Phosphorus use efficiency has crossed the turning point of the environmental kuznets curve: Opportunities and challenges for crop production in China

The overuse of phosphate fertilizer causes waste of resources and is detrimental to the sustainability of agri-culture and aquatic systems. Effective management of phosphorus (P) in agricultural systems is important. Lack of understanding on the temporal and spatial variations of P utilization in farmland systems would constrain the development of more precise and effective policies as well as management practices. Here, we used two in-dicators, P use efficiency (PUE) and P surplus (Psur), to evaluate changes in P utilization in crop production on both national and regional scale in China during 2005-2018. Great heterogeneity of PUE and Psur were found across different regions, with Northeast of China showing the highest PUE (0.67) and lowest Psur (11.0 kg/ha). For temporal trends, our study showed that China crossed the turning point of the environmental Kuznets curve in 2007, which indicates that China has reached a new development stage of P use that is resource-saving and environmentally friendly. Along with the processes of industrialization and urbanization in China, the devel-opment of agricultural mechanization has further resulted in an increase of PUE and decrease of Psur. Although great efforts were made, China still has a relative low PUE and high Psur compared to developed countries. Our results suggest a regionalized perspective for developing policies for the sustainable use of P resources.

Automated summary

The overuse of phosphate fertilizer in China leads to resource waste and harms the sustainability of agriculture and aquatic systems. Effective management of phosphorus (P) is crucial for agricultural systems. However, the lack of understanding regarding the temporal and spatial variations of P utilization in farmland systems hinders the development of precise policies and management practices. This study evaluates changes in P utilization in Chinese crop production using two indicators, P use efficiency (PUE) and P surplus (Psur). The results reveal significant regional heterogeneity in PUE and Psur, with the Northeast of China exhibiting the highest PUE and lowest Psur. The study also shows that China has reached a new stage of resource-saving and environmentally friendly P use. The development of agricultural mechanization, along with industrialization and urbanization, has contributed to increased PUE and decreased Psur. Nevertheless, China still lags behind developed countries in terms of PUE and Psur. The findings emphasize the need for regional perspectives in developing sustainable P resource policies.