我国南方桂东地区农田土壤养分特征及对有机碳驱动分析

Soil organic carbon and soil nutrients frequencies and its correlations in eastern area of Guangxi province

南方高温多雨条件下土壤有机碳及养分含量变化大,把握其含量特征及关联利于制定土壤环境健康的合理施肥模式。对我国南方桂东地区主要肥力因素的分布特征进行分析,通过相关分析及逐步回归分析探明土壤有机碳与土壤养分间的内在联系,借助通径系数明确各养分因素影响土壤有机碳的程度,为我国南方土壤可持续利用提供参考。桂东地区土壤主要肥力指标分析结果表明,土壤有机碳、p H值、全氮、有效磷、速效钾的均值分别为21.6 g·kg-1、6.9、2.1 g·kg-1、23.5 mg·kg^-1和89.3 mg·kg^-1;且各指标频数分布分析结果显示,除速效钾外（仅40%达中、高水平）,其余指标有83%-96%的含量达中、高肥力水平。上述结果说明,尽管近年来该区域土壤肥力得到一定提高,而土壤钾含量低仍是该区域当前土壤肥力提升的限制性因子。在该区域内,土壤有机碳与全氮、p H值、有效磷、速效钾间呈显著相关,其相关系数依次降低。总体上土壤有机碳含量与土壤肥力水平一致,表明该区域下可通过调节土壤p H配合施用氮、磷、钾肥提高土壤有机碳。

It is important to understand the soil organic carbon（ SOC） and soil nutrients characters for selecting a suitable fertilization management for the soil environment health in rainy southern China with high temperature. We analyzed frequencies and the regression correlations of the SOC and other four key nutrients＇ contents in eastern area of Guangxi province. The results showed that the SOC,p H,total N and available P contents of 83%-~ 96% samples were at the medium or high level,with a mean of 21. 6 g·kg-1,6. 9,2. 1 g·kg-1and 23. 5 mg·kg^-1respectively. The average content of available K was 89. 3mg·kg^-1and 40% samples belonged to medium and high level. It showed that although the soil fertility was increasing in the survey place in these years,K application should be encouraged for maintaining high soil fertility. There was significant relationship among the SOC and other key nutrients,and the correlation value was total N p H available P available K. It showed that the optimized fertilization and improved p H were the key factors to improve the soil fertility and the SOC level.