Returning excrement from livestock, poultry, and humans to farmland as nutrient resources for crop growth: Assessment of rural China

Abstract

Traditionally, farmers in China have relied on excrement to supplement organic matter in soils, and to fertilize crops for human and animal consumption. Few studies have quantitatively analyzed the potential of returning livestock-poultry and human excrement in rural China to farmland as nutrient resources for crop growth. This study clarifies the temporal and spatial changes, distribution characteristics, nutrient contents, and econometric analysis of excrement in rural China from 1980 to 2019. Meanwhile, its potential as a nutrient resource for crop growth to substitute the utilization of chemical fertilizers was also assessed. Excrement production showed a large increase (138.49 %) in Northeast China, whereas the Northern, Northwest, Southwest and Southeast regions of China and the middle and lower reaches of the Yangtze River experienced an increase of 51.75, 33.63, 30.47, 24.24 and 24.10 %, respectively. The spatial distribution of both the rural excrement and its nutrients was concentrated in Southwest and Northern China and lower reaches of the Yangtze River, as the nutrients in these areas accounted for 69.67–86.76 % of the total. In this study, new evidence and more comprehensive fundamental data are provided for waste treatment and resource recycling in agriculture. Promoting the return of excrement to farmland has the potential to reduce the use of chemical fertilizers, lessen the emission of odorous gas, and remedy environmental stress, thereby assisting to the development of organic agriculture. Recommendations of sustainable development are made for the future development of returning excrement to farmland in this study. The introduction of practical policies on renewable resources is recommended to ensure the comprehensive utilization of excrement.