中国东部主要农田土壤有机碳库的平衡与趋势分析

ANALYSIS FOR THE BALANCE OF ORGANIC CARBON POOLS AND THEIR TENDENCY IN TYPICAL ARABLE SOILS OF EASTERN CHINA

根据田间测定的有机物料腐殖化系数和土壤有机碳矿化量结果 ,以及统计测算的有机物质进入量 ,分析了中国东部主要农业区农田土壤有机碳库的平衡状况 ,并对其作为大气CO2 的源汇功能进行了初步评价。结果表明 ,各农业区农田土壤中有机物料腐殖化系数的变化趋势为 :松嫩平原 (作物秸秆 0 3 7,作物根 0 47,绿肥 0 2 6 ,粪肥 0 5 4 ) >红壤丘陵区(相应值为 0 2 8,0 45 ,0 2 5 ,0 42 ) >下辽河平原 (相应值 0 3 5 ,0 3 9,0 2 2 ,0 3 3 ) >黄淮海平原(相应值 0 2 5 ,0 3 2 ,0 1 8,0 2 7)。各区间的腐殖化系数并不随气候而呈规律性变异 ,而主要是环境因子综合作用的结果 ,特别是土壤性质有显著影响。现实有机物质进入量条件下 ,各农业区农田土壤有机碳年形成量分别为 :松嫩平原 5 3 8 0kghm- 2 ,下辽河平原 6 79 7kghm- 2 ,黄淮海平原 76 0 7kghm- 2 ,红壤丘陵区 1 0 5 9 7kghm- 2 ;农田土壤有机碳年矿化量分别为 :松嫩平原 90 5 3kghm- 2 ,下辽河平原 72 3 5kghm- 2 ,黄淮海平原 72 3 1kghm- 2 ,红壤丘陵区 782 9kghm- 2 。因此 ,松嫩平原黑土的有机碳库处于亏缺状态 ,土壤有机碳含量还将下降 ,并向大气释放CO2 ;红壤水稻土的有机碳库处于盈余状态 ,土壤有机碳含量还将不断提高 。

Humification coefficients of organic materials and annual mineralization of soil organic carbon were determined in field experiments.Amounts of organic materials application were estimated by statistical data to analyze input and output of organic carbon pools in typical arable soils in important agricultural areas of Eastern China in order to evaluate preliminarily.their functions as source or sink of atmospheric CO 2.Humification coefficients in arable soils of agricultural areas of Eastern China changed in the order:Songnen plain (crop straw 0 37,crop roots 0 47,green manure 0 26,livestock manure 0 54)>Red soil hilly region (with corresponding values of 0 28,0 45,0 25,0 42)>Xialiaohe plain (values:0 35,0 39,0 22,0 33)>Huanghuaihai plain(values:0 25,0 32,0 18,0 27).Humification coefficient did not changed proportionately with temperature and rainfall and was multiply influenced by environmental factors,especially soil properties.Under realistic application of organic materials,Songnen plain,Xialiaohe plain,Huanghuaihai plain and Red soil hilly region would have a soil organic carbon formation annually of 538 0 kg hm -2 ,679 7 kg hm -2 ,760 7 kg hm -2 and 1 059 7 kg hm -2 .Annual mineralization amounts of soil organic carbon are 905 3 kg hm -2 ,723 5 kg hm -2 ,723 1 kg hm -2 and 782 9 kg hm -2 ,respectively.The C balance,calculated as the difference between input and output of soil organic carbon,suggested a deficit (decreasing organic C)in the arable soil of Songnen plain,an increasing organic C content in the paddy soil of Red soil hilly region,an equilibrium in arable soils of Xialiaohe and Huanghuaihai plains.These values determine their functions as source or sink of atmopheric CO 2.