Soil hydraulic properties as influenced by prairie restoration

Abstract

Prairie restoration has received increased public attention in recent years for its ecosystem services. The objective of this study was to evaluate effects of prairie restoration on soil hydraulic properties as compared to native prairie (NP), grass and row-crop management. Soil cores (76mm diam.×76mm long) from six replicate locations were sampled to a 60-cm depth at 10-cm intervals from two prairie treatments, a continuous no-till treatment (NT), a long-term timothy grass (Phleum pratense L.) treatment (TM) and a row-crop (RC) treatment. The NP has never been tilled and the restored prairie (RP) was established in 1993. All treatments have Mexico silt loam (fine, smectitic, mesic, Vertic Epiaqualfs) soil. Bulk density, saturated hydraulic conductivity (Ksat), soil water retention and pore size distribution were determined. In-situ Ksat was measured using a constant head permeameter with five replications. Bulk density was significantly lower for NP than all treatments. Bulk density was significantly lower for the 0 to 10cm depth for all treatments, and the 10 to 30cm depth recorded the highest values. The in-situ Ksat of RP was lower than other treatments. The first horizon had the highest value for this parameter for all treatments. NP had significantly higher laboratory measured Ksat, and it was almost four times higher than RP. The 0 to 10cm depth of all treatments had significantly higher values for laboratory Ksat than other depths and the 50 to 60cm showed the lowest Ksat. NP had the highest macroporosity and fine-mesoporosity, while RP had the highest microporosity. NP had significantly higher water retention at saturation while RP had the highest water retention for soil water pressures of −33kPa, −100kPa and −1500kPa. Soil water retention was significantly higher in NP for −0.4kPa to −10kPa soil water pressures; at −20kPa NP, RP and RC had significantly higher water retention. The NP treatment had higher soil water content than the other treatments for the 0 to 10cm, 10 to 20cm, 20 to 30cm and 50 to 60cm depths at soil water pressure of −20kPa. The 30 to 40cm and 40 to 50cm depths of RP had higher soil water content at all soil water pressures. Results imply that prairie restoration influences some hydraulic properties in claypan soils; however, it is unlikely to achieve the original prairie soil characteristics due to the prior erosion of the top soil.