Grassland Establishment Impacts On Soil Physical Characteristics.

Grasslands are an extensive biome that covers a proportional area in the terrestrial biosphere and their importance is critical to prevent soil degradation.  Grasses help to stabilize soil particles, reduce leaching, add organic matter, and reduce compaction and are one of the most inexpensive conservation methods. The objective of this research was to evaluate selected soil properties under five forage grasses growing in silt loam soils following five years of planting.  Grass types were selected by availability in the fields of Calloway County, Kentucky. Soil samples were collected from the fields of bermuda grass (Cynodon dactylon), tall fescue (Festuca arundinacea), rye grass (Lolium multiforum), johnson grass (Sorghum halapense), and mixed grasses at the depth of 0-15 cm and 15-30 cm. After collecting, the samples were measured for soil total carbon, bulk density, porosity, and the ratio of macro-aggregates to micro-aggregates.  The results show that the surface soils under mixed grasses have the highest total porosity (62%). The lowest soil porosity (52%) and the highest bulk density (1.2 g cm-3) were found in Johnson grass fields. Bermuda grass fields provide the highest total carbon (31g kg-1) and the lowest bulk density (1.0 g cm-3), while rye grass fields have the least amount of total carbon (13 g kg-1).   Mixed grasses had the highest ratio of macro-aggregates to micro-aggregates and the tall fescue fields had the lowest sum of aggregates in the soil.  After five years, no significant changes have been found among the grass species on soil properties.