Translator Disclaimer
29 January 2021 Nitrogen turnover and N2O production in incubated soils after receiving field applications of liquid manure and nitrification inhibitors
Sisi Lin, Guillermo Hernandez-Ramirez
Author Affiliations +
Abstract

Applying abundant manure to soils can accelerate nitrogen (N) transformations and nitrous oxide (N2O) emissions. We conducted a laboratory incubation to examine the turnover of labile N in manured soils. Soils were collected from agricultural fields that had recently received spring-injected liquid dairy manure with or without admixing nitrification inhibitors. Bands and interbands of the manure plots were incubated separately. Time courses of ammonium (NH4+) and nitrate (NO3) were used to derive and contrast zero-, first-, and second-order kinetics models. We found that nitrification rates were consistently better represented by first-order kinetics (k1). Furthermore, across all evaluated soils, the dependency of nitrification rate (k1 of NH4+) on initial NH4+ concentration was modelled by Michaelis–Menten kinetics reasonably well, with an affinity (Km) of 63 mg N·kg−1 soil (R2 = 0.82). Compared with the manure interbands, the initially NH4-enriched bands had a much faster nitrification rate, with half-life for NH4+ of only 4 d and rapid k1 (0.186 versus 0.011 d−1). Soil N substrate and k1 exerted control on N2O production. Nitrous oxide production increased linearly with both measured NH4+ intensity (R2 = 0.47) and modelled k1–NH4+ (R2 = 0.48). Conversely, N2O production increased non-linearly with NO3 intensity (R2 = 0.68), where high NO3 caused a saturation plateau with a threshold of 96 mg N·kg−1·d−1 — beyond which no additional N2O was produced. During peak N transformations, measured N2O-N flux was 1.4% ± 0.3% of the inorganic N undergoing nitrification. Heavily manured soils exhibited augmented N turnover that increased N2O fluxes, but inhibitors reduced these emissions by half.

Copyright remains with the author(s) or their institution(s). Permission for reuse (free in most cases) can be obtained from copyright.com.
Sisi Lin and Guillermo Hernandez-Ramirez "Nitrogen turnover and N2O production in incubated soils after receiving field applications of liquid manure and nitrification inhibitors," Canadian Journal of Soil Science 101(2), 290-304, (29 January 2021). https://doi.org/10.1139/cjss-2020-0102
Received: 13 August 2020; Accepted: 18 January 2021; Published: 29 January 2021
JOURNAL ARTICLE
15 PAGES


Share
SHARE
KEYWORDS
Kinetic
liquid manure
nitrification inhibitor
nitrogen processes
nitrous oxide
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top