中国粮食主产区耕地撂荒程度及其对粮食产量的影响

耕地撂荒严重地影响着我国的粮食安全。以我国粮食主产区为研究区域,在识别撂荒地分布的基础上,测度了撂荒地空间分布格局,并建立耕地撂荒中介效应模型,探究了耕地撂荒对区域粮食产量的影响机制。结果表明：（1）中国粮食主产区耕地撂荒规模为405.53万hm²,撂荒率约为5.85%;空间上撂荒地规模分布呈“T”字形空间格局,黑龙江东北部、吉林西北部以及内蒙古南部地区为撂荒地主要集聚区。（2）耕地撂荒对于粮食主产区粮食产量具有显著负向影响,2017年我国粮食主产区因耕地撂荒损失的农田生产潜力达到1339.15万t,损失的粮食产量高达2265.6万t,损失比例达4.69%;内蒙古自治区成为粮食产出损失量和损失比例最大的地区。（3）粮食播种面积、农田生产潜力和农业技术投入均发挥了部分中介作用,系数分别为-0.194、-0.025和0.006。（4）应遵从城乡融合以及农业农村发展态势,强化粮食主产区农业生产现代要素投入与政策扶植,构建粮食生产—耕地休耕空间转换弹性机制,保障我国粮食安全。

The degree of cultivated land abandonment and its influence on grain yield in main grain producing areas of China

Cultivated land abandonment has a profound impact on China's food security. Taking the main grain producing areas in China as an example and based on the identification of the distribution of abandoned land, this paper measured the spatial distribution pattern of abandoned land, established the mediating effect model of cultivated land abandonment, and explored the influence mechanism of cultivated land abandonment on regional grain yield. The results showed that: (1) The area of abandoned cultivated land in the main grain producing areas of China was 4.0553 million hectares, with a rate of 5.85%; the distribution of abandoned land presented a T-shaped pattern, mainly concentrated in the Northeastern Heilongjiang, Northwestern Jilin and Southern Inner Mongolia. (2) Cultivated land abandonment had a significant negative impact on the grain yield of the main grain producing areas. In 2017, these areas lost a farmland production potential of 13.3915 million tons, and the loss of grain output was as high as 22.656 million tons, accounting for 4.69%; Inner Mongolia was the most affected region. (3) Grain sown area, farmland production potential, and agricultural technology input all played an intermediary role, and their regression coefficients were -0.194, -0.025 and 0.006, respectively. (4) We should follow the trend of urban-rural integration and agricultural-rural development, strengthen the input of modern agricultural production factors and policy support in major grain producing areas, and construct the flexible mechanism of spatial transformation between grain production and cultivated land fallow to ensure food security in China.