坡耕地不同水土保持措施下的养分平衡和土壤肥力变化

在贵州省罗甸县坡耕地上布置长期定位试验 ,研究几种水土保持措施对作物产量和土壤肥力变化的影响。9年的测试结果表明 ,在旱坡耕地上 ,水土流失是造成坡地地力下降、养分损失 ,的主要原因。未采用水土保持措施的坡地种植 ,因水土流失产生的全氮、全磷、有效钾损失 ,分别占总养分消耗量的 5 3.0 % ,6 7.6 %和 19.0 % ,相当于施入土壤的氮素化肥 ,施入的有机和无机磷素 ,有机质的损失与施入的有机肥中有机质含量相当 ,土壤全氮、有机质和有效钾含量趋于下降 ,全磷维持在较低的水平。采取水土保持措施后 ,这些土壤养分可维持平衡或在土壤中逐步积累 ,试验中的植物篱水保处理 ,9年玉米产量平均增产 8.6 % ,并趋于逐年上升。长期的试验证明 ,采用适宜的水土保持措施可提高地力 ,增加产量 ,实现坡耕地的可持续利用

Nutrient Balance and Soil Fertility Change in Different Conservation Measures on Sloping Field

A long term soil conservation site set up on sloping farmland in Luodian county of Guizhou province for studying on changes of crop yield and soil fertility in several soil conservation measures. The results in 9 years showed that runoff and soil erosion was the main factor in affecting the degradation of soil fertility and nutrient loss on sloping farmland. Treatment without erosion control the nutrients loss by runoff and soil erosion on sloping farmland was 53.0 % of total nitrogen, 67.7% of total phosphorous and 19.0 % of available potassium, comparison with the total consumption of those soil nutrients, or almost equaled to the total N input of chemical fertilizer, total P input on both organic and inorganic fertilizers. Soil organic matter loss was nearly same with the input of organic manure. Total N, organic matter and available K in the treatment soils decreased,and total P is kept in lower level by the heave nutrient erosion. Treatments with water and soil conservation the soil fertility kept balance or even increased in soils. For alley cropping treatment corn yield increased 8.6 % in average of nine years and trend to increasing forward. The long term experiment showed that proper soil conservation technology would improve soil fertility, increase crop yield and play an important role for sustainable use of the sloping farmland.