|Mc Cracken, D|
Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/10/2008
Publication Date: 1/5/2009
Citation: Schomberg, H.H., Endale, D.M., Jenkins, M., Sharpe, R.R., Fisher, D.S., Cabrera, M.L., Mc Cracken, D.V. 2009. Soil test nutrient changes induced by poultry litter under conventional tillage and no-tillage. Soil Science Society of America Journal. 73:154-163.
Interpretive Summary: The large numbers of poultry produced in the US results in a large amount of poultry litter (PL mixed bedding material and manure) which has to be removed from poultry houses. This PL is a good source of N, P, and K for crops and pastures. Other plant nutrients in PL, such as copper (Cu), manganese (Mn) and zinc (Zn) can cause problems with plant growth or become toxic to plants and animals when they accumulate to excessive levels in soils. Scientists from the USDA-ARS, J. Phil Campbell, Sr. Natural Resource Conservation Center, Watkinsville, GA., and the University of Georgia, Athens investigated the changes in soil test (ST) nutrients in a Cecil soil over a 10 year period of PL in a cropping sequence of cotton and corn using comparing conservation and conventional tillage. In the cotton cropping phase (1995 to 2000) ST-nutrients changed very little with annual PL applications of 4.4 Mg/ha compared to the conventional fertilizer treatment. When the crop was changed to corn (2001 to 2005) and annual PL inputs increased to 11.2 Mg/ha there were large increases in P and Zn near the soil surface. The increase in P can become a problem due to the potential for P lost in runoff to cause deterioration of water quality. The large amounts of Zn observed are near levels that would be considered toxic for some crops. The increases in nutrients occurred predominately in the surface 0 to 15 cm soil layer and were not different between the two tillage systems. These results further document potential problems with long-term repeated application of PL in agronomic systems. It appears prudent to monitor accumulation of nutrients to avoid contamination or accumulation of toxic levels of nutrients. These results are important for water quality and nutrient management professionals and regulatory agencies. This data will be useful to USDA -NRSC and Extension personnel making recommendations for nutrient management plans to producers and is applicable to the major poultry production states of AL, AR, GA, MS, SC, and NC where more than 60% of the poultry is produced.
Technical Abstract: Poultry litter (PL) is applied to crops and pastures to provide N, P, and K in areas of intensive poultry production. Other plant nutrients, such as copper (Cu), manganese (Mn) and zinc (Zn) are also available but may accumulate to excessive levels with over application of PL. Nutrient availability from PL will be a function of rates of input, crop and tillage management and length of application. Changes in soil test (ST) nutrients in a Cecil soil over an extended period of PL use were evaluated at the USDA-ARS, J. Phil Campbell, Sr. Natural Resource Conservation Center, Watkinsville, GA. In the cotton (Gossypium hirsutum L.) cropping phase (1994 to 2000) ST-nutrients changed very little with annual PL applications of 4.4 Mg/ha. Differential responses for Ca, K, Mg, and Mn were observed between conventional (CT) and no-tillage (NT) treatments with nutrient losses for Ca, Mg, and Mn being greater and accumulation of K and Zn lesser for NT compared to CT. Changes in ST-P were limited during the cotton cropping phase. During the corn (Zea mays L.), cropping phase (2001 to 2005) average annual PL inputs (11.2 Mg PL/ha) resulted in large increases in P and Zn but no differences in ST nutrients were observed between tillage systems. During this phase ST-nutrient values reflected 25, 3, 46, 26, and 100 % of the input amounts for P, K, Ca, Mg, Mn and Zn, respectively. Changes in soil profile ST-nutrients in relation to PL inputs determined in 1997, 2000 and 2005 showed increases predominantly at 0-to 15-cm where P and Zn increased more than 200 %. Accumulation of K, P and Zn at lower depths was observed. Our results further document potential problems with long-term repeated application of PL in agronomic systems. It appears prudent to monitor accumulation of nutrients to avoid contamination or accumulation of toxic levels of nutrients.