Regulation of soil moisture dynamics in agricultural fields using strips of native prairie vegetation

There is a growing interest in the use of native prairie vegetation to restore the hydrologic balance in agricultural watersheds. The objectives of this study were to investigate the effects of establishing strips of native prairie vegetation (SNPV) in agricultural fields (CROP) on soil water dynamics and assess the potential value of SNPV as an agricultural conservation practice to regulate soil water dynamics. Soil water storage (SWS) was monitored biweekly at four soil depth intervals (0-30, 30-60, 0-60, 0-100) during the growing seasons of 2007, 2008, 2009 and 2010 at the Neal Smith National Wildlife Refuge, Prairie City, Iowa. The influence of land cover (SNPV, CROP), topographic position (summit, sideslope footslope), season, and precipitation on SWS was analyzed. Results indicated that SWS was higher under prairie vegetation than CROP the year the SNPV was established (2007), while a reverse pattern was observed for the following three post-treatment years. More pronounced differences among land covers were observed in the first 30 cm of soil. Overall, June-July had the highest SWS and August-September the lowest, but the trend varied within years. In 2009 and 2010, years of low and high precipitation, respectively, the differences in SWS among land covers were minimal and no statistical differences were observed. Overall, results indicate that the introduction of SNPV can contribute to the regulation of the water balance in agricultural watersheds by increasing water holding capacity, and hence, reducing runoff during high rainfall events.