SOIL ORGANIC MATTER AND NUTRIENT CYCLING TO SUSTAIN AGRICULTURE IN THE SOUTHEASTERN USA
Location: Athens, Georgia
Title: Total phosphorous, calcium, aluminum and iron levels in Cecil soil after ten years of poultry litter application
Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 2007
Publication Date: November 4, 2007
Citation: He, Z., Endale, D.M., Schomberg, H.H., Honeycutt, C.W., Jenkins, M., Sharpe, R.R. 2007. Total phosphorous, calcium, aluminum and iron levels in Cecil soil after ten years of poultry litter application. American Society of Agronomy Meetings.
Poultry litter (PL) is a traditionally inexpensive and effective organic fertilizer to improve soil quality and agricultural productivity. However, there is concern with over application as this can lead to excess releases of nutrients, especially phosphorus, and metals into fresh water bodies resulting in impairments such as eutrophication. In this study, we characterized and compared total P, Ca, Al, and Fe levels in a Cecil soil near Watkinsville, GA, following ten years of cotton and corn production (five years each) under combinations of two tillage (conventional tillage and no-till) and two fertilizer sources (PL and inorganic fertilizer, primarily ammonium nitrate). During the cotton, PL application rate of 4.5 Mg ha-1 was based on crop nitrogen requirement. During the corn PL application rates rose 2 to 4 times that of cotton partly because of corn’s greater nitrogen requirement and also due to inclusion of a water quality study component related to hormones. Soil P levels rose markedly in PL plots as a result of PL application rates during the corn. In the surface 15 cm of soil, the average soil total P level nearly doubled from below 300 mg/kg to about 560 mg/kg in both conventional tillage and no-till. We also observed soil P stratification under PL within this 15 cm soil layer. The soil P level averaged 1000 mg/kg in the 0-2.5 cm depth, 700 mg/kg in the 2.5 to 5.0 cm depth, and 450 mg/kg in the 5.0-15.0 cm depth. Application of PL also increased Ca level but only in the 0-15 cm depth. No significant change of Al and Fe was observed but the no-till plots exhibited more variability in the metal data. Application of PL at or above agronomic needs of corn raised soil P levels in Cecil soil. A more elaborate study with different PL rates at the same time might establish the critical level of PL application for corn with respect to increases in soil P levels.