A Longitudinal Study of the Microbial Basis of Nitrous Oxide Emissions Within a Long-Term Agricultural Experiment

Much of the global nitrous oxide emissions are derived from agricultural management driving microbial N transformations. Crop rotation, no-till, and cover cropping feasible conservation agronomic strategies used to prevent losses environment, though their effect on soil cycling at field scale remains relatively unknown. Our goal was determine crop rotation (continuous corn [ Zea mays L.], CCC; continuous soybean Glycine max (L.) Merr.], SSS), tillage (no-till, NT; chisel tillage, T), crops (cover mixture, CC; no crop, NCC) quantification functional genes related cycle different times throughout growing season. The study conducted during season cash following first introduced after 23 years management. Using quantitative polymerase chain reaction (qPCR) techniques, we quantified nifH (N 2 fixation), amoA (nitrification) nirK, nirS , nosZ (denitrification). results show that CCC increased by 44% compared SSS reduced pH nearly 1 unit. reduction in pH, coupled with an increase fertilizer-derived ammonium, caused ammonia-oxidizing bacteria (AOB) nirK copy numbers increase. showed opposite results. Bacterial denitrification via pathway likely mechanism behind CCC. mixture cereal rye Secale cereale L.] hairy vetch Vicia villosa Roth] nitrate levels, they did emissions, due priming inclusion a legume mixture. Nitrous were affected sampling date, use, suggesting factors add abundantly available alter directly or indirectly. Chisel abundance all no-till. Together, our work adds further insight into cycle, especially evolution, three common practices, contributing understanding key biogeochemical processes.