Author(s): R. K. GHOSH, S. SENTHARAGAI AND D. SHAMURAILATPAM

Abstract: The System of Rice Intensification (SRI) shows promise for substantially raising rice productivity by using farmers’ improve thinking and practice with resourceswhat farmers already have, besides offering increase soil & plant health, saving resources & lowering GHG emission. The on station field experiments (weed, nutrient & water management) were conducted at the Viswavidyalaya farm, Mohanpur during summer 2012 - 2014 in transplanted puddled paddy cv. IET 4786 following SRI methodology. In nutrient management the experiment was conducted with RBD replicated four times and with five treatments viz. N -100% NPK through inorganic fertilizers; N 25% organic N + 75% inorganic N + 100% PK through inorganic fertilizers; N - 1 2- 3 50% organic N + 50% inorganic N + 100% PK through inorganic fertilizers; N -75% organic N + 25% inorganic N + 100% PK 4 through inorganic fertilizers and N - 100 % N through organic + 100% PK through inorganic fertilizers. The field experiment on 5 water management was conducted with four treatments (2-3 cm water submergence in active tillering, panicle initiation and flowering only and rest period irrigation at hair crack stage (2-3 cm WS at AT, PI and F + HC), irrigation at hair crack stage (HC), 2-3 cm water submergence (2-3 cm WS) and Farmers’ practice with 3-5 cm water submergence (FP) following RBD replicated six times. There were six treatments on weed management [Weedy check (WC); two mechanical weeding at 15 and 40 DAT (2 MW); three mechanical weeding at 15,25 and 40 DAT (3 MW); hand weeding at 25 DAT + 2 ME (HW + MW); chemical -1 Pretilachlor 50 EC @ 500 g ha at 1 DAT+ 2 MW (CC+ MW) and aqueous extracts of Pathenium, Calotropis and Tectona leaves -1 @ 5 ml litre of water + surfactant Tween 20 at 1 DAT + 2 MW (BC + MW)] and the experiment was laid out in RBD replicated four times. The results revealed that 75 % N as organic + 100% PK through inorganic fertilizers showed better paddy productivity in addition to more soil population of soil biota and nutrient availability. The most interesting result was that keeping PK as constant in 100 % N through organic sources, the insect and pathogenic pest’s infestation was reduced to the tune of 31.13 % fb 75 % N as organic (22.2 %), 50 % N as organic (15.5 %) and 25 % N as organic (4.46%) as compared to 100 % N through inorganic treatment. In water management experiment the results revealed that the total water used in this experiment was 6.88, 4.72, 8.06 -1 and 10.23 million lit ha against treatments 2-3 cm WS at AT, PI and F + HC, HC, 2-3 cm WS and FP, respectively. The corresponding figures for water saving in respect to FP were 32.78, 53.90 and 21.23 %. The grain yield data also revealed that -1 3750.00, 3347.22, 3027.78, and 3138.89 kg ha were obtained against the treatments 2-3 cm WS at AT, PI and F +HC, HC, 2-3 cm WS and FP, respectively. Therefore, the water required for kg yield of rice were 1833.84, 1409.20, 2661.60 and 3259.40 litre, respectively. With a common 20.80 % O in all plots at 25 DAT in FPthe average GHG CO , CO, N O and Methane emissions were 2 2 2 -1 to the tune of 398 ppm, 0.97%, 17 and 40 kg ha , respectively and the corresponding figures at 55 DAT were 399 ppm, 0.99%, 21 -1 -1 and 46 kg ha but in SRI treatment 2-3 cm WS at AT, PI and F + HC these data were 394 ppm, 0.92%, and 16 and 25 kg ha at 25 -1 DATwhile at 55 DAT the corresponding figures are 395ppm, 0.95%, 25 and 32 kg ha . In weed management experiment the BC + MW could be the best alternative of both HW + MW and CC + MW treatments by increasing the NPV (considering biological yield) 3.14 and 3.77 %, respectively and over the WC by 54.1 %. The experimental results were also verified at on farm locations of nine districts of West Bengal (Nadia, Howrah, Hooghly, Burdwan, Birbhum, Purba and Paschim Medinipur, and North and South 24 parganas) during summer 2013 and 2014. An average of 8.0 - 15.5% more paddy grain yield was also observed over the traditional transplanted rice (TTR) . In Conclusion more organic nutrient application with BC + MW at 15 and 40 DAT weed management and 2-3 cm WS at AT, PI and F + HC water management were the best for increasing paddy productivity in SRI system at this Gangetic plains of India

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