maintaining soil fertility and crop yield in traditional farming systems. However, it is
increasingly not recycled, wasting vital resources and damaging the environment. By using
long-term (1986–2017) data from a rural household survey (> 20,000 households) across
China, here we show that the share of rural households with both crop planting and livestock
raising (CPLR) has sharply declined from 71% in 1986 to only 12% in 2017. Compared with …