“双季稻-鸭”共生生态系统稻季磷循环

稻鸭共生是对中国传统农业稻田养鸭的继承与发展。在长江流域双季稻主产区湖南布置了稻田养鸭田间对比试验,以常规稻作为对照,采用投入产出法,分析"稻鸭共生"生态系统P的输入输出及循环情况。结果表明:"早稻-鸭"共生生态系统P输出为52.28kg·hm-2,其中鸭产品P为1.71kg·hm-2;"晚稻-鸭"共生生态系统P输出为83.24kg·hm-2,其中鸭产品P为6.17kg·hm-2;在早、晚稻两季,"稻鸭共生"系统在目前的P养分投入水平下,降低了土壤P的亏缺量;鸭子系统P输入主要来自系统外投入的饲料P;鸭粪P在系统内循环利用,两季循环率分别为12.5%和13.5%;两季稻作后,"稻鸭共生"土壤截存的P量为195.41kg·hm-2,比常规稻作显著提高了36.9%;"稻鸭共生"可对稻田土壤增加鸭粪P为17.75kg·hm-2。

Phosphorus cycling in rice-duck mutual ecosystem in double cropping rice growth seasons

Rice-duck mutualism is the development of raising duck in rice field in Chinese traditional agriculture.In this study,a field experiment of raising duck in rice field was conducted in a double cropping rice region of Hunan Province from May to October 2010,and an input-output analysis was made to analyze the phosphorous(P) cycling in the rice-duck mutual ecosystem,taking a conventional rice field as the control.Neither pesticides nor herbicides were applied throughout the growth period of rice in the rice-duck mutual ecosystem.In the early rice-duck mutual ecosystem,the P output was 52.28 kg·hm-2,of which,the P output from duck was 1.71 kg·hm-2;in the late rice-duck mutual ecosystem,the P output was 83.24 kg·hm-2,of which,the P output from duck was 6.17 kg·hm-2.During the double cropping rice growth seasons,the P inputs of the rice-duck mutual ecosystem decreased the P deficit in soil subsystem.The P input of duck subsystem mainly came from feed P,and the cycling rate of duck feces P in the mutual ecosystem in early rice and late rice growth seasons was 12.5% and 13.5%,respectively.After late rice harvesting,the P sequestration in soil was 195.41 kg·hm-2.In contrast with conventional rice,rice-duck mutualism decreased the deficit of soil P,while increased the soil P sequestration by 36.9%.This study provided reference for further development and utilization of rice-duck mutualism in this country.