scholarly journals Effect of Grazing Intensities on Soil N2O Emissions from an Alpine Meadow of Zoige Plateau in China

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 541
Author(s):  
Wei Zhan ◽  
Zhenan Yang ◽  
Jianliang Liu ◽  
Huai Chen ◽  
Gang Yang ◽  
...  
Keyword(s):  
Alpine Meadow ◽  
Emission Rate ◽  
Grazing Intensity ◽  
N2o Emission ◽  
N2o Emissions ◽  
Grazing Land ◽  
Growing Seasons ◽  
Grazing Intensities ◽  
Zoigê Plateau ◽  
Zoige Plateau

The alpine meadow of Zoige Plateau plays a key role in local livestock production of cattle and sheep. However, it remains unclear how animal grazing or its intensity affect nitrous oxide (N2O) emissions, and the main driving factors. A grazing experiment including four grazing intensities (G0, G0.7, G1.2, G1.6 yak ha−1) was conducted between January 2013 and December 2014 to evaluate the soil nitrous oxide (N2O) fluxes under different grazing intensities in an alpine meadow on the eastern Qinghai–Tibet Plateau of China. The N2O fluxes were examined with gas collected by the static chamber method and by chromatographic concentration analysis. N2O emissions in the growing seasons (from May to September) were lower than that in non-growing seasons (from October to April) in 2013, 1.94 ± 0.30 to 3.37 ± 0.56 kg N2O ha−1 yr−1. Annual mean N2O emission rates were calculated as 1.17 ± 0.50 kg N2O ha−1 yr−1 in non-grazing land (G0) and 1.94 ± 0.23 kg N2O ha−1 yr−1 in the grazing land (G0.7, G1.2, and G1.6). The annual mean N2O flux showed no significant differences between grazing treatments in 2013. However, there were significantly greater fluxes from the G0.7 treatment than from the G1.6 treatment in 2014, especially in the growing season. Over the two years, the soil N2O emission rate was significantly negatively correlated with soil water-filled pore space (WFPS) and dissolved organic carbon (DOC) content as well as positively correlated with soil available phosphorus (P). No relationship was observed between soil N2O emission rate and temperature or rainfall. Our results showed that the meadow soils acted as a source of N2O for most periods and turned into a weak sink of N2O later during the sampling period. Our results highlight the importance of proper grazing intensity in reducing N2O emissions from alpine meadow. The interaction between grazing intensity and N2O emissions should be of more concern during future management of pastures in Zoige Plateau.

scholarly journals Sheep Excreta as Source of Nitrous Oxide in Ryegrass Pasture in Southern Brazil

2015 ◽  
Vol 39 (5) ◽  
pp. 1498-1506 ◽  
Author(s):  
Michely Tomazi ◽  
Emanuelle Cavazini Magiero ◽  
Joice Mari Assmann ◽  
Tatiane Bagatini ◽  
Jeferson Dieckow ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Pore Space ◽  
Grazing Intensity ◽  
Nitrate Content ◽  
N2o Emissions ◽  
Southern Brazil ◽  
Herbage Intake ◽  
N Fluxes ◽  
Grazing Intensities ◽  
The Mean

ABSTRACT Livestock urine and dung are important components of the N cycle in pastures, but little information on its effect on soil nitrous oxide (N2O) emissions is available. We conducted a short-term (39-day) trial to quantify the direct N2O-N emissions from sheep excreta on an experimental area of ryegrass pasture growing on a Typic Paleudult in southern Brazil. Four rates of urine-N (161, 242, 323, and 403 kg ha-1 N) and one of dung-N (13 kg ha-1 N) were applied, as well as a control plot receiving no excreta. The N2O-N emission factor (EF = % of added N released as N2O-N) for urine and dung was calculated, taking into account the N2O fluxes in the field, over a period of 39 days. The EF value of the urine and dung was used to estimate the emissions of N2O-N over a 90-day period of pasture in the winter under two grazing intensities (2.5 or 5.0 times the herbage intake potential of grazing lambs). The soil N2O-N fluxes ranged from 4 to 353 µg m-2h-1. The highest N2O-N fluxes occurred 16 days after application of urine and dung, when the highest soil nitrate content was also recorded and the water-filled pore space exceeded 60 %. The mean EF for urine was 0.25 % of applied N, much higher than that for dung (0.06 %). We found that N2O-N emissions for the 90-day winter pasture period were 0.54 kg ha-1 for low grazing intensity and 0.62 kg ha-1 for moderate grazing intensity. Comparison of the two forms of excreta show that urine was the main contributor to N2O-N emissions (mean of 36 %), whereas dung was responsible for less than 0.1 % of total soil N2O-N emissions.

Does influent COD/N ratio affect nitrogen removal and N2O emission in a novel biochar-sludge amended soil wastewater infiltration system (SWIS)?

2018 ◽  
Vol 78 (2) ◽  
pp. 347-357 ◽  
Author(s):  
Fanping Zheng ◽  
Chaoquan Tan ◽  
Wanyuan Hou ◽  
Linli Huang ◽  
Jing Pan ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Emission Rate ◽  
N2o Emission ◽  
Nitrifying Bacteria ◽  
N2o Emissions ◽  
Intermittent Aeration ◽  
Ratio Increase ◽  
Removal Rates ◽  
N Removal ◽  
Amended Soil

Abstract Nitrogen removal and N2O emission of a biochar-sludge amended soil wastewater infiltration system (SWIS) with/without intermittent aeration under different influent COD/N ratios was investigated. Nitrogen removal and N2O emission were affected by influent COD/N ratio. Under a COD/N ratio between 1:1 and 15:1, average chemical oxygen demand (COD), NH4+-N and total nitrogen (TN) removal rates decreased with COD/N ratio increase in non-aerated SWISs amended with/without biochar-sludge; an increasing COD/N ratio hardly affected COD and NH4+-N removal in a biochar-sludge amended SWIS with intermittent aeration; the N2O emission rate decreased with COD/N ratio increase in the studied SWISs. The biochar-sludge amended SWIS with intermittent aeration achieved high COD (92.2%), NH4+-N (96.8%), and TN (92.7%) removal rates and a low N2O emission rate (10.6 mg/(m2 d)) under a COD/N ratio of 15:1, which was higher than those in non-aerated SWISs amended with/without biochar-sludge. Combining the biochar-sludge amended SWIS with intermittent aeration enhanced the number of nitrifying bacteria, denitrifying bacteria, nitrate reductase activities, nitrite reductase activities, and improved the abundance of nitrogen removal functional genes under a high influent COD/N ratio. The results suggested that the joint use of intermittent aeration and biochar-sludge in a SWIS could be an effective and appropriate strategy for improving nitrogen removal and reducing N2O emissions in treating high COD/N ratio wastewater.

The Response of Vegetation Biomass to Soil Properties along Degradation Gradients of Alpine Meadow at Zoige Plateau

2020 ◽  
Vol 30 (3) ◽  
pp. 446-455
Author(s):  
Miao Liu ◽  
Zhenchao Zhang ◽  
Jian Sun ◽  
Ming Xu ◽  
Baibing Ma ◽  
...  
Keyword(s):  
Soil Properties ◽  
Alpine Meadow ◽  
Vegetation Biomass ◽  
Zoigê Plateau ◽  
Zoige Plateau

scholarly journals Nitrous Oxide Emission from Grazing Is Low across a Gradient of Plant Functional Diversity and Soil Conditions

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 223
Author(s):  
John Kormla Nyameasem ◽  
Carsten S. Malisch ◽  
Ralf Loges ◽  
Friedhelm Taube ◽  
Christof Kluß ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
N Uptake ◽  
N2o Emission ◽  
Soil Conditions ◽  
N2o Emissions ◽  
Mineral N ◽  
Grazed Pastures ◽  
Growing Seasons ◽  
Nitrogen Inputs ◽  
Organically Managed

Nitrous oxide (N2O) emissions from pastures can vary significantly depending on soil and environmental conditions, nitrogen (N) input, as well as the plant’s ability to take up the N. We tested the hypothesis that legume-based N sources are characterized by significantly lower emission factors than mineral N based dairy systems. Therefore, this study monitored N2O emissions for a minimum of 100 days and up to two growing seasons across a gradient of plant species diversity. Emissions were measured from both grazed pastures and a controlled application of urine and dung using the static chamber method. About 90% of the simulated experiments’ accumulated N2O emissions occurred during the first 60–75 days. The average accumulated N2O emissions were 0.11, 0.87, 0.99, and 0.21 kg ha−1 for control, dung, urine patches, and grazed pastures, respectively. The N uptake efficiency at the excreta patch scale was about 70% for both dung and urine. The highest N2O-N emission factor was less than half compared with the IPCC default (0.3 vs. 0.77), suggesting an overestimation of N2O-N emissions from organically managed pastures in temperate climates. Plant diversity showed no significant effect on N2O emission. However, functional groups were significant (p < 0.05). We concluded that legume-containing pasture systems without a fertilizer addition generally appear capable of utilizing nitrogen inputs from excreta patches efficiently, resulting in low N2O emissions.

scholarly journals Belowground Bud Bank Distribution and Aboveground Community Characteristics along Different Moisture Gradients of Alpine Meadow in the Zoige Plateau, China

2019 ◽  
Vol 11 (9) ◽  
pp. 2602
Author(s):  
Xinjing Ding ◽  
Peixi Su ◽  
Zijuan Zhou ◽  
Rui Shi
Keyword(s):  
Plant Community ◽  
Plant Diversity ◽  
Alpine Meadow ◽  
Bud Bank ◽  
Alpine Meadows ◽  
Water Gradient ◽  
Positive Correlations ◽  
Zoigê Plateau ◽  
Plant Community Succession ◽  
Zoige Plateau

The belowground bud bank plays an important role in plant communities succession and maintenance. In order to understand the response of the bud bank to the sod layer moisture, we investigated the bud bank distribution, size, and composition of six different water gradient alpine meadows through excavating in the Zoige Plateau. The results showed: (1) The alpine meadow plant belowground buds were mainly distributed in the 0–10 cm sod layer, accounting for 74.2%–100% of the total. The total bud density of the swamp wetland and degraded meadow was the highest (16567.9 bud/m3) and the lowest (4839.5 bud/m3). (2) A decrease of the moisture plant diversity showed a trend of increasing first and then decreasing. Among six alpine meadows the swamp meadow plant diversity was the highest, and species richness, Simpson, Shannon–Wiener, and Pielou were 10.333, 0.871, 0.944, and 0.931, respectively. (3) The moisture was significantly positively correlated with the total belowground buds and short rhizome bud density. There were significant positive correlations with sod layer moisture and tiller bulb bud density. This study indicates that the moisture affected bud bank distribution and composition in the plant community, and the results provide important information for predicting plant community succession in the alpine meadow with future changes in precipitation patterns.

scholarly journals Effects of Different Grazing Intensities on Soil C, N, and P in an Alpine Meadow on the Qinghai—Tibetan Plateau, China

2018 ◽  
Vol 15 (11) ◽  
pp. 2584 ◽  
Author(s):  
Gang Li ◽  
Zhi Zhang ◽  
Linlu Shi ◽  
Yan Zhou ◽  
Meng Yang ◽  
...  
Keyword(s):  
Soil Carbon ◽  
Management Practices ◽  
Alpine Meadow ◽  
Nitrogen Loss ◽  
Chemical Properties ◽  
Grazing Intensity ◽  
Nitrogen And Phosphorus ◽  
Soil C ◽  
Carbon And Nitrogen ◽  
Grazing Intensities

Inappropriate grazing management is one of the most common causes of grassland degradation, and thus, an assessment of soil properties under different grazing intensities is critical for understanding its effects on ecosystem nutrient cycling and for formulating appropriate management strategies. However, the responses of certain main elements, including soil carbon, nitrogen, and phosphorus, to grazing in alpine meadow ecosystems remain insufficiently clarified. Here, we measured carbon, nitrogen, and phosphorus contents in the topmost 30 cm of soil in an alpine meadow under three grazing intensities (light, moderate, and heavy) and found clear differences in soil physical and chemical properties among different grazing intensities and soil layers. As grazing intensity increased, soil water content, carbon and nitrogen contents and stocks, and carbon to phosphorus and nitrogen to phosphorus ratios decreased, whereas soil bulk density increased. However, soil phosphorus and carbon to nitrogen ratio remained stable. Our findings highlight the negative impacts of heavy grazing intensity, in terms of soil carbon and nitrogen loss and phosphorus mineralization. Moreover, we emphasize that further related studies are necessary to gain a more comprehensive understanding of the effects of grazing on grassland ecosystems, and thereby provide information for sustainable management practices and eco-compensation policies.

Hoof pressure and trampling intensity of yaks are higher than those of Tibetan sheep in a Tianzhu alpine meadow

2019 ◽  
Vol 41 (2) ◽  
pp. 125 ◽  
Author(s):  
Hailei Yang ◽  
Jinjin Sun ◽  
Changlin Xu ◽  
Jianwen Zhang ◽  
Jinlong Chai ◽  
...  
Keyword(s):  
Alpine Meadow ◽  
Grazing Intensity ◽  
Gansu Province ◽  
Grassland Vegetation ◽  
Alpine Meadows ◽  
Average Area ◽  
Tibetan Sheep ◽  
Grazing Intensities ◽  
Grazing Area ◽  
Ovis Ammon

Trampling by grazing animals exerts a comprehensive and serious effect on grassland vegetation and soil. In order to compare the trampling of yaks and Tibetan sheep under different grazing intensities, we examined the hoof pressure and trampling intensity (based on trampling area and hoof-print count) of white yaks (Poephagus grunniens) and Tibetan sheep (Ovis ammon) in an alpine meadow of Tianzhu County, Gansu Province, China, under conditions where either grazing area or livestock number were controlled. The average areas trampled by yaks and Tibetan sheep were 39.2 and 21.6 cm2 respectively. The average hoof pressure of yaks and Tibetan sheep were 6.89 and 3.13 kg cm–2 respectively. The yak-to-sheep ratio of the average area trampled was 1.81:1, whereas the yak-to-sheep ratio of average hoof pressure was 2.20:1. Average ingestion and walking trampling intensities of yaks were 384.8 × 103 and 247.1 × 103 kg cm–2, respectively, in controlled grazing areas, and 439.1 × 103 and 756.3 × 103 kg cm–2, respectively, in areas of controlled livestock numbers. These values for Tibetan sheep were 15.3 × 103 and 120.3 × 103 kg cm–2 in controlled grazing areas, and 42.6 × 103 and 128.2 × 103 kg cm–2 in areas of controlled livestock numbers. In controlled grazing areas, the ingestion and walking trampling intensities of yaks were 25.2 and 5.4 times higher, respectively, than those of sheep. Under areas of controlled livestock numbers, these values were 10.3 and 5.9 times higher, respectively, than those of sheep. The average trampling intensity of yaks was 7.3 times higher than that of the sheep. Therefore, under conditions of similar grazing intensity, yaks cause more damage than Tibetan sheep in alpine meadows.

scholarly journals Nitrous Oxide Emissions in Pineapple Cultivation on a Tropical Peat Soil

2021 ◽  
Vol 13 (9) ◽  
pp. 4928
Author(s):  
Alicia Vanessa Jeffary ◽  
Osumanu Haruna Ahmed ◽  
Roland Kueh Jui Heng ◽  
Liza Nuriati Lim Kim Choo ◽  
Latifah Omar ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Soil Temperature ◽  
Peat Soil ◽  
Farming Systems ◽  
N2o Emission ◽  
Nitrous Oxide Emissions ◽  
Natural State ◽  
N2o Emissions ◽  
Wet Season ◽  
Peat Soils

Farming systems on peat soils are novel, considering the complexities of these organic soil. Since peat soils effectively capture greenhouse gases in their natural state, cultivating peat soils with annual or perennial crops such as pineapples necessitates the monitoring of nitrous oxide (N2O) emissions, especially from cultivated peat lands, due to a lack of data on N2O emissions. An on-farm experiment was carried out to determine the movement of N2O in pineapple production on peat soil. Additionally, the experiment was carried out to determine if the peat soil temperature and the N2O emissions were related. The chamber method was used to capture the N2O fluxes daily (for dry and wet seasons) after which gas chromatography was used to determine N2O followed by expressing the emission of this gas in t ha−1 yr−1. The movement of N2O horizontally (832 t N2O ha−1 yr−1) during the dry period was higher than in the wet period (599 t N2O ha−1 yr−1) because of C and N substrate in the peat soil, in addition to the fertilizer used in fertilizing the pineapple plants. The vertical movement of N2O (44 t N2O ha−1 yr−1) was higher in the dry season relative to N2O emission (38 t N2O ha−1 yr−1) during the wet season because of nitrification and denitrification of N fertilizer. The peat soil temperature did not affect the direction (horizontal and vertical) of the N2O emission, suggesting that these factors are not related. Therefore, it can be concluded that N2O movement in peat soils under pineapple cultivation on peat lands occurs horizontally and vertically, regardless of season, and there is a need to ensure minimum tilling of the cultivated peat soils to prevent them from being an N2O source instead of an N2O sink.

scholarly journals The interaction of seasonal rainfall and nitrogen fertiliser rate on soil N2O emission, total N loss and crop yield of dryland sorghum and sunflower grown on sub-tropical Vertosols

Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 604 ◽  
Author(s):  
G. D. Schwenke ◽  
B. M. Haigh
Keyword(s):  
Crop Yield ◽  
Crop Production ◽  
Field Experiments ◽  
N2o Emission ◽  
N2o Emissions ◽  
N Loss ◽  
N Losses ◽  
Total N ◽  
Tropical Regions ◽  
The Impact

Summer crop production on slow-draining Vertosols in a sub-tropical climate has the potential for large emissions of soil nitrous oxide (N2O) from denitrification of applied nitrogen (N) fertiliser. While it is well established that applying N fertiliser will increase N2O emissions above background levels, previous research in temperate climates has shown that increasing N fertiliser rates can increase N2O emissions linearly, exponentially or not at all. Little such data exists for summer cropping in sub-tropical regions. In four field experiments at two locations across two summers, we assessed the impact of increasing N fertiliser rate on both soil N2O emissions and crop yield of grain sorghum (Sorghum bicolor L.) or sunflower (Helianthus annuus L.) in Vertosols of sub-tropical Australia. Rates of N fertiliser, applied as urea at sowing, included a nil application, an optimum N rate and a double-optimum rate. Daily N2O fluxes ranged from –3.8 to 2734g N2O-Nha–1day–1 and cumulative N2O emissions ranged from 96 to 6659g N2O-Nha–1 during crop growth. Emissions of N2O increased with increased N fertiliser rates at all experimental sites, but the rate of N loss was five times greater in wetter-than-average seasons than in drier conditions. For two of the four experiments, periods of intense rainfall resulted in N2O emission factors (EF, percent of applied N emitted) in the range of 1.2–3.2%. In contrast, the EFs for the two drier experiments were 0.41–0.56% with no effect of N fertiliser rate. Additional 15N mini-plots aimed to determine whether N fertiliser rate affected total N lost from the soil–plant system between sowing and harvest. Total 15N unaccounted was in the range of 28–45% of applied N and was presumed to be emitted as N2O+N2. At the drier site, the ratio of N2 (estimated by difference)to N2O (measured) lost was a constant 43%, whereas the ratio declined from 29% to 12% with increased N fertiliser rate for the wetter experiment. Choosing an N fertiliser rate aimed at optimum crop production mitigates potentially high environmental (N2O) and agronomic (N2+N2O) gaseous N losses from over-application, particularly in seasons with high intensity rainfall occurring soon after fertiliser application.

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