Prior crop season management constrains farmer adaptation to warming temperatures: Evidence from the Indo-Gangetic Plains.

Climate change induced heat stress is predicted to negatively impact wheat yields across the Indo-Gangetic Plains (IGP) of India. Research suggests that early sowing of wheat can substantially reduce this impact. However, a large proportion of farmers sow wheat late across this region, likely resulting in large-scale yield loss. We examined the extent of late wheat sowing across the IGP and which perceptional, management, biophysical, and socio-economic factors are associated with delayed sowing using household survey data from 2429 farmers and the cumulative logit model. Our results indicate that despite understanding that early sowing can be helpful to avoid terminal heat stress, over 50% of farmers sow wheat later than their perceived ideal wheat sowing date. We find that variables related to how wheat fields are prepared prior to sowing are associated with wheat sowing date. Specifically, farmers who had shorter fallow periods prior to sowing wheat and those who used zero tillage were 95% and 65% more likely to sow wheat earlier, respectively. In addition, we found that how farmers managed their rice crop in the preceding cropping season impacted wheat sowing date - farmers who transplanted and harvested rice later and/or planted longer duration rice varieties sowed their wheat later. Our results suggest that policies that promote earlier sowing of rice, such as improved access to irrigation and direct seeding machinery, and reduced field preparation time, such as wider adoption of zero tillage technologies, can help farmers across the IGP sow wheat earlier. This is critical given that warming temperatures will only increase the negative impacts of terminal heat stress on wheat yields across this region over the coming decades.