耕地利用转型碳储量时空分异特征及脱钩效应研究

Spatial⁃temporal heterogeneity and decoupling effect of carbon storage in cultivated land use transition

【目的】研究耕地利用转型的碳储量时空异质性及与粮食生产之间的脱钩关系,为实现低碳农业和保障粮食安全提供科学依据。【方法】以松花江流域哈尔滨段为研究区,基于碳储量测算方法和核密度分析模型,揭示1990—2020年研究区耕地利用转型的碳储量时空分异特征,并借助Tapio脱钩模型,探究耕地利用转型碳储量损失与粮食生产之间的脱钩效应。【结果】①1990—2020年研究区耕地面积逐渐减少,耕地与建设用地之间的转型最为剧烈。耕地利用转型碳储量呈大幅度下降趋势,1990—2000年碳储量增加38.863×10^(4) t,而2010—2020年碳储量损失6012.175×10^(4) t,损失近155.701倍。②1990—2020年耕地利用转型碳储量重心基本保持稳定,向东北方移动了13.396 km,空间上呈现“边密中疏”的分布格局,且集聚性逐渐增强,由单核分布向多核分布转变,破碎化程度加剧。③1990—2020年研究区耕地利用转型碳储量损失与粮食生产脱钩经历了强脱钩—弱脱钩—扩张连接的过程,脱钩关系向非良性趋势发展。④1990—2020年研究区脱钩空间分异特征显著,内部空间差异较大,呈现不均等性,由两级分化向三级分化转变。【结论】1990—2020年松花江流域哈尔滨段耕地利用转型过程中导致碳储量不断下降,且空间破碎化程度显著,碳储量损失严重影响粮食安全,研究区应重视粮食碳储量损失对粮食安全的威胁。

【Objective】In the present study,the decoupling relationship between spatial⁃temporal heterogeneity of carbon storage in cultivated land use transition and the grain production were analyzed,providing scientific basis for realizing low⁃carbon agriculture and ensuring grain security.【Method】Taking Harbin section of Songhua River Basin as the study area,based on the carbon storage calculation method and the nuclear density analysis model,the paper revealed the temporal and spatial heterogeneity of the carbon storage in the study area’s cultivated land use transition from 1990 to 2020,and explored the decoupling effect between the carbon storage loss in the cultivated land use transition and grain production using Tapio decoupling model.【Result】(i)The cultivated land area gradually decreased in 1990-2020,and the tran⁃sition between cultivated land and construction land was the most significant.The carbon storage in the transition of cultivated land use showed a significant downward trend,increasing by 388630 tons in 1990-2000,decreasing by 60121750 tons in 2010-2020,losing nearly 155.701 times;(ii)The gravity center of carbon storage in cultivated land use transition was basically stable,with 13.396 kilometers moving to the northeast in 1990-2020.The spatial distribution showed the pattern of‘dense edges and middle sparse’,and the aggregation was gradually enhanced,showing transformation of single core distribution to multi⁃core distribution,and the fragmentation was intensified;(iii)The decoupling relationship between carbon storage loss and grain production in the study area was the non⁃benign in 1990-2020,showing the process of‘strong decoupling⁃weak decoupling⁃expansion connection’;(iv)The spatial heterogeneity of decoupling in the study area was significant in 1990-2020.The internal spatial difference was large,showing inequality and the transformation from two⁃level differentiation to three⁃level differentiation.【Conclusion】In the process of cultivated land utilization transformation in Harbin section of Songhua River Basin from 1990 to 2020,carbon stocks continue to decline,and the degree of spatial fragmentation is significant,and the loss of car⁃bon stocks seriously affects food security.The study area should pay attention to the threat of grain carbon stock loss to food security.