Dataset Information

Nitrous oxide, methane emissions and grain yield in rainfed wheat grown under nitrogen enriched biochar and straw in a semiarid environment.

ABSTRACT:

Background

Soil application of biochar and straw alone or their combinations with nitrogen (N) fertilizer are becoming increasingly common, but little is known about their agronomic and environmental performance in semiarid environments. This study was conducted to investigate the effect(s) of these amendments on soil properties, nitrous oxide (N₂O) and methane (CH₄) emissions and grain and biomass yield of spring wheat (Triticum aestivum L.), and to produce background dataset that may be used to inform nutrient management guidelines for semiarid environments.

Methods

The experiment involved the application of biochar, straw or urea (46% nitrogen [N]) alone or their combinations. The treatments were: CN₀-control (zero-amendment), CN₅₀ -50 kg ha^-1 N, CN₁₀₀-100 kg ha^-1 N, BN₀ -15 t ha^-1 biochar, BN₅₀-15 t ha^-1 biochar + 50 kg ha^-1 N, BN₁₀₀-15 t ha^-1 biochar + 100 kg ha^-1 N, SN₀ -4.5 t ha^-1 straw, SN₅₀ -4.5 t ha^-1 straw + 50 kg ha^-1 N and SN₁₀₀-4.5 t ha^-1 straw + 100 kg ha^-1 N. Fluxes of N₂O, CH₄ and grain yield were monitored over three consecutive cropping seasons between 2014 and 2016 using the static chamber-gas chromatography method.

Results

On average, BN₁₀₀reported the highest grain yield (2054 kg ha^-1), which was between 25.04% and 38.34% higher than all other treatments. In addition, biomass yield was much higher under biochar treated plots relative to the other treatments. These findings are supported by the increased in soil organic C by 17.14% and 21.65% in biochar amended soils (at 0-10 cm) compared to straw treated soils and soils without carbon respectively. The BN₁₀₀treatment also improved bulk density and hydraulic properties (P < 0.05), which supported the above results. The greatest N₂O emissions and CH₄ sink were recorded under the highest rate of N fertilization (100 kg N ha^-1). Cumulative N₂O emissions were 39.02% and 48.23% lower in BN₁₀₀ compared with CN₀ and CN₁₀₀, respectively. There was also a ≈ 37.53% reduction in CH₄ uptake under BN₁₀₀compared with CN₀-control and CN₅₀. The mean cumulative N₂O emission from biochar treated soils had a significant decrease of 10.93% and 38.61% compared to straw treated soils and soils without carbon treatment, respectively. However, differences between mean cumulative N₂O emission between straw treated soils and soils without carbon were not significant. These results indicate the dependency of crop yield, N₂O and CH₄ emissions on soil quality and imply that crop productivity could be increased without compromising on environmental quality when biochar is applied in combination with N-fertilizer. The practice of applying biochar with N fertilizer at 100 kg ha^-1 N resulted in increases in crop productivity and reduced N₂O and CH₄soil emissions under dryland cropping systems.

SUBMITTER: Yeboah S

PROVIDER: S-EPMC8380423 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Straw returns to the soil is an effective way to improve soil organic carbon and reduce air pollution by straw burning, but this may increase CH4 and N2O emissions risks in paddy soils. Biochar has been used as a soil amendment to improve soil fertility and mitigate CH4 and N2O emissions. However, little is known about their interactive effect on CH4 and N2O emissions and the underlying microbial mechanisms. In this study, a 2-year pot experiment was conducted on two paddy soil types (an acidic Utisol, TY, and an alkaline Inceptisol, BH) to evaluate the influence of straw and biochar applications on CH4 and N2O emissions, and on related microbial functional genes. Results showed that straw addition markedly increased the cumulative CH4 emissions in both soils by 4.7- to 9.1-fold and 23.8- to 72.4-fold at low (S1) and high (S2) straw input rate, respectively, and significantly increased mcrA gene abundance. Biochar amendment under the high straw input (BS2) significantly decreased CH4 emissions by more than 50% in both soils, and increased both mcrA gene and pmoA gene abundances, with greatly enhanced pmoA gene and a decreased mcrA/pmoA gene ratio. Moreover, methanotrophs community changed distinctly in response to straw and biochar amendment in the alkaline BH soil, but showed slight change in the acidic TY soil. Straw had little effect on N2O emissions at low input rate (S1) but significantly increased N2O emissions at the high input rate (S2). Biochar amendment showed inconsistent effect on N2O emissions, with a decreasing trend in the BH soil but an increasing trend in the TY soil in which high ammonia existed. Correspondingly, increased nirS and nosZ gene abundances and obvious community changes in nosZ gene containing denitrifiers in response to biochar amendment were observed in the BH soil but not in the TY soil. Overall, our results suggested that biochar amendment could markedly mitigate the CH4 and N2O emissions risks under a straw return practice via regulating functional microbes and soil physicochemical properties, while the performance of this practice will vary depending on soil parent material characteristics.