30年来辽宁省耕地土壤有机质与pH时空动态变化

Temporal and Spatial Dynamics of Soil Organic Matter and pH in Cultivated Land of Liaoning Province during the Past 30 Years

有机质和p H是反映耕地土壤肥力的重要指标。本研究应用反距离加权空间插值法,对辽宁省1982年、2012年这两个时期的耕地土壤有机质含量和p H的时空动态变化特征进行分析。研究结果表明:两个时期的有机质含量均呈中东部高于其他地区,p H均呈东南酸西北碱的趋势。30年间,辽宁省有79.8%面积的耕地土壤有机质含量在降低,有机质平均值由20.51 g kg^(-1)降低到17.84 g kg^(-1),降低了2.67 g kg^(-1);在不同土壤类型中,除草甸盐土有机质含量有所提升外,其余土壤类型的有机质含量都出现降低趋势,其中白浆土降低趋势最明显。30年间,辽宁省有88.9%面积的耕地土壤发生不同程度酸化,p H平均值由7.08降低到6.59,下降了0.49;在不同土壤类型中,除白浆土的p H值变化有所升高外,其余土壤类型的p H值都有不同程度的下降,其中风沙土p H值降低趋势最为明显。分别对不同时期的有机质含量和p H进行相关分析及方差分析,结果表明每个时期的有机质含量和p H均呈显著的负相关关系(P<0.01),但是对30年间的有机质含量变化和p H变化进行相关分析却呈现弱负相关(r=-0.089),相关性并不显著,说明两者的变化过程并不直接影响,需要其他因素的介入来间接作用。因此,今后有必要对影响它们的变化过程的多个中间因素进行重点分析,这将为耕地土壤有机质含量和p H下降原因的探究以及农田土壤肥力演变提供理论支撑。

Soil organic matter（SOM） and p H were two important indices to soil fertility of cultivated land. Based on the data of the Second Soil Survey of Liaoning Province（in 1982） and the cultivated land fertility evaluation（in 2012）,the temporal and spatial dynamic characteristics of SOM and p H during the two periods（in 1982 and in 2012） were analyzed by the spatial interpolation method of inverse distance weighting in cultivated land of Liaoning Province.Results showed that in both two periods, the region with high SOM content was mainly distributed in the mid-east region, and p H showed an acidification trend in the southeast region but an alkaline trend in northwest region of Liaoning Province. The content of SOM decreased from 20.51 g kg^（-1）to 17.84 g kg^（-1）, with an average of 2.67 g kg^（-1）,which mainly distributed in 79.8% of total cultivated land soil during 30 years. The SOM content in all soil types（except for in Meadow saline soil） was decreased, especially in Albic soil. Moreover, soil p H generally decreased from7.08 to 6.59, which mainly distributed in 88.9% of total cultivated land soil during 30 years. The p H was decreased in almost soil types（except for in Albic soil）, especially in Aeolian sandy soil. Additionally, SOM and p H showed a negative correlation（P 〈0.01）in each period, but between the change of SOM and the change of p H showed not significantly negative correlation（r =-0.089） during 30 years. It suggested that there might be indirectly influenced by the intermediate factors between the changing processes of SOM and p H. Consequently, more attention should be paid to discuss the intermediate factors to the changing processes between them. And this would help to investigate the reason for decrease of SOM and p H and provide theoretical supports for soil fertility evolution.