Effect of turfgrass establishment practices and composted biosolids on water quality

Land application of composted municipal biosolids (CMB) enhances soil physical properties and turf establishment. Yet large, volume-based rates of CMB can increase nonpoint source losses of sediment and nutrients from urban soils to surface waters. The objectives were (i) to compare runoff losses of sediment, N, P, and organic C among contrasting establishment treatments for bermudagrass [Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt-Davy, var. Tifway] and (ii) to evaluate relationships between runoff and soil measurements of N, P, and organic C. Three replications of seven establishment treatments were installed on an excavated slope (8.5%) under field conditions. Five treatments comprised sod transplanted from Tifway bermudagrass grown with and without CMB on soil with and without incorporation of CMB. Two other treatments were composed of Tifway sprigged in soil with and without CMB. Runoff from seven natural rain events was channeled into collection tanks for sampling and analysis. Runoff concentrations and mass loss of dissolved P and organic C forms were greater for CMB-amended sod than for sprigs planted in soil with or without CMB or treatments comprising sod established without CMB. In addition, a linear relationship (R(2) = 0.87) was observed between water extractable soil P of sodded and sprigged treatments and concentrations and mass losses of dissolved P in runoff. Transplanted sod reduced sediment loss compared with sprigged treatments and incorporation of CMB reduced sediment loss from sprigged treatments. Incorporation of CMB within soil on which sod grown without CMB was transplanted proved the best option for achieving benefits of CMB while reducing nutrient runoff loss compared to sod transplanted from Tifway grown with CMB.