典型喀斯特高原坡地土壤养分分布及其影响因素

喀斯特地区生态环境脆弱，石漠化严重，土壤性质对其环境的变化较为敏感，了解研究区环境因素对土壤性质的作用，对该区生态恢复重建有一定的指导意义。本文在前期对喀斯特地区峰丛洼地和峰林平原研究的基础上，以贵州喀斯特高原典型样区为研究对象，采用从坡脚到山顶线形布点(间隔10 m)采集土壤样本，同时调查记录各环境因子，通过对土壤养分指标测定，结合环境因子探讨了研究区内坡地土壤养分随相对高程的变化情况和地形因素(裸岩率、土层厚度和相对高程)之间及其对土壤养分的影响。结果表明：随相对高程的增加，裸岩率显著递增，土层厚度在0 ~ 30 cm范围内，与裸岩率呈极显著负相关(P<0.01)；结合协方差分析结果发现，裸岩率高的地段促进了土壤有机碳以及氮磷养分的积累，土壤有机碳和全氮含量受裸岩率和相对高程的影响，土壤全钾的含量主要受相对高程的影响，而土壤pH则同时受各地形因素的影响，全钾含量不受三地形因素的影响；随机误差分析表明，土壤有机碳及速效养分含量还受到其他因素的影响。

Distribution of Soil Nutrients and Its Influencing Factors in Slope of Typical Karst Plateau

In Karst region, soil property is sensitive to environmental change of environment due to the fragile ecological environment and serious rock desertification. Understanding the effects of environment factors on soil properties will provide guidance for ecological restoration and reconstruction. Taking a slope land of typical Karst plateau as research object, the soil nutrients were measured with setting the sampling site using a line transect from base to top of the slope with a 10 m interval, and simultaneously, the environmental factors were investigated and recorded. The relationships between soil nutrients and the changes of relative elevation were analyzed, and the effects of topographical factors including the bare-rock rate, soil thickness and relative elevation on soil nutrients were discussed. The results showed that with the increase of relative altitude, the bare-rock rate was significantly increased and the soil depth within 0-30 cm was significantly negative correlated with bare-rock rate (P<0.01). The covariance analysis showed that high bare-rock rate promoted the accumulation of the contents of soil organic carbon (SOC), nitrogen and phosphorus. The contents of SOC and total nitrogen (TN) were influenced by bare-rock rate and relative altitude. The content of total potassium (TK) was mainly influenced by the relative altitude. Soil pH was influenced by rock bare-rate, soil depth and relative altitude, but the three topographic factors have no effect on the content of available potassium (AK). The random error analysis indicated that the contents of SOC and available nutrients were also influenced by the other factors, which needs further investigation.