Rice-wheat is the main cropping system in the Punjab state covering 60 % of the cultivable area.The area under rice has increased from 2.28 lakh ha during 1960-61 to 26.47 lakh ha during 2004-05.The corresponding rice productivity level improved from 1009 kg/ha to 3943 kg/ha.Similarly,in wheat the area increased from 13.94 lakh ha (1960-61) to 34.44 lakh ha (2004-05).The corresponding wheat yield improved from 1244 kg/ha to 4207 kg/ha.About 80 % of the 20.2 million tonnes paddy straw is burnt every year leading to environmental pollution and affecting the soil microflora discernibly.A negative balance of 200 kg/ha/annum of NPK is being created every year.The site-specific nutrient management (SSNM) investigations in rice-wheat system were initiated at Punjab Agricultural University,Ludhiana since 2003.The results revealed that with the change in genotype of composite rice with hybrid rice (PHB-71) along with balanced supply of nutrients in combination with micronutrients enabled to break the yield barrier from 12-13t/ha to 16.8 t/ha-a remarkable increase in productivity of rice-wheat by 3-4 t/ha/annum.The yield contributing characters in rice and wheat also improved with a notable margin over the recommended and farmers practices.The results of SSNM experiment have clearly advocated to achieve the climatic potential yield of 18 t/ha/annum under Punjab conditions.In this study,the main contributions were made by rice crop and availability of any wheat genotype responsive to nutrients will certainly lead to the targeted yield of 18 t/ha.
展开▼
