格氏栲天然林土壤有机碳空间分布及其影响因素

摘要

采用GIS技术对格氏栲天然林土壤有机碳空间分布特征及其影响因素进行研究,结果表明:土壤有机碳含量(O)、土壤有机碳密度、土壤有机碳储量均属于中等变异,且随土层深度的增加而减少,表层富集现象明显.土壤有机碳含量在Ⅰ层(0 ～ 20 cm)为32.15 g/kg,分别是Ⅱ层(20～40 cm)、Ⅲ层(40 ～ 60 cm)的2.35、4.63倍,剖面均值为17.60 g/kg;土壤有机碳密度在Ⅰ～Ⅲ层分别为6.76 kg/m2、3.17 kg/m2、1.74 kg/m2,土壤剖面平均有机碳密度为11.67 kg/m2.引入泰森多边形替代土壤类型图,计算得格氏栲天然林土壤有机碳储量为1.49×104 t,Ⅰ层、Ⅱ层、Ⅲ层分别为8.66×103 t、4.01 × 103 t、2.20×103 t.土壤有机碳含量和土壤有机碳密度空间分布情况类似:在西南和东北各有一个高值区,以WS - EN为中线,西北和东南呈近似对称的条带状分布,且向两边表现出递减的趋势.相关分析和逐步回归分析表明,土壤有机碳含量与土壤理化性质相关性均达到极显著水平,与全氮(TN)、全磷(TP)、水解性氮(AN)、有效磷(AP)、速效钾(AK)显著正相关,与全钾(TK)、pH、土壤容重(B)显著负相关,满足O=38.19+72.42 TN+0.04AN+54.47 TP - 7.50pH - 7.04B.同时分析了地形、土壤理化性质、人为活动等对格氏栲天然林土壤有机碳含量的影响.研究结果可为提高土壤有机碳储量精度、评估格氏栲天然林生态效益及其在区域碳循环中的作用和功能提供参考依据.%GIS technology was applied to study the spatial distribution and influencing factors of soil organic carbon in the mid-subtropical Castanopsis kawakamii natural forest of Sanming City,Fujian Province. The results showed that the variation of organic carbon content ( 0) , density and reserve of soil all are moderate, descending with the increase of soil depth and mostly aggregating in layer 1(0 -20 cm). The soil organic carbon content in layer Iwas 32.15 g/kg,2. 35,4. 63 times than the layer E (20 ~ 40 cm) and layer IE (40 ~ 60 cm) respectively, and the entire profile was 17. 60 g/kg. The soil organic carbon density layer I - HE were 6. 76 kg/m2,3. 17 kg/m2 and 1. 74 kg/m2 respectively, the average soil organic carbon density was 11.67 kg/m2. Soil organic carbon reserve in C. Kawakamii National Forest Park stored at 0 ~60 cm was about 1. 49 × 104 t,layer Ⅰ ,Ⅱ , Ⅲ were 8. 66 × 103 t,4.01 ×103 t,2. 20 ×l03 t respectively, which were calculated with voronoi. Soil organic carbon content and density have similar spatial distribution in southwest and northeast, which both have a high value area, along with the direction of WN - ES. They emerged stripe distribution, regularly decreasing from WS - EN line to northwest and southeast respectively. The results of correlation analysis and stepwise regression analysis showed that soil organic carbon content associated with soil physicochemistry properties,reaching a significant level,and were positively correlated with total nitrogen, total phosphorus, hydrolyzable nitrogen, available phosphorous, available potassium, negatively correlated with the PH, total potassium and soil bulk density,and can be further described by the formula; 0 = 27. 77 + 37. 88 TN + 0. 05 AN + 59. 69 TP - 7. 28 pH - 7.04 B. The effects of topography, soil physicochemistry properties and human disturbance on soil organic carbon in C. Kawakamii forest were also analyzed. All these results may be available for enhancing the precision of soil organic carbon reserve, assessing eco-efficiency of the C. Kawakamii natural forest and its roles and functions in regional carbon cycle.