Has climate change shifted US maize planting times?

Background/Question/Methods

Global warming has been accompanied by an earlier onset of spring phenological events across a range of ecosystems. However, the degree to which humans have adapted planting schedules to a changing climate remains an open question; the leading hypotheses for earlier planting are improved hardiness of cultivars and farming equipment. Here we examine the relationship between historical temperature and precipitation from 534 weather stations from the United States Historical Climatology Network (USHCN) with planting schedules from 19 states in the United States Department of Agriculture/National Agriculture Statistics Service (USDA/NASS) database. We construct an empirical model to relate yearly weather conditions to predict planting dates. 

Results/Conclusions

Evidence for a relationship between climate and planting schedules indicates that planting schedules for US maize have been adapted to yearly variations and overall changes in climatology. These findings serve to indicate extant adaptation between US farmers and climate change, and will aid in forecasting future shifts to planting schedules as climate continues to change.  Furthermore, the statistical model should also be useful for estimating planting times for states and years for which records do not otherwise exist.