The pivotal role of farmers’ cropland conservation behavior (CCB) in advancing green agricultural practices is well-recognized. This paper underscores the critical role of stable land tenure in enhancing farmers’ CCB, exemplified by the practice of mulch recycling. Drawing on a survey of 349 cotton farmers in Xinjiang, Northwest China, it offers a systematic examination of how land tenure stability influences CCB and its underlying mechanisms. The findings reveal a significant positive correlation between land tenure stability and CCB. Notably, this relationship is mediated by the facilitation of land mortgages, wherein written contracts and extended land tenure durations enhance farmers’ participation in land mortgages, thereby bolstering CCB. Furthermore, the stabilizing effect of land tenure on CCB also mitigates the negative impacts of risk aversion and time preference. The study additionally highlights the differential effects of land tenure stability based on farm size and technical training; its facilitative role in CCB is more pronounced among larger-scale farmers and those engaged in technical training.