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Greenhouse gases fluxes and soil thermal properties in a pasture in central Missouri

Journal of Environmental Sciences 2010年第7期22卷 1029-1039页

作者： nsalambi vakanda nkongolo Shane Johnson Kent Schmidt Frieda Eivazi Department of Agriculture and Environmental Sciences College of Agriculture and Natural Science Lincoln University Harvard Forest Faculty of Arts and Sciences Harvard University

Fluctuations of greenhouse gases emissions and soil properties occur at short spatial and temporal scales, however, results are often reported for larger scales studies. We monitored CO2, CH4, and N2O fluxes and soil temperature （T）, thermal conductivity （K）, resistivity （R） and thermal diffusivity （D） from 2004 to 2006 in a pasture. Soil air samples for determination of CO2, CH4 and N2O concentrations were collected from static and vented chambers and analyzed within two hours of collection with a gas chromatograph. T, K, R and D were measured in-situ using a KD2 probe. Soil samples were also taken for measurements of soil chemical and physical properties. The pasture acted as a sink in 2004, a source in 2005 and again a sink of CH4 in 2006. CO2 and CH4 were highest, but N2O as well as T, K and D were lowest in 2004. Only K was correlated with C02 in 2004 while T correlated with both N2O （r = 0.76, p = 0.0001） and CO2 （r = 0.88, p = 0.0001） in 2005. In 2006, all gases fluxes were significantly correlated with T, K and R when the data for the entire year were considered. However, an in-depth examination of the data revealed the existence of month-to-month shifts, lack of correlation and differing spatial structures. These results stress the need for further studies on the relationship between soil properties and gases fluxes. K and R offer a promise as potential controlling factors for greenhouse gases fluxes in this pasture.

关键词： greenhouse gases soil thermal properties fluxes

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Soil Hydraulic Properties： Influence of Tillage and Cover Crops

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Pedosphere 2018年第3期28卷 430-442页

作者： Samuel I. HARUNA Stephen H. ANDERSON nsalambi V. nkongolo Syaharudin ZAIBON School of Agriculture College of Basic and Applied Sciences Middle Tennessee State University 1301 East Main Street Murfreesboro TN 37132-0001( USA) Department of Soil Environmental and Atmospheric Sciences 302 Anheuser-Busch Natural Resources Building University of Mis-souri Columbia MO 65211-0001( USA) Institut Facultaire des Sciences Agronomiques (IFA-Yangambi) Boite Postale Kisangani 1232( Democratic Republic of Congo) Department of Land Management Faculty of Agriculture University Putra Malaysia 43400 Serdang Selangor Malaysia

Understanding the effects of cover crops and tillage on soil physical properties is important for determining soil productivity. This study was conducted at Lincoln University＇s Freeman Center, USA to evaluate the effects of tillage and cover crop management on soil hydraulic properties. The field site included three replicate blocks in a randomized complete block design with each plot measuring 21.3 m in length and 12.2 m in width. Treatment factors were tillage at two levels （moldboard plow tillage vs. no tillage） and cover crop at two levels （cereal rye （Secale cereal） cover crop vs. no cover crop）. Soil samples were collected in late spring/early summer from each treatment at 10-cm depth increments from the soil surface to a depth of 40 cm using cores （76.2-mm diameter and 76.2-mm length）. Soil bulk density was 13% lower with tillage compared with no-tillage. Volumetric water content was significantly higher at 0.0 and -0.4 kPa pressures with tillage compared with no tillage. Tillage increased the proportion of coarse mesopores by 32gc compared with no tillage, resulting in 87% higher saturated hydraulic conductivity （Ksat）. Cover crop increased the proportion of macropores by 24~ compared with no cover crop; this can potentially increase water infiltration and reduce runoff. As a result of higher macroporosity, Ksat was higher under cover crop compared with no cover crop. This study demonstrated that tillage can benefit soil hydraulic properties in the short term, but these effects may not persist over time. Cover crops may slightly improve soil hydraulic properties, but longer term studies are needed to evaluate the long-term effects.

关键词： pore size distribution saturated hydraulic conductivity soil bulk density soil water retention volumetric water content

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Utilisation du système d’information géographique et modèle numérique de terrain dans l’analyse des caractéristiques hydro-morphométriques des sous-bassins versants de la rivière Tshopo,République démocratique du Congo Use of Geographic Information System and Digital Elevation Model to Analyze the Hydro-Morphometric Characteristics of the Tshopo River Sub-Catchments,Democratic Republic of Congo

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Revue Internationale de Géomatique 2023年第1期32卷 99-122页

作者： Faidance Mashauri Mokili Mbuluyo nsalambi nkongolo Département de Géologie Facultédes Sciences et TechnologiesUniversitéde l’UéléIsiroBP 670République démocratique du Congo Département de Sciences du Sol et de l’Eau Institut Facultaire des Sciences Agronomiques(IFA)de YangambiKisanganiBP 1232République démocratique du Congo Département de Géologie Facultédes Sciences et TechnologiesUniversitéde KisanganiKisanganiBP 2012République démocratique du Congo Geographic Information Technology Program School of ScienceNavajo Technical UniversityCrownpointNew MexicoUSA

The analysis and quantification of hydro-morphometric characteristics are essential for better management of water resources and more effective planning of hydroelectric projects in the Tshopo ***,few studies have been carried out to assess these characteristics at the scale of this *** methodological approach consists of using Geographic Information System(GIS)software analysis tools applied to the Digital Elevation Model(DEM)derived from the Advanced Land Observing Satellite(ALOS)World 3D-30m *** enabled us to automatically extract the hydrographic network and generate the Tshopo *** results of this analysis show that the Tshopo catchment area is of the order of magnitude 7.A total of 8 sub-watersheds were identified,covering an area of around 19,335 *** are elongated in shape,with a coefficient of compactness(KG)of between 1.84 and *** slopes are low,ranging from 0.84%to 3.58%.Run-off velocity is generally low,with a velocity range(Ve)of 2.3 to 4.79 km/*** duration of run-off concentration(Tc)varies between 30.2 and 70.2 h in the tributaries of the *** hydrographic network is dense,with drainage densities(Dd)ranging from 0.91 to 1.72 km/*** watercourses form a homogeneous dendritic network,but with local *** some places,the network can take on a parallel or rectangular shape.

关键词： Morphometry DEM GIS hypsometry hydrographic network sub-catchments Tshopo river

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Influence des paramètres hydro-morphométriques sur l’écoulement des eaux des sous-bassins versants de la Tshopo,République démocratique du Congo Influence of Hydro-Morphometric Parameters on Water Flow in the Tshopo Sub-Catchments,Democratic Republic of Congo

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Revue Internationale de Géomatique 2023年第1期32卷 79-98页

The most characteristic hydro-morphometric parameters controlling water flow in the Tshopo catchment have not yet been *** analysis,multiple linear regression and hierarchical ascending classification were applied to all the data in order to identify the most characteristic variables that significantly influence water flow velocity,and to group together physically similar *** results highlight the importance of topography on water *** topographical variables,namely median altitude(H50),overall gradient(Dg)and specific gradient(Ds),have a significant influence(p-value≤0.05)on surface water flow velocity(Ve)in the Tshopo *** opposing groups(G1 and G2)of sub-catchments were identified,on the one hand the sub-catchments belonging to the upper and middle course of the Tshopo(SBV1,SBV2,SBV3 and SBV5)and on the other the sub-catchments of the lower course(SBV6,SBV7 and SBV8).The first group is characterized by moderate relief(Ds ranging from 53.19 to 73.6 m),while the second group has low relief(Ds ranging from 18.1 to 29.43 m).

关键词： Hydro-morphometric parameters correlation analysis multiple linear regression hierarchical ascending classification sub-catchments Tshopo river

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