中国典型丘陵区人口密集乡村景观的土壤碳氮磷分布特征

Distribution characteristics of soil organic carbon, nitrogen and phosphorus in densely populated village landscapes of different hilly regions of China

基于IKONOS高分辨率（1m）卫星遥感图,根据生态立地分层分类规则,评价了四川盆地、江南山地和华南山地等典型丘陵区人口密集的乡村景观结构对0-30cm土壤有机碳（SOC）、全氮（TN）和全磷（TP）密度及储量的影响.结果表明：SOC密度的面积加权平均值为江南山地丘陵（2.72±0.76kg·m^-2）〉华南山地丘陵（2.65±0.73kg·m^-2）〉四川盆地丘陵（2.15±0.57kg·m^-2）;TN密度的面积加权平均值为江南山地丘陵（0.28±0.06kg·m^-2）〉四川盆地丘陵（0.27±0.06kg·m^-2）〉华南山地丘陵（0.21±0.06kg·m^-2）;TP密度的面积加权平均值为四川盆地丘陵（0.19±0.04kg·m^-2）〉江南山地丘陵（0.11±0.03kg·m^-2）〉华南山地丘陵（0.08±0.04kg·m^-2）.四川盆地、江南山地和华南山地丘陵SOC、TN和TP储量最高的生态立地类型分别为小规模1年生旱地作物、两季水田和斜坡次生阔叶疏林.SOC和TN密度均以水田或林地最高,而以低覆盖度的挖掘地和山顶旱地最低,TP密度的分布较为复杂.细微尺度的生态立地水平分析可以较好地反映出丘陵区人口密集乡村景观地区的生态结构和SOC、TN、TP的分布情况.

Based on high spatial resolution remote sensing map （ 1 m） and sampling with a stratified design on different site types, the effects of fine-scale land use patterns in villages on top soil （0-30 cm） organic carbon （OC）, total nitrogen （TN） and total phosphorus （TP） within and across the densely populated hilly landscapes, i.e. , Sichuan Hilly Region （ SIHR ; Jintang County, Sichuan Province）, Subtropical Hilly Region （ SUHR ; Yiyang County, Hunan Province ）, and Tropical Hilly Region （THR; Dianbai County, Guangdong Province） , were investigated. The resuits showed that soil OC density was decreased in the order of SUHR （ 2. 72 ± 0. 76 kg ·m^ -2 ） 〉 THR （2.65±0.73 kg ·m^ -2） 〉 SIHR （2. 15± 0.57 kg ·m^ -2）, TN density was in the order of SUHR （0.28± 0.06 kg ·m^ -2） 〉SIHR （0.27 ± 0.06 kg ·m^ -2） 〉THR （0.21 ± 0.06 kg ·m^ -2 ）, and TP density was in the order of SIHR （0. 19± 0. 04 kg ·m^ -2 ） 〉 SUHR （0. 11 ± 0.03 kg- m-2） 〉 THR （0. 08± 0. 04 kg ·m^ -2 ）. The fine-scale landscape units （ecotopes） with the highest soil OC, TN and/or TP stocks were rainfed annual crops in SIHR, paddy rice in SUHR, and open canopy trees and brush in THR, respectively. In all hilly regions, paddy and forest land use classes had the highest soil OC and TN density, while mined areas had the lowest soil OC and TN density, with the distribution of TP density showing a more complicated pattern than that of OC and TN. Ecotope level analysis could reflect the soil organic carbon, nitrogen and phosphorus distribution in densely populated village landscape of hilly regions more comprehensively than land use or land cover analysis.