Zero-tillage wheat provides stable yield and economic benefits under diverse growing season climates in the Eastern Indo-Gangetic Plains

Sustainably enhancing wheat productivity in the Indo-Gangetic Plains (IGP) is vital for ensuring future food security. While in controlled field trials zero-tillage (ZT) wheat has demonstrated considerable yield benefits, empirical assessments of the performance stability of the practice in farmers' fields under varying climatic conditions are lacking. Given progressive climate change, this constitutes an important knowledge gap which we address with a unique panel dataset from 961 farm households in Bihar, India, spanning two favourable and two less favourable growing seasons. We employ an endogenous switching regression (ESR) framework to derive unbiased estimates of the expected impacts of ZT on wheat yields and production costs among the farming population (average treatment effect, ATE). The prevailing ZT practices led to significant yield gains in three out of the four years, notably in the less favourable seasons. Overall, the estimated yield ATE was 660 kg ha(-1). More importantly from the farmers' perspective, ZT led to significant cost savings in all four seasons, commensurate to a 5% increase in average total household incomes. We conclude that ZT for wheat in Bihar provides tangible and consistent benefits to farmers. Policy-makers in Bihar and adjacent states should continue to strongly support its adoption at scale.