Weed dynamics and productivity of wheat after transplanted rice as affected by tillage practices and nitrogen levels. (225)
AbstractThe contributory causes of reduction of wheat (Triticum aestivum) yield (35-50 kg ha-1 day-1) in the Indo-Gangetic Plains Zone of India are related mostly to delayed sowing and sub optimal wheat establishment owing to late harvesting of rice (Oryza sativa) and soil wetness particularly in low lying areas. The yield of wheat can be improved by advancing its sowing through zero tillage technology with reduced cost due to residual soil moisture. This needs to be investigated under real farming conditions in farmers’ fields. Therefore, with the objective to evaluate the performance of this technology under a rice-wheat cropping system, an on-farm trial in a participatory mode on cultivators’ fields was carried out during 2004-05 and 2005-06. The trial was thus laid out in split-plot design with 4 replications allocating treatments consisting of 2 tillage practices (zero and conventional) to main plots and 3 nitrogen levels (120, 150 and 180 kg ha-1) to the sub-plots. Results showed that effective tillers m-1 row length, 1000- grain weight, grain yield and net returns increased significantly by 4.96%, 9.95%, 5.42% and 21.22%, respectively with zero tillage, over the conventionally tilled wheat crop. Significant reduction in mean number of 4-weed species was observed with zero tillage over conventional tillage. Application of 150 and 180 kg N ha-1 being statistically at par with each other, resulted in higher growth and yield attributes and yield of grain and straw over 120 kg N ha-1. The mean number of 4-weed species was minimum with 120kg N ha-1 and it increased successively up to 180kg N ha-1. Wheat sowing by zero-till-drill sustained productivity and proved to be an alternative to conventional tillage after rice. The overall profitability gains for US $58.40 ha-1 over conventional tillage attracted the farmers for adoption of technology on large scale. The non-tilled system has more scope particularly under limited irrigation water conditions of the Indo-Gangetic Plains Zone of India where the conventional tillage system leads to loss of soil moisture in the seed zone, resulting in poor plant stand and consequently low yield.