某些农业措施对土壤酸化的影响

Soil Acidification as Influenced by some Agricultural Practices

用南澳大利亚Tarlee地区一个长期田间试验的土壤样品研究了轮作措施、氮肥施用和残茬管理对土壤酸化的影响。结果表明,所有处理均导致土壤pH下降,几种轮作方式加速土壤酸化的快慢顺序是:小麦-羽扇豆小麦-蚕豆>小麦-小麦>小麦-休闲。每公顷施用80kg铵态氮肥及残茬留田均加速了土壤酸化进程。试验期间,不同的田间处理下土壤的平均酸化速度在0.50—2.22kmolH+·hm-2·a-1范围内。与碳、氮循环有关的土壤和植物过程是加速该地区土壤酸化的主要原因。土壤酸化导致土壤交换性铝和CaCl2提取铝的量显著增加,并有可能对敏感植物产生毒害作用。

Soil acidification, as influenced by N-fertilizer, stubble management and crop rotations, was investigated using soil samples from a long-term rotation trial at Tarlee, South Australia. There was a decrease in soil pH with time with all rotation, stubble management and N-fertilizer treatments. The order of the effects of different rotations on soil pH was: wheat-lupinswheat-bean > wheat-wheat > wheat-fallow. Both the application of N-fertilizerat the rate of 80 kg·hm-2 and the retention of stubble accelerated the soilacidification. The mean acidification rates for the period from 1978 to 1992 varied from 0.5 to 2.22 kmol H+·hm-2(year for different treatments. Soil andplant processes associated with the carbon and nitrogen cycles are main causes of soil acidification at this area. Soil Acidification resulted in the increase in soil exchangeable Al and CaCl2 extractable Al. It is possible that Al toxicity may occur in some treatments for sensitive plants.