Assessing the impact of farmland fragmentation on green productivity in Yellow River Basin: A “quantity-spatial” scale effects perspective and EKC hypothesis test

Abstract

Farmland fragmentation and green productivity are pivotal challenges in global agriculture, especially in ecologically fragile river basins where farming is crucial and the environment is precarious. Yet, the intensity and pathway through which county-level fragmentation undermine green productivity remain largely unexplored. This study examines 447 counties in the Yellow River basin using the CNLUCC dataset to calculate farmland fragmentation index (FFI). Utilizing panel data from 2000, 2005, 2010, 2015, and 2020, we develop an assessment framework of farmland green productivity (FGP), which is estimated using a super-efficiency SBM model. Based on the “quantity-spatial” scale effects and Environmental Kuznets Curve (EKC) theory, this study develops a theoretical model of FFI's impact on FGP and conducts a comparative statics and green elasticity analysis. Furthermore, fixed effects, instrumental variable (IV), mediation, and moderation models are applied to empirically dissect the impact and underlying mechanism of FFI on FGP, complemented by heterogeneity analysis. Our results reveal that: (1) FFI exerts a significant negative influence on FGP, a finding that holds robust across various tests and remains consistent even when road network is used as an IV to address endogeneity. Specifically, a one-unit increase in FFI corresponds to a 0.438-unit decline in FGP, equivalent to a 69 % decrease; (2) the adverse impact of fragmentation on FGP varies markedly across location, topography, development statuses, and fragmentation intensity. In particular, rugged topography exacerbates the negative effect, especially in mountainous areas, while under high grain cropping structures, fragmentation more strongly suppresses FGP in plains by impeding mechanization and resource consolidation; (3) mechanism analysis indicates that FFI diminishes FGP primarily by shifts toward non-grain cropping structures, curtailing mechanization intensity, and escalating agrochemical inputs. Additionally, larger farm size serves to buffer the negative impacts of fragmentation. Furthermore, fragmentation delays the arrival of the EKC turning point. In light of these findings, policy measures should prioritize farmland consolidation, the optimization of cropping structures, the adoption of green technologies, and the expansion of farm size to foster agricultural sustainable intensification and mitigate the deleterious effects of fragmentation on green productivity.