贵州中部岩溶丘陵区不同土地利用和管理方式对土壤肥力的影响

本文研究了黔中岩溶丘陵区几种不同士地利用和管理方式下土壤物理、化学和生物学性状的特征。结果表明,农林(林草)复合利用模式在土壤粒级组成、孔隙分布、持水性能、有机质和N、P养分、酶活性等方面表现出较好的肥力性状特征,有机无机肥配施、精细管理的灌溉农田次之,而粗放管理的旱坡耕地,土壤肥力性状严重恶化,逐步向石漠化景观演变。不同土地利用方式和管理措施显著影响土地肥力变化的程度和方向,调整土地利用结构,实行基本农田精细管理、陡坡耕地退耕还林(革)是保护土地资源,实现区域生态重建和农业可持续发展的根本途径。

Effects of Land Use and Management on Soil Fertility in the Middle Karst Region of Guizhou Province

The changes of soil physical,chemical and biological properties under different land use and management sgstems were investgated in the middle karst region of Guizhou provinve.The results showed that the land use systems marked differences in soil fertility indicators,including soil particle composition,porosity distribution,bulk density,water-holding capacity,organic matter and nutrient contents and soil microbes.Most of these soil fertility indicators were the highest in the forest intercropped with crops and perennial grass(agroforestry systems),intermediate in the well-management irrigated farmland,and the lowest in the sloping cropland.It was suggested that a long-term input of organic matter was needed for the reestablishment of soil carbon and nitrogen pools in the seriously degradaed ecosystem.Inappropriate land use and management could rapidly worsen soil fertility.Hence,from a perspective of soil resource conservation,a preferable way for preventing soil degradation and achieving sustainable land use should be to give up the cultivation of degraded farmlands,and to adopt more effective and appropriate soil management and cultivation practices.