Application of Composted Dairy Solids Affects Soil Quality and Nutrient Losses From Residential Landscapes.

Rapid population growth and land use change has been linked to soil compaction and increased runoff volumes, which can increase nutrient losses to water.  The objective of this research is to determine how tillage, aeration, and organic matter treatments affect soil properties (such as bulk density), the potential for nutrient losses, and the establishment of plant material in new residential landscapes.  Twenty-four mixed landscape plots (3.05 m x 3.66 m) were established on compacted soils in a randomized complete block design at the University of Florida – IFAS Gulf Coast Research and Education Center in Wimauma, FL.  Soil bulk density, pH, moisture content, electrical conductivity, and field moisture capacity were measured before application of the tillage and organic matter treatments and was every 3 months.  Soils where then analyzed for Mehlich-1 P, K, Mg, Ca, Al, and Fe by ICP-AES.  Leachate and runoff samples were collected every week.  Leachate were then analyzed for NO₃-N, NH₄-N, and ortho-phosphate using a discrete analyzer.  Preliminary results show that during the establishment period adding organic matter to the landscape will increase plant growth and quality.  The bulk density of the plots decreases over time, with the bulk density under ornamentals that have organic amendments, lower than those without.  The leachate data does not show significant differences on ortho-phosphate losses among the different treatments.  However, the treatments with organic amendments have a higher nitrate concentration loss that decreases with time; although the load showed no significant differences.