Abstract:
In order to understand the effect of planting flue-cured tobacco on vertical variation of soil nutrients and acidity in Wuling mountains, the typical profile soil of different soil types and planting methods in Xiangxi tobacco area were collected and the vertical distribution characteristics of soil nutrients and acid parameters were analyzed. The results were as follows:Soil nutrients and buffer capacity decreased with soil depth increasing. With the increase of depth of soil profile, the pH of yellow-brown soil changed little, the pH of purple soil and yellow-red soil increased, the pH of yellow soil increased at first, then decreased and then increased. The changes of latent acid in yellow-brown soil and yellow soil changed little, the latent acid in yellow-red soil showed a decreasing trend, and the latent acid in purple soil showed a leaping change pattern. Cation exchange capacity, exchangeable base and base saturation were relatively high at the bottom of yellow-brown soil, purple soil and yellow-red soil, but relatively high on the surface of yellow soil. The acid parameters of topsoil varied greatly. Exchangeable acid, exchangeable hydrogen and exchangeable aluminum in topsoil of purple soil and yellow-red soil were significantly higher than those of yellow-brown soil and yellow soil. Exchangeable base and cation exchange capacity in topsoil of yellow soil were relatively high, and soil base saturation was relatively high in yellow-brown soil and yellow soil. The acid and alkaline buffer capacity was sorted by size in yellow-red soil, yellow soil, yellow-brown soil and purple soil. Long-term cultivation of flue-cured tobacco can lead to soil nutrient aggregation in surface and soil acidification. Employ of paddy-upland rotation and application of lime and planting green manure can ameliorate soil acidification.