丘陵红壤耕作利用过程中土壤肥力的演变和预测

通过区域尺度上两个时段的定位采样 ,结合田块尺度上的长期试验 ,研究了耕作利用变化对我国中亚热带低丘红壤区土壤肥力演变的影响。分析了土壤肥力演变的驱动力 ,建立了土壤养分变化与养分平衡间的相关预测模型。对比分析表明 ,丘陵红壤肥力的变化与养分平衡量的变化趋势一致。在保持荒地和水田利用方式时 ,土壤有机质含量显著降低 ;旱地系统中速效磷和速效钾含量增加 ,但在不施肥的针阔混交林中却下降 ;荒地开垦为水田后 ,土壤肥力有增加趋势。旱坡地红壤全氮和速效钾的变化量与氮、钾的平衡量的显著相关 ,而土壤速效磷与磷的平衡量间相关不显著 ,其原因是没有考虑磷的固定和矿化。

CHANGES OF RED SOIL FERTILITY AND ITS PREDICTION DURING THE LAND-USE AND CULTIVATION IN LOW HILL REGION

The effect of cultivation and management on changes of soil fertility was investigated with pointing sampling at different periods at small catchment scale combined with long term field experiment in a low hilly red soil region in subtropical China. The key driving force for changes of soil fertility was analyzed, and the correlation models were set up between the changes of soil nutrients and the nutrient balance of various land use systems. The results showed that changes of soil nutrient contents coincide with that for nutrient balances. Soil organic matter content decreased in wastelands and paddy fields; soil available P and K contents increased when changing the wasteland into upland but decreased into mixed forest land; and soil nutrient contents trend to rising after changing into paddy field. The changes of soil total N and available K correlated significantly with the balance of N and K in slopping upland systems. However, correlation appeared unmarkedly between soil available P and P balance, which was caused possibly by excluding soil fixation and decomposition processes in the calculation of P balance.;