Seasonal responses of carbon, nitrogen, and phosphorus cycling to woodland reduction and different organic matter additions in the semiarid Great Basin

Abstract:Disturbances that impact microbially-mediated processes of decomposition and mineralization of organic matter carry ecosystem-level consequences because soil microorganisms can immobilize nutrients or render them available for plant uptake. The stochastic nature of resource availability in drylands may cause these ecosystems to be particularly susceptible to disturbance. We used two common fuel reduction treatments - mastication and cut-and-lop - in piñon-juniper encroached sagebrush ecosystems in the semiarid Great Basin to quantify how organic matter additions affect pools and fluxes of C, N, and P. We found that organic matter additions from woodland reduction altered microbial substrates and C dynamics but that microbial functions that regulate cycling of N and P were resilient to disturbance two years following implementation of the treatments. Our results shed light on how fuels treatments that alter organic matter inputs can in turn influence the ratios of C to nutrients in soil. These findings improve our understanding of how environmental perturbations affect nutrient dynamics in semiarid ecosystems and provide insight on the degree to which intra-annual seasonal variation regulates biogeochemical dynamics. Our results can help land managers predict how piñon-juniper encroached sagebrush ecosystems and other arid or semiarid ecosystems might respond to fuels treatments or other disturbances that alter organic matter additions to the soil.

Level thesis:degree_level

Master's Degree

Year dc:date.issued

2021

Author dc:creator

• Jacobs, Jordin

Advisor dc:contributor.advisor

• Tittiger, Claus

Committee members dc:contributor.committeemember

• Stringham, Tamzen
• Hanan, Erin
• Pringle, Elizabeth

• coupled biogeochemistry
• decomposition
• organic matter
• piñon-juniper expansion
• sagebrush shrub-steppe
• soil biogeochemistry

Handle dc:identifier.uri

http://hdl.handle.net/11714/8095

OAI identifier oai:identifier

oai:scholarwolf.unr.edu:11714/8095