Roles of land-scale expansion and household labor allocation in nitrogen fertilizer use in Chinese croplands

The roles of land scale and household labor allocation have always been a hot button in nitrogen (N) fertilizer use. Rural part-time farming is the main form of household labor allocation in China. This study aimed to quantify the N fertilizer use responses to land-scale expansion and rural part-time farming with different degrees and types in Chinese croplands. Using data on 1159 households extracted from a rural household survey in three great agricultural plains, China, we applied Ordinary Least Squares and Tobit model to yield the consistent results. The results showed that N fertilizer use significantly decreases by 2.23 kg/ha with per unit increase in land scale (p < 0.1), while rural part-time farming degree significantly increases N fertilizer use by 29.72 kg/ha (p < 0.01). Particularly, different effects are detected on the different types of part-time farming households. PTF II (part-time farming degree ranges from 50% to 80%) and OFH (degree higher than 80%) types are proved to be responsible for increasing N fertilizer use of 25.41 kg/ha (p < 0.01) and 22.86 kg/ha (p < 0.05), respectively. These findings imply that the government should encourage part-time farming households to transfer agricultural croplands, thereby expanding land scale so as to reduce N fertilizer use.