南亚热带丘陵赤红壤理化性质变化及其原因

本文研究了南亚热带丘陵赤红壤物理、化学性质变 (退 )化的特征及其原因。结果表明 ,丘陵赤红壤在物理性质退化方面 ,主要表现在土壤团聚体稳定性下降、土壤孔隙性和土壤水分性能变劣 ;在化学性质退化方面 ,主要表现在养分贫瘠化、保肥供肥能力降低。植被破坏会引起土壤养分减少、保肥供肥能力降低 ,有机质的减少是丘陵赤红壤物理性质退化的主要原因。有必要保护植被、提高土壤有机质含量 ,以防止丘陵赤红壤理化性质退化

Studies on physical and chemical properties change (degradation) and its affected factors of latored soils in southern subtropical hills

This paper deals with the physical and chemical properties characteristic and its affected factors of latored soils in southern subtropical hills Results showed that compared with the soil under zonal natural vegetation it suffered more physical and chemical properties degradation under secondary or man made vegetation It was found that the physical properties degradation in latored soils was characterized by the lowering of aggregates stability with decreasing water stable aggregates, the deteriorating of soil porosity with increasing bulk density and decreasing bigger pore content and the deteriorating of water properties with lowering water permeability and available water retention capacity For natural latored soils, the increasing bulk density and lowering bigger pore content were more obvious, but for cultivated one, the lowering structural stability was more serious It was showed that the chemical properties degradation was characterized by nutrients improvement and nutrients supplying ability with lowering organic matter, nitrogen, phosphate, potassium and cation exchange capacity Statistic analysis indicated that the 10～0 25mm water stable aggregate and its mean geometric diameter value were obviously positively correlated with the organic matter content and total nitrogen content in the soils, that the total porosity and >0 05mm porosity were also positively correlated with the organic matter content in the soils; that the soil structure coefficient and <0 005mm porosity were positively correlated with soil clay content This means that nutrients improvement, especially the organic matter deficient might be the main factor which caused the latored soils physical properties degradation Natural vegetation destroyed by human disturbance might induce soil nutrients improvement, in order to prevent soil degradation, more attention should be paid to protecting vegetation and increasing soil organic matter content