Influence Of Cover Crops On Soil and Water Properties In a Southeast Alabama Soil.

Cover crops have been used to improve soil quality by decreasing erosion and improving water infiltration.  While much is understood about the effects of cover crops on the soil surface, little is known about the effect of specific cover crops on soil/water properties below the surface.  This study examined the impact of different cover crops on soil/water properties by evaluating macroporosity, carbon content, and permeability.  In addition, the effect of cover crops on residual soil nitrogen was also evaluated.  Crop treatments were established on a sandy loam in two neighboring areas.  Area 1 had been maintained in a peanut-cotton rotation with specific cover crop treatments (i.e., oat (Avena L.), rye (Secale L.), wheat (Triticum L.)) and fallow in a long-term study.  Area 2 had been cropped without cover crops and was newly established with the following treatments: fallow, crimson clover (Trifolium incarnatum L.), oat, and an oat/rye mixture.  Soil cores were extracted prior cover crop termination and evaluated for macropore distribution using X-ray computed tomography.  Cores were also divided into five interval depths and analyzed for bulk density, total C and N, nitrate, and ammonium.  Saturated hydraulic conductivity (Ksat) was measured in each plot using a compact constant-head permeameter.   Various cover crops did not affect soil bulk density, but Ksat differed among the cover crop treatments.  In area 1, the Ksat of oat and rye treatments were greater than the fallow treatment.  In area 2, treatments with oat had the highest Ksat; however, only oat was significantly greater than the lowest treatment, crimson clover.  Results indicate differences among the cover crops may affect water properties of the soil.