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F J P M Kwaad - One of the best experts on this subject based on the ideXlab platform.
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Saturation Overland Flow on Loess Soils in the Netherlands
Modelling Soil Erosion by Water, 1998Co-Authors: F J P M KwaadAbstract:Evidence of saturation overland flow in Dutch South Limburg is discussed. Besides Horton overland flow saturation overland flow may be a cause of rainfall-induced accelerated erosion, which has not been given due consideration in the area so far. Implications for soil erosion modelling and soil conservation are: (1) that a soil erosion model should have a saturation overland flow module, and (2) that soil conservation measures that only protect the soil surface will have little or no effect on soil loss caused by saturation overland flow.
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soil conservation and maize cropping systems on sloping Loess Soils in the netherlands
Soil & Tillage Research, 1998Co-Authors: F J P M Kwaad, M Van Der Zijp, P M Van DijkAbstract:During the last three decades, damage by rainfall induced accelerated erosion with associated off-site effects (flooding, sedimentation), has increased in Dutch South-Limbourg. Damage affects a hilly area with 40,000 ha of Loess Soils. In 1985, a plot study started to evaluate the effects of various conservation cropping systems of fodder maize on runoff, erosion and crop yield under natural and simulated rainfall. In this paper, 1992 and 1993 results are presented. It can be concluded that (a) conservation cropping systems are much more effective in reducing soil loss than runoff on a plot scale and (b) a surface mulch of straw was the most effective measure to reduce runoff and erosion, by 46.5 and 89.5% respectively, compared with the conventional system.
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runoff generation and soil erosion in small agricultural catchments with Loess derived Soils
Hydrological Processes, 1996Co-Authors: P M Van Dijk, F J P M KwaadAbstract:Over a two-year period, rainfall, runoff and sediment output were measured in six small agricultural catchments (3-10 ha) in south Limburg (The Netherlands). These measurements were needed for validation of an erosion model for South Limburg (LISEM). In this paper, results of the measurements are presented and processes that determine surface runoff and sediment yield during winter and summer rainfall are identified. Before the start of the measurement programme, surface slaking and crust formation on the erodible Loess Soils were thought to be the main cause of overland flow and soil erosion in South Limburg. This was the starting point for soil conservation measures in the area. The measurement results discussed in this paper show that in some catchments much runoff occurred in winter and that soil moisture storage capacity may be just as important for runoff generation as infiltration capacity. Therefore, when modelling soil erosion and optimizing erosion control measures for South Limburg, runoff generation through Hortonian as well as through saturation overland flow must be considered.
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summer and winter regimes of runoff generation and soil erosion on cultivated Loess Soils the netherlands
Earth Surface Processes and Landforms, 1991Co-Authors: F J P M KwaadAbstract:Monthly runoff and soil loss data of three fallow experimental plots are presented, comprising a summer and following winter season. The fallow plots were only tilled once, at the end of April. Summer runoff appeared to be controlled by rainfall intensity and conforms to the Horton model of overland flow generation. Winter runoff was primarily controlled by rainfall amount and conforms to the saturation or storage control model of runoff generation. Summer runoff volume was one fourth of winter runoff volume. Summer soil loss was twice as high as winter soil loss and was caused by high intensity, high energy rainfall. Winter soil loss was due to detachment limited erosion, caused by low intensity, low energy rainfall. Mean sediment concentration of winter runoff was one seventh of that of summer runoff. Implications for runoff and erosion of climatic change, involving increased rainfall amounts or intensities in summer or winter, are given.
Jorg Richter - One of the best experts on this subject based on the ideXlab platform.
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in situ comparisons of ammonia volatilization from n fertilizers in chinese Loess Soils
Nutrient Cycling in Agroecosystems, 2002Co-Authors: Marco Roelcke, Xiaohong Tian, Y J Gao, Jorg RichterAbstract:Ammonia volatilization loss from mineral N fertilizers was determined on a calcareous Chinese Loess soil with a pH (CaCl2) of 7.7. An original in situ method that required no electricity or laboratory analyses was used. By means of a bellows pump, ambient air was drawn through four conical cups placed onto the soil (total area 400 cm2) and subsequently through an NH3-specific detector tube with direct colorimetric indication of the ammonia concentration (measuring range, 0.05–700 vol.-ppm NH3). Duration of measurement was about 3 min. Following N fertilization to winter wheat in 1990 and to summer maize in 1991, the application methods surface broadcast, uniform incorporation into the 0–15-cm layer, and for maize, a point placement at 10 cm depth were investigated. Ammonium bicarbonate and urea were applied at rates of 100 and 200 kg N ha−1. In the autumn of 1990, ammonia losses following NH4HCO3 application were more than twice as large as with urea, fertilizer incorporation reduced NH3 losses 15-fold, and doubling the nitrogen application rate resulted in a 1.7-fold increase in the percentage of nitrogen loss. Cumulative ammonia fluxes were about 2 times higher in the summer of 1991. Comparing application methods in summer, losses were significantly (3 times) lower only with point placement. The above differences were all significant at the P<0.05 level. Due to the very low air exchange rate (0.9 volumes min−1), actual volatilization rates were underestimated by this method. Though not yielding absolute amounts, the Drager-Tube method proved very suitable for comparing relative differences in ammonia fluxes. The measurements clearly reflected the characteristic flux patterns for the different treatments and the effects of environmental factors on their time course.
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the effect of fertilizer placement on nitrogen uptake and yield of wheat and maize in chinese Loess Soils
Nutrient Cycling in Agroecosystems, 1996Co-Authors: R M Rees, Marco Roelcke, X Q Wang, E A Stockdale, Iain P Mctaggart, K A Smith, Jorg RichterAbstract:Field trials were carried out to study the fate of15N-labelled urea applied to summer maize and winter wheat in Loess Soils in Shaanxi Province, north-west China. In the maize experiment, nitrogen was applied at rates of 0 or 210 kg N ha−1, either as a surface application, mixed uniformly with the top 0.15 m of soil, or placed in holes 0.1 m deep adjacent to each plant and then covered with soil. In the wheat experiment, nitrogen was applied at rates of 0, 75 or 150 kg N ha−1, either to the surface, or incorporated by mixing with the top 0.15 m, or placed in a band at 0.15 m depth. Measurements were made of crop N uptake, residual fertilizer N and soil mineral N. The total above-ground dry matter yield of maize varied between 7.6 and 11.9 t ha−1. The crop recovery of fertilizer N following point placement was 25% of that applied, which was higher than that from the surface application (18%) or incorporation by mixing (18%). The total grain yield of wheat varied between 4.3 and 4.7 t ha−1. In the surface applications, the recovery of fertilizer-derived nitrogen (25%) was considerably lower than that from the mixing treatments and banded placements (33 and 36%). The fertilizer N application rate had a significant effect on grain and total dry matter yield, as well as on total N uptake and grain N contents. The main mechanism for loss of N appeared to be by ammonia volatilization, rather than leaching. High mineral N concentrations remained in the soil at harvest, following both crops, demonstrating a potential for significant reductions in N application rates without associated loss in yield.
Hui Chen - One of the best experts on this subject based on the ideXlab platform.
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Sorption kinetics of naphthalene and phenanthrene in Loess Soils
Environmental Geology, 2004Co-Authors: Hui Chen, Huiying Zhan, Kun Zhu, Ronny BerndtssonAbstract:A laboratory study was executed to investigate the effect of surfactants to enhance sorption of polycyclic aromatic hydrocarbon (PAH) contaminants in Loess soil. Phenanthrene and naphthalene were chosen as organic contaminant indicators in Loess soil modified by the cation surfactant hexadecyltrimethylammonium (HDTMA) bromide. The kinetic behavior of sorption during transport in natural and modified Loess soil was studied. The results indicated that sorption rate in the cation surfactant modified Loess Soils was at least 3 times faster than that of the natural soil. A first-order kinetics model fitted the sorption data well for both Soils. The sorption rates of the two organic compounds were related to their primary residual quantity on the Soils. The experiments showed that sorption amounts approached constant values approximately within 30 and 90 min for naphthalene and phenanthrene at 298–318 K, respectively. The rate constants, however, displayed negative correlation with increasing temperature. With changing temperature, the activation energy was calculated at −6.196–1.172 kJ/mol for naphthalene and −28.86–15.70 kJ/mol for phenanthrene at 298–318 K. The results can be used to predict the sorption kinetics of phenanthrene and naphthalene in Loess Soils, and in a wider perspective, be used to better understand the transport of petroleum contaminants in the soil environment.
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Attenuating toluene mobility in Loess soil modified with anion-cation surfactants.
Journal of hazardous materials, 2002Co-Authors: Hui Chen, Kun Zhu, Ruiqiang Yang, Wenjun Zhou, Mei JiangAbstract:Soils, subSoils, and aquifer materials can be modified with hydrophobic cationic surfactants to increase their sorption capabilities for organic contaminants. The objective of this study was to examine in detail the sorptive characteristics of the natural Loess soil and the resultant organo-modified Soils for aqueous-phase neutral organic compounds (NOCs) in an attempt to define the operative sorptive mechanisms. Under the laboratory conditions, a series of modified Loess Soils in this study were prepared by replacing the cations of Loess soil with both cationic surfactant hexadecyltrimethylammonium bromide (HDTMA-Br) and anionic surfactant sodium dodethylbenzene sulfonate (SDBS). Toluene was selected as an indicator to study the sorption behavior of the NOCs in Loess Soils. The sorption isotherms of toluene in soil samples obtained using the batch equilibration method. The results indicated that natural Loess had a poor sorption capability for NOCs, and sorption isotherms of toluene appeared likely nonlinear and fit the Freundlich equation very well. When the Soils were coated with large alkyl surfactants such as HDTMA-Br, sorption isotherms correspondingly became linear and the sorptive capability was prominently dependent on the quantity of hexadecyltrimethylammonium (HDTMA) and SDBS added into the Soils. The study could provide an essential basis on attenuation of organic contaminants in the subsurface environment.
A. M. Dzagov - One of the best experts on this subject based on the ideXlab platform.
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determination of characteristics of the proneness of Loess Soils to slump type settlement
Soil Mechanics and Foundation Engineering, 2009Co-Authors: A. M. DzagovAbstract:Various approaches to assessment of the relative proneness of soil to Slump-type settlement is examined. In deformation calculations, it is proposed to use the structural strength of the wetted soil in lieu of the pressure initiating slump-type settlement. It is emphasized that the relative proneness of soil to slump-type settlement should be determined under conditions whereby it is wetted with water or solutions corresponding in terms of temperature and chemical composition to the liquid circulating in utilities laid for the entity.
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On the Stress State of the Foundation Bed during Installation and Loading of a Pile Cast in a Hole Predrilled in Clayey Soils
Soil Mechanics and Foundation Engineering, 2002Co-Authors: A. M. Dzagov, V. F. SidorchukAbstract:Results are presented for field investigations of the stress state of the shaft of a cast-in-place pile and the surrounding soil mass in stages of the pile's installation, and its static loading in Loess Soils with the natural moisture content. Data indicating that the soil mass functions preferentially in an elastic state both during pile fabrication, and its vertical loading are obtained.
Daniel Eduardo Buschiazzo - One of the best experts on this subject based on the ideXlab platform.
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Degradation of the soil surface roughness by rainfall in two Loess Soils
Geoderma, 2011Co-Authors: Laura Andrea De Oro, Daniel Eduardo BuschiazzoAbstract:Abstract The soil surface roughness is one of the main factors affecting wind erosion. Little is known about the influence of rains on the degradation rate of the soil surface roughness in different tillage systems and soil types. The purpose of this paper was to evaluate the dynamics of the oriented (Kr) and the random (Crr) soil surface roughness as affected by three tillage tools: a disk tandem (DT), a lister-bedder (LB) and a drill-hoe (DH), and two rain amounts (7 and 28 mm), in two soil types (an Entic Haplustoll and a Typic Ustipsamment). Measured Kr and Crr decay rates were compared with the predicted data, according to the equations provided by the Revised Wind Erosion Equation (RWEQ). Results indicated that initial Kr values were different in each tillage tool in both Soils (LB > DH > DT, p
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clay mineralogy cation exchange capacity and specific surface area of Loess Soils with different volcanic ash contents
Geoderma, 2006Co-Authors: E N Hepper, Daniel Eduardo Buschiazzo, Graciela Gloria Hevia, A M Urioste, L E AntonAbstract:The Loessical Soils of the semiarid Argentinean Pampas (SAP) contain variable amounts of volcanic ashes. Their influence on the mineral composition and some physicochemical properties of Soils like soil specific surface area (SSA) and cation exchange capacity (CEC) have been still not elucidated. Because of that we analyzed 24 topsoil samples (0 to 20 cm) of Soils with high and low volcanic ashes contents for clay mineralogy and its influence on soil chemical and physical properties and CEC and SSA. Results showed that ash enriched Soils were placed to the south and ash free Soils to the north-east of the SAP in agreement with the volcanic ash deposition pattern of 1932 Quizapu vocano eruption. Mineralogy of the clay fraction was dominated by amorphous minerals and less crystallized and expansible smectites in ash enriched Soils, and by illites in ash free Soils. No differences in crystallinity or expansibility were found between montmorillonites of ash free and ash enriched Soils. Fine sized clays (< 0.2 μm) were dominated by illites and illite–montmorillonite intergrades in ash free Soils and by amorphous materials in ash enriched Soils. Such results indicated that montmorillonites tend to form more when volcanic ashes are present but their crystallinity and expansibility do not change with ashes content. SSA was positively related with silt contents in both ash free and ash enriched Soils (r2 = 0.70, p < 0.05). The clay fraction (< 2 μm) explained only 9% of SSA variability and the fine clay fraction (< 0.2 um) did not affect SSA. The influence of silt on SSA was attributed to the existence of 2 : 1 minerals in the silt fraction. These results also indicated that ash contents did not influence SSA. CEC correlated positively with clay (R2 = 0.67, p < 0.001) in ash enriched Soils, and with organic matter in ash free Soils (R2 = 0.837, p < 0.001) but it did not correlate with fine clay contents in any of both soil types. These trends were explained on the basis of the higher CEC conferred by smectites in ash enriched Soils and by OM in ash free Soils. It can be deduced that soil degradation processes producing losses of fine sized particles, like wind or water erosion, will decrease SSA in both the ash enriched and the ash free Soils, but only CEC in ash enriched Soils. Organic matter losses due to excessive cultivation will decrease CEC in ash free Soils.
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wind erosion in Loess Soils of the semiarid argentinian pampas
Soil Science, 1999Co-Authors: Daniel Eduardo Buschiazzo, Ted M Zobeck, Silvia Beatriz AimarAbstract:This study is the first effort to measure wind erosion in the field in South America. Wind erosion of two bare Soils, a loamy sand surface Typic Ustipsamment and a sandy loam surface Entic Haplustoll of the Semiarid Argentinian Pampas, were measured in the field during wind storms that started on June 16 (mean wind speed = 14 km/h; storm duration 103 h) and June 30 (mean wind speed = 21.4 km/h; storm duration 25 h) of 1995. Measurements were made with dust samplers placed at heights of 0.135, 0.54, and 1.47 m within a 1-ha field. Mass flux (amount of eroded material within a given time) was larger in the Ustipsamment Soils than in the Haplustoll Soils in both storms. A maximum amount of transported dust was found within the limits of the studied field (100 x 100 m 2 ) during the June 16 wind storm and outside the studied field during the June 30 wind storm. This was attributed to the variation in wind direction on June 16. The total amount of material eroded from the field during each storm reached 1.82 mt ha -1 in the Ustipsamment and 0.29 mt ha -1 in the Haplustoll on June 16 and 0.98 mt ha -1 in the Ustipsamment and 0.75 mt ha -1 in the Haplustoll on June 30. Wind velocity was high enough to erode the loosened Ustipsamment but not the better structured Haplustoll on June 16. On June 30, wind velocity was high enough to erode both Soils, but a shorter storm duration did not allow the erosion of large amounts of soil.
