黑龙江省旱地土壤有机碳动态模拟与预测

Dynamic Simulation and Prediction of Soil Organic Carbon in Dryland of Heilongjiang Province

研究土壤SOC的变化,对准确评价土壤固碳潜力具有重要意义。用嫩江实测数据对CENTURY模型进行验证,然后用该模型模拟和预测黑龙江表层(0~20cm)SOC的动态变化。结果表明:(1)40年来,黑龙江旱地SOC整体呈下降趋势,SOCD下降了2.42Mg C·hm^(-2);SOC减少了29.78Tg;(2)1980年黑龙江90.77%的旱地SOCD都介于30~70Mg C·hm^(-2)之间,主要分布在黑龙江东部、西部和西南部;2020年SOCD空间分布与1980年基本一致。但与1980相比,有50.05%的旱地面积的SOCD在减少,减少的有机碳大于增加的有机碳;40年间,丢碳(dSOCD<0)的旱地面积占76.8%,主要分布在黑龙江西部和东部;(3)模拟期间SOCD最大的一直是暗棕壤和草甸土,储量最高的是草甸土。(4)30年后,黑龙江SOC呈下降趋势,且下降的速率在减缓;2050年SOCD为48.42Mg C·hm^(-2),相比2020年减少了0.69Mg C·hm^(-2);2050年储量为595.59Tg,相比2020年减少了8.48Tg,未来30年黑龙江表现为“碳源”。

Studying the change of SOC is great significance to accurately evaluate the carbon se-questration potential of soil.The CENTURY model is verified by the measured data of Nenjiang.Then the dynamic change of SOC of surface layer(O~20cm)in Heilongjiang Province is simulated and predic-ted.The results showed that:(1)In the past 40 years,the SOC of dry land in Heilongjiang has shown a downward trend as a whole,and the SOCD has decreased by 2.42 Mg C.hm^(-2);SOC decreased by 29.78 Tg.(2)In 1980,90.7.7%of the'dry land SOCD in Heilongjiang Province was 30~70 Mg C·hm^(-2),mainly distributed in the east,west and southwest of Heilongjiang Province.The spatial distribution of SOCD in 2020 is basically the same as that in 1980.However,compared with 1980,the SOCD of 50.O5%of the dry land area is decreasing,and the decreased organic carbon is greater than the increased or-ganic carbon.In the past 40 years,76.8%of the dry land has lost carbon(dSOCD<0),mainly dis-tributed in the east and west of Heilongjiang.(3)During the simulation period,the largest SOCD has been Dark brown forest soil and Meadow soil,and the highest stock is Meadow soil.(4)After 30 years,the SOC in Heilongjiang showed a downward trend,and the rate of decline was slowing down.In 2050,the SOCD was 48.42 Mg C.hm^(-2),which was 0.69 Mg C.hm^(-2) lower than that in 2020.In 2050,the stock was 595.59 Tg,which was 8.48Tg lower than that in 2020.Heilongjiang will be a"carbon source"in the next 30 years.