Composted Dairy By-products as Soil Amendment
By Kellie Potucek, April 2004
Fort Hood, in conjunction with the Texas Water Resources Institute (TWRI, College Station, TX), the Blackland Research & Extension Center (BREC, Temple, TX), and the USDA-Natural Resources Conservation Service is exploring the benefits of composted dairy by-product utilization in an effort to improve the area’s environmental quality while maintaining its premier training facilities.
Fort Hood encompasses 339 square miles of Texas Hill Country terrain characterized by prairies, shallow soils, rolling hills, woodlands and rocky streams. Throughout its 62 years of operation, Fort Hood has used this land to train troops specializing in ground combat vehicles. Many of these vehicles are designed with forceful tread that rips through soil, uproots vegetation, and leaves behind a denuded, compacted surface prone to water runoff as well as soil erosion. These effects increase sedimentation which hinders the recovery of vegetation and impacts surrounding water resources.
The Department of Army and Department of Defense recognize the severity of these concerns and are actively pursuing methods to incorporate sound stewardship practices together with combat training requirements. Working through the Rangeland Revegetation Pilot Project and in close collaboration with the USDA-Natural Conservation Service, TWRI, BREC and the Texas Agricultural Experiment Station (TAES) strive to assist the military in establishing management practices conducive to environmental prosperity and quality training facilities.
When soil is compacted, as is the case on the 67,000 acre West Range at Fort Hood, the surface seals and water infiltration rates are significantly reduced. Because water is not absorbed into the soil, it becomes runoff and begins to flow downhill. At the same time, as raindrops hit the soil, the impact detaches particles causing them to be swept away by runoff. These soil particles are collectively referred to as “sediment.”
The problem with sediment is two fold. First, runoff ultimately ends up in water sources such as rivers and lakes. At Fort Hood, runoff flows and their accompanying sediment are impacting the main drinking water source for surrounding communities, Lake Belton. Second, top soils contain nutrients essential to growth and survival of plants. Erosion robs the land of these nutrients, reducing vegetation’s ability to restore itself. Amending impacted soils increases the capacity for rangeland revegetation.
Regrowth of vegetation is a chief focus in the Fort Hood ecological restoration process because it inherently combats water runoff and soil erosion. Plant cover shields top soil from direct raindrop impact, root networks restrain soil, and plant litter creates a coarse surface area that reduces velocity of runoff flows. The vegetation serves as a filter to help remove sediment from water.
While commercial fertilizers are traditionally used as soil amendments, the research team is studying whether composted dairy by-products will provide an efficient substitute. Composted materials are obtained through the processing of dairy cattle manure. Composting dairy manure destroys most disease microbes, parasites and weed seeds. The result is a product high in nutrient value that may prove to be extremely beneficial in the fight against vegetation loss and soil erosion.
In April of 2003, TWRI and BREC established a 75 acre demonstration area at Fort Hood. Compost was introduced to the soil and a native seed mix was then distributed throughout. Water quality and vegetation has since been monitored. After initial promising results, the area was increased to 200 acres. The research team is testing the application of various levels of compost and seed in this extended area.
The compost used in this research is acquired from the Bosque River Watershed in North Central Texas. Currently, this watershed is in crisis due to the overwhelming amount of manure generated by surrounding dairy farms. Increasing numbers of cattle per acre quickly saturate man-made lagoons built to contain animal waste. The resulting overflows impact water quality most notably with high levels of phosphates. Removing the excess manure from the watershed in the form of compost is vital to reversing these effects. The TAES Rangeland Revegetation Pilot Project is assisting this effort.
In short, dairy compost utilization fights environmental concerns on two fronts. First, the ongoing TAES research suggests that dairy compost amends poor quality soils with nutrients necessary to enhance vegetation growth. Second, removal and treatment of manure reduces waste, improving environmental quality within the North Bosque River Watershed.
Fort Hood’s proactive approach in addressing environmental concerns will help to secure the future of the area’s ecosystem and quality of its training facilities and help maintain the environmental and economic viability of the Bosque River Basin dairies. Additionally, research will contribute to the health and preservation of environments downstream in both regions.
