Global patterns and controlling factors of soil nitrification rate

Abstract

Soil nitrification, an important pathway of nitrogen transformation in ecosystems, produces soil nitrate that influences net primary productivity, while the by‐product of nitrification, nitrous oxide, is a significant greenhouse gas. Although there have been many studies addressing the microbiology, physiology, and impacting environment factors of soil nitrification at local scales, there are very few studies on soil nitrification rate over large scales. We conducted a global synthesis on the patterns and controlling factors of soil nitrification rate normalized at 25°C by compiling 3,140 observations from 186 published articles across terrestrial ecosystems. Soil nitrification rate tended to decrease with increasing latitude, especially in the Northern Hemisphere, and varied largely with ecosystem types. The soil nitrification rate significantly increased with mean annual temperature (MAT), soil nitrogen content, microbial biomass carbon and nitrogen, soil ammonium, and soil pH, but decreased with soil carbon:nitrogen and carbon:nitrogen of microbial biomass. The total soil nitrogen content contributed the most to the variations of global soil nitrification rate (total coefficient = 0.29) in structural equation models. The microbial biomass nitrogen (MBN; total coefficient = 0.19) was nearly of equivalent importance relative to MAT (total coefficient = 0.25) and soil pH (total coefficient = 0.24) in determining soil nitrification rate, while soil nitrogen and pH influenced soil nitrification via changing soil MBN. Moreover, the emission of soil nitrous oxide was positively related to soil nitrification rate at a global scale. This synthesis will advance our current understanding on the mechanisms underlying large‐scale variations of soil nitrification and benefit the biogeochemical models in simulating global nitrogen cycling.

Soil nitrogen substrates determine global N2O emission more than climate and other soil properties

“…Moreover, soil organic N can increase soil microbial biomass and subsequently increase N mineralization (Liet al 2019). A recent study revealed that the content of soil total N is the main driver for soil nitrification rate at the global scale (Li et al 2020). In line with our finding, a recent study revealed that manure application also substantially increases N 2 O emission by 5.1-58.2% (Zhou et al 2017).…”

“…Of climatic factors, higher temperature usually motivates soil N 2 O emission in terrestrial ecosystems through denitrification (Zhang et al 2019c;. Mean annual temperature also significantly influences soil nitrification on the global scale (Li et al 2020), which may eventually impact global soil N 2 O emission. Since water condition affect both nitrification and denitrificationvia altering soil oxygen availability (Bollmann & Conrad 1998), higher soil water content significantly increases soil N 2 O emission (Wu et al 2017).…”

Effects of inorganic and organic fertilizers on CO2 and CH4 fluxes from tea plantation soil

“…Soil nitrate nitrogen (NO 3 --N) and NH 4 þ -N not only provides essential nutrients for microbes but also indirectly affects soil microbes and gas emissions. The process of nitrification and denitrification was affected by the soil pH and affected the activity of soil microbes (Sauze et al 2017;Li et al, 2020). Furthermore, denitrifying intermediates can inhibit methanogenic microorganisms during nitrate reduction (Clarens et al, 1998;Bao et al, 2016).…”

Excessive plant compensatory growth: a potential endogenous driver of meadow degradation on the Qinghai-Tibetan Plateau

“…Moreover, fewer plant litters introduce into soil because of the ingestion of livestock, which could make these soil dwellers hard to survive (Bardgett, Denton, and Cook 1999). In addition, low-temperature can restrict the decomposition rate of matter in alpine meadow ecosystems (Xu et al 2013;Li et al 2020b). Consequently, the supply of soil available nutrients would become unsustainable.…”