Evaluation of Soil Physical Indices Under Different Uses in River Basin (original) (raw)
Related papers
Study of soil physical properties and water infiltration rates in different types of land use
Semina: Ciências Agrárias, 2018
Studying the changes in soil properties caused by different land uses allows measures to be adopted that will reduce the risk of future negative effects. The aim of this study was to evaluate soil physical properties and quantify water infiltration for different types of land use in the Santa Catarina Plateau of southern Brazil. The research was conducted on a 1,200 ha rural property. The land use types selected were natural forest (NF), planted pine (PP), crop-livestock integration (CLI), and burned natural rangeland (BR). A sample survey was carried out in nine different areas for each land use. Samples were collected from four soil layers and the soil bulk density (Bd), total porosity (Tp), and macropore (Ma), micropore (Mi), and biopore (Bio) volumes were measured. Water infiltration tests were performed to obtain the initial (ii) and final (fi) water infiltration rates into the soil, and the total amount of water that had infiltrated the soil (Ti). In NF, Bd was lower and Tp wa...
Bioscience Journal, 2011
The aim of this work was to analyze the spatial distribution of soil compaction and the influence of soil water content on the resistance to penetration. The latter variable was described by the cone index. The soil at the study site was a Nitisol and the cone index data were obtained using a penetrometer. Soil resistance was assessed at 5 different depths, i.e. 0-10 cm, 10-20 cm, 20-30 cm, 30-40 cm and deeper than 40 cm, whereas soil water content was measured at 0-20 cm and 20-40 cm. Soil water conditions varied during the different samplings. Coefficients of variation for cone index ranged from 16.5% to 45.8% while those for soil water content varied from 8.96% to 21.38%. Results suggested a high correlation between soil resistance, as assessed by the cone index, and soil depth. However, the expected relation with soil water content was not observed. Spatial dependence was observed in 31 out of 35 data series, both cone index and soil water content. This structure was fitted to exponential models with nugget effect varying from 0 to 90% of the sill value. Four of the data series showed a random behaviour. Inverse distance technique was used in order to map the distribution of the variables when no spatial structure was observed. Ordinary kriging showed a smoothing of the maps compared to those from inverse distance weighing. Indicator kriging was used to map the cone index spatial distribution for recommendation of further soil management.
Avaliação de índices físicos do solo sob diferentes usos em uma bacia hidrográfica
2018
The present study aimed to analyze the changes in the physical properties of the soil under different uses in a watershed. The undisturbed soil samples were collected in 26 different locations and analyzed at the Federal University of Santa Maria, RS – Campus Frederico Westphalen, following the methodologies proposed by Klein (2008) and Embrapa (1997). The penetrometer Penetrolog 1020 was used to determine the Penetration Resistance (PR). The PR values range from 2752 (pasture soil) to 9612 kPa (native forest soil). Regarding the physical parameters, the Permanent Wilting Point (PWP) parameter shows that soils occupied by rice cultivation, urban occupation, pasture and native feld presented a higher influence on this parameter (higher mean values). The soils occupied by soybean cultivation and native forest have not shown a signifcant difference between them per this parameter. The other parameters didn’t show a signifcant difference for the utilized test. The PWP parameter shows a posit...
Soil hydraulic properties as related to soil structure
Soil structure is one of the main attributes of soil quality. It influences the soil pore system and through it all parameters of equations describing the transport processes in soil. Soil pore size distribution is either log-normal, or the log-normal distribution is an acceptable approximation. Kosugi [Water Resour. Res. 30 (1994) 891] has applied the log-normal distribution to data on the soil water retention curve and has replaced the empirical equation by the physically-based model. Log-normal pore size distributions were used for the estimation of the unsaturated hydraulic conductivity function. This paper deals with the application of Kosugi's model to the description of the retention curve and of the unsaturated conductivity function in soils exhibiting a bimodal distribution of pores, typical for all soil horizons having a certain type of structure. The domain of structural pores and the domain of matrix pores are defined in these structured soils. Results from this study show that two hydraulic functions, the retention curve and the unsaturated conductivity are well described by models based on a log-normal distribution of pores in both the structural and the matrix domains of the soil porous system. The exponents a, b defined as parameters of the unsaturated conductivity are different for the structural and matrix domains. It is therefore, assumed that the configuration of soil pores including the tortuosity differs in these domains. The destruction of soil structure changes distinctly the configuration of soil pores which is demonstrated by the change of parameters a, b Consequently, the saturated and unsaturated conductivity is changed, too.
2008
SUMMARY Hydraulic and morphological properties of soils with hardened subsurface plinthite were investigated under three adjacent land use types, which were coconut plantation, continuous arable (maize-soybean rotation) and a pastureland. Apart from the description of soil morphology, measurements carried out included laboratory saturated hydraulic conductivity on the undisturbed soil core samples collected from the field, conductivity of the pan material and field infiltration capacity. The hardened plinthite layer under these adjacent land use types varied with thickness and structural characteristics. Hardened plinthite found under the coconut plantation was a petro-plinthite and spongy in nature, while those found under the arable and pasture management systems were petroferric contact. While the hardened plinthite under the arable land was very compact with unbroken sesquioxide sheet, the pan under the pasture was vesicular and less compact. The thickness of the pan was 0.56m u...
Measurement and Estimation of Soil Water Characteristic Curvefor Four Unsaturated Tropical Soils
2019
Infrastructures are mostly built on unsaturated soil in the tropical region such as Nigeria, yet soil investigations and designs are based on saturated soil mechanics owing to difficulties associated with soil suction measurements using direct methods such as pressure plate extractor, triaxial testing equipment for testing unsaturated soil, etc. Soil water characteristic curve is an important parameter for estimating unsaturated soil property function. This research considered an indirect method (filter paper) of laboratory soil suction measurement (which is relatively simple, fast and inexpensive) and predictive correlation equations for estimating soil water characteristic curve from index properties of soil for four unsaturated tropical soils of Nigeria, three predictive correlation equations were used in this research namely; Navid et al model (2012), Zapata et al model (2000) and Witczak model (2006), the soil water characteristic curve constant parameters computed from these m...
Hydrostructural characteristics of two African tropical soils
European Journal of Soil Science, 2005
This paper describes the characteristic shrinkage curve of a soil as it dries. It also introduces a new method to measure specific soil moisture states such as permanent wilting point and field capacity using the shrinkage curve. The model considers the soil fabric as a non-rigid, aggregated and unsaturated soil water medium. Its functional parameters (defined as pedohydral parameters) are the independent parameters of the shrinkage curve, which defines two major aspects of the structure of the fabric: (i) the volumetric functional elements of the soil fabric, and (ii) the arrangement of solid, water and air as functions of water content. Two African tropical soils were characterized and analysed according to a structural model with parameters of their shrinkage curve. The parameters of four soil horizons for the two soil types were determined continuously along their shrinkage curves. They were then used as descriptive variables representing the soil's hydrostructural behaviour in a canonical variate analysis, the results of which showed the A horizons to be distinct from the lower horizons, which appear as continua down the profiles. Analysis of the results reveals the importance of the clay and of the iron/clay ratio in the hydrostructural properties of the two soils. Transitional points of the shrinkage curve matched well some particular moisture states of the water potential curve, such as wilting points and field capacities. A more precise method of calculating water-holding characteristics and other structural properties such as air capacity and swelling index can be obtained from the characteristic shrinkage curve. peds constitutes the pedostructure. Braudeau et al. (2004a)
Soil Physical Quality of Brazilian Crop Management Systems Evaluated with Aid of Penetrometer
Journal of Agricultural Science, 2016
Crop management affects soil attributes as well as its quality. We evaluated the following soil physical attributes: saturated hydraulic conductivity (K 0), soil resistance (RP) and soil bulk density (BD), in Araras-SP, Brazil. Areas with sugarcane (Saccharum officinarum), soybean (Glycine max), physic nut (Jatropha curcas L.) and native forest presented an increase of soil compaction in the 0.10 m surface layer for the three attributes in a following order: native forest <physic nut < soybean < sugarcane. Significant regressions were obtained for RP × K 0 ; BD × K 0 and BD × RP. Penetrometer measurements were essential to indicate differences among areassugarcane, native forest, physic nut and soybean; but for the measurements of K 0 , only between sugarcane and native forest. RP measurements confirm anthropogenic changes in the soil profile up to the 0.3 m depth. In the "Canarache soil resistance classification" soils showed "low resistance" "without limitations to root development" for native forest and physic nut; "medium resistance" for soybean area with "some limitations to root development" and "high resistance" for sugarcane with "limitations to root development". The use of penetrometers is discussed in relation to the readiness of field measurements.
2009
Site-specific soil hydraulic quality index to describe the essential conditions for the optimum soil water regime. Can. J. Soil Sci. 89: 645Á656. This study was conducted in northeast Thailand (i) to identify soil hydraulic quality (SHQ) factors under four common cropping systems in a specific soil series, (ii) to configure indicators from these factors that can be used to develop SHQ indices for each cropping system, and (iii) to describe the essential conditions for the optimum soil water process in the study area. The cropping systems were (i) maize (Zea mays L.)-maize, (ii) mungbean (Vigna radiate L.)-maize, (iii) maize-fallow and (iv) cassava (Manihot esculenta Crantz). Ten representative farms under each system were used to develop location-specific SHQ indices. Soil hydraulic quality indices were determined for two soil layers, such as the Ap (0Á20 cm) and the EB (20Á65 cm) horizons at each farm. Principal component analysis (PCA) and factor analysis identified eight factors affecting soil hydraulic quality, such as pore size and distribution frequency, water-stable aggregates, aggregate shape and grade, shrinking-swelling, infiltration rate (IR) and percent sand particle for the Ap horizon. Aggregate shape, size and grade, pore distribution frequency, shrinkingswelling, packing density, soil organic matter (SOM), porosity and root density influenced water movement in the sub-soils (EB horizon). A comprehensive SHQ index was developed for both soil layers under each of the cropping systems. The mungbean-maize (Mn-M) system scored the highest total SHQ index (0.726) in topsoil followed by maize-fallow (M-F) (0.708), cassava (C) (0.663) and maize-maize (M-M) (0.623). Finally, SHQ indices were ranked into three distinctive classes under the selected cropping systems, i.e., I-Mn-M; II-M-F and C; and III-MM. The Mn-M system is better compared with the MM in sustaining SHQ due to favorable individual soil parameters such as pore distribution frequency, root density, SOM (2.80%) and IR (494.95 mm h (1). For the rooted subsoil, no significant differences could be identified irrespective of cropping systems. All SHQ indices for sub-soils scored higher index values compared with their respective topsoil scores indicating less deteriorating effect of crop husbandry practices in this layer. Our findings could be used to advance the assessment of valid location-specific SHQ indicators to describe the essential conditions for sustainable soil water processes.
Soil-water resistivity curve of a tropical soil
MATEC web of conferences, 2021
The evaluation of soil-water characteristic curve is one of the most important procedures in the matter of understanding the soil behaviour during wetting and drying processes. Even though it might be carried out by established methods, this practice is considered a time-consuming technique, and because of this it is still under-used in comparison with its potential applications. In this way, this paper aims to analyse the correlation of soil suction and soil resistivity to produce a time-reduced soil-water characteristic curve (SWCC), based on resistivity measured values. To perform this research, it was used a set of soil samples collected from Nova Friburgo, Rio de Janeiro-Brazil. The material was geotechnically characterized by standard methods. To determine the (SWCC), it was used the filter paper method and the volumetric water content/suctions were obtained by wetting and drying stages for two paths that emerged from the field moisture content. The results revealed a remarkable relationship between suction and the resistivity measured data, emphasizing the feasibility of determining the Soil-Water Characteristic Curve by resistivity measurements, here named Soil-Water Resistivity Curve (SWResC).