Effect of prolonged use of liquid swine manure and nitrogen fertlizaton on components of soil acidity

Abstract

The objective of this study was to examine the long-term effects of liquid swine manure and mineral nitrogen applications on soil acidity atributes of a clay loam no-tll Oxisol. Four treatment levels of nitrogen (0, 60, 120 and 180kg/ha) were administered yearly from 1996 to 1999, and twice a year from 2000 to 2009 as ammonium nitrate (N-AN) and liquid swine manure (N-LSM). In 2010, soil samples were taken from up to 2.5, 2.5 to 5, 5 to 10, 10 to 20, 20 to 30, and 40 to 50cm depths and analyzed for pH, exchangeable catons (Al3+, Ca2+, Mg2+ and K+), and Al and base saturaton percentage were calculated. Long-term N-AN fertlizaton reduced soil pH and increased exchangeable Al in the 30cm top soil. This acidity
increase was accompanied by decrease exchangeable Ca2+ in the top 20cm and Mg2+ in the 30cm top soil. Signifcant increases in exchangeable acidity and decreases in exchangeable bases with N-AN fertlizaton resulted in a litle base saturaton in the 30cm top soil. The N-LSM applicaton did not cause any signifcant change in soil pH, exchangeable Al3+, Ca2+, Mg2+ or base
saturaton.