Rainfall reduction amplifies the stimulatory effect of nitrogen addition on N2O emissions from a temperate forest soil

Abstract

Soil is a significant source of atmospheric N2O, and soil N2O emissions at a global scale are greatly affected by environment changes that include continuous deposition of atmospheric nitrogen and changing precipitation distribution. However, to date, field simulations of multiple factors that control the interaction between nitrogen deposition and precipitation on forest soil N2O emissions are scarce. In this study, we conducted a 2-year continuous assessment of N2O emissions from November 2012 to October 2014 at a nitrogen addition and rainfall reduction manipulation platform in an old broad-leaved Korean pine mixed forest at Changbai Mountain in northeastern China. We found that N2O emissions from control plots were 1.25 ± 0.22 kg N2O-N ha−1 a−1. Nitrogen addition significantly increased N2O emissions, with the emission factor of 1.59%. A 30% reduction in rainfall decreased N2O emissions by 17–45%. However, in combination, nitrogen addition and rainfall reduction increased N2O emissions by 58–140%, with the emission factor of 3.19%, and had a larger promotional effect than the addition of nitrogen alone. Our results indicated that drought slightly decreases forest soil N2O emission; however, with increasing deposition of atmospheric N in temperate forest soils, the effect of drought might become altered to increase N2O emission.

Effects of precipitation exclusion on N2O emissions in a savanna ecosystem in SW China

“…Only a few precipitation exclusion experiments have been conducted, but they were not focused on savanna ecosystems (Table S2). In the Yuanjiang savanna, precipitation exclusion had a significant negative effect on N 2 O emissions, which is similar to the effect of precipitation exclusion observed in some other ecosystems (Geng et al, 2017;Wood and Silver, 2012); however, this finding contradicts some studies that showed positive effects (Cattânio et al, 2002;Wieder et al, 2011).…”

“…4). The decrease in the net nitrification and nitrogen mineralization rates inhibited the growth and activity of nitrifying bacteria and decreased the production of N 2 O (Chen et al, 2017;Geng et al, 2017;Hartmann and Niklaus, 2012;Shi et al, 2012). In the meantime, precipitation exclusion decreased the DOC (Table 2).…”

“…Numerous studies have examined the response of soil N 2 O emissions to precipitation reduction, but the results are inconsistent. Some studies have found that a lack of precipitation reduces N 2 O emissions by decreasing the soil water content and net nitrification and nitrogen mineralization rates as well as the dissolved organic carbon (Davidson et al, 2004;Geng et al, 2017;Wood and Silver, 2012), whereas other studies have shown that precipitation reduction increases the soil content of dissolved organic carbon (as delivered from the litter to the soil under drier conditions) or the availability of nitrogen (due to root mortality and reduced plant uptake of nitrogen), thereby increasing N 2 O emissions (Cattânio et al, 2002;Wieder et al, 2011). However, those studies primarily focused on tropical and subtropical forests and had one treatment without precipitation, which might cause uncertainty and confuse the effect of the precipitation reduction on the details.…”

Variations in the natural 13C and 15N abundance of plants and soils under long-term N addition and precipitation reduction: interpretation of C and N dynamics

“…In addition, plant N uptake could also cause isotope fractionating processes leading to N losses depleted in 15 N, enriching soil N with the heavier isotope (Evans 2001). The previous study in the experiment site showed that N addition significantly increased N 2 O emission (Geng et al 2017), which could partially explain the increase of soil δ 15 N value. Soil N availability is the source of plant N of non-N 2 -fixing plants; thus the change of plant δ 15 N value (foliage and root) was directly linked to the increase of soil δ 15 N value (Table 4).…”

Straw amendments did not induce high N2O emissions in non‐frozen wintertime conditions: A study in northern Germany

“…Precipitation increases the water‐filled pore space in soils and restricts the availability of O 2 , again favoring complete denitrification (Davidson, 1992; de Klein et al., 1996; Rudaz, Wälti, Kyburz, Lehmann, & Fuhrer, 1999). Geng, Chen, Han, Wang, and Zhang (2017) reported that rainfall reduces the stimulatory effect of the addition of N on N 2 O emissions.…”