Coastal Bermudagrass Yield and Soil Properties as Affected by Surface‐Applied Dairy Manure and its Residue

Land spreading of animal manure is a common practice for waste disposal and plant nutrient utilization, but it may cause problems by polluting runoff and ground water. Field experiments were conducted on two soils: Dothan loamy sand (Plinthic Paleudults) and Lucedale fine sandy loam (Rhodic Paleudults). Dairy manure was surface‐applied for 3 years as a solid at rates of 45 and 90 metric tons ha −1 year −1 and as a liquid at rates of 45, 90, and 135 metric tons ha −1 year −1 , dry wt basis. Check plots received N, P, and K at the rates of 470, 225, and 470 kg ha −1 year −1 from mineral fertilizer. The effects of manure on soil properties and on period of time coastal bermudagrass [ Cynodon dactylon (L.) Pers.] responds to residue were determined. Residue from the manure 3 years after the final manure application with no additional fertilizer was still producing considerably higher yields of coastal bermudagrass on both soils than on the check plots at the beginning of the residual phase of study. Yields were higher the third year on the Dothan than on the Lucedale soil, but organic N was higher in the forage from the Lucedale soil. Nitrogen was one of the most limiting factors of production on both soils by the end of three cropping seasons. Additions of manure increased K, Mg, and pH in the subsoil, and the increase was still evident after three cropping seasons. There was also some downward movement of P, but less than there was of the other elements. There was more movement of all ions in the sandier Dothan soil than in the Lucedale soil. Projection of the loss of organic N in the surface soil indicated that residue would be negligible 45 to 55 months after applications ceased.