Contour Ripping and Composted Dairy Manure for Erosion Control on Fort Hood Military Installation, Texas

Training activities on the Fort Hood Military Installation have imposed serious impacts to its grass-dominated landscape. Six decades of tracked vehicle impacts have caused soil compaction and vegetation reduction which has lead to severe surface erosion. This investigation examined two conservation practices directed at improving and creating sustainable training conditions on Fort Hood training lands, contour ripping and the application of composted dairy manure. The application of composted dairy manure may increase vegetation, while contour ripping may decrease discharge, both of which will lead to a decrease in erosion. Three small 0.30 ha watersheds were established on Fort Hood in January 2005. Each watershed had 0.46 m berms installed on all four sides with a 0.305 m H-flume and was equipped with automated storm sampling equipment. Soil samples were collected prior to any treatments, and twice after compost applications. Discharge and precipitation was collected continuously on each watershed. Stormwater samples were collected during storm events and analyzed for water quality parameters. Water quality samples, discharge and precipitation records were collected between January 2005 and July 2007. Three composted dairy manure application rates at 0, 28 and 57 m3 ha-1 were applied on watersheds C0, C1 and C2, respectively; watersheds were evaluated for effects on NO3 and soluble reactive phosphates (SRP) concentrations and loadings in storm events and on stormwater discharge. Twenty two months after the initial compost application, the two previously composted watersheds (C1 and C2) were treated with contour ripping and C2 received a second compost application. The compost application caused the spikes in NO3 and SRP concentrations and loads immediately after application. Both NO3 and SRP concentrations decreased as the number of days from application increased. Compost application did not appear to have an effect on the discharge from watersheds. Contour ripping had a significant effect on stormwater discharge. Contour ripping decreased discharge by 74 and 80% on C1 and C2, respectively when compared to the untreated control (C0).