A number of field experiments were conducted in Tamil Nadu, India during the last six years on different aspects of increasing the productivity and input use efficiency. Recent research on soil and crop management carried out in Tamil Nadu has resulted in three technologies that would result in sustaining the rice production besides increasing efficiency of inputs. One is the modified rice cultivation technique on the basis of SRI, which has been found to increase the yield with reduced seed, water and labour use. The second is the use of polymer coated urea which has been found to reduce the total amount of N for rice without offsetting the productivity. If manufactured with biodegradable polymer coating and supplied to farmers, this would not only save considerable foreign exchange on import of raw material for urea manufacture but also reduce the pollution hazards of N in ground water. The third technology emphasizes the resource recycling in rice cultivation especially in a rice-rice cropping system. Incorporating of the straw of first crop before transplanting second crop would not only be an organic source to sol microbes but also an efficient substitute of potassium. This also would save the use of K fertilizers and help in the country’s economy by reduced import of K fertilizers.

    作者单位：Agricultural College and Research Institute, Tamil Nadu Agricultural University, India；
    论文来源：水稻可持续生产——政策、技术与推广国际会议（中国杭州，2004年）。