A spatial analysis of lateral and vertical fluxes of water associated with a perched watertable in a duplex soil

Soil Research ◽  
2000 ◽  
Vol 38 (4) ◽  
pp. 879 ◽  
Author(s):  
J. Eastham ◽  
P. J. Gregory ◽  
D. R. Williamson
Keyword(s):  
Spatial Analysis ◽  
Water Movement ◽  
Soil Surface ◽  
Vertical Movement ◽  
Climatic Conditions ◽  
Clay Layer ◽  
Lateral Movement ◽  
Vertical Fluxes ◽  
Heavy Clay ◽  
Experimental Plots

Rates of lateral and vertical movement of water were investigated when severe waterlogging occurred as a result of a perched watertable over a clay subsoil in a duplex soil on a low (1.6%) slope in Western Australia. The severity of waterlogging and both the lateral and vertical fluxes of water at the 1.4 ha site were very spatially variable. Lateral water movement occurred in response to topographical gradients in the soil surface and the depth of the clay layer. As a result of this lateral redistribution of water, the depth of the watertable was greater in some areas, causing higher rates of vertical water loss (1.6–1.7 mm/day) compared with the rest of the site (1.2–1.5 mm/day). Net gains or losses in water in experimental plots at the site due to lateral flow were 1–2 orders of magnitude smaller than vertical losses. Net lateral losses were less than 0.3 mm/day, but vertical losses ranged from 1.2 to 1.7 mm/day. We conclude that vertical drainage beneath crops growing on a duplex soil with a heavy clay subsoil can be significant when a head of water develops under climatic conditions conducive to waterlogging. In contrast, net lateral movement was generally small because of the low slope at the site (gradient of 0.016), and is likely to be insignificant at this site and other sites with duplex soils on similarly low slopes.

scholarly journals An Integrated Approach Using Spatial Analysis to Study the Risk Factors for Leishmaniasis in Area of Recent Transmission

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Júlia Alves Menezes ◽  
Eduardo de Castro Ferreira ◽  
José Dilermando Andrade-Filho ◽  
Alessandra Mara de Sousa ◽  
Mayron Henrique Gomes Morais ◽  
...  
Keyword(s):  
Spatial Analysis ◽  
Integrated Approach ◽  
Climatic Conditions ◽  
Sand Fly ◽  
Leishmania Braziliensis ◽  
Lutzomyia Longipalpis ◽  
Recent Transmission ◽  
Current Transmission ◽  
Canine Infection ◽  
The City

Some epidemiological aspects of leishmaniasis in the municipality of Formiga, Brazil, an important touristic site, were evaluated. Those included phlebotomine sand fly vectors, canine infection, and geoprocessing analysis for determining critical transmission areas. Sand flies (224 insects) belonging to ten different species were captured. The most captured species includedLutzomyia longipalpis(35.3%),Lutzomyia cortelezzii(33.5%), andLutzomyia whitmani(18.3%). A significant correlation between sand fly densities and climatic conditions was detected. Serological diagnosis (DPP and ELISA) was performed in 570 dogs indicating a prevalence of 5.8%. After sequencing the main species circulating in the area wereLeishmania infantumandLeishmania braziliensis. Spatial analysis demonstrated that vegetation and hydrography may be related to sand fly distribution and infected dogs. The municipality of Formiga has proven leishmaniasis vectors and infected dogs indicating the circulation of the parasite in the city. Correlation of those data with environmental and human cases has identified the critical areas for control interventions (south, northeast, and northwest). In conclusion, there is current transmission of visceral and canine human cases and the city is on the risk for the appearance of cutaneous cases.

scholarly journals Integrating forest-pasture: Spatial analysis and delineation of zones of litter production and nutrient return

2015 ◽  
Vol 36 (6Supl2) ◽  
pp. 4377
Author(s):  
Sabino Pereira da Silva Neto ◽  
Antonio Clementino dos Santos ◽  
Raimundo Laerton de Lima Leite ◽  
José Expedito Cavalcante da Silva ◽  
Durval Nolasco Neves Neto ◽  
...  
Keyword(s):  
Spatial Analysis ◽  
Treatment Plant ◽  
Principal Component ◽  
Soil Surface ◽  
Plant Litter ◽  
Litter Production ◽  
Nutrient Accumulation ◽  
Nutrient Return ◽  
Forest Strata ◽  
Equidistant Points

This study aimed to quantify, describe, and identify plant litter production and nutrient accumulation zones in different forest-pasture integration (FPI) systems and forest strata of the Cerrado-Amazon transition on typical orthic Quartzarenic Neosol using spatial analysis, principal component analysis, and non-hierarchical fuzzy k-mean clustering logic techniques. The evaluations were performed at two FPI systems comprising a combination of Brachiaria brizantha cv. Marandu and thinned native vegetation with 50 and 75% (FPI-I and FPI-II, respectively) shade in an original thinned forest (NFI) and in an original intact forest (NF-II) with 80 and 95% shade, respectively. An area of 4,000 m² (40 x 100 m) that contained 32 sampling points arranged in a 4 x 25 m grid was demarcated for each treatment. Plant litter was collected using 32 collectors installed at equidistant points. Twelve nylon bags were placed on the soil surface at each point to evaluate the plant litter decomposition, totaling 384 bags per treatment. It was possible to quantify, describe, and define plant litter production and nutrient accumulation zones in different FPI systems and forest strata of the Cerrado-Amazon transition on orthic Quartzarenic Neosol using geostatistical analysis, principal components, and non-hierarchical fuzzy k-mean clustering logic procedures.

Ethylene: A Witchweed Seed Germination Stimulant

Weed Science ◽  
1975 ◽  
Vol 23 (5) ◽  
pp. 433-436 ◽  
Author(s):  
Robert E. Eplee
Keyword(s):  
United States ◽  
Seed Germination ◽  
Clay Soil ◽  
Soil Surface ◽  
Field Studies ◽  
The United States ◽  
Major Contributor ◽  
Single Treatment ◽  
Striga Asiatica ◽  
Heavy Clay

Ethylene gas (C2H4) was found to stimulate the germination of witchweed [Striga asiatica(L.) O. Kuntze] seeds. Ethylene diffuses greater than 120 cm horizontally from point of injection and more than 90 cm below the soil surface. Rates of 0.42 kg/ha induced germination of witchweed seeds in sandy soil; but 1.1 kg/ha is required on a heavy clay soil. Witchweed seeds respond to ethylene after a period of preconditioning that is necessary to break dormancy. Under field conditions in the Carolinas, maximum response of seeds to ethylene occurs between late April and late July. Field studies indicate a 90% reduction in viable witchweed seeds occurs where a single treatment with ethylene has been applied. The use of ethylene appears now to be a major contributor toward the eventual eradication of witchweed from the United States.

scholarly journals Impacts of ditch cleaning on hydrological processes in a drained peatland forest

2008 ◽  
Vol 5 (1) ◽  
pp. 147-182 ◽  
Author(s):  
H. Koivusalo ◽  
E. Ahti ◽  
A. Laurén ◽  
T. Kokkonen ◽  
T. Karvonen ◽  
...  
Keyword(s):  
Water Balance ◽  
Water Movement ◽  
Soil Surface ◽  
Snow Accumulation ◽  
Forest Growth ◽  
Understorey Vegetation ◽  
Growing Stock ◽  
Network Maintenance ◽  
Stock Volume ◽  
Ditch Cleaning

Abstract. One fourth (5.5 Mha) of forests in Finland are growing on peatlands that have been drained to improve forest growth. Forestry operations such as cuttings and ditch network maintenance in these areas may increase export of suspended solids and nutrients, and deteriorate water quality in receiving lakes and rivers. Mitigation of the deterioration calls for understanding how forest management operations affect peatland hydrology. A process-based simulation model FEMMA was applied to quantify the effects of ditch network maintenance on peatland water balance. The model has separate computation routines for evapotranspiration in tree stand and understorey vegetation, snow accumulation and melt, water movement in unsaturated and saturated soil, and drainage. Hydraulic characteristics of peat, as well as different drainage designs can be parameterised in the model. The model was applied in artificially delineated research catchments in northern Finland, where the ditch network was maintained by cleaning and digging the ditches deeper. The simulation results indicated that ditch cleaning affected the water balance slightly and the effect was dependent on stand characteristics and soil structure. When the growing stock volume was low and poorly conductive soil extended close to the soil surface, ditch cleaning increased evapotranspiration. In stands with a high stock volume and a thick topmost layer of highly conductive soil, evapotranspiration was less affected. In the study catchments, the effect of ditch cleaning on runoff was small compared to the error between measured and modelled runoff.

scholarly journals Impact of skidder and high-lead system logging on forest soils and advanced regeneration

2012 ◽  
Vol 49 (No. 6) ◽  
pp. 273-280 ◽  
Author(s):  
M. Modrý ◽  
D. Hubený
Keyword(s):  
Czech Republic ◽  
Forest Ecosystem ◽  
Natural Regeneration ◽  
Soil Surface ◽  
Beech Forest ◽  
Climatic Conditions ◽  
Lead System ◽  
The Impact ◽  
High Lead ◽  
Stand Conditions

The applied skidding technology strongly influences the impact of harvest on the ecosystem and success of natural regeneration. The impact of skidder SLKT 81 and high-lead system Larix 3T on forest soil and natural regeneration was compared under analogical site and stand conditions in a production beech forest in the environs of Brno, Czech Republic. The skidder was found to have greater effects on the soil surface consistency, soil properties and natural regeneration than the high-lead system operations. Although high-lead system operations are more friendly to all parts of forest ecosystem, the skidder may not cause excessive damage when applied under suitable terrain and climatic conditions.

scholarly journals Predicted Infiltration for Sodic/Saline Soils from Reclaimed Coastal Areas: Sensitivity to Model Parameters

2014 ◽  
Vol 2014 ◽  
pp. 1-12
Author(s):  
Dongdong Liu ◽  
Dongli She ◽  
Shuang’en Yu ◽  
Guangcheng Shao ◽  
Dan Chen
Keyword(s):  
Water Movement ◽  
Soil Surface ◽  
Coastal Areas ◽  
Model Parameters ◽  
Wetting Front ◽  
Sodic Soils ◽  
Infiltration Process ◽  
Infiltration Model ◽  
Soil Physical Quality ◽  
Cumulative Infiltration

This study was conducted to assess the influences of soil surface conditions and initial soil water content on water movement in unsaturated sodic soils of reclaimed coastal areas. Data was collected from column experiments in which two soils from a Chinese coastal area reclaimed in 2007 (Soil A, saline) and 1960 (Soil B, nonsaline) were used, with bulk densities of 1.4 or 1.5 g/cm3. A 1D-infiltration model was created using a finite difference method and its sensitivity to hydraulic related parameters was tested. The model well simulated the measured data. The results revealed that soil compaction notably affected the water retention of both soils. Model simulations showed that increasing the ponded water depth had little effect on the infiltration process, since the increases in cumulative infiltration and wetting front advancement rate were small. However, the wetting front advancement rate increased and the cumulative infiltration decreased to a greater extent whenθ0was increased. Soil physical quality was described better by theSparameter than by the saturated hydraulic conductivity since the latter was also affected by the physical chemical effects on clay swelling occurring in the presence of different levels of electrolytes in the soil solutions of the two soils.

Evaluation of the potential to dispose of sewage-sludge. 1. Soil hydraulic and overland-flow properties of Pinus plantations in Queensland

Soil Research ◽  
1995 ◽  
Vol 33 (6) ◽  
pp. 1041 ◽  
Author(s):  
A Costantini ◽  
RJ Loch ◽  
SF Glanville ◽  
DN Orange
Keyword(s):  
Sewage Sludge ◽  
Ground Water ◽  
Overland Flow ◽  
Water Movement ◽  
Soil Surface ◽  
Water Infiltration ◽  
Podzolic Soils ◽  
Antecedent Conditions ◽  
Ground Water Pollution ◽  
Sludge Application

The studies reported in this paper were designed to evaluate the potential for disposal of sewage sludge in commercial Pinus plantations at Beerburrum, 50 km north of Brisbane. Soil descriptions and measurements of hydraulic properties were made in three soils, covering the range of perceived site suitability for sludge application. Disc permeameters and a rainfall simulator were used to characterize surface infiltration properties both with and without sludge, and ponded rings were used to assess permeability of the upper B horizon. Although surface hydraulic conductivities were potentially high, infiltration into dry soil was reduced by water repellence associated with fungal matting at the soil surface and mycelia extending through the Al horizon. Surface runoff could be generated from dry soils by relatively low intensity rainfall events, and the rate and volume of runoff was not increased by broadcast sludge application. Hydraulic conductivities of the upper Bt horizons in the lateritic and yellow podzolic soils were high, suggesting that persistent perched watertable development was unlikely. However, the presence of bleached A2 horizons and gleyed Bt horizons with prominent mottling in these soils were interpreted as evidence of periodic regional ground-water intrusion. By contrast, hydraulic conductivity in the Bt horizon of the soloth was low, suggesting that locally restricted drainage occurs. Likely pathways of water movement were inferred for three representative soil types in the proposed sludge application project. There is potential for both Hortonian runoff when antecedent conditions are dry, and saturated runoff during prolonged wet periods. Potential off-site pollution could therefore occur if either solids or solutes from the sludge are susceptible to transport. In addition, preferential how paths of water infiltration were demonstrated, and the potential for accelerated water and solute movement to ground watertables was inferred. The studies reported in this, and the second, paper in the series were used to appraise the potential for either surface water or ground water pollution from land-based sludge disposal.

Nitrogen fixation in summer-grown soybean crops and fate of fixed-N over a winter fallow in subtropical sugarcane systems

Soil Research ◽  
2019 ◽  
Vol 57 (8) ◽  
pp. 845
Author(s):  
Lee J. Kearney ◽  
Emma Dutilloy ◽  
Terry J. Rose
Keyword(s):  
Cover Crops ◽  
N2 Fixation ◽  
Cropping Systems ◽  
Soil Surface ◽  
Climatic Conditions ◽  
Peat Soils ◽  
N Losses ◽  
Soybean Residue ◽  
Glycine Max L ◽  
Winter Fallow

Legumes including soybeans (Glycine max L.) can provide substantial nitrogen (N) inputs into cropping systems when grown as a part of a rotation. However, in the wet subtropics where land is fallowed for 4–6 months after soybean crops before planting of sugarcane (Saccharum L. spp. hybrids), climatic conditions over winter can be conducive to rapid mineralisation of N from residues with consequent N losses through nitrate leaching or denitrification processes. Using 15N natural abundance methodology, we estimated N2 fixation in 12 summer-grown soybean crops in the Australian wet subtropics, and tracked the fate of soybean residue-N from brown manure crops (residue from plants at late pod-filling left on the soil surface) using 15N-labelled residue in three of these fields over the winter fallow period. Disregarding two poor crops, N2 fixation ranged from 100–290 kg N ha–1 in shoots at mid pod-filling, equating to 170–468 kg N ha–1 including estimated root N contributions. Following the winter fallow, 61 and 68% of soybean residue-N was recovered in clay and peat soils respectively, to 0.9 m depth at one location (Coraki) but only 55% of residue-N could be accounted for to 0.9 m depth in a sandy soil at another location (Ballina). In addition, around 20% of the recovered 15N at this site was located at 0.3–0.6 m depth in the soil profile. Our results indicate that substantial loss of soybean residue-N can occur during winter fallows in the wet subtropics, suggesting that winter cover crops may be necessary to retain N in fields and minimise losses to the environment.

The transport of water through heavy clay soils. II

1936 ◽  
Vol 26 (1) ◽  
pp. 128-141 ◽  
Author(s):  
H. H. Nicholson ◽  
E. C. Childs
Keyword(s):  
Water Movement ◽  
Diffusion Theory ◽  
Preceding Paper ◽  
Numerical Data ◽  
Vertical Column ◽  
Heavy Clay ◽  
The Difference ◽  
Moisture Profiles ◽  
Water Contents ◽  
Rate Of Movement

In a preceding paper(1) were deduced some of the consequences of assuming that water movement in a heavy clay soil is a process akin to diffusion. The only idealisation of the medium was the assumption that the ratio of k, the diffusion coefficient, to σ, the apparent specific gravity of the dry matter in the soil, is constant, independent of depth, and we shall see that this is justified by the experimental evidence. As long ago as 1907, Buckingham(2) showed that the quantity of moisture moving in a given time from a block of wet soil to a drier block in contact with it was dependent mainly on the difference between the respective water contents, and that there was no definite dependence on the actual water contents themselves. Veihmeyer(3), in 1927, placed blocks of wet soil between blocks of drier soil, arranged in a vertical column. Subsequent moisture profiles were typical of a redistribution obeying diffusion laws, and were nearly the same both for upward and downward movement. He demonstrated furthermore that the movement of the water in these conditions was extremely slow, and that the rate of movement was related to the difference in moisture content between the dry and wet soil. Unfortunately insufficient numerical data were given to apply diffusion theory to Veihmeyer's experimental results.

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