Influence Of Soil Characteristics Research Articles

The Influence of Soil Characteristics on Plant Species Diversity and their Distribution Patterns in Western Serengeti, Tanzania

The Influence of Soil Characteristics on Plant Species Diversity and their Distribution Patterns in Western Serengeti, Tanzania

On-farm productivity of Acacia angustissima, Calliandra calothyrsus and Leucaena leucocephala in a subhumid area in Zimbabwe

Smallholder dairy farmers in Natural Region II, especially in Chikwaka Communal Area, adopted Acacia angustissima, Calliandra calothyrsus and Leucaena leucocephala in the 1995/96 season as alternatives for supplementing expensive commercial dairy feeds. Although several on-station trials have been done in the subhumid region of Zimbabwe, there have been no studies assessing on-farm yields of the introduced fodder species. This study evaluated productivity in a communal area under varying soil (pH, nitrogen, phosphorus and potassium) and management conditions (protection and tree density). Leaf productivity was high on farms with relatively higher soil P. Leaf yields ranged from 0.4–3.3 t DM ha−1 for A. angustissima, 0.8–5.6 t DM ha−1 for C. calothyrsus and 0.2-0.7 t DM ha−1 for L. leucocephala, with mean values of 2.2, 2.6 and 0.4 t DM ha−1, respectively. The low yields of L. leucocephala were associated with psyllid (Heteropsylla cubana) infestation. Decrease in tree density (low population) resulted in reduced yield. Poor performance was also attributed to uncontrolled browsing. Influence of soil characteristics could not be confirmed, but there were indications that low soil phosphorus may have adversely affected tree growth. The yields were generally lower than on-station, which implies that there is room for improving fodder tree yields in this subhumid region, through improving the availability of P, planting a high density of trees, and protecting them from uncontrolled browsing.

The influence of soil characteristics on plant productivity and ecological stability

The influence of soil characteristics on plant productivity and ecological stability

Formulation affecting alachlor efficacy and persistence in sandy soils

The development of controlled-release formulations of alachlor to extend the period of weed control was studied. This extended duration reduces the need for high herbicide application rates that could lead to environmental contamination. For this purpose, the influence of formulation, as well as the influence of soil characteristics, on alachlor efficacy and persistence in soil of a commercial formulation (CF) and different ethylcellulose microencapsulated formulations (MEFs) was evaluated. Higher alachlor rates yielded an enhanced initial herbicidal activity. The prolonged release of alachlor provided by the MEFs resulted in a higher herbicidal efficacy and a longer period of weed control compared with the effects of CF in the two soils tested (at 40 days after treatment, oat growth inhibition for CF and MEFs was 1.96% and 93.5% respectively). Soil characteristics strongly influenced alachlor efficacy and weed control by MEFs. The highest alachlor efficacy and persistence were observed in the soil with lowest microbial activity and clay and organic matter content. The use of MEFs can be advantageous because they permit the maintenance of the desired concentration of the herbicide in the soil for longer periods of weed control.

The Influence of Soil Characteristics in Low Flows Regionalization

Problem statement: For the purpose of low flows regionalization, relevant issue for water resources management like environmental flows requirements definition, this study focused on the controls on the seasonal and spatial variability of q95 (i.e., the specific discharge that was exceeded on 95% of all the time) with particular reference to the role of soil characteristics, that, like soil infiltration rate, aquifers recharge, evapotranspiration and topography, usually play a relevant role in low flows seasonality and occurrence within a river. Approach: Piemonte and Valle d'Aosta Regions (North-Western Italy) were the investigated study area (30,027 km2) where 41 catchments were analyzed with the aim of robust regression models enabling the transfer of hydrological information from gauged to un-gauged sites. Results: The regionalization method consisted of multiple regression models between low flows and catchment characteristics. Twenty-five catchment descriptors were used, checking their relative influence with the multi-regressive procedure and a special attention was devoted to the selection of significant soil characteristics in the regionalization process. Seasonality indices were used to classify catchments into two sub-regions and separate multiple regressions was performed by checking the prediction performance with cross-validation. Also a global regression was fitted out but it yielded a lower performance. In the study domain land use, topography and Thornthwaite moisture index demonstrated to be the most significant variables in order to represent relationships between catchment soil characteristics and low flows regime. Conclusion/Recommendations: Results obtained in this study were comparable with other regionalization studies carried out in Austria and Switzerland. The interpretation of the identified regression models provided, at local scale, new tools for water management and environmental flows requirements and, from a wider point of view, useful insights into the general comprehension of low flows processes.

The Influence of Soil Characteristics in Low Flows Regionalization

The Influence of Soil Characteristics in Low Flows Regionalization

Influence of Soil Characteristics on Copper Sorption from a Copper Oxychloride Fungicide

The objective of this work was to assess the sorption of copper (Cu) applied as a Cu-oxychloride metalaxyl formulation by soils characterized by anthropogenic accumulation of Cu due to agricultural activity. The methods involved batch incubation of soils with a Cu-oxychloride metalaxy-based fungicide suspended in 0.01 M CaCl(2), phase separation, and determination of the concentration of Cu (Cu) in solution. Results showed that specific soil properties influenced solubilization of the Cu from the fungicide. The amount of dissolved Cu depended on the soil pH, its potential acidity, and its cation exchange capacity. The amount of anthropogenic Cu in the soil had a minor influence on soluble Cu after the addition of the fungicide. Thus, Cu-based antifungal treatment can increase the local concentration of soluble Cu in acid soils but is not likely to affect the [Cu] in moderately acidic or neutral soils.

Influence of Soil Characteristics and Formulation on Alachlor Dissipation in Soil

Alachlor [2‐chloro‐N‐(2,6‐diethylphenyl)‐N‐(methoxymethyl)acetamide] is one of the most commonly found herbicides in surface and groundwaters of the United States and Europe, and it contaminates these environments even when it is used according to the manufacturer's instructions for conventional formulations. To determine how its persistence in soil is affected by herbicide formulation and soil type, alachlor was applied to several soils in different formulations: technical grade (AT), a commercial formulation (CF), and different ethylcellulose microencapsulated formulations (MEFs). The results show that MEFs provided a prolonged release of the herbicide into the soil solution and protected against its dissipation in soil more than AT or the CF. The half‐life in soil (t1/2) for the AT, CF, and MEFs was up to 2.7, 6.4, and 32.54 d, respectively. The lowest herbicide loss was observed in MEFs prepared using a lower stirring speed or a higher ethylcellulose viscosity during the microencapsulation process. As with AT and the CF, the microencapsulated alachlor persisted longer in the soils with low pH and high clay content. In the soil where alachlor showed the least persistence, MEFs reduced the herbicide loss by 54% compared with the CF. The use of MEFs extended the alachlor concentration in the soil, thereby avoiding the need for using high herbicide application rates and decreasing the risk of environmental contamination.

Laboratory drying of organic-matter rich soils: Phosphorus solubility effects, influence of soil characteristics, and consequences for environmental interpretation

Agronomic soil test P (STP) and soil type data may be used to predict diffuse soluble P loss from soil to water (e.g. Withers, P.J.A., Dils, R.M., Hodgkinson, R.A., 1999. Transfer of phosphorus from small agricultural basins with variable soil types and land use. p. 41. In: Impact of Land use change on nutrient loads from different sources. IAHS publication no. 257; Daly, K., Mills, P., Coulter, B., McGarrigle, M., 2002. Modelling phosphorus concentrations in Irish rivers using land use, soil type, and soil phosphorus data. J. Environ. Qual., 31: 590–599). However, previous studies quantifying the effect of STP and soil type on P solubility have usually relied on laboratory analyses of dried soil samples to quantify P solubility. Drying soil samples has been found to substantially increase P solubility (e.g. Bartlett, R., James, B., 1980. Studying dried, stored soil samples—some pitfalls. Soil Sci. Soc. Am. J., 44: 721–724; Turner, B.L., Haygarth, P.M., 2001. Phosphorus solubilization in rewetted soils. Nature, 411: 258–258), and microbial biomass and organic matter (OM) have been implicated in this (e.g. Chepkwony, C.K., Haynes, R.J., Swift, R.S., Harrison, R., 2001. Mineralization of soil organic P induced by drying and rewetting as a source of plant-available P in limed and unlimed samples of an acid soil. Plant Soil, 234: 83–90; Turner, B.L., Driessen, J.P., Haygarth, P.M., McKelvie, I.D., 2003. Potential contribution of lysed bacterial cells to phosphorus solubilisation in two rewetted Australian pasture soils. Soil Biol. Biochem., 35: 187–189). Many grassland soils in western Ireland contain high OM and moisture contents, and may therefore be particularly susceptible to drying-induced soluble P release. This study quantifies drying-induced changes in P solubility, by measuring water-extractable P (P w) and desorbable P (P feo) contents in moist and dried samples of a range of 33, mainly grassland, soils from western Ireland. Molybdate analyses of P w extracts before and after acid digestion were used to quantify dissolved reactive P (P wDRP), taken to represent predominantly readily soluble inorganic P, and dissolved molybdate-unreactive P (MUP), taken to represent predominantly readily soluble organic P. Dried soil samples were analysed for a wide range of general and P-specific characteristics, including STP (Morgan P and Olsen P) and the degree of sorption saturation (DPSS). Based on OM content, soils were divided into peat (> 30% OM) and predominantly mineral (< 30% OM) soils after Daly et al. (2000). Almost all soils exhibited large increases in P solubility after drying, with the size of drying-induced soluble P increases increasing in the order P wDRP < P wMUP< P feo. Absolute drying-induced increases were statistically similar between peat and mineral soil groups (e.g. P feo mean increases of 9.06 and 13.81 for peat and mineral soil groups, respectively). However, when expressed as a proportion of moist sample P solubility, all soluble P increases were significantly greater for peat compared with mineral soils (e.g. P feo percentage increases 735% and 155% for peat and mineral soil groups, respectively). Consequently, some differentiation in P solubility between peat and mineral soil groups was lost after drying. Drying-induced P w increases appeared to be related to soil OM and moisture contents, indicating drying-induced P release through microbial cell lysis and OM destabilisation. Increases were not related to moist sample P solubility or STP, resulting in the loss of some differentiation in P solubility between high and low STP soils. Drying-induced P feo increases were positively related to DPSS, reflecting chemical equilibrium control of desorbable P released from dried samples. It was concluded that the standard practice of drying soils prior to P solubility analyses reduces the inferred importance of soil type and STP as risk factors in diffuse soluble P losses.

Competitive sorption and desorption of heavy metals in mine soils: Influence of mine soil characteristics

Many mine soils are chemically, physically, and biologically unstable and deficient. They are sometimes amended with sewage sludge and ashes but often contain heavy metals that increase the already high mine soils' heavy metal contents. Cd, Cr, Cu, Ni, Pb, and Zn in mutual competition were added to five mine soils (Galicia, Spain). Soil capacities for heavy metal sorption and retention were determined by means of distribution coefficients and selectivity sequences among metals. Influence of soil characteristics on sorption and retention was also examined. Retention selectivity sequences indicate that, in most of the soils, Pb is the preferred retained metal, followed by Cr. The last metals in these sequences are Ni, Cd, and Zn. Soil organic matter content plays a fundamental role in control of Pb sorption. Gibbsite, goethite, and mica influence Cr retention. Soil organic matter, oxides, and chlorite contents are correlated with K d ∑ sp medium . Heavy metals are weakly adsorbed by soils and then desorbed in high amounts. To recover these soils it is necessary to avoid the use of residues or ashes that contain heavy metals due to their low heavy metal retention capacity.

The influence of soil characteristics on the extractability of Cd, Pb and Zn in upland and moorland soils

A study was undertaken to investigate the feasibility of using existing data sets of total soil metal concentrations and soil parameters, such as pH, to predict available metal concentrations on a regional or national basis. The attraction of such an approach is that it would provide valuable data for initiatives requiring information on the availability and mobility of metals in soils without the need for costly soil sampling and analysis. Ninety-seven topsoil and subsoil samples were collected from 6 soil series in a catenary sequence in north Wales to provide data for the development of an empirical model. These were analysed for total, 0.01 M CaCl 2-extractable and porewater metal concentrations and for a range of soil properties including pH, solid and dissolved organic matter and cation exchange capacity. Regression analysis showed that, of the soil parameters measured, pH was the most important predictor variable for the estimation of CaCl 2-extractable Cd, Pb and Zn. pH accounted for up to 86% of the variance in the proportion of ‘total’ metals which were extracted by CaCl 2, a reagent that is commonly used to estimate plant uptake of elements. However, the relationships recorded between soil parameters and K d (total metal/porewater metal) were much weaker, indicating that porewater metal concentrations can less readily be predicted from total soil metal concentrations and soil properties.

Effect of soil characteristics on Cd uptake by the hyperaccumulator Thlaspi caerulescens

The influence of soil characteristics on the phytoremediation potential of Thlaspi caerulescens is not well understood. We investigated the effect of soil pH and Cd concentration on plant Cd uptake on one soil type, and the variation in Cd uptake using a range of field contaminated soils. On soils with total Cd concentrations of 0.6–3.7 mg kg −1, T. caerulescens (the Ganges ecotype) produced greater biomass in the pH range 5.1–7.6 than at pH 4.4. The highest plant Cd concentration (236 mg kg −1) and Cd uptake (228 μg pot −1) were observed at pH 5.1. On soils with total Cd concentrations of 2.6–314.8 mg kg −1, shoot Cd concentrations were 10.9–1196 mg kg −1. Multiple regression analysis indicated that higher Cd in soil, low pH (within the range of >5) and coarser texture were associated with higher Cd concentration and Cd uptake by T. caerulescens.

An environmentally friendly method for the extraction and determination of priority phenols in soils using microwave-assisted micellar extraction

A non-ionic surfactant, polyoxyethylene 10 lauryl ether (POLE), was used for the microwave-assisted extraction (MAE) of priority phenolic compounds from soil samples. A central composite design was applied to optimize the extraction parameters, namely, time and power. Under the optimized conditions, the method was applied to different soil samples in order to analyze the influence of soil characteristics on the phenol extraction. Results demonstrated that most of these compounds can be recovered from the soils investigated in good yields (higher than 80%). The standard deviation is lower than 9% (n = 6) for most analytes. Validation of the method by analyzing a reference soil sample containing eight phenols and a comparison with Soxhlet extraction are also reported.

Numerical formulation for solving soil/tool interaction problem involving large deformation

Purpose – The aim of this work is to provide a global 3D finite element (FE) model devoted to the modelling of superficial soil ploughing in the large deformation range and for a vast class of soil treatment tools. Design/methodology/approach – We introduced soil constitutive equation in a FE software initially designed for the metal forming. We performed the numerical integration of the non‐linear ploughing problem. Non‐linearities encountered by the problem can be summed up: as soil constitutive equation (idealized with non‐associated compressible plastic law), unilateral frictional contact conditions (with a rigid body), geometrical non‐linearities (the ploughing tool) and large deformation range. To handle such difficulties we performed several numerical methods as implicit temporal scheme, Newton‐Raphson, non‐symmetric iterative solver, as well as proper approximation on stress and strain measures. Findings – Main results deal with the validation of the integration of the non‐linear constitutive equation in the code and a parametric study of the ploughing process. The influence of tool geometric parameters on the soil deformation modes and on the force experienced on the tools had been point out. As well, the influence of soil characteristics as compressibility had been analyzed. Research limitations/implications – This research is devoted to perform a numerical model applicable for a large range of soil treatment tools and for a large class of soil. However, taking into account all kind of soil is utopist. So limitations met are essentially related to the limit of the accuracy of the elasto‐plastic idealization for the soil. Practical implications – In practice the numerical model exposed in the paper can clearly help to improve and optimize any process involving superficial soil submitted to the mechanical action of a rigid body. Originality/value – The original value of the paper is to provide a global and an applicable numerical model able to take into account the main topics related to the ploughing of superficial soils. Industrials in geotechnics, in agriculture or in military purposes can benefit in using such numerical model.

Vertical profile of 137Cs in soil

In this paper, a vertical distribution of 137Cs in undisturbed soil was investigated experimentally and theoretically. Soil samples were taken from the surroundings of the city of Kragujevac in central Serbia during spring-summer of 2001. The sampling locations were chosen in such a way that the influence of soil characteristics on depth distribution of 137Cs in soil could be investigated. Activity of 137Cs in soil samples was measured using a HpGe detector and multi-channel analyzer. Based on vertical distribution of 137Cs in soil which was measured for each of 10 locations, the diffusion coefficient of 137Cs in soil was determined. In the next half-century, 137Cs will remain as the source of the exposure. Fifteen years after the Chernobyl accident, and more than 30 years after nuclear probes, the largest activity of 137Cs is still within 10 cm of the upper layer of the soil. This result confirms that the penetration of 137Cs in soil is a very slow process. Experimental results were compared with two different Green functions and no major differences were found between them. While both functions fit experimental data well in the upper layer of soil, the fitting is not so good in deeper layers. Although the curves obtained by these two functions are very close to each other, there are some differences in the values of parameters acquired by them.

The distribution of phosphorus fractions and desorption characteristics of some soils in the moist savanna zone of West Africa

The fractionation of soil P into various organic and inorganic pools with differing levels of bioavailability, coupled with knowledge of the P adsorption and desorption characteristics of the soils, provides insights into management strategies that enhance P availability to crops. Sequential soil P fractionation was conducted on samples from 11 soil profiles and different experimental fields selected from the derived savanna (DS) and northern Guinea savanna (NGS) zones of the West African moist savanna to assess the influence of soil characteristics and management on soil P pools. Phosphorus adsorption and desorption studies were conducted on samples from the surface horizon of the soil profiles. The total P content varied within and among the soil profiles and tended generally to decrease as depth increased. The total P content in topsoil varied from 90 to 198 mg kg–1 of which about 30% was organically bound P. The resin P fraction was generally low (mean = 5 mg kg–1, topsoil) and decreased with depth. These low resin P levels indicate low P availability. Within the DS, where the organic resource (OM) was Senna siamea residues, the effects on soil P fractions of OM and soluble P fertilizer (PF), whether sole or in combination, were site-specific. While resin P was significantly increased by OM in some sites, no significant differences were observed in others. In the NGS fields, farmyard manure (organic resource, OM) combined with PF and PF applied alone increased the inorganic P (Pi) fractions extractable with resin, bicarbonate, and NaOH by about 400% but had no significant effect on the organic P (Po) pools and the more stable Pi forms. The P sorption capacities were low, with the adsorption maximum deduced from the Langmuir equation ranging from 36 to 230 mg kg–1. The amount of P sorbed to maintain 0.2 mg l–1 in solution ranged between 0.6 and 16 mg kg–1. Phosphorus desorption with anion exchange resin differed among the soils, with the recovery of added P ranging from 17 to 66% after 96 h. On average, more of the applied P was recovered in the DS soils than in the NGS soils. Because of the relatively low sorption capacity and the relatively high percentage recovery, small additions of P to most of the soils studied might be adequate for crop growth. In essence, quantities of P fertilizer needed in these soils might be estimated based on considerations of P uptake by crops rather than on sorption characteristics.

Phthalates and nonylphenols in profiles of differently dressed soils

The concentrations of nonylphenols and phthalates in depth profiles of eight differently dressed, fertilised and cultured fields were investigated. The fields were typical for Danish agriculture and comprised an uncultured location, two manured fields, an artificially fertilised field and three fields amended with different amounts of sewage sludge. In addition, a location receiving run-off from a sewage sludge storage facility were investigated. At each location, two 50 cm vertical soil cores were taken, divided into sections of 10 cm each and analysed for nonylphenols and phthalates by high-resolution mass spectrometry. Di-(2-ethylhexyl)-phthalate (DEHP) was the most abundant phthalate in all samples whereas Di-( n-butyl)-phthalate (DBP) played a minor role. Nonylphenols occurred in significant concentrations only in soil samples exposed to high amounts of sludge and at the run-off location. A close relationship was found between the concentrations of contaminants in the soil samples and the method of dressing. The concentrations were low at comparable levels in the soil samples from the artificially fertilised field and in the fields amended with low amounts of sludge, as well as in the manured fields. Remarkably, these concentrations did not differ significantly from the level in an uncultured recreational preserved area, which was used as a reference. In contrast, much higher levels of contaminants were found in the soil samples from fields exposed to high amounts of sludge. We must conclude that sludge amendment below a certain limit does not lead to elevated levels of nonylphenols and phthalates in the soils, whereas heavy sludge amendment leads to the accumulation of these contaminants. For the vertical distribution of substances in the soils, an influence of soil characteristics on the concentration profile was noted. Thus, in soils with visible clay in the upper layers, a DEHP maximum occurred at a depth of 10–20 cm, whereas in most sandy soils no such maximum was observed. A 2-year time trend study of the highly sludge amended soil showed no measurable reduction in the substances during this period. The time study further suggested a downward movement of the DEHP maximum of approximately 10 cm per year.

Radiocaesium contamination of meadow vegetation—time-dependent variability and influence of soil characteristics at grassland sites in Austria

Long-term trends of 137Cs and 40K concentrations in meadow grass and soil–plant transfer data at eight different sites in Upper Austria are presented. Geometric means of 137Cs TF-data and T agg values vary between 0.03–1.06 and 0.0005–0.0184 depending on site, respectively. 40K results are less variable with TF values covering a range of 0.31–2.01. Only at one site was a significant decrease of 137Cs concentration (decay-corrected) in meadow vegetation observed during the observation period 1992–1999. Seasonal trends of 40K and 137Cs were investigated at one site in 1996. Both elements show decreasing concentrations in plants from beginning of May–July, followed by a peak in September. Although this pattern was not very pronounced, there are some hints that it may explain deviations of long-term trends in 137Cs levels in grass caused by unusual weather conditions as indicated by phenological climate data (beginning of sweet cherry and black elder blossoming). Finally, TF values were correlated with soil characteristics, revealing a negative correlation of radiocaesium soil–plant transfer with soil pH, exchangeable and extractable fractions of Mg, Ca and Na as well as a positive correlation with exchangeable Al.

Impact of metal pools and soil properties on metal accumulation inFolsomia candida(Collembola)

AbstractSoil‐dwelling organisms are exposed to metals in different ways. Evidence exists for predominant pore water uptake of metals by soft‐bodied oligochaete species. In the present research, uptake kinetics of metals and the metalloid As by the semi‐soft‐bodied springtailFolsomia candidawere studied, for which uptake via the pore water is less obvious. Springtails were exposed in 16 field soils and in metal‐spiked artificial Organization for Economic Cooperation and Development (Paris, France) soil (OECD soil). Subsequently, accumulation parameters were statistically related to soil metal pools and soil properties. In Cd‐spiked OECD soil, internal Cd levels were linearly related to external Cd concentrations, whereas the springtails maintained fixed internal levels of Cu and Zn regardless of spiked concentrations. In the field soils, all body concentrations of the elements As, Cr, and Ni were below detection limit. The essential metals Cu and Zn were presumably regulated, and no influence of soil characteristics could be demonstrated. For Cd and Pb, accumulation patterns were correlated mainly to solid‐phase soil characteristics. The presence of these explanatory variables in the multiple correlations suggests that an uptake mechanism that is solely determined by pore water concentrations should not be taken as a universally applicable principle in risk assessments of metals for soil invertebrates. Cadmium in OECD soils was more available for uptake than in the field soils. The difference remained when extractability was taken into account. The results suggest that experiments in OECD soil cannot be used directly in risk assessment for nonessential metals (at least forF. candida), although a reduction of uncertainties in metal risk assessment can be reached by consistent use of body residues rather than external concentrations.

Test designs to assess the influence of soil characteristics on the toxicity of copper and lead to the oligochaete Enchytraeus albidus.

Statistical test designs were used to identify and quantify the soil parameters important for determining the ecotoxicological effects of copper and lead to the potworm Enchytraeus albidus. The application of a Fractional Factorial Design revealed that the acute toxicity of copper and lead to E. albidus can vary over more than two orders of magnitude depending on the physico-chemical characteristics of the (artificial) soils. The differences in metal ecotoxicity were mainly determined by pH and organic matter content or cation exchange capacity (CEC). Using a Central Composite Design, models were developed describing the ecotoxicity of copper and lead to E. albidus as a function of these parameters. To validate the developed response surface models, two field soils and the standard artificial soil prescribed by OECD were spiked with copper and lead and the acute toxicity to E. albidus was assessed. These validation experiments confirmed that the toxicity of copper and lead could be predicted using information on the total metal concentration, the pH and the CEC of the soil with toxicity decreasing with increasing pH and CEC.