Selected Soil Characteristics Research Articles

Effects of Integrated Application of Vermicompost and Inorganic Fertilizers on Selected Soil Characteristics and Productivity of Wheat (Triticum aestivum L.) and Faba Bean (Vicia faba L.) in Dire and Legedadi Watersheds of Ethiopia

The adoption of integrated soil fertility management (ISFM) practices can improve soil quality and sustainably increase crop yield while slowing down the rate of ongoing degradation. This research assessed the effects of selected ISFM practices on soil properties at the Dire and Legedadi watersheds, central highlands of Ethiopia, in the 2021 and 2022 cropping seasons. Eight treatments were selected (sole wheat, sole faba bean, 100% recommended NPS + urea fertilizers, 100% recommended vermicompost (VC), wheat with half dose both NPS + urea and VC, wheat and faba bean intercropping with half dose both NPS + urea and VC, wheat and faba bean intercropping with half‐dose NPS + urea fertilizers, and wheat and faba bean intercropping with 50% VC). The treatments were studied on farmers’ fields using a randomized complete block design with three replications. Analysis of variance showed that soil samples collected from each plot indicated significant differences in soil organic carbon (SOC), total nitrogen (TN), available phosphorus (Pav), exchangeable bases (Ca2+, Na+, and Kexc), and cation exchange capacity (CEC). Soil pH and moisture showed improvement in combined fertilizers application compared to the preplanting soil sample. A combined application of VC and NPS + urea fertilizers significantly (p < 0.05) increased SOC, Pav, K+, Na+, and CEC compared to the control. A combined application of VC and NPS + urea fertilizers improved the soil quality. The highest TN contents of 0.36% at the Dire site and 0.30% at the Legedadi site were obtained with the full dose VC treatment. Additionally, this treatment resulted in the greatest water‐holding capacity and soil carbon stock at both sites. Similarly, the wheat‐faba bean intercropped plots showed a significant (p < 0.05) effect on the soil carbon stock and sequestration over the control in both study sites. Based on the results of the current study, it can be concluded that the combined application of a half dose of each VC and NPS + urea fertilizers improved most soil physicochemical properties at both sites. This suggests that using a combination of VC and NPS + urea fertilizers can help farmers reduce their inorganic fertilizer needs by 50%.

Potentially toxic elements in soil and air along an altitudinal gradient in Tatra National Park

With a growing number of tourists, national parks are facing high pressure in terms of production and spreading the potentially toxic elements (PTEs). Car parks, roads or civil amenities have become a source of PTEs, which are spreading not only in their immediate vicinity, but can contaminate much wider surroundings. Total content of Cd, Co, Cu, Cr, Fe, Mn, Ni, Pb and Zn was determined in soil samples and, also in mosses and lichen samples, which were used as bioindication method for air pollution monitoring. Soil pollution was evaluated by contamination factor (Cf), degree of contamination (Cd) and the pollution load index (PLI). The impact of pollution on selected soil characteristics (soil enzymes, soil respiration, total nitrogen, organic carbon, soil pH) was also evaluated. Content of PTEs in moss and lichen samples was expressed by relative accumulation factor values (RAF).The most serious soil pollution was recorded at the first (lowest in terms of altitude) sampling point, but soil contamination reached significant values also at higher altitudes. All evaluated soil properties showed decreasing tendency under the soil pollution, with exception of soil pH, which showed positive correlation with PTEs. The ability of mosses and lichen to accumulate pollution in their insoles varied depending on the toxic element. High levels of PTEs have also been captured at higher altitudes due to their ability to spread, transport and accumulate in the environment.

Effect of Potassium humate fertilizers on soil nutrients and productivity of Rice crop in vertisols of Southern India

Humic acid is an eco-friendly product needed in lesser quantity when compared to other chemical fertilizers and manures. A field experiment was conducted for three Kharif seasons (2019, 2020 and 2021) at Regional Agricultural Research Station, Nandyala, Andhra Pradesh to study the effect of potassium humate fertilizers on soil quality and productivity of Rice crop in scarce rainfall zone of Andhra Pradesh, India. Applications of potassium humate with different doses of fertilizers showed a significant effect on selected soil characteristics. The levels of available N, P, K, and micronutrients like Fe, Zn, Cu and Mn in soil increased with different humic treatments. Significantly highest plant height, productive tillers per hill, panicle length and number of grains per panicle was observed with treatment (T4) 100% RDF + Soil application of humic acid @ 30 kg ha-1at tillering, panicle initiation and at harvest stages of crop over other treatments. Highest grain and straw yield of 6074 & 8374kg ha-1 respectively, was recorded with treatment T4 (100% RDF+30 kg ha-1Humic acid as soil application) which was on par with T2 and T3 treatments. The lowest yield was recorded with T1 (Control) 2453 kg ha-1 in all three years.

Relationships Between pH Buffer Capacity and Selected Soil Properties of an Agrarian area in Samaru, Nigeria

The objectives of this research were to investigate the nature of pH buffer capacity and evaluate its association selected soil characteristics the study area. Soil samples from ten profile pits from within the study area were collected from genetic horizons. Soil samples were tested in the laboratory for electrical conductivity and pH buffer capacity using standard procedures. Soil data were analyzed using descriptive statistics. One-way analysis of variance and correlation analysis were applied to determine effects and relationships of selected soil properties with soil pH buffer capacity. The selected soil properties included particle size distribution, electrical conductivity, organic matter, cation exchange capacity and soil pH. Analysis of variance indicated that there were no significant effect of soil depth or drainage condition on distribution of pH buffer capacity in the study area. Correlation analysis indicated a non-significant weak relationship between pH buffer capacity and selected soil properties of the study area. This suggest that multiple interrelated factors could be responsible for the distribution of pH buffer capacity in the study area.

Reclaimed Mine Sites: Forests and Plant Diversity

The relationship between vegetation and selected soil characteristics in different monoculture forest types was investigated as part of a landscape restoration project after brown coal mining. Six forest types were selected: alder (Alnus sp.), spruce (Picea sp.), pine (Pinus sp.), larch (Larix sp.), long-term deciduous forest (Quercus robur, Tilia sp.), and forest created by spontaneous succession. These stands were classified into two age categories (younger and older). The soil attributes, C/N, TC, TN, pH, and A horizon depth were assessed. The observed species were categorized into functional groups by life history, life forms according to Raunkiær, and affinity to the forest environment. C/N ratio, humus thickness, and canopy cover were the main soil parameters affecting plant communities. The highest C/N values were recorded in Pinus and Larix stands, which were significantly different from deciduous and succession stands. The highest diversity index was noted in younger stands of Alnus and the lowest in younger stands of Picea. Intermediate values of the diversity index were achieved in successional stands at both age levels and in Larix and Alnus stands. The species belonging to a functional group was not an important factor in these habitat types. The species composition and vegetation change over time in the Alnus, long-life deciduous, and Larix stands show that these species are more suitable for forestry reclamation than spruce or pine. The study also emphasizes the great value of spontaneous succession areas as full-fledged alternatives to forestry reclamation.

Evaluation of phosphate sorption capacity and external phosphorus requirement of some agricultural soils of the southwestern Ethiopian highlands

<span>One of the most soil fertility management problems for crop production on acidic soils of the Ethiopian highlands is phosphorus fixation. The research was executed to assess the P-sorption capacity and to determine the external P requirement of different acidic soils in the Southwestern highlands of Ethiopia. Phosphorus sorption capacity (Kf) and its relation with selected soil characteristics were assessed for some major agricultural soils in the Ethiopian highlands to answer the questions, ‘What are the amount of P-sorption capacity and external P requirement of Nitisols, Luvisols, Alisols, and Andosols in Ethiopia?’. Twelve surface soil samples (at depth of 0-30 cm) were gathered and the P-sorption capacity was estimated. Phosphorus-sorption data were obtained by equilibrating 1 g of the 12 soil samples with 25 ml of KH<sub>2</sub>PO<sub>4</sub> in 0.01 M CaCl2, having 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, and 330 mg P L<sup>-1</sup> for 24 hours. The data were adjusted to the Freundlich adsorption model and the relationship among P-sorption and soil characteristics was established by correlation analysis. Clay content and exchangeable acidity, organic matter, Al<sub>2</sub>O<sub>3</sub>, and Fe<sub>2</sub>O<sub>3</sub> oxides have affected phosphorus-sorption at a significance level of (P < 0.05). Alisols had the highest Kf value (413 mg kg<sup>-1</sup>) but Nitisols had the lowest Kf (280 mg kg<sup>-1</sup>). The external phosphorus fertilizer requirement of the soils was in the order of 25, 30, 32, and 26 mg P kg<sup>-1</sup> for Nitisols, Luvisols, Alisols, and Andosols sequentially. The Kf varies among different soil types of the study area. The magnitude of the soil’s Kf was affected by the pH of the soil, soil OM content, and oxides of Fe and Al. Therefore, knowledge of the soils’ P retention capacity is highly crucial to determine the correct rate of P </span><span>fertilizer</span><span> for crop production.</span>

Performance Characterization of Unsaturated Granular Soils Using Static and Dynamic Plate Load Test

Abstract Determination of the modulus of subgrade reaction (ks) is an essential geotechnical design parameter that describes the relationship between stress and the associated settlement of soils. The ks is typically obtained using a laborious and costly method called the plate load test (PLT), and thus, to overcome the limitations related to the PLT, determining an alternative testing technique that can easily predict the ks is a priority. The feasibility of using a light weight deflectometer (LWD), also known as the dynamic PLT, to determine the ks of unbound pavement layers was thus investigated in this research. Eighteen laboratory testing models of granular soils were prepared and tested using the dynamic PLT (LWD) in conjunction with the static PLT (PLT). The soils’ characteristics examined under both dynamic and static loading conditions were analyzed and correlated. A series of multiple nonlinear regression analyses were conducted using three groups of independent variables: (1) LWD measurements, (2) basic soil properties, and (3) LWD data plus basic soil properties. Several nonlinear regression models were developed to predict the modulus of subgrade reaction on the basis of the LWD measurements and selected soil characteristics. The results revealed that certain LWD measurements, including dynamic modulus (Ed), surface deflection (δ), and degree of compatibility (Dc), are strongly correlated with the results from PLT. Additionally, good correlations were identified between ks and maximum dry density, suggesting that using LWD measurements along with basic soil properties yields correlations with adequate prediction quality.

Reusing urine and coffee processing wastewater as a nutrient source: Effect on soil characteristics at optimum cabbage yield

Treatment and application of wastewater as a plant nutrient source is one of the waste management approaches currently used. This study attempted to investigate the effect of the application of human urine and coffee processing wastewater (UCPWW) on selected soil characteristics and compared it with rainwater and synthetic fertilizer in a completely randomized design. One-way analysis of variance (ANOVA) for difference and principal component analysis for correlation was employed. It was found that the soil organic carbon (SOC) and available phosphorus after production in a 1:2 ratio of UCPWW was significantly varied from the values before production and the soil treated with synthetic fertilizer (F=24.01, p=0.001; F=49.03, p=0.001, respectively). No significant difference was observed on micro-nutrients and the cation exchange capacity, but on some of the exchangeable cations: Na+(F=15.27, p=0.001) and Mg2+ (F=12.99, p=0.001) of 1:2 ratio application. The soil salinity was significantly increased and varied from other treatments: Na+ (F=11.88, p=0.04), Cl−(F=17.24, p=0.001), and total salinity (EC) (F=11.88, p=0.003), and significantly correlated with SOC and nutrients. The exchangeable sodium percentage (ESP), saturated electrical conductivity (ECe), and pH values for single round cultivation indicated no effects of sodicity, saline-sodicity, and salinity. However, the effect for repeated applications and cultivations, and mechanism of minimizing the salinity by the substrate should be studied before large-scale application.

Soil Water Characteristics of Gleysols in the Bamenda (Cameroon) Wetlands and Implications for Agricultural Management Strategies

Water budgeting in agriculture requires local soil moisture information as crops depend mainly on moisture available at root level. The present paper aims to evaluate the soil moisture characteristics of Gleysols in the Bamenda (Cameroon) wetlands and to evaluate the link between soil moisture content and selected soil characteristics affecting crop production. The work was conducted in the field and laboratory, and data were analyzed by simple descriptive statistics. The main results showed that the soils had a silty clayey to clayey texture, high bulk density, high soil organic carbon content, and high soil organic carbon stocks. The big difference between moisture contents at wilting point and at field capacity testified to very high plant-available water content. Also, the soils displayed very high contents of readily available water and water storage contents. The soil moisture characteristics give sigmoid curves and enabled noting that the Gleysols attain their full water saturation at a range of 57.68 to 91.70% of dry soil. Clay and SOC contents show a significant positive correlation with most of the soil moisture characteristics, indicating that these soil properties are important for soil water retention. Particle density, coarse fragments, and sand contents correlated negatively with the soil moisture characteristics, suggesting that they decrease soil water-holding capacity. The principal component analysis (PCA) enabled reducing 17 variables described to only three principal components (PCs) explaining 73.73% of the total variance; the first PC alone expressed 45.12% of the total variance, associating clay, SOC, and six soil moisture characteristics, thus portraying a deep correlation between these eight variables. Construction of contoured ditches, deep tillage, and raised ridges management techniques during the rainy season while channeling water from nearby water bodies into the farmland, opportunity cropping, and usage of water cans and other irrigation strategies are used during the dry season to combat water constraints.

Remediation of trichloroethylene contaminated soil by unactivated peroxymonosulfate: Implication on selected soil characteristics

The advanced oxidation process (AOP) based on activated Peroxymonosulfate (PMS) has been attracting many people in the field of soil and water remediation in many ways while ignoring the shortcomings. The high cost of activators, and energy input, as well as the expense to separate the catalyst and transition metal reducing agent from the treated soil, were some disadvantages of using activated PMS. Based on the above rationales of problems related to the use of activated PMS, this study aimed to study the performance of using unactivated peroxymonosulfate for the advanced oxidation process to remediate soil contaminated by trichloroethylene (TCE), and to evaluate the synergistic effect on selected soil properties after treatment. The results showed that within 45 min, a single injection of 5 mM PMS at its initial pH value can degrade 86.90% of the total TCE in the soil. However, when PMS was continuously injected, the removal rate was increased to 95.25%. The direct reaction of TCE and PMS was the main cause of degradation. PMS can degrade TCE in a wide pH range (pH 3–11), but the maximum degradation was at pH = 2.9 (the initial pH of PMS). After the treatment, the soil organic matter (SOM) was degraded significantly. In contrast, FTIR, SEM, and hydrometer tests conducted on the soil showed that the treatment had no significant effect on the functional groups and particle size distribution of the treated soil. The study on the effect of the treatment on the concentration of bioavailable heavy metals in the treated soil showed that only manganese and copper metals were significantly increased after the treatment. According to the results obtained in this study, it is more beneficial and feasible to use unactivated peroxymonosulfate in the advanced oxidation process when remediating soil contaminated by chlorinated organic matter.

Multi-temporal analysis of erosional plots using aerial images and deep soil probes

ABSTRACT Evaluating erosion processes and their influence on soil degradation over extensive agricultural landscape is difficult. Because of the need for analysis and mapping of this problem, we elaborated a procedure applicable to a specific, intensively farmed, erosion-threatened chernozem area of CZ or similar regions. The aim of the research was to verify the possibility of digital aerial image analysis, along with a control study of soil sampling. To define and compare the boundaries and extent of erosion and deposition processes, we used images from two different years, showing changes in soil degradation. Orthorectification and unsupervised image classification were followed by interpretation and statistical evaluation. The results, locating erosional, transitional and depositional areas, were verified in laboratory analysis of soil samples for selected soil characteristics. Comparison of aerial images showed changes in the agricultural landscape over 35 years, showing an increase of ca. 60% in erosional areas. Extensive changes also occurred in transitional and depositional areas as material from the subsoil horizon of erosional areas covered some depositional areas. Importantly, our research confirmed the potential of digital aerial image analysis as a method of studying soil erosion over extensive landscape, and the possibility of using it in planning anti-erosion measures.

Effect of coppice forest clearance on soil moisture, temperature and certain selected soil characteristics

Effect of coppice forest clearance on soil moisture, temperature and certain selected soil characteristics

Relationship between soybean yield from high and low yielding field sites and selected soil characteristics

AbstractThe sporadically occurring high and low yielding field sites is a commonly observed manifestation of the within‐farm spatial heterogeneity of soybean [Glycine max (L.) Merr.] yield in Pennsylvania. Understanding the causes behind this phenomenon is important for implementing site‐specific management practices, leading to greater attainable yields at farm scale. To explore the problem, bulk soil samples were systematically collected in 2018 from farmer‐designated high and low yielding sites at V1 (early season) and R8 (late season) soybean growth stages from 14 farms in Pennsylvania. Soil organic matter; cation exchange capacity; pH; P, K, Mg, Ca, S, Zn, and Cu; soil texture; site slope; number of putatively pathogenic fungal colonies (Fusarium, Pythium, and Phytophthora species and Rhizoctonia solani); and plant pathogenic nematodes were assayed. No measured variables differed significantly between two site types at V1 or R8. Principal component analysis did not distinctly cluster high and low sites based on the variables included in the analysis. Hierarchical clustering on principal components showed situations where sites from different farms are more similar than sites from the same farm. Correlation analysis performed for variables collected with high sites showed that yield is significantly and positively correlated with V1‐spiral nematode count, R8‐R. solani colony count, and soil K content at V1 and R8. For low sites, yield was significantly and positively correlated with V1‐spiral nematode count and soil P/Zn content at R8. Taken together, our findings indicate that the causes behind within‐farm spatial heterogeneity of soybean yields are complex and beyond the variables investigated in this study.

Changes of some soil chemical and microbiological characteristics in a long-term fertilization experiment in Hungary

Agricultural management practices – directly or indirectly – influence soil properties.
 Fertilization rates and crop rotation can strongly affect soil pH, soil nutrient supply and soil organic matter content due to the changes of microbial processes. The objective of this study was to compare the effects of different fertilization doses in monoculture and tri-culture of maize (monoculture: only maize grown since 1983, tri-culture: it is a three-year crop rotation system: pea – winter wheat – maize) on selected soil characteristics. The long-term fertilization experiments were set up in 1983 in Eastern Hungary. These experiments are situated west of Debrecen in Hajdúság loess region, on calcareous chernozem (according to WRB: Chernozems).
 The test plant was maize (Zea mays L.). One-one pilot blocks were selected from monoculture and tri-culture of the long-term experiments. The observed soil samples were taken in the 30th year of the experiment, in 2013. The doses of NPK fertilizers increased parallel together, so the effects of N-, P- and K-fertilizers cannot be separated.
 With the increasing fertilizer doses, the soil pH has decreased in both crop production systems and, in parallel, the hydrolytic acidity has significantly increased. A close negative correlation was proved between the pHH2O, pHKCl and hydrolytic acidity. An increased nutrient content in soil was recorded in every NPK treatment and the available phosphorus and nitrate content increased in higher proportion than that of potassium. Of the measured parameters of C-and N-cycles, fertilization has mostly had a positive effect on the microbial activity of soils. Besides the effects of fertilizer doses, correlation were looked for between soil microbiological properties. Evaluating the ratios among the measured parameters (organic carbon and microbial biomass carbon, OC/MBC ratio; carbon-dioxide and microbial biomass carbon; CO2/MBC proportion), the fertilization rate seems to be favoured by the increase of amounts of organic compounds

Impact of recreation and tourism on selected soil characteristics in the Lisia Góra Nature Reserve area (south-east Poland)

Abstract The aim of the research was to estimate changes in soil properties caused by intensive recreation and tourism in protected areas within the urban borders of Rzeszów (south-east Poland). The research was conducted on two objects: (1) on protected areas of the Lisia Góra Nature Reserve and (2) along the Wisłok Valley. The difference in anthropopressure between the areas was taken into consideration. Soil penetration resistance and moisture were analysed in the spring and autumn period. Soil texture, pH, total carbon, and electrical conductivity (EC) in a 1:10 soil:water suspension were measured in soil material collected in spring. The ion content (Ca2+, Mg2+, K+, Na+) was measured in the same suspension with an ion chromatograph. There were significant correlations (determined by the Pearson coefficient) between soil acidity, EC, total exchangeable bases, ions of calcium and magnesium, and soil penetration resistance. A significant difference was found in soil penetration resistance between objects (higher in the Wisłok Valley area) and between the distances from the border of the intensively managed area (a decrease as the distance increased). The Z coefficient (the ratio of sodium ions, the sum of calcium and magnesium ions) was significantly lower for the the Lisia Góra Nature Reserve sites.

Application of airborne gamma-ray imagery to assist soil survey: A case study from Thailand

Airborne gamma-ray imagery (AGRI) provides coarse-resolution (approximately 400×400m pixel) spatial information on gamma-ray emitting elements, i.e. potassium (K), thorium (Th) and uranium (U), in the upper half meter of the soil. These radioelements are a potential information source for soil mapping since their abundance is related to soil geochemistry, specifically the chemical composition of parent materials and their weathering products resulting from geomorphic and pedogenic processes.The aim of this study was to evaluate the potential of AGRI for improving digital soil survey process in two phases: (1) a preliminary phase, where hypotheses of soil-landscape relationships are developed, and (2) a phase where soil map unit boundaries are placed or revised. The study also evaluated the match between AGRI and existing lithologic, geopedologic, and soil series maps. The study was conducted in a well-characterized complex soil landscape: the 560km2 upper Pa Sak watershed in Petchaboon province, Thailand. The relationship between gamma-ray data and geological units was examined with box-and-whisker plots and confirmed by rock and soil samples. Rock and soil sample classifications were compared with the gamma-ray image and to typical radioelement responses found in the literature.To interpret AGRI data in terms of regolith and soil genesis, we compared AGRI to two existing soil maps: geopedologic and soil series maps. First, the geopedologic map was split into four maps according to the geopedologic hierarchy: landscape, lithology, relief, and landform; at the latter (lowest) level, soil units are also associated. Secondly, soil series and geopedologic soil units were used to examine the distribution of radioelement response to selected soil characteristics: parent material, texture, mineralogy, and thickness. The interpretations from best correlation in both soil maps were described in terms of the radioelement changes during pedogenic and geomorphic processes, based on a review of literature and supported by soil samples.In the hypotheses-generating stage, AGRI provided useful information in three forms (single signal, ratio, and ternary images enhanced with a hill shaded DEM) by relating these to lithology, material transport, and internal pedogenetic processes. AGRI correlated well with the classes of the geopedologic map (1:50,000) at the two higher levels (landscape and lithology) but to a lesser degree at the two lower levels (relief and landform in geopedologic approach). In the mapping stage, AGRI showed deficiencies in the soil series map (1:50,000) made by conventional aerial photo analysis and limited field surveys, especially in inaccessible areas but also in low-relief terraces and flood plains, which provided a basis for future field sampling to correct these deficiencies. AGRI suggested new boundaries, differentiating topsoil properties and the presence of plinthite, despite its coarse resolution.Clustering of gamma ray and elevation data (DEM) was carried out using fuzzy logic to generate various classification layers. Final map was produced using total weighted inverse distance of all the classes in a 3 by 3 window. Class label was assigned to the one with the largest total inverse distance over the entire set of fuzzy classification bands. The result shows relatively higher classification accuracy for soil parent material differentiation (overall accuracy of 72%) as compared to the classification for soil types (67%).

Observed and simulated changes in the water balance components over Malawi, during 1971–2000

Estimation of the spatial and temporal characteristics of key water balance components in data scarce regions is a large challenge worldwide. This paper presents the derivation of the 30-year surface water balance components (rainfall, temperature, potential and actual evapotranspiration (ETp and ETa) runoff). Monthly rainfall and mean temperature from 28 synoptic stations in Malawi during 1971–2000, together with soil moisture capacity extracted from the International Geosphere-Biosphere Programme Data Information Services (IGBP-DIS) Global Gridded Surfaces of Selected Soil Characteristics database at 0.5° × 0.5° grid resolution were used as model input. Ordinary Kriging was applied to examine the spatial distribution of the components using a 0.5° × 0.5° grid resolution. Temporal trends were investigated using the Mann–Kendall test at α = 0.05 significance level. The results showed: (1) an area of high rainfall, ETa and runoff areas located in the south east and north east highlands and decreasing westwards. Temperature and ETp were highest in the lower Shire River valley and along Lake Malawi; (2) Mann–Kendall trends suggested statistically significant positive trends in mean annual temperature and ETp and declines in annual rainfall, ETa and runoff, though their trends were not statistically significant. The contrasting trends ETp and ETa are a manifestation of the complementary relationship. The decline in rainfall coupled with temperature increase suggests that Malawi became more water-limited during 1971–2000.

The development of detailed soil maps on the basis of interpolation of data on soil properties

A methodology for creating detailed soil maps on the basis of a dense grid of soil testing points and the numerical interpolation of experimental data on the soil properties is discussed. The study of the soil cover patterns combines regular sampling grids with equal spacing and additional sampling points chosen with due account for the soil cover specificity in particular areas. Soil diagnostics are performed at each of the points, and the diagnostic features of the soils are recorded in the field. In a laboratory, these data are arranged into a database, and a legend to the soil map is created. The necessary and sufficient set of the quantitative soil characteristics is selected, and quantitative criteria of the boundaries between the separate soil polygons are determined on the basis of numerical interpolation. Algorithms to delineate soil polygons on the basis of the selected indices are developed. Separate thematic map layers are produced for each of the selected soil characteristics. An integral soil map for the investigated area is obtained via the superposition of these layers. The thickness and/or the depths of the upper/lower boundaries of the soil layer with definite diagnostic characteristics making it possible to distinguish the given soil from its neighbors are used as the criteria for delineating the boundaries between soil polygons. Special criteria based on the proportions between the thicknesses or depths of several layers can also be applied for this purpose. The creation of a detailed soil map of a plot on the Kamennaya Steppe is discussed as an example of the practical application of this methodology.

Effects of Coal- Derived Humic Substance on Some Soil Properties and Bread Wheat Yield

In the present study, gyttja and its humic–fulvic concentrate were applied to soil either alone or in combination with a chemical fertilizer in a 2-year replicated field experiment with continuous bread wheat cropping during two seasons between 2005 and 2007 in Cukurova, Adana, Turkey. The changes in soil organic matter (SOM) characteristics and available micronutrient status were monitored by soil samplings performed immediately after the harvest in the 2005 and 2006 cropping seasons. The results showed that single and combined applications of humic substances with different types and doses showed different inclinations on selected soil characteristics in consecutive cropping seasons. The levels of SOM, available phosphorus, and grain yield significantly increased under different humic treatments in the first year of the experiment. However, humic substances added to the soil did not affect selected soil parameters and macro- and micronutrient status in the second year of the experiment.

Effects of horse grazing on plant species richness and abundance of Iris setosa in a boreal semi-natural grassland, Japan

We investigated plant community attributes and selected soil characteristics of a Japanese boreal semi-natural grassland among day-grazed (24 h), night-grazed and ungrazed sites in Akkeshi, eastern Hokkaido. We also evaluated the effects of horse grazing on plant species richness and the population of Iris setosa, a hygrophilous target species for conservation. Species richness and iris dominance were the highest and community height was the lowest at the day-grazed site; however, plant coverage and light intensity at ground level did not differ significantly among the sites. Soil aeration and water permeability of the surface soil were the lowest at the day-grazed site. Logistic regression analyses suggested direct and/or indirect positive effects of grazing on the occurrence probability of nine species. Species richness was negatively correlated with community height, soil aeration and water permeability of the surface soil and positively correlated with bulk density and soil hardness. Iris dominance was negatively correlated with aeration and water permeability and positively correlated with surface soil bulk density and volumetric water content. Iris dominance was also positively correlated with species richness. Canonical correspondence analyses demonstrated different species composition among the sites that mainly segregated with grazing intensity, soil bulk density, surface soil aeration and community height. Our results showed that all-day horse grazing in a boreal semi-natural grassland modifies surface soil characteristics and increases plant species richness and dominance of I. setosa.