Zhang Xiao-Wei, Xu Ming-Xiang
College of Resource and Environment, Northwest A&F University, Yangling 712100, China.
Huan Jing Ke Xue. 2013 Jul;34(7):2793-9.
Take Wugong County as an example, soil carbon storage and soil carbon sequestration rate were calculated, the change law of farmland soil organic carbon was explored, and the relationship of farmland soil organic carbon and natural factors, human factors was further revealed. The results of the study showed that: (1) The soil organic carbon contents in 80% of the sampling sites were in the range of 8.0-12.0 g x kg(-1), and the organic carbon contents in 0-20 cm soils showed a normal distribution. (2) In 2011, the organic carbon density of the 0-20 cm farmland soil was 26.3 t x hm(-2), below the national average soil organic carbon density (33.45 t x hm(-2)) of the arable layer. In the last 30 years, the soil carbon sequestration rate in the 0-20 cm layer was 71.3 kg x (hm2 x a)(-1), and in the past five years, the carbon sequestration rate was 480 kg x (hm x a)(-1). The recent carbon sequestration rate was higher than the national average soil carbon sequestration rate of the arable layer [380.78 kg x (hm2 x a)(-1)]. (3) In the semi-humid plain region, soil organic carbon was mainly affected by soil types, landform types, organic fertilizer. Soil types accounted for 30.2% of the organic carbon variability; the landform types and the organic fertilizer could explain 37.7% and 32.1%, respectively. The results of the comprehensive analysis showed that the farmland soil organic carbon density of Wugong County in the past 30 years is increasing, and this probably relies on the utilization of chemical fertilizer and the returning straw. Further study should be conducted on the impact of the chemical fertilizer and returning straw.
以武功县为例，计算土壤碳储量和土壤固碳速率，探究农田土壤有机碳变化规律，并进一步揭示农田土壤有机碳与自然因素、人为因素的关系。研究结果表明：（1）80%的采样点土壤有机碳含量在8.0 - 12.0 g×kg(-1)范围内，0 - 20 cm土层有机碳含量呈正态分布。（2）2011年，0 - 20 cm农田土壤有机碳密度为26.3 t×hm(-2)，低于全国耕地层平均土壤有机碳密度（33.45 t×hm(-2)）。近30年，0 - 20 cm土层土壤固碳速率为71.3 kg×(hm²×a)(-1)，过去五年固碳速率为480 kg×(hm×a)(-1)。近期固碳速率高于全国耕地层平均土壤固碳速率[380.78 kg×(hm²×a)(-1)]。（3）在半湿润平原区，土壤有机碳主要受土壤类型、地形类型、有机肥影响。土壤类型对有机碳变异的贡献率为30.2%；地形类型和有机肥分别可解释37.7%和32.1%。综合分析结果表明，武功县近30年农田土壤有机碳密度呈增加趋势，这可能得益于化肥的施用和秸秆还田。应进一步研究化肥和秸秆还田的影响。
