Effects of phosphorus addition on N₂O and NO emissions from soils of anAcacia mangiumplantation

Abstract

An incubation experiment was conducted to examine the effects of the phosphorus (P) application on nitrous oxide (N2O) and nitric oxide (NO) emissions from soils of an Acacia mangium plantation in Indonesia. The soils were incubated with and without the addition of P (Ca[H2PO4]2; 2 mg P g soil−1) after adjusting the water‐filled pore space (WFPS) to 75% or 100%. The P addition increased N2O emissions under both WFPS conditions and NO emissions at 75% WFPS. Some possible mechanisms are considered. First, the P addition stimulated nitrogen (N) cycling, and N used for nitrification and/or denitrification also increased. Second, the P addition could have relieved the P shortage for nitrifying and/or denitrifying bacteria, producing N2O and NO. Our results suggest that the application of P fertilizer has the potential to stimulate N2O and NO emissions from Acacia mangium plantations, at least when soils are under relatively wet conditions.

Effects of phosphorus addition on N₂O emissions from an <i>Acacia mangium</i> soil in relatively aerobic condition

“…Nevertheless, the increase in microbial N immobilization observed in our experiment at 1 day (Table 2) was not associated with reduced N 2 O emissions at 0-1 day at lower C condition (P addition rather increased the N 2 O emissions at WFPS 60 %, Tale 1). Stimulated total N cycling by P addition (Mori et al 2010), including N mineralization, nitrification, denitrification, and microbial N immobilization, probably offset the decrease in soil inorganic N. This is supported by data showing no differences in soil inorganic N contents and DN contents between P-added soils and soils without P addition at 1 day (Table 3 and 4). Higher MBN contents in P-added soils could also be due to the reduced N investment of microbes for synthesizing phosphatase (Turner and Wright 2014), making microbes possible to reserve more N in their bodies.…”

“…It is possible that the microbial growth reached its peak and microbes started dying more quickly in P-added soils, which caused lower MBN contents in P-added soils in higher C condition at 1 day (see also that MBC contents in H60 were lower in 3 day than in 1 day, Table 2). Possible reasons for the stimulated N 2 O emissions by P addition at WFPS 60 % at 0-1 day are stimulated N cycling (Mori et al 2010), promoted anaerobic condition (Mori et al 2013b), and re-mineralization of dead microbes (Wu and Brooks 2005) provided by quick microbial growth and death.…”

“…Our previous reports (Mori et al 2010(Mori et al , 2013b showed that P addition with and without carbon (C) and/or N addition on Acacia mangium plantation soils stimulated N 2 O emission under relatively anaerobic condition, which is preferable for producing N 2 O in our study site . The result was attributed to stimulated N cycling, activated denitrifying and/or nitrifying bacteria, and promoted anaerobic condition derived from stimulated heterotrophic microbial activities (Mori et al 2013b).…”

Azolla cover significantly decreased CH4but not N2O emissions from flooding rice paddy to atmosphere

“…N 2 O is a byproduct or an intermediate product of microbial nitrification and denitrification on the N cycling in soil-plant ecosystems (Cheng et al 2004a, b). There are many studies showing N 2 O emissions from symbiotic N 2 fixation plants, such as leguminous crops and acacia trees as being larger than nonsymbiotic N 2 fixation plants (Arai et al 2008;Mori et al 2010;Uchida and Akiyama 2013;Zhang et al 2014). The N 2 O emission from soybean ecosystems could be mitigated by inoculation of high N 2 O reductase N-fixing rhizobium (Akiyama et al 2016).…”

The effects of tannins derived from <i>Acacia mangium</i> bark on N₂O emissions from water saturated acacia plantation soil

“…After 3 days pre-incubation at 60 % water-filled pore space (WFPS), 2 mg g soil -1 of crude tannin, HMT, LMT or tannic acid, and 20 µg-N g soil -1 KNO 3 dissolved in distilled water, were added. Soil water contents were adjusted to 100 % WFPS to induce greater amounts of N 2 O emission through denitrification under relatively wet soil conditions rather than nitrification (Mori et al 2010). Control soils were also prepared with the addition of 20 µg-N g soil…”