| Transgenic crops have caused extensive disputes since it comes into being. The disputes are focused on if it has positive impacts on economy, environment and human health. Transgenic pest resistance cotton (Bt (Bacillus thuringiensis) cotton) has been adopted in China for nearly 6 years. The adopted area has been nearly 1500 thousand ha by 2001. Its impacts on economy, ecology and human health are of great concern. The research objective of this paper is to analyze the impact of the adoption of this crop on economy and farmers' health.In order to fulfill the objective, we surveyed 1052 cotton planting households in Hebei, Shandong, Henan, Anhui and Jiangsu, and obtained data for 1783 sample fields. Using these data, we estimated cotton planting farmers' pesticides application equation and damage control production function, calculated the impact of Bt cotton on pesticides use and cotton yield, and compared the poisonging probability due to pesticides application between Bt cotton and Non-Bt cotton planting farmers . Using Bt cotton adoption area and the above results, this paper calculates the impacts of Bt cotton on pesticides application, cotton production and poison cases all over China since the beginning of its adoption in China in 1997.The results demonstrate that the adoption of Bt cotton reduced pesticides use approximatly 35kg per ha; this is equivalent to 875 yuan of cost reduction. We also found that different Bt cottonseeds with different gene have similar pest resistance effects. But Bt cottonseeds with different quality have quite different pest resistance effects; quantity of pesticide use on high quality Bt cottonseeds is 5kg less than that on inferior Bt cottonseeds, although the latter one is 33kg less than that on non-Bt cotton.Impacts of Bt cotton on cotton yields are also different. Although Bt cotton altogether can increase yield by 9.6%, the yield performance of Bt cottonshybridized by Monsanto or CAAS genes acquired from informal channels with local cotton varieties is 5.6% less than that of CAAS and Monsanto formal seeds, though it's yield is 1.4% higher than that of non-Bt cottons. Bt cottonseeds with different quality have different impacts on yield. The high quality cottonseeds can increase cotton yield 14% more than inferior cottonseeds.Because of decrement in pesticide use, from 1999-2001,the poisoning probability caused by pesticides use for farmers who plant Bt cottonseeds is respectively 17%, 22% and 4% lower than those who plant non-Bt cottonseeds, with an average number of 11 % in this three years. Meanwhile, Bt cotton planting farmers in Yellow River watershed and Changjiang River shed saved 48.4 yuan and 107.8 yuan per time in pesticide and wage losing cost, with the average of 68 in sample areas.Inspected from Bt cotton planting area of China from 1997-2001, due to Bt cotton adoption, it's estimated that the increment in cotton production is totaly 798 thousand ton, equivalent to 2630 million yuan in output value (the cotton price is average cotton price of China) .The decrements in pesticides use in these 5 years were respectively 0.1(thousand ton), 0.3, 14.7, 31.4 and 51.8. All together about 100.3 thousand-ton pesticides was reduced in five years. Take the average of 25yuan/kg, the decrement in pesticides cost was 2 million, 59 million, 368 million, 785 million and 1295 million yuan per year respectively, totalling 2509 million yuan. At the same time, because of decrement in pesticides use, the poisoning cases of Chinese cotton planting farmers have reduced at least 1,21, 138, 291, and 490 thousand each year, adding up to at least 940 thousand, and the correspondingly reduced cost in medicine and wage loss is no less than 52.910 thousand yuan in this five year period.According to the estimated results of production model, Chinese cotton production has increased 450 thousand ton in 2001. Because of the increment ofcotton supply, the economic surplus increased 2700 million yuan, and if the cotton demand price elasticity is 1, the supply pri...
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