Utilizing the decomposition of organic residues to increase infiltration rates in water spreading

Decomposition rates were determined for several plant residues which were incubated under controlled conditions in the absence of soil. Three of these plant residues, having a range in decomposition rate from high to low, were mixed with soil, and incubated. The decomposition rates in the absence of soil were similar to those obtained when the plant residues were mixed with soil. Microbial counts made during the decomposition of the plant residues in soil showed that the greatest number of microorganisms occurred in the soils containing plant residues which decompose rapidly. Ammonium nitrate applied to the soil mixed with plant residue stimulated decomposition slightly. Percolation rates of soil mixed with organic residues varied with the amount of material applied, decomposition rate of the material, and the length of the incubation period. These studies indicate that initial decomposition at a moisture content near field capacity followed by decomposition at saturation may produce the highest infiltration rate for a given amount of organic residue. Infiltration rates on 0.005‐acre test ponds containing vegetative cover or treated with cotton gin trash and alfalfa hay are presented. The use of organic residues to increase the infiltration rate of water‐spreading areas is discussed.