Much of the farmland was eroded in the aftermath of the Dust Bowl. In 1941, a Kansas agricultural experiment station released a bulletin that suggested reestablishing native grasses by the "hay method". Developed in 1937 to speed up the process and increase returns from pasture, the "hay method" was originally supposed to occur in Kansas naturally over 25–40 years. After much data analysis, the causal mechanism for the droughts can be linked to ocean temperature anomalies. Specifically, Atlantic Ocean sea surface temperatures appear to have had an indirect effect on the general atmospheric circulation, while Pacific sea surface temperatures seem to have had the most direct influence.