Grassland management effects on soil surface properties in the ozark highlands

Much of the research regarding the effects on soil properties of grazing and land-use conversion from native prairie to pasture and hay meadows has been concentrated in the northern Great Plains where the climate is relatively cool and dry. However, little research has been conducted to ascertain similar effects on soil properties in the much warmer and wetter mid-southern latitudes. The objective of this study was to characterize the effects of prairie conversion to agricultural grasslands on soil properties in the Ozark Highlands of northwest Arkansas. Three native prairie sites were identified with adjacent grazed or hayed grasslands on silt-loam soils. Four prairie-agricultural grassland comparisons were made for this study, with each comparison occurring on the same soil-mapping unit. Conversion of native prairie to grazing and hay harvesting created significantly (P < 0.05) higher bulk density, soil pH, and extractable P, Mg, and Mn within the top 10 cm. There was a significantly (P < 0.2) larger difference in electrical conductivity, extractable K, Na, and Fe, but a significantly smaller difference in total N and C and organic matter concentration, in the top 10 cm between prairie-grazed and prairie-ungrazed landuse combinations. Overall, soil surface properties of agricultural grasslands in the Ozark Highlands were similar to those of native, undisturbed prairie, indicating that either negligible responses occurred following conversion, parameters recovered to original equilibrium levels, or the magnitudes of agricultural inputs following conversion were too low to change equilibrium levels substantially. The baseline soil data generated in this study for undisturbed prairie and agriculturally managed grasslands can serve as standards for assessing impacts of high-input agriculture and future land-use changes in the Ozark Highlands.