Long-Term Effects of Clipping and Nitrogen Management in Turfgrass on Soil Organic Carbon and Nitrogen Dynamics
- Y. L. Qian *a,
- W. Bandaranayakea,
- W. J. Partonb,
- B. Mechamc,
- M. A. Harivandid and
- A. R. Mosiere
- a Department of Horticulture and Landscape Architecture, Colorado State University, Fort Collins, CO 80523-1173
b Natural Resource Ecology Laboratory (NREL), Colorado State University, Fort Collins, CO 80523-1173
c Northern Colorado Water Conservancy District, Loveland, CO 80539
d University of California Cooperative Extension, Alameda, CA 94502
e USDA-ARS, Soil–Plant–Nutrient Research Unit, Fort Collins, CO 80522
Experiments to document the long-term effects of clipping management on N requirements, soil organic carbon (SOC), and soil organic nitrogen (SON) are difficult and costly and therefore few. The CENTURY ecosystem model offers an opportunity to study long-term effects of turfgrass clipping management on biomass production, N requirements, SOC and SON, and N leaching through computer simulation. In this study, the model was verified by comparing CENTURY-predicted Kentucky bluegrass (Poa pratensis L.) clipping yields with field-measured clipping yields. Long-term simulations were run for Kentucky bluegrass grown under home lawn conditions on a clay loam soil in Colorado. The model predicted that compared with clipping-removed management, returning clippings for 10 to 50 yr would increase soil C sequestration by 11 to 25% and nitrogen sequestration by 12 to 28% under a high (150 kg N ha−1 yr−1) nitrogen (N) fertilization regime, and increase soil carbon sequestration by 11 to 59% and N sequestration by 14 to 78% under a low (75 kg N ha−1 yr−1) N fertilization regime. The CENTURY model was further used as a management supporting system to generate optimal N fertilization rates as a function of turfgrass age. Returning grass clippings to the turf–soil ecosystem can reduce N requirements by 25% from 1 to 10 yr after turf establishment, by 33% 11 to 25 yr after establishment, by 50% 25 to 50 yr after establishment, and by 60% thereafter. The CENTURY model shows potential for use as a decision-supporting tool for maintaining turf quality and minimizing negative environmental impacts.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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