Dataset Information

Nitrogen Addition Affects Nitrous Oxide Emissions of Rainfed Lucerne Grassland.

ABSTRACT: Nitrous oxide (N₂O) is a potent greenhouse gas. Assessing the N₂O emission from lucerne grasslands with nitrogen addition will aid in estimating the annual N₂O emissions of such agriculture areas, particularly following summer rainfall events in light of precipitation variation associated with global change. Here, we measured soil N₂O emissions, soil temperature and water content of lucerne grasslands with four levels of nitrogen addition over 25 days, which included 10 rainfall events. Results showed that nitrogen addition was observed to increase soil NO₃^--N content, but not significantly improve dry matter yield, height or leaf area index. Nitrogen addition and rainfall significantly affected N₂O emissions, while the response of N₂O emissions to increasing nitrogen input was not linear. Relative soil gas diffusivity (D_p/D_o) and water-filled pore space (WFPS) were good indicators of N₂O diurnal dynamics, and D_p/D_o was able to explain slightly more of the variation in N₂O emissions than WFPS. Collectively, nitrogen addition did not affect lucerne dry matter yield in a short term, while it induced soil N₂O emissions when rainfall events alter soil water content, and D_p/D_o could be a better proxy for predicting N₂O emissions in rainfed lucerne grasslands.

SUBMITTER: Li Y

PROVIDER: S-EPMC9265669 | biostudies-literature | 2022 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Nitrogen Addition Affects Nitrous Oxide Emissions of Rainfed Lucerne Grassland.

Li Yuan Y Wang Gang G Shurpali Narasinha J NJ Shen Yuying Y

International journal of environmental research and public health 20220624 13

Nitrous oxide (N2O) is a potent greenhouse gas. Assessing the N2O emission from lucerne grasslands with nitrogen addition will aid in estimating the annual N2O emissions of such agriculture areas, particularly following summer rainfall events in light of precipitation variation associated with global change. Here, we measured soil N2O emissions, soil temperature and water content of lucerne grasslands with four levels of nitrogen addition over 25 days, ...[more]

PMID: 35805448

Similar Datasets

Project description:BackgroundSoil 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.MethodsThe 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.ResultsOn 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.

Project description:Lucerne (Medicago sativa L.) is a major component of the crops used in dry-land farming systems in China and its management is associated with notable nitrous oxide (N2O) emissions. A high proportion of these emissions is more likely to occur during periods when the soil undergoes freezing and thawing cycles. In this study, the effects of freeze/thaw cycles on N2O emissions and related factors were investigated in lucerne grasslands. The hypothesis was tested whether increased emissions resulted from a disruption of nitrification or denitrification caused by variations in soil temperatures and water contents. Three days (3 × 24 h) were chosen, where conditions represented freezing and thawing cycles. N2O emissions were measured for a fallow control (F) and two grasslands where lucerne had been cultivated for 4 and 11 years. Soil temperature, soil water content, soil microbial biomass carbon (MBC), soil microbial biomass nitrogen (MBN), soil ammonium nitrogen (NH4 +-N), and soil nitrate nitrogen (NO3 --N) contents were measured. Moreover, the quantities of soil nitrification and denitrification microbes were assessed. Variations in N2O emissions were strongly affected by freeze/thaw cycles, and emissions of 0.0287 ± 0.0009, 0.0230 ± 0.0019, and 0.3522 ± 0.0029 mg m-2 h-1 were found for fallow, 4-year-old, and 11-year-old grasslands, respectively. Pearson correlation analyses indicated that N2O emissions were significantly correlated with the soil water content, temperature, NH4 +-N content, and the number of nitrosobacteria and denitrifying bacteria at a soil depth of 0-100 mm. The numbers of nitrosobacteria and denitrifying bacteria correlated significantly with soil temperature at this soil depth. MBN and soil NH4 +-N contents correlated significantly with soil water content at this depth. Principal component analysis highlighted the positive effects of the number of denitrifying bacteria on N2O emissions during the freeze/thaw period. Furthermore, soil temperature and the number of nitrosobacteria at the tested soil depth (0-100 mm) also played a significant role. This shows that soil freeze/thaw cycles strongly impacted both N2O emissions and the diurnal range, and the number of denitrifying bacteria was mainly influenced by soil temperature and soil NH4 +-N content. The number of denitrifying bacteria was the dominant variable affecting N2O emissions from lucerne grasslands during the assessed soil freeze/thaw period on the Loess Plateau, China.

Project description:Few studies have assessed the common, yet unproven, hypothesis that an increase of plant nitrogen (N) uptake and/or recovery efficiency (NRE) will reduce nitrous oxide (N2O) emission during crop production. Understanding the relationships between N2O emissions and crop N uptake and use efficiency parameters can help inform crop N management recommendations for both efficiency and environmental goals. Analyses were conducted to determine which of several commonly used crop N uptake-derived parameters related most strongly to growing season N2O emissions under varying N management practices in North American maize systems. Nitrogen uptake-derived variables included total aboveground N uptake (TNU), grain N uptake (GNU), N recovery efficiency (NRE), net N balance (NNB) in relation to GNU [NNB(GNU)] and TNU [NNB(TNU)], and surplus N (SN). The relationship between N2O and N application rate was sigmoidal with relatively small emissions for N rates <130 kg ha-1, and a sharp increase for N rates from 130 to 220 kg ha-1; on average, N2O increased linearly by about 5 g N per kg of N applied for rates up to 220 kg ha-1. Fairly strong and significant negative relationships existed between N2O and NRE when management focused on N application rate (r2 = 0.52) or rate and timing combinations (r2 = 0.65). For every percentage point increase, N2O decreased by 13 g N ha-1 in response to N rates, and by 20 g N ha-1 for NRE changes in response to rate-by-timing treatments. However, more consistent positive relationships (R2 = 0.73-0.77) existed between N2O and NNB(TNU), NNB(GNU), and SN, regardless of rate and timing of N application; on average N2O emission increased by about 5, 7, and 8 g N, respectively, per kg increase of NNB(GNU), NNB(TNU), and SN. Neither N source nor placement influenced the relationship between N2O and NRE. Overall, our analysis indicated that a careful selection of appropriate N rate applied at the right time can both increase NRE and reduce N2O. However, N2O reduction benefits of optimum N rate-by-timing practices were achieved most consistently with management systems that reduced NNB through an increase of grain N removal or total plant N uptake relative to the total fertilizer N applied to maize. Future research assessing crop or N management effects on N2O should include N uptake parameter measurements to better understand N2O emission relationships to plant NRE and N uptake.

Dataset Information

Nitrogen Addition Affects Nitrous Oxide Emissions of Rainfed Lucerne Grassland.

Publications

Nitrogen Addition Affects Nitrous Oxide Emissions of Rainfed Lucerne Grassland.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets