DEVELOPMENT OF LOW INPUT, NO-TILL WHEAT SEEDING TECHNOLOGIES FOR CROP RESIDUES MANAGEMENT IN RICE-WHEAT CROPPING SYSTEM.

A considerable amount of rice stubbles (7-10 ton ha^-1) are produced yearly in rice-wheat cropping system. Suitable management of these crop stubbles maintains soil health and natural balance of the cropping systems. Rice stubbles management requires number of tillage operations to prepare the seedbed which ultimately delayed the wheat sowing process. Consecutive two-year trail was conducted at Agriculture Extension and Adaptive Research Farm, Gujranwala, Pakistan i.e. 2012-13 and 2013-14, with the objectives to determine the most profitable economical rice residues management technique for this system. Trail was comprised of seven tillage methods; turbo seeder (TS), happy seeder (HS), zone disc tiller drill (ZDT), zero tillage drill (ZTD), ZTD after physical elimination of rice stubbles, ZTD after straw burning, conventional tillage and three nitrogen application timings; all N application at sowing time; 0.5 N at as basal dose + 0.5 N at first irrigation; 0.5 N at first irrigation + 0.5 N at second irrigation. Statistically, higher plant height was noted in turbo and happy seeded wheat as compare to other wheat sowing methods while nitrogen application timings gave maximum plant height where N fertilization was done, 0.5 N during seed bed preparation and 0.5 N at first irrigation. Turbo seeded treatment gave 265.33 fertile tillers m² that were 5%, 7%, 12%, 11%, 6% and 4 % more than HS, ZDT drill, ZTD, conventional ZTD after rice straw removal manually, conventional ZTD after rice straw burning and conventional wheat sowing, respectively. Turbo seeded wheat produced substantial higher spike length compared to other ZT methods. Statistically, maximum grains per spike were recorded in experimental units where wheat cultivation was done with turbo seeder followed by conventional tillage method of wheat sowing. Among nitrogen application timings higher grains per spike were calculated where N fertilizer was applied, 0.5 N during seedbed preparation and 0.5 N at primary watering. Uppermost thousand grain weight (TGW) was recorded in conventional sowing method and it was similar with TS, HS, ZTD, ZTD after physical elimination of rice stubbles and ZTD after straw blazing while, in case of N application timings, utmost TWG was obtained when N fertilization was done half N as basal dose and half at the time of primary irrigation. Turbo seeder treatment gave substantially highest total crop biomass as compared with other sowing methods. Wheat sown with turbo seeder gave 5.69%, 14.95%, 12.18%, 9.33%, 5.1% and 1.99% higher yield than HS, ZDT, zero tillage drill, ZTD after physical elimination of rice stubbles ZTD after straw blazing and conventional method of wheat sowing, respectively. Among nitrogen application timings, higher grain yield was obtained where N fertilization was done with 0.5 N at sowing and 0.5 N at time of primary irrigation. During both year of experimentation, LAI and crop growth rate (CGR) at 75 days after sowing (DAS) and total dry matter (TDM) and leaf area duration (LAD) at 120 DAS was maximum in turbo seeded wheat when N was added 0.5 N dose as a basal and 0.5 N at the time of primary irrigation. Net assimilation rate was higher in turbo seeded wheat when N was added 0.5 N during seedbed preparation and 0.5 N at primary watering. Moreover, highest grain protein contents (12.95%), fat contents (0.85%), and fiber contents (0.14%) were observed in TS experimental unit. Among different zero tillage sowing methods turbo seeder gave better returns and in case of nitrogen application timing the treatment gave better returns when half nitrogen was applied at sowing time and half nitrogen was applied at first irrigation. [ABSTRACT FROM AUTHOR]