Drivers of livestock manure nitrogen recycling on county scale in China

As the world's largest livestock producer, China faces pressing challenges in recycling manure to minimize resource waste and environmental degradation resulting from the vast amounts of manure generated. Understanding the drivering forces behind manure recycling is essential for advancing sustainable agriculture in China. This study estimated the manure recycling ratio (MRR), measured by nitrogen content, across 2853 Chinese counties using data from 390,000 farms representing four major livestock farming types in 2017. Northern Chinese counties demonstrated significantly higher MRRs, with values exceeding 50 %, compared to Southern regions, with values being lower than 30 %. Higher MRRs were linked to larger cropland size, higher urbanization levels, and a greater proportion of chicken farming. In contrast, MRRs declined in regions with higher temperatures, increased precipitation, higher manure production per livestock unit, a greater emphasis on pig farming, and an ageing rural population. Notably, natural factors such as temperature and precipitation predominantly influenced MRRs in both Southern and Northern China, whereas socioeconomic factors like cropland size and urbanization were more impactful in Eastern and Southwestern regions. These findings highlight the need for region-specific strategies that account for natural and socioeconomic conditions to enhance manure recycling practices across China.