Effects of Tillage and Organic Matter on Soils and Nutrient Losses in a Residential Landscape.

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 completely randomized 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 will be measured every 3 months.  Soils are also analyzed for Mehlich-1 P, K, Mg, Ca, Al, and Fe by ICP-AES and water-soluble P colorimetrically.  Leachate and runoff samples are collected as needed following irrigation or storm events.  Leachate and runoff samples are analyzed for NO₃-N, NH₄-N, and ortho-phosphate using a discrete analyzer.  We hypothesize that nutrient losses will be higher and landscape plant quality and growth will be lower in untreated compacted urban landscapes than in landscapes that receive tillage or organic amendments.  From our results we hope to develop new management practices for residential landscapes that reduce runoff and nutrient losses and improve infiltration and plant establishment.