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Your search keyword '"Pascal Nsengumuremyi"' showing total 3 results
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3 results on '"Pascal Nsengumuremyi"'

1. Effect of Biochar and Straw Application on Nitrous Oxide and Methane Emissions from Eutric Regosols with Different pH in Sichuan Basin: A Mesocosm Study

Author

Tite Ntacyabukura, Ernest Uwiringiyimana, Minghua Zhou, Bowen Zhang, Bo Zhu, Barthelemy Harerimana, Jean de Dieu Nambajimana, Gratien Nsabimana, and Pascal Nsengumuremyi

Subjects
nitrous oxide, methane, soil pH, biochar, maize straw, Meteorology. Climatology, QC851-999
Abstract

Adoption of crop residue amendments has been increasingly recommended as an effective management practice for mitigating greenhouse gas emissions while enhancing soil fertility, thereby increasing crop production. However, the effect of biochar and straw on nitrous oxide (N2O) and methane (CH4) emissions in soils of differing pH remains poorly understood. Three treatments (control (i.e., no amendment), maize straw, and biochar derived from maize straw) were therefore established separately in soils with different pH levels, classified as follows: acidic, neutral, and alkaline. N2O and CH4 were investigated using a static chamber–gas chromatography system during 57 days of a mesocosm study. The results showed that cumulative N2O emissions were significantly higher in acidic soils than in other experimental soils, with the values ranging from 7.48 to 11.3 kg N ha−1, while CH4 fluxes ranged from 0.060 to 0.089 kg C ha−1, with inconclusive results. However, a weak negative correlation was observed between log N2O and log NO3-N in acidic soil with either biochar or straw, while the same parameters with CH4 showed a moderate negative correlation, suggesting a likelihood that these amendments could mitigate GHGs as a result of the NO3-N increase in acidic soils. It is also possible, given the alkaline nature of the biochar, that incorporation had a significant buffer effect on soil acidity, effectively increasing soil pH by >0.5 pH units. Our findings suggest that for the rates of application for biochar and straw used in this study, the magnitude of reductions in the emissions of N2O and CH4 are dependent in part on initial soil pH.

Published
2021
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2. Effect of Rock Fragments on Tracer Transport in Broadleaved and Coniferous Forest Soils: Column Study

Author

Ruxin Yang, Pascal Nsengumuremyi, and Junfang Cui

Subjects
Mass transfer coefficient, Qinghai tibetan plateau, Partition coefficient, Rock fragment, Chemistry, TRACER, Soil water, Soil science, Preferential flow, Tortuosity
Abstract

This study investigated the effect of rock fragments on tracer transport in broadleaved and coniferous forest soils from the 0 - 100 cm depth of Gongga Mountain in eastern margin of Qinghai Tibetan Plateau. Using repacked soil columns (20 cm in height and 10 cm in diameter) with different rock fragments contents (0%, 5%, and 15% in v/v), breakthrough curves of bromide (as non-reactive tracer) were obtained under saturated condition. A two-region model was applied and the parameters were estimated by inverse modeling. Results show that with increasing rock fragment content the dispersivity (λ) generally increased while the mobile-immobile partition coefficient (β) and the mass transfer coefficient (ω) decreased. The presence of rock fragments led to an increase in the fraction of immobile domain as well as soil tortuosity. A plausible explanation is that the soil beneath the rock fragments behaved as immobile domain and soil-rock interfaces could serve as preferential flow paths.

Published
2021
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3. Soil aggregate stability response to hydraulic conditions in water level fluctuation zone of the Three Gorges Reservoir, China

Author

Tite Ntacyabukura, Jinlin Li, Ling Yang, Xiubin He, Ernest Uwiringiyimana, Jean de Dieu Nambajimana, Yuhai Bao, Gratien Nsabimana, and Pascal Nsengumuremyi

Subjects
Aggregate (composite), 010504 meteorology & atmospheric sciences, Soil test, Water level fluctuation, Soil science, 04 agricultural and veterinary sciences, 01 natural sciences, Soil quality, Soil aggregate stability, Soil water, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, Environmental science, Wetting, 0105 earth and related environmental sciences, Earth-Surface Processes, Three gorges
Abstract

Soil aggregate stability is a key indicator of soil quality and susceptibility to water erosion. The water level fluctuation zone (WLFZ) of Three Gorges Reservoir (TGR) experiences hydraulic disturbances induced by rainfall, reservoir wave, and water-level fluctuation. Soil aggregate in this region has a unique mechanism of disintegration different from other terrestrial soils. The traditional methods of soil aggregate stability measurement cannot reveal the complex external factors of the soil in the WLFZ. In the present study, an attempt has been made to establish an approach mimicking the real situation in the WLFZ to deeply understand the effects of water movement and periodical wetting on soil aggregate stability in the WLFZ. The soil samples from different elevations were allowed to stay under wetting and wet-shaking conditions for 3 and 81 min, followed by a quantitative separation of disintegrated aggregates by wet-sieving. The mean differences between wetting and wet-shaking for the mean weight diameter (ΔMWD) were highly significant at all elevations for 81 min. Contrary, both treatments applied within a short time period disintegrated aggregates at the same magnitude. Additional to slaking, the kinetic energy applied to soil has induced a mechanical breakdown as a result of water movement. The difference of aggregate stability index (ASI) was highly significant among the elevations p

Published
2021
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