山地酸性土壤耕层重构的理化性状及酶活性动态变化

为揭示垂直深旋耕配施石灰、绿肥、生物有机肥重构酸性土壤耕层的效果，以湘西山地酸性土壤为研究对象，研究了耕层重构后植烟土壤的pH、物理性状、主要养分含量和酶活性的动态变化。结果表明：（1）酸性土壤耕层重构后，随烤烟生育进程发展，pH快速升高后缓慢下降并逐渐趋于稳定，孔隙度先升高后略有下降，有机质提高后呈波动变化，碱解氮快速升高后缓慢下降，有效磷快速升高后呈下降趋势，速效钾快速升高后下降再缓慢提升，蔗糖酶、脲酶先升高后下降并趋于稳定。（2）酸性土壤耕层重构可降低土壤容重，提高pH、孔隙度、有机质、碱解氮、有效磷和速效钾的含量以及蔗糖酶和脲酶活性。至烤烟移栽后120 d，容重降低7.32%~8.45%，pH、孔隙度、有机质、碱解氮、有效磷、速效钾分别提高0.78~1.04、8.17%~9.23%、16.89%~27.72%、13.39%~18.81%、69.83%~245.17%和47.05%~100.91%，蔗糖酶和脲酶活性分别提高53.19~163.53和0.76~1.24 mg/（g·d）。（3）垂直深旋耕+石灰+绿肥+生物有机肥处理的效果最好，其次是垂直深旋耕+石灰+绿肥处理。因此，采用垂直深旋耕结合施用石灰、绿肥、生物有机肥等重构酸性土壤耕层，可实现土壤酸度改良与培肥同步、表层与表下层土壤酸度改良同步的改良效果。

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.