Cycling and balance of copper in farmland ecosystem of Jianghan plain in Hubei Province
湖北江汉平原农田生态系统钢的循环与平衡

The cycling and balance of copper in 8 cropping systems, i.e., wheat-rice, rice-rice, rape-soybean, rape-peanut, wheat-sesame, wheat-cotton, pepper-cabbage and radish-eggplant in Jianghan plain of Hubei Province were studied. The results showed that the main output of copper was crop harvesting, up to 85.9%-95.1% of total output, and the output of copper by field runoff and soil leaching was low. The main inputs of copper were organic fertilizer, rainfall, falldrop, and natural return. The inputs of copper from inorganic fertilizer and seeds (seedlings) were low. The balance analysis pointed out that copper had an accumulative trend in two patterns of rice and commercial vegetable ecosystem, and was in balance in upland field ecosystem.