The Effects of Synethtic and Natural Organic Fertilizers and Composts On Turfgrass and Soil Health.

Natural organic fertilizers and composts are becoming increasingly popular as a sustainable source of turfgrass nutrition and soil remediation. Documented benefits have included enhanced turf quality and improvements in soil bulk density, nutrient status and organic matter content. Most fertilizers and composts derived from natural organic sources contain appreciable phosphorus in addition to nitrogen, with some N:P ratios in fertilizer as high as 1:1 or 2:1. Composts derived from sewage and manures and applied as topdressing at 6mm depth may contain as much as 500 kgs N Ha-1, or ten times the acceptable application rate. Soil tests on native soil (silt clay loam) showed that organic fertilizers applied at a turf maintenance rate increased soil Bray-1 P levels from 31 mg/kg to 70 mg/kg within three years. More significantly, applications of biosolid compost applied at 6mm twice per year increased P levels in excess of 400 mg/kg. Phosphorus saturation levels and potential leeching are also being studied.