Wednesday, November 15, 2006
287-25
Seasonal Dynamics of Soil Micronutrients in Compost-amended Turfgrass Soils.
Alan Wright1, Tony Provin2, Frank Hons2, David Zuberer2, and Richard White2. (1) Everglades Research & Education Center, University of Florida, 3200 E. Palm Beach Rd., Belle Glade, FL 33430, (2) Texas A&M University, 2474 TAMU, College Station, TX 77843
Compost application to turfgrasses can increase plant-available nutrient concentrations in soil and improve growth, but may alter micronutrient dynamics and increase leaching and runoff losses. The objectives of this study were to investigate the influence of composts on the seasonal dynamics of plant-available Mn, Fe, Cu, and Zn in soil after a single compost application to bermudagrass [Cynodon dactylon (L.) Pers.] turf. On average, extractable Mn and Cu increased 157 and 2680% by 29 months, but Fe and Zn decreased by 52 and 57%. Composts only influenced the magnitude of changes in micronutrient concentrations, as similar trends were observed for both compost-amended and unamended soils. Dynamics of extractable Mn and Cu were closely related to dissolved organic C (DOC). Seasonal variation of extractable Mn and Cu was related to growth stages of bermudagrass and its subsequent impacts on DOC. Losses of DOC-associated Mn and Cu from the soil surface occurred after high levels of precipitation during winter dormancy but not during the growing season. Thus, seasonal variation of soil micronutrients was related to growth stages of bermudagrass, its effect on DOC, and precipitation events which likely leached DOC and complexed nutrients from surface soil.