This paper explores the effects of environmental regulation (ER) and rural residents’ health investment (RRHI) on agricultural eco-efficiency (AEE) to provide a reference for the Chinese Government and other developing countries for implementing environmental regulation policies and to provide new paths to further improve green development in agriculture. Using the panel data of 31 Chinese provinces from 2009–2018, the Super-SBM model was used to measure AEE. The role of ER on AEE was analyzed based on panel two-way fixed effects with endogeneity treatment and a robustness test, and this mediating effect analysis was conducted to analyze the role of RRHI in ER and AEE, examining the extent of the effect of ER on AEE in three regions of China—eastern, central and western—using a heterogeneity analysis. The results of the study show that: (1) from a national perspective, ER has a significant positive impact on AEE, showing that ER is effective at this stage; (2) when RRHI is used as a mediating variable, the rising ER’s intensity can promote AEE by increasing RRHI; and (3) the results of the heterogeneity analysis show that ER has the greatest impact on AEE in the economically developed eastern region; the western region with a weaker level of economic development is in second place. However, ER has a negative impact on AEE in the central region with a medium level of economic development. Thus, the impact of ER on AEE will show great differences depending on the stage of economic development.

Farm household pluriactivity has become increasingly prevalent in China; however, its influence on crop structure remains insufficiently explored. This study examines the impact of farm household pluriactivity on crop structure in China, focusing on factor input mechanisms. Based on survey data from 473 farm households in Sichuan Province, this study employs ordinary least squares (OLS), two-stage least squares (2SLS), and mediation analyses to systematically assess the impact of pluriactivity on crop structure through factor input mechanisms. The analysis reveals three key findings. First, rather than reducing the grain planting area, an increase in part-time farming is associated with a significant rise in the proportion of grain cultivation. Second, factor inputs partially mediate this relationship: while pluriactivity tends to reduce staple crop cultivation through mechanisms such as cultivated land transfer-out, land abandonment, and increased non-agricultural labor input, it simultaneously promotes staple crop expansion via enhanced agricultural technical services. Third, heterogeneity tests indicate that the positive effect of pluriactivity on staple crop cultivation is especially pronounced among households in hilly areas and those that have adopted agricultural insurance. These findings provide valuable policy insights for fostering sustainable agricultural transitions and enhancing food security in developing regions.