三峡库区复合农业生态系统及其建设途径

通过田间试验研究了长江三峡库区主要的复合农业生态系统类型及其特点。应用生态学原理和间套作技术，在三峡地区建立了“小麦－玉米－红薯、小麦－蔬菜、柑桔－小麦、稻田复合系统”等多种复合农业生态系统。田间试验结果表明，旱地采用“小麦－蔬菜”方式比传统的“小麦－玉米－红薯”方式提高经济效益４０％￣４７％，“中稻鸭鱼”模式的水稻产量达到了９５４０ｋｇ／ｈｍ＾２，比对照提高１２．５％。中稻－鱼、中稻－鸭鱼、中稻

CHARACTERISTICS OF INTEGRATED AGROECOSYSTEM AND ITS CONSTRUCTION IN THREE GONGES RESERVOIR AREA

A field experiment was conducted to deal with the characteristics of integrated agroecosystems in Three Gorges Reservoir Area in upper region of Yangtze River. Based on ecological principle and intercropping technology, several integrated agroecosystems such as wheat - malie-sweatpotato, wheat-vegetable, citrus intercropped with wheat and different rice rotation systems weredeveloped in this region. The experimental results revealed that the output and economic benefitof wheat intercropped with vegetable were increased by 40% - 47% compared to the normalwheatrmaize-sweat potato cropping system in upland soils. The rice yield in single riceduck-fish system reached at 9 540 kg/hm2, 12. 5 % higher than rice alone system. The economic ratio of output/input was 3. 92 in rice-fish system, 3. 81 in rice-duck-fish system and 4. 72in rice-straw berry system, respectively, which was 50% higher than the rice alone system.Additionally, the harmful effects infected by injurious insects were retarded at great extent inrice-fish or rice-duck system and the harmful weed in rice field was reduced, so that the pestifcide and herbicide application could be reduced in these systems. By practising rice-duck orrice-duck-fish system for several years the soil properties were improved, especially the organicmatter and total nitrogen content, available nitrogen and phosphorous in rice field were increasedsignificantly. Therefore, to develop different lute.rcropping systems in upland and different riceoriented rotation systems in rice field can increase the crop yields and get a high economic benefit,so that the Income of local farmers can be increased at some extent.