Dynamic of Soil Physi-Chemical Properties and Enzymatic Activities After Restructured Arable Layer of Mountainous Acidic Soil

To reveal the synergistic effect of restructured arable layer of mountainous acidic soil by deep vertical rotary tillage combined with lime, green manure and bio-organic manure, the dynamic of pH, physical properties, main nutrients and enzyme activities of the tobacco-planting acidic soil were studied in the western Hunan mountainous area. The results showed that:(1) After restructured arable layer, as to tobacco grow, soil pH increased rapidly, then decreased slowly and tended to be stable, porosity ascended firstly and then descended slightly, organic matter firstly rose and then fluctuated, alkali-hydrolyzable nitrogen rose sharply and then dropped slowly, available phosphorus increased rapidly and then tended to fall, available potassium increased significantly first, then declined and finally rose steadily, activities of invertase and urease firstly rose, then dropped and at last tended to be stable. (2) Application of restructured arable layer technology can reduce soil bulk density, increase soil pH, increase soil porosity and contents of soil organic matter, alkali-hydrolyzed nitrogen, available phosphorus, available potassium, and increase the activities of soil invertase and urease. One hundred and twenty days after tobacco transplanting, soil pH was increased by 0.78-1.04 unit, bulk density was reduced by 7.32%-8.45%. In addition, porosity, the contents of organic matter, alkali-hydrolyzable nitrogen, available phosphorus and available potassium, the activities of invertase and urease were elevated by 16.89%-27.72%, 8.17%-9.23%, 13.39%-18.81%, 69.83%-245.17%, 47.05%-100.91%, 53.19-163.53 and 0.76-1.24 mg/(g·d), respectively. (3) The treatment of deep vertical rotary tillage+lime+green manure+biological organic manure was most effective, followed by the treatment of deep vertical rotary tillage+lime+green manure. Therefore, the deep vertical rotary tillage combined with lime, green manure and biological organic manure to reconstruct the arable layer can achieve synchronous improvement of soil acidity and fertilization, synchronous improvement of the acidity in topsoil and subsurface soil.