10 Jan 2014

Soil fertility on sloping lands is mainly affected by nutrient management practices and land slope

A study was conducted to investigate the soil nutrient status on sloping lands as affected by elevation and land use in Qujing, Yuannan province. The results showed that the contents of soil organic matter, N, P and K are decreased with an increase in elevation. This trend in spatial nutrient variation can be attributed to 1) sloping lands with higher elevations are usually with steeper slope and thus less fertile than the lands with lower elevations, 2) Less fertilizers are applied to the lands with higher elevations due to lower crop yields, and 3) the lands with lower elevations receive eroded sediments and nutrients from the above erosive lands. As land use is concerned, soils in the paddy fields with rice/tobacco – wheat/soybean rotations and in the uplands with maize/tobacco – wheat/soybean rotations contain much higher contents of organic matter and nutrients than those in the fruit (pear and peach) orchards and forest. This variation resulting from the different land uses is mainly attributed to different nutrient management practices. In both paddy fields and uplands, fertilizers used are sufficiently high with both mineral and manure combined to meet demand for high yield production, while in the fruit orchards only manures are applied. There is no fertilizer applied to the forest. Soil available P is low or deficient no matter what elevations or types of land uses are. The pH variation is minor across the studying area. The results suggest that soil fertility on sloping lands is mainly affected by nutrient management practices and followed by elevations or land slopes.

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