Grazing and No-Till Cropping Impacts on Nitrogen Retention in Dryland Agroecosystems

Authors

Megan L. Mobley, University of Wyoming
Rebecca L. McCulley, University of KentuckyFollow
Ingrid C. Burke, University of Wyoming
Gary Peterson, Colorado State University, Fort Collins
David S. Schimel, California Institute of Technology
C. Vernon Cole, Colorado State University, Fort Collins
Edward T. Elliott, Colorado State University, Fort Collins
Dwayne G. Westfall, Colorado State University, Fort Collins

Abstract

As the world's population increases, marginal lands such as drylands are likely to become more important for food production. One proven strategy for improving crop production in drylands involves shifting from conventional tillage to no-till to increase water use efficiency, especially when this shift is coupled with more intensive crop rotations. Practices such as no-till that reduce soil disturbance and increase crop residues may promote C and N storage in soil organic matter, thus promoting N retention and reducing N losses. By sampling soils 15 yr after a N tracer addition, this study compared long-term soil N retention across several agricultural management strategies in current and converted shortgrass steppe ecosystems: grazed and ungrazed native grassland, occasionally mowed planted perennial grassland, and three cropping intensities of no-till dryland cropping. We also examined effects of the environmental variables site location and topography on N retention. Overall, the long-term soil N retention of >18% in these managed semiarid ecosystems was high compared with published values for other cropped or grassland ecosystems. Cropping practices strongly influenced long-term N retention, with planted perennial grass systems retaining >90% of N in soil compared with 30% for croplands. Grazing management, topography, and site location had smaller effects on long-term N retention. Estimated 15-yr N losses were low for intact and cropped systems. This work suggests that semiarid perennial grass ecosystems are highly N retentive and that increased intensity of semiarid land management can increase the amount of protein harvested without increasing N losses.

Document Type

Article

Publication Date

11-10-2014

Notes/Citation Information

Published in Journal of Environmental Quality, v. 43, no. 6, p. 1963-1971.

This article is freely available online through the author-supported open-access option.

Digital Object Identifier (DOI)

http://dx.doi.org/10.2134/jeq2013.12.0530

Repository Citation

Mobley, Megan L.; McCulley, Rebecca L.; Burke, Ingrid C.; Peterson, Gary; Schimel, David S.; Cole, C. Vernon; Elliott, Edward T.; and Westfall, Dwayne G., "Grazing and No-Till Cropping Impacts on Nitrogen Retention in Dryland Agroecosystems" (2014). Plant and Soil Sciences Faculty Publications. 43.
https://uknowledge.uky.edu/pss_facpub/43