Does balanced fertilization reduce combine harvesting loss of maize: Evidence from 24 provinces in China

Imbalanced fertilization not only affects yield but is a critical, yet overlooked, factor contributing to grain losses. This study utilizes microdata from 2541 farm households across 24 provinces in China to empirically analyze the nonlinear, threshold, and moderation effects, as well as the heterogeneity, of balanced fertilization (BF) on the combine harvesting loss rate of maize (CHLRM). Research findings demonstrate that the average CHLRM in China is 2.575%. The impact of BF on CHLRM is not linear; rather, it exhibits a significant and robust “U-shaped” nonlinear effect, which remains significant after addressing endogeneity. Marginal effect analysis indicates that the average marginal effects of BFI and BFI 2 on CHLRM are −0.402 and 0.131, respectively. However, this U-shaped effect is contingent upon planting scale and agricultural income. The effect is significant for households with planting scale below 24.34 mu and agricultural income shares below 40%. Additional analysis reveals that the adoption of agricultural digital technology significantly amplifies BF's U-shaped loss-reduction effect. Heterogeneity analysis indicates that the loss-reduction effect of BF is more stable in major grain-producing regions. However, this effect exhibits structural variation: BF demonstrates stronger loss reduction at high loss quantiles but becomes insignificant for farmers already at the lowest loss quantile (Q0.10). Therefore, policies should shift from singular fertilizer reduction targets to promoting precision balancing. This requires implementing tailored guidance: BFI technology should be prioritized for small-to-medium-scale and low-income farm households, while large scale and professional farmers should be supported in adopting capital substitution pathways such as advanced machinery. • Balanced fertilization exhibits a robust U-shaped impact on harvest losses. • Impact is asymmetric: Under-fertilization causes greater losses than excess. • Loss reduction is significant for small-scale farms and part-time groups. • Agricultural digital technology amplifies the loss-reduction effect. • Diminishing returns: The effect vanishes at the lowest loss quantile.