of 1.5 kg/ha butachlor followed by one ha weeding at a PE pretilachlor 0.5 kg/ha. These ree treatments had comparatively taller plants an e oer treatments. However, number of tillers/m row leng a dry matter accumulation in plants were maximum in weed free check. The treatments next in desceing orders were butachlor fb1 HW a pretilachlor applications. Leaf area iex (LAI) was also more or less similar in weed free check a butachlor fb 1 HW. The least values for all of e above referred grow characters were noted uer weedy check. Bo CGR a e NAR were significantly more uer weed free environment. The treatment next in is regards was PE butachlor 1.5 kg/ha fb 1 HW at. These two treatments had higher CGR a NAR an e oer treatments. Better expression of grow parameters uer e coitions in which plots were kept weed free is self explanatory. The treatment Sesbania broadcast followed by e application of, 4-D at also got weed suppressing measure at two different grow stages. However, e luxuriant grow of Sesbania not only checked e weed grow, but also provided serious competition to weeds, ough ey also might have suppressed rice plant grow giving tough competition. Leguminous crop Sesbania rough its nodules also might have supplemented rice plants wi extra nitrogen, but e benefits derived out of e increased nitrogen supply might have been overshadowed by e competition Sesbania gave to rice plants for light, space a carbon dioxide. Thus, e resultant effect might have gone against is treatment. The reproductive phase even uer e 1 July sowing completed well before e drop in e temperature which in general is expected to affect flowering a anesis due to low temperature. The only difference in e two sowing dates might have been due to variation in rainfall which might have gone marginally in favour of June sowing (Maity a Mukherjee 008). No yield attributing characters were affected significantly due to dates of sowing. The panicle leng a 1000-grain weight too were not affected significantly due to weed management practices (Table ). So far as panicles/m was concerned, it was significantly maximum (.5) in e plots where plants experienced weed free environment. Amongst e herbicides treatments, maximum panicles/m () were recorded from e plots getting pre-emergence application of 1.5 kg/ha butachlor followed by 1 HW at. These two treatments had higher panicles per unit area an e rest of e treatments. However, grains per panicle were also higher in e above two treatments, having been adjudged at par emselves, an e rest of e treatments. The control weedy check had significantly e least panicles/m (1) a fertile grains per panicle (74). The number of grains per panicle uer weed free check a butachlor fb1 HW was 96. a 9, respectively. The effect of dates of sowing, in general, relates to e climatic coitions met wi during e vegetative a reproductive phases of crop grow. So far as vegetative phase was concerned, e maximum a minimum temperatures were in e congenial range for bo e dates of sowings. These were more or less similar from July to September. The June sowing got greater quantum of rainfall after transplanting an e 1 July sowing which might have gone in its favour as e semi aquatic nature of rice loves to grow uer submerged coitions. Normally an early sown variety of medium maturity may face adverse situations due to heavy rains at its flowering a anesis stages. But even e June sowing did not experience any such situation helping it marginally in grow a development. In general, when, e late sown crop enters its reproductive phase in later part of October, e temperature starts falling abruptly due to which flowering a anesis in rice are badly affected. However, during October in e year 008, e temperature did not show any abrupt drop which might have gone in favour of 140

3 Devera Maal, D Singh, Rakesh Kumar, Anupma Kumari a Vinod Kumar Table 1. Effect of sowing date a weed management techniques on grow attributes of direct seeded rice (pooled data of two years) at different days after sowing () Treatments D1 - Before onset of monsoon, D - ( June After onset of monsoon, ( 1 July ) Plant height (cm) Tillers/m Plant dry weight (g) CGR (g/m /day) NAR (g/m /day) LAI At At NS NS 0. NS NS NS NS NS NS NS Weed management meods - ) W1 Pretilachlor 0.5 kg/ha (PE 5) W - Butachlor 1.5 kg/ha (PE) fb HW ( ) W3 - Fenoxaprop g/ha (POE ) W4 - Sesbania (broadcast)+,4-d kg/ha at ) NS At LAI - Leaf area iex Table. Effect of sowing date a weed management techniques on yield attributes a yield of direct seeded rice (pooled data of two years) Treatments D1 - Before onset of monsoon, ( June) D - After onset of monsoon, (1 July) Weed management meods W1 - Pretilachlor) 0.5 kg/ha (PE 5) W - Butachlor 1.5 kg/ha (PE) fb 1HW ( ) W3 - Fenoxaprop g/ha (POE ) W4 - Sesbania (broadcast)+, 4-D 0.5 kg/ha at Fertile Leng panicle panicles/m (cm) Grains/ panicle grain wt.(g) Grain yield (kg/ha) Straw yield (kg/ha) Harvest Iex (%) NS NS NS NS NS NS NS NS 9.1 NS NS 141

4 Effects on production potential a economics of direct seeded rice sowing dates a weed management techniques e 1 July sowing. As a result, e two sowing dates did not differ markedly in respect of grow, development a yield. The 1000-grain weight was not affected significantly by any of e factors studied.superiority of ha weeding over herbicidal control, especially during rainy season is an established fact. The weedy check a butachlor fb 1 HW excelled over e oer treatments. The treatment involving Sesbania broadcast +,4-D at alough controlled weed effectively yet could not result in better grow, development a yields. On e oer ha, fenoxaprop was applied at leaving e plots unatteed in earlier grow stage. All e aforesaid factors combined togeer fully explain e yield behavior uer e weed management practices (Ravisankar et al. 008, Subramanian a Martin 006). Commensurating wi e grow a yield attributing characters, e grain a straw yields a iex uer e two dates of sowings also did not differ significantly. Amongst e weed management practices, e maximum grain yield (5000 kg/ha) was recorded uer weed free check; butachlor fb 13 HW yielding 4440 kg/ha was inferior to weed free check but superior to rest of e treatments. Amongst e treatments solely restricted to herbicidal application, e application of 0.5 kg/ha PE- pretilachor gave e highest grain yield of 370 kg/ha. However, it had statistical similar to fenoxaprop g/ha at yielding 3350 kg/ha. So far as straw yield was concerned, e treatments weed free check a butachlor fb 1 HW did not vary significantly. Butachlor fb 1HW in its own turn was also comparable wi pretilachlor. Significantly e least grain a straw yields were recorded uer e control weedy check. Grow characters are e fouation on which e yield attributes are laid on a e sum total of yield attributes is ultimately reflected in economic yields. (Table ). The yields uer e two dates of sowings did not differ significantly. Broadly, it is e lowering temperature in later part of October which invariably affects flowering a anesis of medium a late duration varieties of rice. However, even e flowering a anesis in 1 July sowing completed before drop in temperature warding off any adverse effect of late sowing. The effect of weed management practices have also been explained in details earlier, which might have been e reasons for higher yields uer e treatments involving ha weeding (Singh et al. 005). Nutrient uptake Alough, amongst N, P a K concentrations in grain a straw it was only P in straw which was marginally higher in weed free check a butachlor + 1 HW an Sesbania broadcast +,4-D a weedy check (Table 3). All oer nutrients did not differ significantly for eir concentrations in grain a straw. The N, P a K concentration in grain a straw does not appear to be a function of dates of sowing a weed management meods. Since, e available N, P a K were at e same level for all e treatments ese might not have differed significantly. The P a K uptake in grain a K uptake in straw were higher in June sowing. The variations clearly related to e variations in yields a not due to e concentration of nutrients. The N, P a K uptakes bo in grain a straw were higher in plots experiencing weed free environment. The next best treatment in order was butachlor fb 1 HW (Singh a Patel 1989). Effect on weeds Weed population a weed dry matter accumulation were marginally higher uer 1 July sowings (Table 4). The heavy rains affecting germination of plants in June sowing might have restricted grow of weeds due to submerged coitions invariably faced in e mon of July when it rains very heavily. However, weed control efficiency was not affected significantly due to dates of sowing. Nutrient concentrations too as not affected by date of sowings. Nutrient uptake by weed which appeared to be mainly e fraction of weed dry matter was higher in 1 July sowing. Weed population, weed dry matter a weed control efficiency were better in weed free check followed in desceing order by butachlor fb 1 HW a Sesbania broadcast +, 4-D. Nutrients concentrations in weeds were also not affected significantly by weed management practices. Falling quite in e lines of weed dry matter, e nutrients removal by weeds were e least in weed free check followed by butachlor fb 1 HW a Sesbania broadcast +, 4-D. The reasons ascribed to grow yield attributes a yields also explain e reasons for variation in weed intensity a nutrients removal uer em (Singh a Tripai 007). Economics Gross return, net return a B : C ratio were higher in June sowing uer all e coitions except at in case of weedy check. It was e 1 July sowing which fetched higher gross return, net return a B : C ratio an e June sowings. Bo gross return (Rs 40,695/ha) a net return (Rs 19,945/ha) were maximum uer e treatment combination of June sowing a weed free environment (Table 5). This treatment combination was followed by June sowing a butachlor fb 1 HW which earned gross return of Rs 36,4/ha a net return of Rs 19,4/ha. The net return earned by e aforesaid two treatment combinations was statistically similar. The B: C 14

5 Devera Maal, D Singh, Rakesh Kumar, Anupma Kumari a Vinod Kumar Table 3. Effect of sowing date a weed management techniques on nutrient concentration eir uptake in grain a straw of direct seeded rice (pooled data of two years) Treatments Nutrient concentration (%) Nutrient uptake (kg/ha) Grain Straw Grain Straw D1 - Before onset of monsoon, ( June) D - After onset of monsoon, (1 July) Weed management meods W1 - Pretilachlor 0.5 kg/ha (PE 5) W - Butachlor 1.5 kg/ha (PE) fb 1HW ( ) W3 - Fenoxaprop g/ha (POE ) W4 - Sesbania (broadcast) +, 4-D 0.5 kg/ha at N P K N P K N P K N P K NS NS NS NS NS NS NS NS NS NS NS NS NS 0.0 NS Table 4. Effect of sowing date a weed management techniques on grow, plant population, dry matter accumulation nutrient content a eir uptake of weed in direct seeded rice Treatments D1 - Before onset of monsoon, ( June) D - After onset of monsoon, (1 July) Weed management meods W1 - Pretilachlor 0.5 kg/ha (PE 5) W - Butachlor 1.5 kg/ha (PE) fb 1HW ( ) W3 - Fenoxaprop g/ha (POE ) W4 - Sesbania (broadcast) +, 4-D 0.5 kg/ha at Total weed count/m at different Weed dry weight (g/m ) at different Nutrient content (%) in weeds Nutrient uptake (kg/ha) by weeds N P K N P K Weed control efficiency (%) NS NS 4.4 NS NS NS NS NS NS N NS

6 Effects on production potential a economics of direct seeded rice sowing dates a weed management techniques ratio was e maximum (1.14) uer June sowing a butachlor fb 1 HW. The treatment combination next in order (1.09) was June sowing a pre-emergence application of 0.5 kg/ha pretilachlor. The treatment weed free check which headed almost all e tables took ird place in respect of B:C ratio. Alough, e gross a net returns were e reflections of economic yields while B: C ratio also iicated cost of cultivation, which was higher in weed free check. The cost of weeding is comparatively higher an herbicidal applications (Sanjay et al. 008). Table 5. Effect of sowing date a weed management techniques on gross return, net return a B :C ratio of direct seed rice (pooled data of years) Gross return (Rs) Net return (Rs) B:C ratio D 1 D Mean D 1 D Mean D 1 D Mean Weed Management Meods W1 - Pretilachlor 0.5 kg/ha (PE 5) W - Butachlor 1.5 kg/ha (PE) fb 1HW ( ) W3 - Fenoxaprop g/ha (POE ) W4 - Sesbania (broadcast) +, 4-D 0.5 kg/ha at LSD (P = 0.05) Weed management meods Interaction W at same D D at same W REFERENCES Gogoi AK Weed management in dirct seeded, lowla rice (Oryza sativa). Iian J. Agron. 40 (3) : Maity SK a Mukherjee PK Integrated weed management in dry direct seeded rainy season rice (Oryza sativa). Iian J. Agron. 53 (): Ravisankar N, Charasekaran B, Raja R, Din M a Chaudhuri SG Influence of integrated weed-management practices on productivity a profitability of wet-seeded rice (Oryza sativa). Iian J. Agron. 53 (1): Sanjay MT, Setty TK, Prabhakaran a Nanjappa HV Investigation of crop establishment meods a weed management practices on productivity a economics in rice. Mysore J. Agril. Sci. 4 (1): -66. Singh G, Singh RG, Singh OP, Kumar T, Mehta RK, Kumar V a Singh PP Chemical weed control in direct seeded rice (Oryza sativa) wi or wiout sequential application of, 4-D (EE). Iian J. Agron. 50 (1): Subramanian E a Martin GJ Effect of chemical, cultural a mechanical meods of weed control on wet seeded rice. Iian J. Weed Sci. 38 (3&4): Singh K a Tripai HP. 007.Effect of nitrogen a weed-control practices on performance of irrigated direct seeded rice (Oryza sativa). Iian J. Agron. 5 (3): Singh Raj a Patel CS Effective weed control measures for upla rice in NEH Region. Iian J. Agron. 34 (4):