360-6 Soil Chemical Properties After 50 Years of N and P Fertilization.

See more from this Division: S04 Soil Fertility & Plant Nutrition
See more from this Session: Symposium--Synthetic Fertilizer Use In Sustainable Cropping Systems: Benefits and Consequences
Wednesday, October 19, 2011: 10:50 AM
Henry Gonzalez Convention Center, Room 213B
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Alan Schlegel, Kansas State University, Tribune, KS and Kent Martin, Kansas State University, Garden City, KS
Nitrogen and phosphorus fertilizers were applied annually since 1961 to irrigated continuous corn and grain sorghum grown on a Ulysses silt loam in west central KS.  Treatments were a factorial of six N rates (0, 45, 89, 134, 179, and 224 kg ha-1) and two P rates (0 and 45 kg P2O5 ha-1).  Soil samples were collected in the fall of 2010 (after 50 years of fertilization) and analyzed for selected chemical properties.  In the surface soil (0-15 cm), application of N to corn decreased pH, Ca, Mg, Na, and S while increasing NO3, Mn, and soil organic matter (SOM).  With grain sorghum, N fertilization decreased pH, Ca, Zn, and Na while increasing NO3, Mn, and SOM in the surface soil.  For both crops, fertilizer P increased soil test P and SOM with minimal effect on other chemical properties.  Profile soil samples (300 cm depth) indicated some movement of NO3 to 300 cm at the higher N rates with P fertilization and at lower N rates without P fertilization.
See more from this Division: S04 Soil Fertility & Plant Nutrition
See more from this Session: Symposium--Synthetic Fertilizer Use In Sustainable Cropping Systems: Benefits and Consequences