Delineation of Fallow Priority Areas Under Food Security Constraints Using the MARXAN

Abstract

Fallow is a crucial strategy for sustainable agricultural resource management and environmental conservation. Previous studies have mainly focused on the scale of fallow areas, but have rarely considered the connectivity and spatial prioritization of fallow areas during delineation, resulting in scattered and fragmented outcomes. To address these problems, this study proposes a method for fallow area delineation that considers food security constraints. The modified cropland pressure index and principal component analysis were used to estimate the optimal fallow scale for the 21 cities in Guangdong Province, China. Then, the MARXAN was employed to assess the fallow demand of each city in Guangdong, which enabled effective delineation of priority areas for fallow. Connectivity was a key consideration to ensure the contiguous management of fallow areas. The results indicated that fallow scale could be better estimated after considering food security constraints. The modified cropland pressure index revealed that 17 of the 21 cities were necessary for the implementation of fallow management, and the proportion of cropland eligible for fallow was 2.12%. The delineation of fallow areas was influenced by several factors, including the limited availability of high‐quality cropland, low production capacity, poor crop growth, excessive groundwater extraction, and imbalance between food supply and demand. An evaluation of these factors provided a quantitative basis for prioritizing fallow areas. It is imperative to implement fallow in the identified priority areas of Shantou, Huizhou, Jiangmen, Zhanjiang, and Maoming. Specifically, a total of 20 counties were identified as needing priority implementation of fallow, including the fallow area I of 2.45 × 104 hm2 and the fallow area II of 1.33 × 104 hm2. This study is significant in balancing the relationship between agricultural production and environmental conservation, and provides methodological support for developing agricultural and environmental management strategies.