Sunday, November 12, 2006 - 5:15 PM

Phosphorus, Potassium and Micronutrient Stratification in Long-Term No-Till Soils.

Catherine Byers, Virginia Tech, 2933 Cara Court, Blacksburg, VA 24060, John Spargo, Crop & Soil Environmental Sci- 0404, Blacksburg, VA 24060, and Marcus Alley, Crop & Soil Env Sci Dept, Blacksburg, VA 24061-0403.


Permanent no-till crop production systems eliminate incorporation of nutrients from fertilizers and plant residues.  The objective of our research was to measure P, K and micronutrient levels and stratification ratios at depths of 0-2, 3-7, and 8-15 cm in selected soil series in the Virginia Coastal Plain.  The selected soils are widely used for grain crop production.  Nutrient levels from no-till sites were compared to the same soil type with conventional tillage.  As expected, concentrations of P and K were highest in the surface 0-2 cm layer in both no-till and conventional tillage sites, but P was consistently higher at each depth in the no-till managed soil as compared to the same soil series with tillage. Values for P and other nutrients were compared to levels in other research to determine if stratification may result in crop nutritional problems.  Potential environmental concerns associated with surface runoff of soluble nutrients were also considered.