Farmland scale and chemical fertilizer use in rural China: New evidence from the perspective of nutrient elements

Chemical fertilizer overuse has resulted in serious agricultural pollution. Many studies have analyzed the effect of farmland scale on fertilizer use. Fertilizer has different nutrient elements, such as nitrogen, phosphorus and potassium, but little evidence of the effect of farmland scale on nutrient elements application rate has been found. Using micro-survey data of 1015 households across 5 provinces of China, this study empirically identified the effect of farmland scale on fertilizer use from the perspective of nutrient elements. The instrumental variable method was used to solve endogenous problems. Results showed that farmland scale had a significant negative impact on the total nitrogen application rate from fertilizer and the nitrogen application rate from urea but had no statistically significant impact on the nitrogen application rate from non-urea, phosphorus application rate or potassium application rate. The nitrogen application rate on average decreased by 0.93% for each 1% increase in average farm scale. Heterogeneity analysis indicated that the effect of farmland scale on the nitrogen application rate were different among groups with different crops, gender, age and education of head of household, and differences in proportion of farmland transfer. Scale effect was found only in maize cultivation. The proportion of farmland transfer is higher, the scale effect for fertilizer reduction is less obvious. The findings offer new insights that farmland scale has heterogeneity effects on nutrient element application rates and fertilizer reduction should focus on nitrogen application rate from non-urea.