Impacts of irrigation-climate interactions on irrigated soybean yields in the US Arkansas Delta from 2003 to 2017

Irrigation has been widely implemented across the globe as a mitigation strategy to combat climate change and erratic rainfall. Irrigation in the confined geographic region like the Arkansas Delta of the US has likely affected heat and moisture fluxes at the land surface with possible effects on regional climate conditions. Irrigation unquestionably benefits crop yields with direct water supplies. However, the effect of irrigation-climate interactions on Arkansas Delta crop yields remains unclear. In this study, we applied multiple satellite and climatic datasets to assess the influence of soybean irrigation in the US Arkansas Delta on the regional climate from 2003 to 2017 and how the resultant climate variability has affected soybean yields. Our findings show that soybean irrigation in the Arkansas Delta leads to statistically insignificant precipitation change and significant daytime and night time cooling during the growing season from June to August over the period of 2003-2017. Using a statistical crop yield model, we further demonstrate that such surface temperature cooling due to irrigation could enhance soybean yields as much as similar to 1.13 (+/- 0.87) bu/acre, accounting for 7.78% of total soybean yields gain due to irrigation. Our results highlight the important positive effects of irrigation-climate interactions on soybean yields, which may be more important in the Arkansas Delta, given the depletion of groundwater that farmers relied on most for irrigation.