Effect of legume and grazing intensity on soil organic carbon and total nitrogen stock in Himalayan rangeland

Organic carbon and total nitrogen are important components of global carbon and nitrogen cycle in rangeland ecology.Objective of this study is to identify and quantify the present status of carbon and nitrogen pool in Himalayan rangeland and to make recommendations for enhancing carbon and nitrogen storage for rangeland management. To meet the aforementioned objectives, the field study was conducted in 2011 -2013. The study showed that soil organic carbon was highest in legume seeding sub-plot in top soil (28.53 ± 2.6) t/ha of heavily grazed area. Similarly, total nitrogen was highest in bottom soil (2.81 ± 0.16) t/ha in legume seeding sub-plot of enclosed un-grazed area. Usually, heavily grazed and legume seeding sub-plots had more soil organic carbon and total nitrogen concentration compared to others. The value of above ground biomass was in increasing trend with decreasing grazing intensity but for below ground biomass, it was just the reverse. On the basis of the results of this study, the grazing intensity is positively correlated with above ground and below ground biomass and soil organic carbon but no correlation with soil total nitrogen and soil bulk density.

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Alteration of carbon, nitrogen, and phosphorus stoichiometry and their related enzymes as affected by increased soil coarseness

10.5194/bg-2016-483 ◽

2016 ◽

Author(s):

Ruzhen Wang ◽

Linyou Lü ◽

Courtney A. Creamer ◽

Heyong Liu ◽

Xue Feng ◽

...

Keyword(s):

Microbial Biomass ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Total Nitrogen ◽

Enzyme Activities ◽

Microbial Biomass Carbon ◽

Soil Parameters ◽

Available Phosphorus ◽

Carbon And Nitrogen ◽

Acid Phosphomonoesterase

Abstract. Soil coarseness decreases ecosystem productivity, ecosystem carbon and nitrogen stocks, and soil nutrient contents in sandy grasslands. To gain insight into changes in soil carbon and nitrogen pools, microbial biomass, and enzyme activities in response to soil coarseness, a field experiment of sand addition was conducted to coarsen soil with different intensities: 0 % sand addition, 10 %, 30 %, 50 %, and 70 %. Soil organic carbon and total nitrogen decreased with the intensification of soil coarseness across three depths (0–10 cm, 10–20 cm, and 20–40 cm) by up to 43.9 % and 53.7 %, respectively. At 0–10 cm, soil microbial biomass carbon (MBC) and nitrogen (MBN) declined with soil coarseness by up to 44.1 % and 51.9 %, respectively, while microbial biomass phosphorus (MBP) increased by as much as 73.9 %. Soil coarseness significantly decreased the activities of β-glucosidase, N-acetyl-glucosaminidase, and acid phosphomonoesterase by 20.2 %–57.5 %, 24.5 %–53.0 %, and 22.2 %–88.7 %, respectively. Soil coarseness enhanced microbial C and N limitation relative to P, indicated by the ratios of β-glucosidase and N-acetyl-glucosaminidase to acid phosphomonoesterase (and MBC:MBP and MBN:MBP ratios). As compared to laboratory measurement, values of soil parameters from theoretical sand dilution was significantly lower for soil organic carbon, total nitrogen, dissolved organic carbon, total dissolved nitrogen, available phosphorus, MBC, MBN, and MBP. Phosphorus immobilization in microbial biomass might aggravate plant P limitation in nutrient-poor grassland ecosystems as affected by soil coarseness. We conclude that microbial C:N:P and enzyme activities might be good indicators for nutrient limitation of microorganisms and plants.

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Spatial Variability of Soil Organic Carbon and Total Nitrogen in Desert Steppes of China’s Hexi Corridor

Frontiers in Environmental Science ◽

10.3389/fenvs.2021.761313 ◽

2021 ◽

Vol 9 ◽

Author(s):

Xuyang Wang ◽

Yuqiang Li ◽

Yulong Duan ◽

Lilong Wang ◽

Yayi Niu ◽

...

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Soil Carbon ◽

Total Nitrogen ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Elevation Gradient ◽

Dominant Factor ◽

Desert Steppe ◽

Carbon And Nitrogen

Stock estimates are critical to quantifying carbon and nitrogen sequestration, quantifying greenhouse gas emissions, and understanding key biogeochemical processes (i.e., soil carbon and nutrient cycling). Many studies have assessed soil organic matter and nutrients in different ecosystems. However, the spatial distribution of carbon and nitrogen and the key influencing factors in arid desert steppe remain unclear. Here, we investigated the soil organic carbon (SOC) and soil total nitrogen (STN) to a depth of 100 cm at 126 sites in a desert steppe in northwestern China. SOC and STN contents decreased with increasing depth; the highest average SOC and STN contents were 12.70 and 0.65 g kg−1 in the surface 5 cm, and the lowest were from 80 to 100 cm (4.49 and 0.16 g kg−1, respectively). SOC density (SOCD) and STN density (STND) to a depth of 100 cm averaged 8.94 and 0.45 kg m−2, respectively. The top 1 m of the soils stored approximately 1,041 Tg SOC and 52 Tg STN in the study area. Geostatistical analysis showed strong and moderate spatial autocorrelation for SOCD in different soil layers, but the autocorrelation for STND gradually weakened with increasing depth. SOCD and STND decreased from southwest to northeast in the study area, along an elevation gradient. Both were significantly positively correlated with topographic variables, precipitation, and the normalized-difference vegetation index, but negatively correlated with temperature and aridity. More than 40% of the SOCD and STND spatial variation was explained by elevation, which was the dominant factor. The data and high-resolution maps from this study will support future soil carbon and nitrogen analyses.

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Small Roots of Parashorea chinensis Wang Hsie Decompose Slower than Twigs

Forests ◽

10.3390/f10040301 ◽

2019 ◽

Vol 10 (4) ◽

pp. 301

Author(s):

Gbadamassi G. O. Dossa ◽

Yan-Qiang Jin ◽

Xiao-Tao Lü ◽

Jian-Wei Tang ◽

Rhett D. Harrison

Keyword(s):

Mass Loss ◽

Nutrient Dynamics ◽

Nitrogen Concentration ◽

Nitrogen Transfer ◽

Litter Bag ◽

Carbon And Nitrogen ◽

Ground Biomass ◽

Study Results ◽

Small Roots ◽

Below Ground

Plants produce above- and below-ground biomass. However, our understanding of both production and decomposition of below-ground biomass is poor, largely because of the difficulties of accessing roots. Below-ground organic matter decomposition studies are scant and especially rare in the tropics. In this study, we used a litter bag experiment to quantify the mass loss and nutrient dynamics of decomposing twigs and small roots from an arbuscular mycorrhizal fungal associated tree, Parashorea chinensis Wang Hsie, in a tropical rain forest in Southwest China. Overall, twig litter decomposed 1.9 times faster than small roots (decay rate (k) twig = 0.255, root = 0.134). The difference in decomposition rates can be explained by a difference in phosphorus (P) concentration, availability, and use by decomposers or carbon quality. Twigs and small roots showed an increase in nitrogen concentration, with final concentrations still higher than initial levels. This suggests nitrogen transfer from the surrounding environment into decomposing twigs and small roots. Both carbon and nitrogen dynamics were significantly predicted by mass loss and showed a negative and positive relationship, respectively. Our study results imply that small roots carbon and nitrogen increase the resident time in the soil. Therefore, a better understanding of the carbon cycle requires a better understanding of the mechanisms governing below-ground biomass decomposition.

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Modeling impacts of climate change and grazing effects on plant biomass and soil organic carbon in the Qinghai–Tibetan grasslands

Biogeosciences ◽

10.5194/bg-14-5455-2017 ◽

2017 ◽

Vol 14 (23) ◽

pp. 5455-5470 ◽

Cited By ~ 6

Author(s):

Wenjuan Zhang ◽

Feng Zhang ◽

Jiaguo Qi ◽

Fujiang Hou

Keyword(s):

Climate Change ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Negative Relationship ◽

Grazing Intensity ◽

Ecosystem Change ◽

Future Climate Change ◽

Climate Change Scenarios ◽

Above Ground Biomass ◽

Ground Biomass

Abstract. The Qinghai Province supports over 40 % of the human population of the Qinghai–Tibetan Plateau (QTP) but occupies about 29 % of its land area, and thus it plays an important role in the plateau. The dominant land cover is grassland, which has been severely degraded over the last decade due to a combination of increased human activities and climate change. Numerous studies indicate that the plateau is sensitive to recent global climate change, but the drivers and consequences of grassland ecosystem change are controversial, especially the effects of climate change and grazing patterns on the grassland biomass and soil organic carbon (SOC) storage in this region. In this study, we used the DeNitrification-DeComposition (DNDC) model and two climate change scenarios (representative concentration pathways: RCP4.5 and RCP8.5) to understand how the grassland biomass and SOC pools might respond to different grazing intensities under future climate change scenarios. More than 1400 grassland biomass sampling points and 46 SOC points were used to validate the simulated results. The simulated above-ground biomass and SOC concentrations were in good agreement with the measured data (R2 0.71 and 0.73 for above-ground biomass and SOC, respectively). The results showed that climate change may be the major factor that leads to fluctuations in the grassland biomass and SOC, and it explained 26.4 and 47.7 % of biomass and SOC variation, respectively. Meanwhile, the grazing intensity explained 6.4 and 2.3 % variation in biomass and SOC, respectively. The project average biomass and SOC between 2015 and 2044 was significantly smaller than past 30 years (1985–2014), and it was 191.17 g C m−2, 63.44 g C kg−1 and 183.62 g C m−2, 63.37 g C kg−1 for biomass and SOC under RCP4.5 and RCP8.5, respectively. The RCP8.5 showed the more negative effect on the biomass and SOC compared with RCP4.5. Grazing intensity had a negative relationship with biomass and positive relationship with SOC. Compared with the baseline, the biomass and SOC changed by 12.56 and −0.19 % for G0, 7.23 and 0.23 for G−50, and −5.17 and 1.19 % for G+50. In the future, more human activity and management practices should be coupled into the model simulation.

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Effect of a urea and urease/nitrification inhibitor combination on rice straw hydrolysis and nutrient turnover on rice growth

BioResources ◽

10.15376/biores.16.2.3059-3074 ◽

2021 ◽

Vol 16 (2) ◽

pp. 3059-3074

Author(s):

Chunxiao Yu ◽

Lili Zhang ◽

Lijie Yang ◽

Wei Bai ◽

Chen Feng ◽

...

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Rice Straw ◽

Microbial Biomass Carbon ◽

Nitrification Inhibitor ◽

Carbon Accumulation ◽

Nitrification Inhibitors ◽

Above Ground Biomass ◽

Carbon And Nitrogen ◽

Ground Biomass

Stabilized fertilizers that contain nitrification inhibitors and/or urease inhibitors are widely used in China. A pot experiment was conducted to analyze soil enzymatic characteristics related to carbon and nitrogen turnover and metabolism under the use of rice straw and stabilized fertilizer. Results showed that stabilized fertilizer exhibited the highest yield production, panicle numbers, and above-ground biomass. Compared with urea treatment with straw, adding inhibitors reduced soil organic carbon and the enzyme activity related to acquisition of carbon, but increased soil organic carbon accumulation, rice yield, and above-ground biomass. Stabilized fertilizer increased protease activity; however, it decreased N-acetyl-β-glucosaminide. Addition of straw significantly increased dissolved organic and microbial biomass carbon or nitrogen, as well as the enzyme activities of α-D-glucosidase, β-D-glucosidase, β-N-acetyl-glucosidase, and cellulase at the seedling and tillering stages. The principal components analysis showed that the synthesis of extracellular enzyme related to carbon and nitrogen acquiring act as a proxy for straw decomposing under nitrogen conditions. The combination delayed the release of ammonia, which affected the carbon and nitrogen coupling by microbial organisms. These results demonstrated a relationship between soil carbon and nitrogen dynamics and soil enzymes in different fertilization management.

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