梯田土壤有机碳密度分布及影响因素

研究丘陵地区不同土地利用方式下土壤有机碳密度的分布及其影响因素,为丘陵地区土壤肥力培育和生产力提升提供技术参考。通过密集采样,分析东南丘陵水田、旱地、果园和茶园4种典型利用方式下耕层土壤有机碳密度变化及其影响因素。结果表明,东南丘陵地区土壤有机碳密度平均为4.14kg/m2,其变化受地形、土地利用方式及土壤化学性状等因素影响。海拔为200～800m时有机碳密度最高,平均为4.38kg/m2;坡度对土壤有机碳密度影响表现为2°～6°>6°～15°>15°～25°>0～2°>25°以上;从坡向看,南北坡有机碳密度较高,东西坡较低;不同土地利用方式土壤有机碳密度果园>茶园>水田>旱地;水田土壤有机碳密度与土壤中碱解氮、速效磷和速效钾呈显著正相关,与缓效钾呈极显著负相关,旱地与速效磷和速效钾呈显著正相关,果园与碱解氮和速效钾呈正相关,茶园仅与碱解氮呈显著正相关。

Distribution and Affecting Factors of Soil Organic Carbon Density in Terraced Fields

Study on distribution and affecting factors of soil organic carbon(SOC) density in hilly area under different land use type will contribute to technique researches for soil fertility and soil productivity improvement.Through the centralized sampling,the paper analyzed SOC density and affecting factors of paddy field,dry land,orchard and tea plantation in hilly area of southeastern China.The results showed that the overall mean of SOC content in the surface layer(0-20 cm) was 4.14 kg/m2,which change was effected mainly by landscape,land use type and soil chemical properties.The mean of SOC density at 200～800 m was 4.38 kg/m2,which was larger than that for soils from other height.The SOC density followed the variety trend of 2°～6°>6°～15°>15°～25°>0～2°>above 25°,which was the higher in south and north slope than that in east and west slope.The SOC density was the highest in orchard,followed by tea plantation,paddy field and dry land.SOC density in paddy field had a significantly positive correlation with available nitrogen,available phosphorus,available potassium,respectively,which had a significantly negative correlation with slowly available potassium.SOC density in dry land had a significantly positive correlation with available phosphorus and available potassium;that in orchard had a significantly positive correlation with available nitrogen and available potassium;that in tea plantation had a significantly positive correlation with available nitrogen.