Impact of climate change on soil erosion, runoff and wheat productivity in central Oklahoma

The potential for global climate changes to increase the risk of soil erosion is clear, but the actual damage is not. The objectives of this study were to evaluate the potential impacts of climate change on soil erosion, surface runoff, and wheat productivity in central Oklahoma. Monthly projections were used from the Hadley Centre's general circulation model, HadCM3, using scenarios A2a, B2a, and GGal for the periods of 1950-1999 and 2070 2099. Projected changes in monthly precipitation and temperature distributions between the two periods were incorporated into daily weather series by means of a stochastic weather generator (CLIGEN) with its input parameters adjusted to each scenario. The Water Erosion Prediction Project (WEPP) model was run for four climate scenarios including a recent historical climate and three tillage systems (conventional tillage, conservation tillage, and no-till). HadCM3-projected mean annual precipitation during 2070-2099 at El Reno, Oklahoma decreased by 13.6%, 7.2%, and 6.2% for A2a, 132a, and GGal, respectively; and mean annual temperature increased by 5.7, 4.0, and 4.7 T, respectively. Predicted average annual soil loss in the tillage systems other than no-till, compared with historical climate (1950-1999), increased by 18-30% for A2a, remained similar for B2a, and increased by 67-82% for GGal. Predicted soil loss in no-till did not increase in the three scenarios. Predicted mean annual runoff in all three tillage systems increased by 16-25% for A2a, remained similar for B2a, and increased by 6-19% for GGal. The greater increases in soil loss and runoff in GGal were attributed to greater variability in monthly precipitation as projected by HadCM3. The increased variability led to increased frequency of large storms. Small changes in wheat yield, which ranged from a 5% decrease in B2a to a 5% increase in GGal, were because the adverse effects of the temperature increase on winter wheat growth were largely offset by CO2 rise as well as the bulky decrease in precipitation occurred outside the growing season. The overall results indicate that no-till and conservation tillage systems will be effective in combating soil erosion under projected climates in central Oklahoma. Published by Elsevier B.V