Soil Hydro-physical Characteristics Research Articles

MINIMUM NUMBER OF POINTS FOR A RELIABLE SOIL WATER RETENTION CURVE USING RICHARDS’ PRESSURE CHAMBER

The soil hydro-physical characteristics are very important for studies about soil water dynamics. The soil water retention curve it is a soil characteristic sometimes expensive and time consuming to be done and could be a problem for farmers. The numbers of points and its tension evaluated are normally choose arbitrarily. This study aimed to define the fewest pairs of soil moisture and water soil potential points which result in a reliable water retention curve in two different soils (sandy and clay). Using different tensions by suction table and Richards’ pressure chamber, nine replications were adjusted by van Genuchten's equation. Curves with 4, 5, 7, 8, 9, 10 and 13 points were studied and the curve with 13 points was adopted as standard. The obtained parameters for different pairs of soil moisture and their corresponding soil water potential were compared to the equivalent standard curve and submitted to analysis of variance (F test), and their values were compared by the Scott-Knott test (5% of probability). The curve with 7 points, using the tensions of 0; 40; 100; 300; 1,000; 5,000 e 15,000 hPa, was the lower number of points that did not showed statistical difference in any parameters of the model and the point with 15,000 hPa shown to be important and should be used on the combination of points to obtain a good adjustment.

Economic assessment of sugarcane pulp as amelioration of soil hydro-physical characteristics, water productivity, and wheat yield

Economic assessment of sugarcane pulp as amelioration of soil hydro-physical characteristics, water productivity, and wheat yield

SOIL HYDRO-PHYSICAL CHARACTERISTICS AFTER MAIZE CULTIVATION INTERCROPPED WITH Urochloa brizantha CULTIVARS

The intercropping of maize with forage plants is a farming technique aimed at producing grains and grazing, with beneficial results for the sustainability of production. Most of the research carried out with maize (Zea mays) intercropped with palisadegrass (Urochloa brizantha) has evaluated the agronomic performance of the crops. Therefore, there is a lack of research on the effects of this technique on the soil hydro-physical characteristics. For this reason, the objective of this study was to evaluate the effects of the cultivation of maize intercropped with U. brizantha on the soil hydro-physical characteristics. The study was conducted in an experimental area at Faculdade Católica of Tocantins, in Palmas/Tocantins, Brazil; using a randomized complete block design, in a 4x2 factorial scheme, with three repetitions. The study comprised four types of intercropping: i) maize with U. brizantha cv. Marandu sown by broadcast; ii) maize with U. brizantha cv. Marandu sown between the maize rows; (iii) maize with U. brizantha cv. Piatã sown by broadcast; iv) maize with U. brizantha cv. Piatã sown between the maize rows; and two implantation periods: v) simultaneous sowing; vi) sowing 20 days after the maize. The hydro-physical properties evaluated were soil density, total soil porosity and soil water holding capacity. There was a significant interaction between the type of intercrop and the sowing time in the soil density and total soil porosity, but no significant differences in soil water holding capacity. Results show that the intercropping of maize with U. brizantha sown simultaneously improves the physical properties of the soil such as density and porosity, in comparison to the U. brizantha implantation 20 days after sowing maize. The intercrop of i) maize with U. brizantha cv. Marandu sown between the maize row and ii) maize with U. brizantha cv. Piatã sown by broadcast between the maize row (in simultaneous sowing) improvedthe soil physical attributes.

The influence of litter on soil hydro-physical characteristics in an area of Acuri palm in the Brazilian Pantanal

The hydraulic properties of the soil surface strongly depend on the physical attributes of the soil and, understanding such hydro-physical soil dynamics is both economically (e.g. recharging of the water table) and ecologically (e.g. maintenance of available moisture for the vegetation) important. The objective of this work was therefore to characterize the hydro-physical characteristics of the soil in an area dominated by Acuri palms in the northern Brazilian Pantanal. Transects of 50m was delimited and two treatments with six replicates were demarcated. In one treatment, soil litter accumulated on the soil was collected monthly during a period of two years. In the other treatment, soil litter was left under natural conditions. Data were collected on: soil density, particle density, total porosity, volumetric humidity, texture, hydraulic conductivity (saturated and unsaturated) and infiltration. Soil density was higher when soil litter was absent, and had deeper layers, greater volumetric moisture and higher total porosity when soil litter was present. Infiltration rate was significantly higher in the absence of litter, probably due to the lower matrix potential when the soil is drier. Significantly, saturated hydraulic conductivity was higher in the litter treatment and had a positive correlation with volumetric moisture (0–5cm depth), indicating that soil water fluxes are enhanced by natural vegetation cover. In contrast, unsaturated hydraulic conductivity was significantly higher in the absence of litter. These results clearly demonstrate that soil litter exerts a strong influence on the hydro-physical characteristics of the soil, improving physical quality leading to greater water flow.

Effect of conservation agriculture on soil hydro-physical properties, total and particulate organic carbon and root morphology in wheat (Triticum aestivum) under rice (Oryza sativa)-wheat system

Short-term (5 years) effect of conservation agriculture (CA) practice on soil hydro-physical characteristics, soil organic carbon status and root morphology in wheat (triticum aestivum L.) was monitored under rice (Orgza sativa L.)-wheat rotation in a clay loam soil at the Indian Agricultural Research Institute, New Delhi. A small improvement in soil water content and a marginal decrease in bulk density by CA contributed in significant reduction (30-37%)in sub-surface compaction. The CA improved soil structure in the plough layer (0-15 cm) with significant increase in soil organic carbon status (27-38%). A marginal change in pore size distribution was recorded in favour of larger volume of retention pores (11-12%), in expense of macro- or drainable pore space. Steady-state infiltration, which was essentially profile-controlled, was therefore lower in the CA plots. Decrease in sub-surface soil strength and better soil water retention facilitated root growth in wheat in the sub-surface layer under CA. Results implied thatthe CA practice in rice-wheat system, although with a shorter period, led to an overall physical improvement of the most active root zone. This had positive impact on root morphology, which contributed to increase in the crop yield.

Ecohydrological functioning of an upland undergoing reclamation on post‐mining landscape of the Athabasca oil sands region, Canada

AbstractEcohydrological functioning of natural Boreal forest in Canada's Boreal Plains is a product of interactions between soil hydrophysical characteristics and hydrogeochemical processes. These interactions create a moisture–nutrient gradient within the surface soils, increasing along low‐relief transitions from upland to riparian zone, and in turn influence the distribution of vegetation communities. It is not yet known if/when analogous ecohydrological functions can be achieved in constructed uplands following industrial disturbance, such as that following oil sands development. Hence, to assess this, we studied interactions between hydrogeochemical processes and vegetation colonization in a constructed upland relative to hydrophysical properties of 2 reclamation cover substrates during a typical continental climate's growing season. Our results indicated that in 3 years of postconstruction, the establishment of a moisture–nutrient gradient that supports vegetation colonization along slope positions was still limited by heterogeneity of cover substrates. Portions of the upland under peat–mineral mix were characterized by lower nutrient availability, high moisture content, and establishment of planted shrubs and trees. In contrast, forest floor materials plots were characterized by poor soil quality, but higher nutrient availability and greater colonization of invasive grasses and native shrubs. We suggest that the colonization of underdeveloped soils by invasive grasses may facilitate pedogenic processes and thus should be accepted by reclamation managers as a successional milestone in the recovery of ecohydrological functioning of constructed uplands. Poor soil structure under forest floor materials could not support edaphic conditions required by plants to efficiently utilize fertilizer, making this practise futile at the early stage of soil development.

Assessment of the SOILWAT model for predicting soil hydro-physical characteristics in three agro-ecological zones in Nigeria

Soil hydro-physical characteristics influence soil nutrients availability and consequently affect crop performance. However, field determination of these properties for effective management of water for irrigation is laborious, time consuming and expensive. Hence, this study was initiated to assess the performance of the SOILWAT model for the estimation of soil hydro-physical properties. A total of 180 disturbed and 120 undisturbed soil samples were collected from three agro-ecological zones (Savannah, Derived savannah and rainforest) in Nigeria. The samples were analyze for hydro-physical and chemical properties. Soil texture and salinity data were varied in the SOILWAT model (Version 6.1.52) to predict soil physical properties for the three agro-ecological zones of Nigeria, respectively. Measured and predicted values of field capacity, permanent wilting point and soil available water were compared using T-test at α.05. The prediction of soil textural class using the SOILWAT model was sufficiently accurate for the three agro-ecological zones. However, bulk density, maximum water holding capacity, permanent wilting point and soil available water showed significant (p < .05) differences between measured and predicted values, and there were positive relationships between SOILWAT values and the observed values. Thus, the SOILWAT model could be adopted for predicting soil texture and permanent wilting point for savannah, derived savannah and rainforest zones of Nigeria. Also, the inclusion of organic matter input, silt adjustment and addition of salinity in the various moisture characteristics relationships and equations could enhance its performance.

Soil hydro-physical characteristics and water retention function of typical shrubbery stands in the Yellow River Delta of China

The shell ridge worldwide that presents a combination of old and new shell ridges is located in the Yellow River Delta of China. The water storage and retention capacities of the shell sand soil are key factors for the growth and development of vegetation and act as important indicators in evaluations of vegetation-related soil and water conservation. We investigated the hydrological and physical characteristics of the soil and the interactions of these characteristics for the following dominant shrubbery stands on the shell ridge: Tamarix chinensis Lour, Periploca sepium Bunge and Ziziphus jujuba var. Spinosa. The different shrubbery stands presented significantly different physical shell sand parameters, such as water storage capacity, permeability and water-holding capacity. Compared with the bare soil, the shrubbery-covered shell sand soils showed significantly reduced bulk densities; increased porosities, water storage capacities, infiltration rates and water-holding capacities; and reduced particle sizes. The shrubbery increased the amount of soil water-stable aggregates and reduced the amount of soil air-dried aggregates, and the fractal dimension of the soil water-stable aggregates was significantly higher than that of the air-dried aggregates. T. chinensis shrub growth yielded a better soil aggregate structure compared with that of Z. jujuba, whereas the P. sepium shrub yielded the poorest structure. The soil porosity and the mean weight diameter of the soil aggregates were the major factors that affected the water retention capability of the shell sand. The best water retention capability was observed with the T. chinensis shrub stand followed by the Z. jujuba and P. sepium stands, whereas the bare soil exhibited the poorest results. Our results indicate that T. chinensis seedlings are the best choice for planting to improve soil porosity and soil aggregates on the shell ridges of the Yellow River Delta.

Soil hydrophysical characteristics in the Nitra river basin (Slovakia): Their monitoring, analysis, online publishing

The paper is focused on the purpose made, or local monitoring of areal unit of the Nitra river basin (Slovakia, Central EU with total area 4501 km 2 ) in order to obtain the inputs on soil, moisture and hydrophysical characteristics of the given area. In this study, there was evaluated the share of individual soil texture classes in the Nitra river basin on the basis of map records and its comparison with the soil samples taken from the 111 selected sites. Soil samples were taken from two depths of soil profile (15-20 cm, 40-45 cm). The sites were chosen according to the percentage representation of individual soil texture classes. Based on the identification of sampling points localization and following analysis of granularity ratio, it can be concluded that the grain composition from the soil samplings does not correspond fully with the map records. Subsequently, drainage branches of moisture retention curves were measured for all sites Obtained hydrophysical data were enabled on the web-portal. With the use of OpenGeo Suite software, version 4.0.2 and its components Geoserver and Geoexplorer, the data on soil characteristics were published online at: http://fzki.uniag.sk/02FacultyStructure/02Departments/KBH/02Research/Hydrophysics.Thus, information about the soil characteristics in the basin is available to specialists.

Soil hydro-physical changes in natural grassland of southern Brazil subjected to burning management

Burning of vegetation can promote changes in soil physical properties and also create hydrophobic substances, which accumulate and result in the formation of water-repellent layers. A study was conducted between 2005 and 2011 on an Albaqualf, with natural grassland composed mainly of Andropogon lateralis, in southern Brazil, to investigate the induction of hydrophobicity by burning and changes in the soil hydro-physical characteristics. The treatments consisted of no burning, and burned 60, 36, 12, 6, 4, and 2 months before sampling. Burning management did not change the saturated hydraulic conductivity, whereas air permeability was significantly reduced in the surface layer, nearly reaching the original values 4 months after burning. Saturated hydraulic conductivity and air permeability correlated with total porosity and macroporosity. The surface layer was the most sensitive to fire effects, with an increased degree of hydrophobicity for up to 2 months after vegetation burning. Hydrophobicity and contact angle correlated positively with soil organic matter content.

Effect of Organic Residue Management on Soil Hydro-Physical Characteristics and Rice Yield in Eastern Himalayan Region, India

Monocropping of lowland rice is the predominant system in valley land and high-rainfall regions of northeastern India. Recently, the unsustainability of this system has owing to soil structural deterioration and nutrient depletion, become evident, resulting from continuous puddling on the same piece of land even if recommended inorganic fertilizers have been applying regularly. To regenerate and maintain soil structure in rice fields, farmers in this region frequently use farm yard manure (FYM), but low availability of FYM because of its other uses indicates that it could not meet the organic matter requirements of this system. We evaluated the long-term effects of different locally available jungle grasses and weeds on soil hydro-physical properties and rice yield through a 5-year field experiment (2000 to 2005) at the Indian Council of Agricultural Research (ICAR) Complex for North Eastern Hilly (NEH) Region, Umiam, Meghalaya, India and also compared their negative or positive effects with FYM in acidic, Typic Hapludalf soil. The objective was to determine whether locally available grasses (Jungle grass) and weeds (Ambrosia sp.) could be used as alternative sources of organic materials for lowland rice in scarcity of FYM. Results showed that incorporation of FYM or jungle grass or Ambrosia sp., continuously for 5 years in puddled rice soil improved soil organic carbon (SOC) by 21.1%; the stability of micro-aggregates, moisture retention capacity, and infiltration rate of the soil by 82.5, 10, and 31.3%, respectively; and soil bulk density decreased by 12.6%. Application of FYM produced better soil physical environment than that under jungle grass and Ambrosia sp. However, as these grasses and weeds contained higher nutrient levels than FYM and increased the SOC slowly, these organics may serve as alternative to FYM and may have a dramatic effect on long-term productivity of rice. The gradual improvement in soil physical properties led to a significantly higher yield of rice. We conclude that applying organic manure or organic residue annually may mitigate the negative effect of puddling and related properties and therefore could contribute to the sustainability of the wetland rice ecosystem.

Determination of soil hydrophysical characteristics in the Ivankovo Reservoir watershed

The capillary-sorption potential and the unsaturated hydraulic conductivity of soils as functions of soil water content are derived for forest, meadow, and agricultural ecosystems of the Ivankovo Reservoir watershed. The parameters of van Genuchten-Mualem equations were determined for the same soils based on data on soil particle size distribution and density. Computer code HYDRUS-1D and the obtained data were used to calculate the values of field capacity of soils in forest, meadow, and agricultural ecosystems in the drainage basin of the Ivankovo Reservoir.