Impacts of Soil Moisture and Fertilizer on N2O Emissions from Cornfield Soil in a Karst Watershed, SW China

Abstract

Incubation experiments using a typical cornfield soil in the Wujiang River watershed, SW China, were conducted to examine the impacts of soil moisture and fertilizer on N2O emissions and production mechanisms. According to the local fertilizer type, we added NH4NO3 (N) and glucose (C) during incubation to simulate fertilizer application in the cornfield soil. The results showed that an increase in soil moisture and fertilizer significantly stimulated N2O emissions in cornfield soil in the karst area, and it varied with soil moisture. The highest N2O emission fluxes were observed in the treatment with nitrogen and carbon addition at 70% water-filled pore space (WFPS), reaching 6.6 mg kg−1 h−1, which was 22,310, 124.9, and 1.4 times higher than those at 5%, 40%, and 110% WFPS, respectively. The variations of nitrogen species indicated that the production of extremely high N2O at 70% WFPS was dominated by nitrifier denitrification and denitrification, and N2O was the primary form of soil nitrogen loss when soil moisture was >70% WFPS. This study provides a database for estimating N2O emissions in cropland soil in the karst area, and further helped to promote proper soil nitrogen assessment and management of agricultural land of the karst watersheds.

Impacts of Chicken Manure Biochar on Nitrous Oxide and Methane Emissions from Vegetable Field in Subtropical China

“…N 2 O emissions were noticeably low when the WFPS in the top 20 cm of the soil was less than 30% (Fig. 8), which is comparable to the outcome of a eld experiment conducted on cropland in North China Plain (Gao et emission uxes, reaching 6.6 mg kg − 1 h − 1 , which was 22, 310, 124.9, and 1.4 times greater than those at 5%, 40%, and 110% WFPS, respectively (Wei et al 2022). However, we saw a considerable increase in N 2 O emissions as WFPS reached about 60% (Fig.…”

Impacts of High-Frequency Chicken Manure Biochar Application on N2O and CH4 Emissions from Vegetable Field in Subtropical China

“…Our findings can also be supported by the outcomes of an incubation study conducted in the Wujiang River basin, Southwest China, using normal cornfield soil. According to this study, the treatments with N and carbon addition at 70% WFPS had the largest N 2 O emission, reaching 6.6 mg kg −1 h −1 , which was 22, 310, 124.9, and 1.4 times greater than those at 5%, 40%, and 110% WFPS, respectively [29]. Moreover, we saw a considerable increase in N 2 O emissions as the WFPS reached about 60% (Figure 8).…”

Reduction of nitrous oxide emission by using stearic acid combined zinc coated urea in silty clay and sandy loam soils under bare and planted conditions

“…Most probably that would be because of higher soil moisture contents (70–80% of the field capacity) throughout the experimental period. It was reported the moisture content in the range of 70–80% of field capacity is ideal for denitrifiers activity and resulted in the higher N 2 O production [ 14 , 59 , 60 ]. Apart from the moisture contents higher temperature and the higher N application rate could also be the reason behind higher cumulative N 2 O emission.…”