耕地利用转型碳储量时空分异特征及脱钩效应研究.

[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 transition 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 388 630 tons in 1990-2000, decreasing by 60 121 750 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 carbon stocks seriously affects food security. The study area should pay attention to the threat of grain carbon stock loss to food security. [ABSTRACT FROM AUTHOR]