Sandy Loam Research Articles

Surface soil sampling underestimates soil carbon and nitrogen storage of long-term cover cropping

Cover cropping is a promising management practice for soil health and climate change mitigation by improving soil organic carbon (SOC) and total nitrogen (TN) stocks. However, limited studies focused on deeper soil layers (>30 cm depth) where soil C is more stable than that in surface soil (≤30 cm depth). Here, deep soil sampling was conducted in a 15-year cover cropping experiment, in a horticulture-grain system on sandy loam soil. The SOC and TN stocks were expressed on an equivalent soil mass basis using a cubic spline model. Overall, long-term cover cropping had significantly greater SOC and TN stocks by 22 % (95 %CI: 5–43 %) and 26 % (95 %CI: 6–49 %), respectively in the 0–120 cm depth, compared to no cover cropping. Additionally, the mean SOC and TN sequestration rate (0–30 cm depth) was 0.53 Mg C ha−1 yr−1 and 0.06 Mg N ha−1 yr−1, respectively. However, if only 0–15 cm depth was evaluated, long-term cover cropping did not significantly affect SOC and TN stocks. These results indicated that shallow sampling (<15 cm depth) may not provide comprehensive information on the effect of long-term cover cropping on soil C and N storage. To better understand the mechanism of bulk soil C and N storage, we investigated their distribution between particulate and mineral-associated organic matter pools (POM and MAOM). We found POM pool was the main store of bulk SOC and TN stocks in surface soils while it was the MAOM pool in deeper soil layers, without soil texture change with soil depth. These findings indicated that soil C and N sources for bulk SOC and TN accrual differed in surface and deeper soils. Our study demonstrated that long-term cover cropping can facilitate SOC accumulation in the soil below 15 cm deep, which calls into question carbon capture protocols that focus on shallow soil depths.

Mechanisms of Cd immobilization in contaminated calcareous soils with different textural classes treated by acid- and base-modified biochars

Acid or base modification of biochars has shown promise for enhancing the immobilization of potentially toxic elements (PTEs) such as cadmium (Cd) in contaminated soils. However, limited information is available on the interaction between soil textural classes and modified biochar application for Cd stabilization in contaminated calcareous soils. Therefore, the objective of the study was to examine the extent of Cd immobilization in contaminated calcareous soils with diverse textural classes, utilizing both acid (HNO3) and alkali (NaOH) modified and unmodified biochars derived from sheep manure and rice husk residues. The modified or unmodified biochars were applied at a rate of 2% (w/w) to Cd-contaminated silty clay loam, loam, and sandy loam soils, followed by a 90-day incubation at field water capacity. Sequential extraction and EDTA-release kinetics studies were used to assess the effect of the treatments on the extent and mechanisms of Cd immobilization. Among the treatments, acid-modified manure biochar was most effective at reducing water soluble and exchangeable Cd fractions (-20.5%), by converting them into metal oxide and organic matter bound fractions. This effectiveness was primarily attributed to the significant increase in surface oxygen functional groups in the acid-modified biochar which could promote Cd complexation. However, the acid-modified manure biochar released more immobilized Cd during EDTA extraction than the base-modified manure biochar, suggesting that EDTA extraction of R-O-Cd complexes was easier than extracting Cd associated with insoluble compounds. This difference was likely due to the acidic pH and lower ash content of the acid-modified biochars compared to the base-modified manure biochars. Additionally, the extent of Cd immobilization was lower in sandy loam soil, highlighting the importance of immobilizing Cd in light-textured soils to prevent its transfer to organisms.

Release of selected nutrients from polymer-coated fertilisers in the soil environment

The aim of the study was to evaluate the release of NH4-N and PO4-P from polymer-coated fertilisers in the soil environment, and to analyse their impact on pH and conductivity of the soil leachates. In this investigation mineral NPK(S) 6-20-30(7) fertiliser (as a starting material), commercial, controlled-release OsmocoteTM fertiliser (as a reference material) and four polymer-coated fertilisers have been used. Biodegradable polybutylene(succinate-co- dilinoleate), polyethylene(succinate-co-terepftalate) and chitosan have been used as coating materials. The experiments were conducted in the laboratory conditions, in PVC columns filled with air-dry soil. The nutrients release from the investigated materials was explained based on the diffusion mechanism and it was interpreted with the use of the Korsmeyer–Peppas kinetic model. Two mechanisms dominate in the release process of nutrients: the mechanism based on quasi-Fickian diffusion and non-Fickian (anomalous case) mechanism. The largest changes of pH and electrical conductivity (EC) of soil leachates occurred in the initial period of research for all tested fertilisers (pH: 9.5–20.3% – loamy sand (S1) 7.9–20.6% – sandy loam (S2); EC: 438–1667% – S1, 771–1509% – S2). The polymer coating significantly reduces the nutrient release from the fertiliser core. The size of these changes depends on the type and thickness of the polymer layer and the physicochemical properties of the soils.

Assessment of Soil Fertility Status in Vegetable Growing Area of Daman-Palung, Nepal

Soil fertility assessment is essential for sustainable planning for a particular area. Considering this, a study was conducted in November 2018, to determine the soil fertility status of the vegetable growing area of Makwanpur district, Nepal. In total, 50 soil samples were collected randomly from a depth of 0-20 cm using a soil sampling auger. A standard analytical method was used to analyze the texture, soil pH, (Organic matter (OM), Nitrogen (N), Phosphorus (P2O5), and Potassium (K2O) status of samples at the National Soil Science Research Centre, Khumaltar. The sand, silt and clay content were 45.67±2.08, 35.6±51.37 and 18.49±0.93 respectively and were indicated as loam and sandy loam in texture. The soil was moderately acidic (pH 5.11±0.5) in nature. Soil organic matter ranged from low to medium but the medium (3.37±1.72 %) was prevalent. Total nitrogen content (0.22±0.01 %) and available phosphorus (230.58 ±85.61 ppm), were found to be high. Furthermore, available potassium (97.4±70.04 ppm) content was medium in the soil. The purpose of this soil fertility assessment is to help researchers and farmers in Daman, Palung know the soil fertility status of their area and to guide sustainable soil fertility practices. This soil fertility assessment aims to help researchers and farmers in Daman, Palung understand soil fertility status and determine the best soil fertility practices for their area.

The productivity of selected soybean cultivars grown using various cultivation methods

Soybean is an important legume crop globally due to its rich protein, oil content, and functional components. The purpose of this study was to evaluate the yield of selected soybean cultivars depending on cultivation methods. The three-year field experiment, conducted from 2018 to 2020 at the Agricultural Experimental Station in Kępa-Puławy, Osiny farm (Institute of Soil Science and Plant Cultivation – State Research Institute in Puławy), investigated these variations. The first experimental factor was the soil cultivation method: A – conventional tillage, B – reduced tillage, and C – strip tillage. The second variable was soybean cultivar: ‘Aldana’ and ‘Merlin’. The soybean cultivars were selected for their differing maturity rates: ‘Aldana’ (000) is an early cultivar, while ‘Merlin’ (000++) semi-late cultivar. The field experiment utilised a split-plot design on Luvisol soil with sandy loam texture, belonging to a good rye complex, class IIIb–IVa, and was replicated four times. The study showed that the productivity (seed and protein yield) of the ‘Merlin’ cultivar grown in the central-eastern part of Poland was approximately 8% higher than that of the ‘Aldana’ cultivar. The cultivation method had a relatively minor influence on soybean yield, the content of selected nutrients, morphological features, and elements of the yield structure. The soil in strip-tillage method was more compact than the soil cultivated with a plough. After harvesting soybeans at a depth of 30, and 40 cm, the compactness of soil in strip-tillage or with reduced tillage was much lower than in spring, highlighting a positive effect of soybean cultivation on loosening the arable layer.

Water retention characteristics and mechanical properties of vegetated biopolymer and biochar-reinforced sandy loam

Vegetation is a sustainable strategy for erosion control and slope stabilization, though its initial cultivation can be lengthy and potentially weaken soil structures. This study compared two bio-mediated ground improvement techniques, biopolymer and biochar, known for their supportive effects on vegetation growth. Additionally, a novel treatment combining biopolymer and biochar was examined for its potential in vegetated-engineering practices. Engineering performance was assessed through soil water characteristic curve, vegetation growth, direct shear testing, and rainfall simulation. The results revealed that biopolymer and biochar treatments enhanced soil water capacity but negatively impacted vegetation germination rates and shear strength of the reinforced soil, attributed to hydrogel formation and increased soil water content from irrigation. In comparison, soil reinforced with the combined method showed a promotion in the vegetation while maintaining the soil’s mechanical performance throughout the cultivation period and exhibited only minor reductions in the shear strength compared to other reinforced soils. Moreover, the new treatment showed improved soil erodibility under a majority of rainfall occasions, regardless of the vegetation coverage. This enhanced engineering performance by the new treatment is believed to be the polymerisation between the biopolymer hydrogel, biochar and soil particles.

Effect of IBA on Rooting and Growth of (Ixora chinensis L.) Terminal Cutting

The experiment was conducted at College of Horticulture, Dapoli under Dr. Balasaheb Konkan Krishi Vidyapeeth, Dapoli, in 2023. It comes under tropical location with an average well distributed rainfall 3500-4000 mm during June to October. The soil is come under lateritic textural class varied with loam, clay, sandy loam. Ixora is popular ornamental but difficult to root plant was used for the experiment. The experiment was laid out in randomized block design with eight treatments and three replications. Mature terminal cuttings of size 10-15 cm length with 4-5 leaves are dip for 5 min in the solution consisting different Indole Butryic Acid concentrations i.e. (control) 250, 500, 1000, 1500, 2000, 2500, 3000 ppm solutions. The cuttings under study recorded significant variation with respect to all the parameters, The results showed that among all treatments survival percentage (60%) maximum plant height (18.17cm), maximum number of leaves (14.08), stem girth (3.91 mm), longest root length (9.03cm), number of secondary roots (17.93), fresh and dry weight of shoot ( 3.55, 1.03g), fresh and dry weight of root (1.40, 1.18g) was recoded in T4 treatment consisting 1000 ppm IBA solution. However, for maximum number of primary roots (7.27) was observed in T3 (500 ppm) treatment.

Physico-chemical characteristics and quality assessment of soil in parts of the Banganga Basin in northeastern Rajasthan, NW India.

Soil is a vital natural resource that has a bearing on any developmental activity. A database comprising primary physicochemical characteristics and soil suitability would assist the planners in devising an appropriate land use policy and any intervention strategy for soil quality improvement. The physicochemical characteristics of soils in parts of the Banganga Basin, located in the semi-arid terrain of NW India were evaluated mainly through surface samples and sub-surface ones wherever sections were exposed in stream banks. The soil in the studied terrain is a Quaternary age, pale brown to dark brown and occasionally red, alluvial soil. Sandy loam is the dominant soil type, while sandy soil and loamy sand types also occur. The soil maintains a depth-wise consistency in physicochemical characteristics. The average soil pH value is 8.55, indicating a slightly alkaline and healthy soil. The soil has a high available nitrogen content (0.53 to 2.24%), adequate available phosphorus (23.58 and 62.18mg/kg), and low potassium (22.5 and 200mg/kg) contents. The organic carbon, Mg, and Ca levels are generally on the lower side. A consistency in overall soil characteristics is evident in the narrow range of the Soil Quality Index, varying between 10 and 14, and soil can be categorized into three categories with overlapping soil qualities.

Origin and distribution of clay minerals in semi-arid Sahelian soils: case of Kori Ouallam watershed, south-western Niger

Abstract This study examines the origin and distribution of clay minerals of the pedological horizons of Kori Ouallam watershed (south-western Niger). It is based on field sampling campaigns and a series of laboratory analyses. A total of 49 samples were analysed, 28 from surface horizons (0–10 cm depth) and 21 from pedological profiles (0–1 m depth). The samples were analysed by X-ray diffraction on bulk and clay (&lt;2 μm) fractions, X-ray fluorescence spectrometry, laser granulometry, organic matter and calcium carbonate content, macroscopic observations (binocular loupe) and scanning electron microscopy equipped with an energy-dispersive spectrometry system. The pedological horizons are characterized by low organic matter contents (&lt;1%) and no calcium carbonate. The particle-size distribution shows net textural differentiation, with a predominance of sandy loam to sandy clay loam textures in the upper horizons and clay loam to clay in the deep horizons. The main major oxides were SiO2 (46.3–89.0%), Al2O3 (5.0–24.2%) and Fe2O3 (1.0–27.9%). Kaolinite (64–98%) is the predominant clay mineral at all horizons, associated with low to moderate proportions of illite (1–34%) and traces of chlorite. Kaolinite is essentially inherited from the parent rock, whereas illite results from chemical alteration by bisialitization of the primary minerals initially rich in potassium feldspar contained in the parent rock. However, soil texture and organic matter vary independently with clay mineralogy. An extended study of all of the pedological facies that make up south-western Niger, combined with supplementary analyses, would further improve our understanding of clay mineralogy in the Sahelian zone.

Effects of Long-Term Reed Plantation on Saline Habitat

In recent years, the improvement and utilization of saline-alkaline soil has gradually shifted from engineering measures to biological measures. As a salt-tolerant plant, the reed has been preliminarily proven to have a role in improving saline-alkaline land. In order to explore the long-term effect of planting unharvested reeds on the improvement of saline-alkaline land, a pilot plot was set up in Fuping Pilot Test Base (34° 42'180"E; 109°11'49" N) near Lubo Beach, Fuping, Shaanxi, in 2012 to ascertain the improvement effect of long-term reed cultivation on saline–alkaline land. The objective was to study the long-term changes in soil pH, electrical conductivity, Ca2+, Mg2+, Cl-, SO42-, HCO3-, and CO32- contents, soil particle size and soil fertility. Results showed that (i) reed cultivation could effectively reduce soil salinization in the long term. From 2012 to 2022, the average pH of saline soil decreased from 9.42 to 8.86, and the electrical conductivity decreased from 1.20 μS/cm to 0.70 μS/cm. (ii) Reed cultivation considerably reduced the contents of Ca2+, Mg2+, Cl-, SO42-, HCO3-, and CO32- in the soil in the long term, and the reduction in each index was 5.9, 41.7, 63.5, 90.6, 81.7, 90.6, 77.9and 90.3%, respectively. (iii) Reed cultivation changed the soil structure. The soil texture of the 0–60 cm soil layer changed from silty sandy loam to silty loam from 2018 to 2022. (iv) Long-term reed planting without harvesting effectively improved soil fertility. In 2012, the content of soil organic matter was only 2.74 g/kg, but in 2022, the value reached 12.8 g/kg. Reed planting improved the physical and chemical properties of saline soil. Therefore, biological restoration of reed can be considered in low-lying saline–alkaline areas with high water volumes. Bangladesh J. Bot. 53(3): 665-672, 2024 (September) Special

In Situ Seedling Establishment and Performance of Cyperus esculentus Seedlings

Cyperus esculentus seeds are often considered irrelevant for C. esculentus spread as their fragile seedlings would not establish or survive in agricultural soils. However, the ever-increasing spread and upsurge of genetically different clonal populations in NW-Europe raises questions about the establishment of C. esculentus seeds and the reproductive performance of seedlings. Indeed, little is known about the potential of C. esculentus seedlings to grow and propagate under outdoor conditions relative to plants grown from tubers. Seeds from different clonal populations were sown outdoors in various soil types and under different irrigation levels (rainfed, irrigated) to assess seed germination and seedling establishment. Additionally, two pot experiments were conducted with three different plant types (plants originating from mother tubers and from seeds harvested on open- or self-pollinated plants) obtained from eight clonal populations. Plant performance was investigated by measuring vegetative and generative parameters. Germination under outdoor conditions was significantly affected by clonal population and was highest in irrigated sand (5.3%). Germination in sand was 4.1 times higher in irrigated plots than in rainfed plots. In irrigated plots, germination was 3.8 and 4.7 times higher in sand than in sandy loam and clay, respectively. Depending on the year, three out of five to five out of six clonal populations produced more tubers when grown from mother tubers than from seeds. Maximal tuber reproduction factors of 1:965, 1:752, and 1:618 were achieved for plants from mother tubers and seeds from open- and self-pollinated flowers, respectively. Plants originating from open-pollinated seedlings have the potential to equal or exceed the vegetative reproductive capacity of plants originating from mother tubers. As a result of their ability to establish in situ and their substantial vegetative reproductive capacity, C. esculentus seedlings are highly relevant for agriculture and merit appropriate attention in any integrated weed management system targeting C. esculentus.

Investigating Different Planting Geometry and Nutrient Management to Enhance Teff Productivity in Eastern Dry Zone of Karnataka, India

A field experiment was conducted at Zonal Agricultural Research Station (ZARS), Gandhi Krishi Vignana Kendra, University of Agricultural Sciences, Bangalore, Karnataka on red sandy loam soil to study the “Investigating different planting geometry and nutrient management to enhance teff productivity”. The experiment was laid out in Factorial Randomized Complete Block Design, consisting two factors viz., Factor 1: Two planting geometry (S1: 30 cm × 10 cm and S2: 45 cm × 10 cm) and Factor 2: Five Nutrient management (N1: 50 % RDF, N2: 75 % RDF, N3: 100 % RDF, N4: 125 % RDF and N5: Absolute control (6 t FYM ha-1 commonly applied to all except control treatments) and replicated thrice. The uptake of nitrogen, phosphorus and potassium was higher under 30 cm × 10 cm spacing (5.74, 1.04 and 3.29 kg ha-1, respectively) and among nutrient levels, application of 125 per cent RDF resulted in statistically higher uptake nitrogen (7.35 kg ha-1), phosphorous (1.33 kg ha-1) and potassium (4.28 kg ha-1). Significantly higher (12.58 %) grain protein content was obtained with application of 125% RDF. Maintaining 30 cm × 10 cm spacing recorded significantly higher grain (2.37 q ha-1) and straw yield (3.65 q ha-1). Application of 125 % RDF resulted in significantly higher straw yield, however significantly higher grain yield (2.73 q ha-1) was obtained under 100% RDF. Application of 100% RDF along with narrow spacing yielding substantially higher gross returns (₹90,776 ha-1), net returns (₹60,021 ha-1), and a commendable B:C ratio of 2.77.

Productivity, quality and suitability for processing of various potato varieties when grown in the conditions of the Central region of the Russian Federation

Relevance. The study of the reaction of potato varieties, especially new ones, to the use of a complex of agrotechnical techniques, including foliar top dressing with water-soluble fertilizers, is an urgent task. For this purpose, 4 potato varieties of different ripeness groups (Red Scarlett, Nevsky, Golubizna, Grand) were studied in two regions of Russia using agrochemicals Agrovin Micro. Methods. The article presents experimental data on the study of biometric indicators, yield and quality of potatoes for non-root top dressing in conditions of leached chernozem and sod-podzolic sandy loam soils of the Central region of Russia. The objects of research were potato varieties of various ripeness groups. Foliar fertilization of plants with agrochemicals Agrovin Micro was carried out in the phases of germination, budding and 20 days after the last treatment in two consumption rates – 1.0 and 2.0 l / ha. Control – without processing (K) with background N90Р90К135.Results. On average, over the years of research, the best options for all varieties turned out to be options with the use of additional leaf treatment with an agrochemical at a maximum dose of 2 liters /ha. Due to three-fold foliar top dressing for the critical phases of potato plant growth, the greatest yield increases and maximum values of dry matter and starch content to the mineral background were obtained. In the conditions of the Tambov region, the increase in yield, depending on the variety, ranged from 24.2 to 59.3% or 6.0-10.5 /ha and in the conditions of the Moscow region – 3.3-28.9% or 1.2-7.1 t/ha. The most suitable for processing into fried potato products from the studied varieties turned out to be Red Scarlett and Grand. All other things being equal, the color index of crispy potatoes and fries on these varieties was higher than the Nevsky variety by 1.0-1.5 points.

Identification of plant soil water and soil aeration corequisites: A management tool

AbstractPlant‐available soil‐water and adequate soil aeration within the root zone are essential corequisites for successful plant growth. Characterization of these two requirements for plant growth is generally done by independent measurements of water and air phase properties and functions in soil, with limited emphasis on their combined effect. This study investigated soil‐water characteristic (SWC) measurements in vadose soil profiles (up to 117‐cm depth) in six pasture soils to examine the combined behavior of soil‐water and diffusion‐controlled aeration within the root zone. The soil moisture measurements were made over matric potentials ranging from −1 to −1500 kPa using tension table and pressure plate apparatus. The van Genuchten model was used to parameterize the measured SWC curve, while the Millington–Quick model was used to derive soil‐gas diffusivity from measured soil physical properties. Based on two simple indices, derived to represent plant‐available soil‐water and soil aeration status at a given moisture content, we propose an assessment matrix, which illustrates how a soil satisfies the corequisites for successful plant growth, as it drains to different matric potentials upon irrigation. Results show a pronounced effect of soil texture and, to a lesser extent, soil structure on satisfying these corequisites. With the aid of the assessment matrix, we observed that loam, sandy loam textures exhibited a good overall performance, while sand, clay loam, and clay soils struggled to meet these corequisites during drainage.

New insights into synergistic interactions of root-knot nematode and wilt causing fungi on pigeon pea in sandy loam soil

AbstractA study under pot conditions was undertaken to know the relationship between plant biomass and inoculum densities of Meloidogyne incognita. Similarly, plant biomass—Fusarium udum relationship was also observed. Results revealed that increased inoculum densities resulted in corresponding decrease in plant biomass markers. Compared to control plants, 2000 nematode inoculation caused significant damage in phytobiomass (23.07–26.32%) of pigeon pea. 2.0 g F. udum inoculation caused significant impairment in different plant growth characteristics (22.96–26.02%) over control plants at P &lt; 0.05. The interactive study revealed that concomitant, M. incognita + F. udum inoculation caused the maximum reduction (33.68–56.66%) in plant biomass. Next to this, M. incognita inoculation 15 days prior to F. udum and F. udum inoculation 15 days prior to M. incognita caused an impairment of (28.55–50.11%) and (23.99–43.33%), respectively. However, they were statistically either at par or non-significant over each other. Disease assay revealed that M. incognita multiplication rate was correspondingly augmented upon the rise of nematode concentration, conversely, the reproduction factor was progressively decreased. Pathogens interactive facet revealed that M. incognita inoculated plants showed a higher root galls (99.40), eggs (79.20), fecundity (199.80), and nematode population (13,785.60). The presence of F. udum suppressed nematode multiplication ability. However, concomitant inoculation of M. incognita and F. udum aggravated percent wilt severity (65.48%) thus exhibiting a synergistic interaction between the vascular pathogens.

Response of Biofertilizer and Molybdenum on Growth and Yield of Barley (Hordeum vulgare L.)

The field experiment was conducted during rabi season, 2023-24 at research farm, Vivekananda Global University, Jaipur. The experiment was layout in Randomized Block Design (RBD). The treatments consisted of biofertilizers like Azotobacter and Phosphate Solubilizing Bacteria (PSB) and three level of Molybdenum (400, 600 and 800 ppm) and control. The soil in the experimental area was sandy loam with pH (7.81), Organic Carbon (0.21%), Available N (132.5 kg/ha), Available P (21.13 kg/ha) and Available K (203.24 kg/ha). Seed rate is 100 kg/ha. The application of biofertilizers + PSB + 800 ppm Mo significantly increased the Plant height (110.46 cm), Dry matter accumulation (542.54 g/m2), No. of tillers/ running row meter (93.51), Number of effective tillers m-2 (199.86), Number of grains spike-1 (53.60), Grain yield (3450 kg/ha) and Straw Yield (6562 kg/ha) of barley over the control.

Impact of fertilizer levels and treated sewage water on heavy metal uptake,growth, agrometeorological indices, and quality of wheat

A field experiment was conducted at Vegetable Research Farm, CCS Haryana Agricultural University, Hisar, Haryana, India to study the agro-physiological, agrometeorological, heavy metals, and quality parameters of wheat under different fertilizer levels and treated sewage water application on sandy loam soil. Among varieties, signifi- cantly higher yield attributes viz effective tillers and yield were observed with variety HD 3086 being at par with WH 1105 over HD 2967, WH 1124, and DBW 90. A higher value of agrometeorological indices viz. thermal (2.67 kg/ ha/0 C day), helio-thermal (0.77 kg/ha degree day hr), and photothermal (0.23 kg/ha degree day hr) use efficiencies were found with variety HD 3086 over other varieties. Among fertilizer levels, significantly higher yield attributes and grain yield were found with 125 % RDF over 75 and 100 % RDF. Significantly higher values of thermal, heliothermal, and photothermal use efficiencies were observed with the application of 125 % RDF over 75 and 100 % RDF Neither the varieties nor the fertility levels bring any significant variation in normalized difference vegeta- tion index and canopy temperature. However, varying levels of fertilizer did have a substantial impact on chloro- phyll content. Similarly, quality parameters viz. hectoliter weight and protein content were not affected significantly by varieties and fertilizer levels. However, sedimentation value was significantly affected by varieties and fertilizer levels. Heavy metal concentration was found in wheat grain, but these were within the permissible limit.

Содержание валовых форм цинка, свинца и кадмия в дерново-подзолистых супесчаных почвах земель сельскохозяйственного назначения

Abstract. Purpose and objectives. The research is aimed at studying the peculiarities of the distribution of gross forms of zinc, mumps, cadmium according to the soil profile of sod-podzolic sandy loam soils of agricultural lands of the Ryazan region and determining the current regional background. Methodology and methods. To solve the tasks set, pits with a depth of 1.5 m were laid in different regions of the region, the depth and structural features of the soil layer and the effect on the migration conditions of the studied elements were analyzed. Based on the results of determining the content of the studied elements in the soil at intervals of 0.1–0.2 m to the maternal, the calculation of background concentrations was performed. A comparative analysis of the proposed background values with well-known values of world and domestic researchers has been carried out. The scientific novelty of the conducted research lies in the fact that the proposed background values are modern and calculated directly for the sod-podzolic sandy loam soil of the Ryazan region. Results. The structure of soil profiles of sod-podzolic sandy loam soil at a depth of 110–120 cm has the following form: O – A – EL – ELBt – Bt – BtC – C. At the same time, noticeable geochemical barriers delaying the migration of heavy metals are noted in the horizon A and Bt. The obtained values of the studied elements were in the concentration ranges for Zn (5.4–12.8 mg/kg), Pb (2.1–7.4 mg/kg), Cd (0.031-0.081 mg/kg). Background concentrations are proposed: Zn – 8.3 mg/kg, Pb – 4.2 mg/kg, Cd – 0.053 mg/kg, which differ from the well-known values of world and domestic researchers presented in a comparative analysis and give a modern idea of the regional background content of gross forms of zinc, lead and cadmium in sod-podzolic sandy loam soils Ryazan region.

Evapotranspiration and Rainfall Effects on Post‐Storm Salinization of Coastal Forests: Soil Characteristics as Important Factor for Salt‐Intolerant Tree Survival

AbstractFlooding and salinization triggered by storm surges threaten the survival of coastal forests. After a storm surge event, soil salinity can increase by evapotranspiration or decrease by rainfall dilution. Here we used a 1D hydrological model to study the combined effect of evapotranspiration and rainfall on coastal vegetated areas. Our results shed light on tree root uptake and salinity infiltration feedback as a function of soil characteristics. As evaporation increases from 0 to 2.5 mm/day, soil salinity reaches 80 ppt in both sandy and clay loam soils in the first 5 cm of soil depth. Transpiration instead involves the root zone located in the first 40 cm of depth, affecting salinization in a complex way. In sandy loam soils, storm surge events homogeneously salinize the root zone, while in clay loam soils salinization is stratified, partially affecting tree roots. Soil salinity stratification combined with low permeability maintain root uptakes in clay loam soils 4/5‐time higher with respect to sandy loam ones. When cumulative rainfall is larger than potential evapotranspiration ETp (ETp/Rainfall ratios lower than 1), dilution promotes fast recovery to pre‐storm soil salinity conditions, especially in sandy loam soils. Field data collected after two storm surge events support the results obtained. Electrical conductivity (a proxy for salinity) increases when the ratio ETp/Rainfall is around 1.76, while recovery occurs when the ratio is around 0.92. In future climate change scenarios with higher temperatures and storm‐surge frequency, coastal vegetation will be compromised, because of soil salinity values much higher than tolerable thresholds.

Modeling wear of different surface layers of agricultural tools in soil abrasive mass

Uniform quantitative measures have not been developed to identify the areas with the greatest intensification of tool wear. Therefore, this paper developed original approach to assess the wear of cutting elements by identifying the intensity of local volumetric wear. A tribological test was conducted under natural operating conditions in two soil types: sandy loam and loam. The specimens were mounted on a 9-tined cultivator with spring tines aggregated with an agricultural tractor. A method was developed to discretise the local volume changes of a component using surface scanning models developed from 3D scanning. The notion of the rake angle has been defined, allowing the assessment of changes in the shape of the element during wear. The practical usefulness of the developed method was verified on three types of surface layers, i.e. 38GSA steel, ELHARD70 deposited on it, and a G10 layer of carbide. For each of the tested variants, local volumetric consumption was defined based on the identification of the wear grid. These should be the basis for developing the technology of surface strengthening of elements. The work confirmed the complexity of the process of wear of working elements in natural soil conditions, presented in many research works. A different course of wear of the 38GSA steel and the Elhard 70 weld layer was shown, depending on the type of treated soil. In the case of samples made of G10 cemented carbide, the largest volumetric wear for heavy soil occurred outside the place of reinforcement application. The highest volumetric wear in the front zone was recorded for 38GSA steel in heavy soil. Wear results from the modelling are similar to those obtained from the experiment under natural conditions in light soil using the nominal model (CAD) and the actual friction surface.