Internal Temperatures and Rates of Subsidence of Landscape Berms Constructed with Soil and Organic Materials.

Training areas on military reservations are commonly separated by soil berms which are 2 or more meters in height.  Construction of berms using soil from the site or trucked in is destructive to the environment and often costly.  Soil berms are quite dense and reconfiguration between training missions is costly and energy intensive.  Also, when the berms are disturbed, the potential for soil erosion and water pollution is increased.  In an effort to address these issues, we investigated the use of several locally available organic materials as an alternative to soil berm construction.  Berms were constructed in a replicated experiment using shredded pine bark, composted yard waste, hardwood chips from a tree trimming operation and soil from an adjacent site.  These materials were each used alone and in various combinations.  Of these materials, pine bark was the most costly.  Berms were approximately 7 meters long and 1.5 meters high.  The south side was constructed with a 3:1 slope to represent an area that could be mowed if need be while the opposite side had a 1:1 slope to conserve material.  The berms were packed with a tracked vehicle during construction.  Several physical and chemical evaluations of the berm material and runoff from the berms were conducted periodically.  This poster focuses on internal temperatures of the berms over several months which indicated whether composting took place after the berms were finished.  The rate of subsidence of various berms was also measured frequently.  Internal temperatures of all berms containing pine bark and yard waste were elevated above the temperatures of the soil and wood chip berms for several months indicating significant continuing biological activity.  Subsidence was greatest in those berms which maintained the greatest temperature differentials.  Soil and wood chip berms were the most stable over the first year.