Spatio-temporal differentiation of carbon offset rate of conservation tillage and its evolution trend in China

An in-depth study of the net carbon effect of conservation tillage can provide an important basis for promoting the green and low-carbon transformation of agriculture. This study takes the carbon offset rate of conservation tillage in 30 provinces in China from 2000 to 2021 as the research object, and with the help of Dagum’s Gini coefficient and its decomposition method, reveals the regional differences in carbon offset rate and its causes among east, middle and west China as well as the main grain producing area, the main marketing area and the balance of production and sales area, and explores the dynamic evolution trend of the rate by using the spatial Markov chain and the dynamic convergence model. The study found that: 1) 1)The carbon offset rate of conservation tillage in China from 2000 to 2021 shows a fluctuating trend of increasing, then stabilizing and then decreasing, with an overall upward trend, an upward trend in the main grain-producing areas, and a fluctuating downward trend in the main grain-marketing areas and the balance-of-production and marketing areas. The national growth rate of carbon offset rate of conservation tillage is 0.71%, and regions show significant spatial variability. Sub regionally speaking, the annual average increase in carbon compensation rates for conservation tillage in major grain producing areas, major sales areas, and balanced areas is 0.40%, −0.73% and −4.70%, respectively, showing significant spatial differences, while the annual average contribution rate of the super variable density difference is as high as 51.01%, becoming the main source of regional differences in carbon compensation rates for conservation tillage in China. 2) China’s conservation tillage carbon offset rate shows a strong“club convergence”, that is, there is a convergence of the development level, the gap is gradually narrowing, reflecting the existence of spatial dependence among provinces. 3) The α value of each region fluctuates, resulting in the national conservation tillage carbon offset rate not having an absolute α convergence trend. The dynamic spatial absolute β and β conditional convergence values are insignificant and negative, which indicates that regional conservation tillage is unbalanced, and regional differences are not fully correlated with regional endowment conditions. Accordingly, it should be recommended to strengthen the joint application of technology, give full play to the spillover effect of its technological innovation, and at the same time formulate a sound institutional strategy and accelerate cross-regional cooperation, so as to promote the coordinated development of China’s conservation tillage carbon offset rate in the region. The results of the study can provide a reference for 30 provinces in China to establish a sound carbon compensation mechanism for conservation tillage that meets regional characteristics, and contribute to the coordinated development of green and low-carbon agricultural economy and the realization of the“dual-carbon”goal.