Soil Structuring in the Presence of the Chitosan–Polyacrylic Acid Interpolymer Complex

Eurasian Soil Science - This article presents the results of the study of a new soil structuring agent—the interpolymer complex of a chitosan biopolymer and a synthetic polymer of polyacrylic...     

Implication of Tillage and Soil Mineralogy on the Setting and Sieving Efficiency of FTLHV–0200 Filtra Electromagnetic Sieve Shaker

Soil sieving is an essential laboratory procedure in every soil investigation. Soil tillage and mineralogy are critical factors to soil mechanical properties. The implication of tillage and mineralogy on the settings and sieving efficiency of FTLHV–0200 filtra electromagnetic sieve shaker was studied in soils of 13 ecotopes in Eastern Cape Province. The sieve shaker had T = time, I = interval, and P = power settings. The tillage systems were conventional tillage (CT) and no tillage (NT), while the soil mineralogy was mainly quartz and kaolinite. After sieving, 72% of the aggregates were retained on the 2 mm sieve for soils under CT and 69% were retained on the 2 mm sieve for soils under NT. Soils under NT required sieving for at least 5 min to be broken into particle sizes, while soils under CT required at least 35 min. The setting T4I4P4 (time = 35 min, sieving interval = 9 s, and power level = 9) significantly (p ≤ 5%) affected the percentage of aggregates passing through the stack for all the soils irrespective of mineralogy. Quartz-dominated soils required a sieving time of 15 min to disintegrate, while kaolinite-dominated soils required a sieving time of more than 35 min. Sieving efficiency for aggregate analysis was achieved at T4I4P4 setting for soils under CT and at T2I4P3 (time = 5 min, interval = 9 s, power level = 6) setting for soils under NT. While sieving efficiency was achieved at T3I4P3 (time = 15 min, interval = 9 s, power level = 6) setting for quartz-dominated soils and at T4I4P3 (time = 35 min, interval = 9 s, power level = 6) setting for kaolinite-dominated soils.     

Technosols in the World Reference Base for Soil Resources – history and definitions

ABSTRACT

The World Reference Base for Soil Resources (WRB) is an international soil classification system for naming soils and creating legends for soil maps. The currently valid version is the update 2015 of its third edition. WRB has two levels: first and second. The first level comprises 32 Reference Soil Groups (RSGs), identified using a Key. At the second level, the soil names are constructed by adding a set of qualifiers to the name of the RSG. In the WRB, diagnostic horizons, properties and materials are defined. Diagnostic materials are materials that significantly influence soil-forming processes. Diagnostic properties and horizons have a combination of attributes that mostly reflect results of soil-forming processes.

The RSG Technosols was introduced in the second edition of the WRB in 2006. In the current version of the WRB, two diagnostic materials are defined for Technosols: artefacts and technic hard material. Artefacts are substances that are created or substantially modified by humans or brought to the surface from a depth, where they were not influenced by surface processes. The technic hard material is a (relatively) continuous consolidated material resulting from an industrial process. The Technosols are at the third place in the Key after Histosols and Anthrosols. A soil is a Technosol if it has technic hard material within 5 cm or a geomembrane or a significant amount of artefacts within 100 cm. If a soil has no technic hard material and no geomembrane but a layer with artefacts that has undergone enough soil formation to develop a diagnostic horizon typical for advanced pedogenesis, the soil is excluded from the Technosols. There are specific qualifiers to further characterise the Technosols. They are also important to characterise soils other than Technosols that have artefacts or technic hard material. Human-transported natural soil material does not qualify as Technosol.     

Evaluation of the Physical–Chemical Characteristics of Wastewater After Disinfection with Peracetic Acid

Water, Air, &; Soil Pollution - The use of peracetic acid (PAA) in the disinfection of sanitary effluents has been proposed by various authors. However, there are still doubts about its...     

Evaluation of the Migration Capacity of Zn in the Soil–Plant System

The mobility and migration capacity of Zn in the soil-plant system were studied in a series of pot experiments with barley as a test plant. The parameters of Zn accumulation depending on the metal concentrations in soils and soil solutions were estimated by soil and water culture methods. Experiments with barley in water culture were performed on a nutrient (soil) solution extracted from soddy-podzolic soil (Albic Retisol (Loamic, Ochric)) to which Zn²⁺ was added to reach working concentrations increasing from 0.07 to 430 μM. Different responses of barley plants to changes in the concentration of Zn in the studied soil were identified. Ranges of the corresponding concentrations in the soil and aboveground barley biomass were determined. Parameters of Zn accumulation by test plants were determined depending on the metal content in soddypodzolic soil and the soil solution. A new method was proposed for evaluating the buffer capacity of soils with respect to a heavy metal (Zn) using test plants (BCS(P)_Zn). The method was used to evaluate the buffering capacity of loamy sandy soddy-podzolic soil. The considered methodological approach offers opportunities for using data obtained during the agroecological monitoring of agricultural lands with heavy metals (HMs), including the contents of exchangeable HMs and macroelements (C and Mg) in soils and concentrations of HMs and (Ca + Mg) in plants, in the calculation of the buffering capacity of the surveyed soils for HMs.     

Soil pollution by mining activities in Andalusia (South Spain)—the role of Mineralogy and Geochemistry in three case studies

Purpose

Geochemical and mineralogical studies of soils potentially polluted by trace elements are basic to find the source of pollution, to understand the behavior of the contaminants in the environment, and to propose remediation and reclamation actions. This work reviews the role of the Mineralogy and Geochemistry to assess the hazard of soil contamination by trace elements in mining areas, focusing on three different case studies carried out in the Andalusian community (South Spain), with a Mediterranean temperate climate.

Materials and methods

Two significant mining districts were selected for this work: the Linares-La Carolina (Pb-Zn ores) and the Riotinto (Iberian Pyrite Belt, IPB) mining areas. Another case study was the Guadiamar basin, which soil was polluted by the spill produced in 1998 by the breakage of a mine tailing impoundment in Aznalcóllar mines (IPB). Soils, mine waste, and secondary precipitates were studied to approach the source of the pollution and the fate of the contaminants. Chemical composition (major and trace elements), soil parameters, and mineralogy of all materials selected were studied. In addition, the bioavailability of trace elements was determined by different methods.

Results and discussion

Pyrite and secondary phases are the main sources of pollution in the Riotinto area. Their stability is a key factor in the release of trace elements. The availability of trace elements in soils was lower in unpolluted leptosols than in contaminated orchards. In Linares-La Carolina, a severe pollution by Pb and a high availability (10–70% extracted with EDTA) were found. In Guadiamar basin, the residual pyrite sludge continues releasing trace elements to soil. Cd and Zn were mobile at pH <?6 and As at pH >?8, and Pb was quite immobile. Cd, Zn, and Pb can be coprecipitated by carbonates while As is mainly adsorbed by clays and iron oxyhydroxides.

Conclusions

The geochemical studies of soils polluted by mining activities allow to evaluate the availability of trace elements and their retention in soils. Therefore, geochemical and mineralogical studies are necessary for the assessment of soil pollution and remediation actions.

     

Effect of Magnesium Chloride–Induced Salinity on Carbon Dioxide Evolution and Nitrogen Mineralization in a Silty Clay Loam Soil

A laboratory incubation experiment was conducted to evaluate the effect of magnesium chloride–induced salinity on carbon dioxide (CO₂) evolution and nitrogen (N) mineralization in a silty loam nonsaline alkaline soil. Magnesium chloride (MgCl₂) salinity was induced at 0, 4, 8, 12, 16, 20, 30, and 40.0 dS m^?1 and measured CO₂ evolution and N mineralization during 30 days of incubation. Both CO₂ evolution and N mineralization decreased significantly with increasing salinity. The cumulative CO₂ evolution decreased from 235 mg kg^?1 soil at electrical conductivity (EC) 0.65 dS m^?1 to 11.9 mg kg^?1 soil at 40 dS m^?1 during 30 days of incubation. Similarly, N mineralization decreased from 185.4 mg kg^?1 at EC 0.65 dS m^?1 to 34.45 mg kg^?1 at EC 40.0 dS m^?1 during the same period. These results suggested that increasing magnesium chloride salinity from 4 dS m^?1 adversely affect microbial activity in terms of carbon dioxide evolution and N mineralization.     

Diethylenetriaminepentaacetic Acid–Extractable Micronutrients Status in Soil under a Rice–Wheat System and Their Relationship with Soil Properties in Different Agroclimatic Zones of Indo‐Gangetic Plains of India

Available micronutrient status of zinc, copper, manganese, and iron (Zn, Cu, Mn, and Fe) in surface soil samples under a rice–wheat system collected from farmers' fields in 40 districts representing different agroclimatic zones of the Indo‐Gangetic Plain (IGP) were determined. The selection of farmers, villages, blocks, and districts within an agroclimatic zone was made on the basis of a multistage statistical approach. In Trans‐Gangetic Plains, the diethylenetriaminepentaacetic acid (DTPA)–extractable Zn ranged from 0.11 to 5.08, Cu ranged from 0.22 to 4.72, Mn ranged from 2.9 to 101.2, and Fe ranged from 1.05 to 97.9 mg kg^?1. In the Upper Gangetic Plains, the DTPA‐extractable Zn ranged from 0.04 to 2.53, Cu ranged from 0.06 to 4.32, Mn ranged from 11.1 to 421.0, and Fe ranged from 3.48 to 90.2 mg kg^?1. In the Middle Gangetic Plains, the DTPA‐extractable Zn ranged from 0.17 to 8.60, Cu ranged from 0.09 to 7.80, Mn ranged from 3.0 to 155.1, and Fe ranged from 9.22 to 256.7 mg kg^?1. In the Lower Gangetic Plains, the DTPA‐extractable Zn ranged from 0.04 to 3.46, Cu ranged from 0.21 to 4.38, Mn ranged from 9.54 to 252.2, and Fe ranged from 3.60 to 182.5 mg kg^?1. The intensively cultivated Trans‐Gangetic transect representing the midplain and Siwalik had more available micronutrients than the arid plain. Midplain and arid plain showed 17 to 20% of soil samples were low to medium in Zn and 5 and 8% were low in Fe. In the Upper Gangetic Plains, only 25% samples were deficient in Zn, especially in central and southwest plains. In the Middle Gangetic Plains, 20 to 30% of samples were deficient in Zn, and very few samples were deficient in other micronutrients. In the Lower Gangetic Plains, a majority of the samples were medium to high in micronutrients except in Barind and Rarh Plains where 30% of samples were deficient in Zn. In the Lower Gangetic Plains, the available micronutrients were plentiful. Available micronutrients increased with increase in organic C content and decreased with increase in sand content, pH, and calcium carbonate. These soils are alluvial in nature, and there was no definite pattern of micronutrient distribution with depth in the profile. However, there was more accumulation in the Ap horizon than in the B horizon.     

Assessment of Intra-Biogeocenotic Variability of Forest Litters and Dwarf Shrub–Herbaceous Vegetation in Spruce Stands

Eurasian Soil Science - The differences in the species composition of the ground cover in spruce forest in dependence on the position in tessera are identified. Tessera is perceived as a...     

Location of Bare Soil Surface and Soil Line on the RED–NIR Spectral Plane

Soil as a separate natural body occupies certain area with its own set of spectral characteristics within the RED–NIR spectral space. This is an ellipse-shaped area, and its semi-major axis is the soil line for a satellite image. The spectral area for a bare soil surface is neighboring to the areas of black carbon, straw, vegetating plants, and missing RED–NIR values. A reliable separation of the bare soil surface within the spectral space is possible with the technology of spectral neighborhood of soil line. The accuracy of this method is 90%. The determination of the bare soil surface using vegetation indices, both relative (NDVI), and perpendicular (PVI), is incorrect; the accuracy of these methods does not exceed 65%, and for most of the survey seasons it may be lower than 50%. The flat part of the “tasseled cap” described as the soil line, is not a synonym for the area of the bare soil surface. The bare soil surface on the RED–NIR plots occupies significantly smaller areas than the area of soil line according to Kauth and Thomas.     

Distribution and Accumulation of Copper and Cadmium in Soil–Rice System as Affected by Soil Amendments

The effects of seven amendments on the distribution and accumulation of copper and cadmium in a soil–rice system were investigated using a pot experiment. Results showed that application of limestone, calcium magnesium phosphate (Ca–Mg–P fertilizer), calcium silicate (silicon fertilizer), Chinese milk vetch, pig manure, and peat significantly decreased the concentrations of Cu and Cd in rice roots by 24.8–75.3% and 9.7–49.9%, respectively. However, no significant difference was observed between zinc sulfate (zinc fertilizer) and the control treatment. The concentrations of Cu and Cd in different parts of rice followed the order: root > straw > grain, and all amendments restrained the transfer of Cu and Cd from rice root to stem. Copper and Cd concentrations in rice stems at the tillering stage were the highest, and then decreased from the tillering stage to the heading stage. However, they increased again at the ripening stage. The results also showed that application of amendments changed Cu and Cd solubility in soil and decreased their bioavailability, which resulted in the reduction of Cu and Cd uptake by rice. Significant correlations between the concentrations of Cu and Cd in soil solutions and in rice stems were found. The result demonstrated that limestone has the best efficiency among all the amendments used in reducing Cu and Cd contamination to rice production.     

Potassium Fixation and Release Characteristics of Some Benchmark Soil Series under Rice–Wheat Cropping System in the Indo‐Gangetic Plains of Northwestern India

Abstract

Potassium (K) fixation and release in soil are important issues in long‐term sustainability of a cropping system. Fixation and release behavior of potassium were studied in the surface and subsurface horizons in five benchmark soil series, viz. Dhar, Gurdaspur, Naura, Ladowal, and Nabha, under rice–wheat cropping system in the Indo‐Gangetic plains of India. Potassium fixation was noted by adding six rates of K varying from 0 to 500 mg kg^?1 soil in plastic beakers while K release characteristics were studied by repeated extractions with 1 M HNO₃ and 1 M NH₄OAc extractants. The initial status of K was satisfactory to adequate. Potassium fixation of added K increased with the rate of added K irrespective of soil mineralogy and soil depth. Soils rich in K (Ladowal and Nabha) fixed lower amounts (18–42%) of added K as compared to Gurdaspur, Dhar, and Naura (44.6–86.4%) soils low in K. The unit fertilizer requirement for unit increase in available K was more in low‐K soils. The study highlights the need for more studies on K fixation in relation to the associated minerals in a particular soil. Potassium‐release parameters such as total extractable K, total step K, and CR‐K varied widely in different soil series, indicating wide variation in the K‐supplying capacity of these soils. K released with 1 M NH₄OAc extractant was 20–33% of that obtained with 1 M HNO₃. Total extractable K using 1 M HNO₃ varied from 213 to 528 mg kg^?1 and NH₄OAc‐extractable K ranged from 71 to 312 mg kg^?1 soil in surface and subsurface layers of different soil series. The Ladowal and Nabha series showed higher rates of K release than Gurdaspur, Dhar, and Naura series, indicating their greater K‐supplying capacity.     

Influence of Glomus–Rhizobium Symbiosis on Productivity,Root Morphology and Soil Fertility in Garden Pea in Himalayan Acid Alfisol

The influence of dual inoculation of arbuscular mycorrhizal fungi (AMF) and Rhizobium was assessed on garden pea productivity, root morphology and soil fertility during 2011–2012 at Palampur, India, in a medium phosphorus (P) acid Alfisol. Field experimentation comprised 13 treatments involving Rhizobium, AMF and inorganic fertilizers in (RBD) replicated thrice. The dual inoculation of Rhizobium and AMF exhibited nominal effect on pea pod length, pod girth and number of seeds per pod. However, average pod weight (APW) and productivity increased by 14.1 and 20% following dual inoculation, respectively, over generalized recommended nitrogen, phosphorus and potassium (NPK) dose general recommended dose (GRD). Dual inoculation of pea seed with both symbionts sharply increased the root volume (RV), root dry weight (RDW), root weight density (RWD) and root nodules per plant by 34.5, 13.3, 13 and 44%, respectively. Similarly, the highest AMF root colonization was registered under dual-inoculated plots compared to sole application of Rhizobium or AMF. Different treatments including dual-inoculated ones did not alter the soil organic carbon (SOC), available N, K and diethylenetriaminepentaacetic acid (DTPA)-extractable micronutrients iron, zinc, copper and manganese (Fe, Zn, Cu and Mn) status significantly; however, a nominal buildup in the above-mentioned parameters was registered under dual inoculation. Available P status increased to the tune of 6.7 and 8.7% following dual inoculation with Rhizobium and AMF over their respective sole inoculations. Overall, the current study suggests that Glomus–Rhizobium symbiosis has great potential in enhancing productivity through better proliferation of the root system and improved soil fertility status. Furthermore, dual inoculation of AMF and Rhizobium can save up to 25% fertilizer N and P in garden pea in acid Alfisol of the northwestern Himalayas (NWH).     

Sorption and Desorption of Fluoride in Soil Polluted from The Aluminium Smelter at Årdal in Western Norway

Fluoride (F) accumulation and transport in soil columns near the aluminium smelter at Årdal in Western Norway are studied together with fluoride sorption capacity, and the effect of pH and ionic strength on F solubility in soil. Unpolluted soil columns of 50 cm height placed at different distances from the smelter (1–0 km) accumulated from 0.27 g F m-² to 1.5 g F m-² during a 5 months period. Fluoride accumulation was high in the upper 0–10 cm of the soil columns where 50–90% of the accumulated F was found. Laboratory sorption experiments showed that the sorption of added F in the Ah-horizons increased with increased distance from the smelter at Årdal, in accordance with decreasing previous pollution from the smelter. The B-horizons sorbed considerably more F than the Ah-horizons, due to higher content of Al-oxides/hydroxides. Maximum sorption of F occurred at pH 4.8–5.5. Fluoride solubility increased with increased ionic strength. Continued deposition of F may increase the availability to plants and soil organisms. Leaching of F from soil to groundwater or surface water will be strongly dependent on the presence and thickness of a B-horizon, and probably also on underlying horizons.     

Investigation of Nitrate–Nitrogen (NO3–N) Mass Balance Between Effluent and Soil Under the Effect of Raw Pistachio Residues and its Biochar Application

Disruption in the nitrogen (N) cycle balance has a negative impact on the overall trend of sustainable development, and using soil amendments is necessary to reduce these hazards. This study was carried out as a factorial experiment in a completely randomized design. The treatments consisted of three levels of amendments (0, 7.5 g/kg of pistachio residues, and 7.5 g/kg of biochar) and four levels of irrigation water salinity including 0.5 (urban water), 5.5, 8, and 10.5 dS/m and in three replications. Two pistachio seedlings were transferred to all columns and then in three steps, and in each step, 25 mg N/kg of potassium nitrate was added. The results indicated that pistachio residuals and its biochar increased nitrate outflow from effluent by 9% and 52%, respectively. The effects of amendment treatment and irrigation water salinity on all three characteristics of output nitrate, soil nitrate, and absorbed plant nitrate were significant at 1% level.     

Soil Potassium‐Release Characteristics and the Correlation of its Parameters with Garlic Plant Indices

Abstract

Potassium (K)‐release characteristics (PRC) of soil play a significant role in supplying available K. Information about PRC in the Hamadan soils is limited. The objective of this research was to study the PRC in nine soils from the Hamadan province by successive extraction with 0.01 M CaCl₂ over a period of 2000 h. The correlation of kinetic equation rate constants with soil properties and garlic indices was also studied. The release of K was initially rapid. More than 60% of the total K released during the first 168 h. The amount of K released after 168 h varied among soils and ranged from 292.8 to 736.8 mg kg^?1. The amount of K released after 2000 h was significantly correlated with K extracted by 1 M HNO₃, 0.01 M CaCl₂, and 0.1 M BaCl₂, whereas it was not significantly correlated with other soil properties. Potassium‐release characteristics were evaluated using five kinetic equations. Statistical analysis showed that the Elovich equation described the K‐release kinetics. A plot of other equations shows a discontinuity in slope at 168 h. Thus, two equations were applied to segments of the total reaction time (2 to 168 and 168 to 2000 h). The release‐rate constants (slope) in segment 1 are higher than in segment 2. The release‐rate constant of the Elovich equation and the zero‐order equation in two segments were significantly correlated with 1 M HNO₃, 0.01 M CaCl₂, and 0.1 M BaCl₂. Rate constants of the other equations were not significantly correlated with soil properties. The release‐rate constants of the Elovich equation and release‐rate constants of the zero‐order equation in two segments were significantly correlated with garlic indices. Rate constants of other equations were not significantly correlated with garlic indices. The results of this research showed that the Elovich and zero‐order equations can be used to describe K‐release characteristics.     

Soil–landscape relationships in the basalt-dominated highlands of Tigray,Ethiopia

Though knowledge about the distribution and properties of soils is a key issue to support sustainable land management, existing knowledge of the soils in Tigray (Northern Ethiopian Highlands) is limited to either maps with a small scale or with a small scope. The goal of this study is to establish a model that explains the spatial soil variability found in the May-Leiba catchment, and to open the scope for extrapolating this information to the surrounding basalt-dominated uplands. A semi-detailed (scale: 1/40 000) soil survey was conducted in the catchment. Profile pits were described and subjected to physico-chemical analysis, and augerings were conducted. This information was combined with information from aerial photographs and geological and geomorphologic observations. The main driving factors that define the variability in soil types found were: 1) geology, through soil parent material and the occurrence of harder layers, often acting as aquitards or aquicludes; 2) different types of mass movements that occupy large areas of the catchment; and 3) severe human-induced soil erosion and deposition. These factors lead to “red-black” Skeletic Cambisol–Pellic Vertisol catenas on basalt and Calcaric Regosol–Colluvic Calcaric Cambisols–Calcaric Vertisol catenas on limestone. The driving factors can be derived from aerial photographs. This creates the possibility to extrapolate information and predict the soil distribution in nearby regions with a comparable geology. A model was elaborated, which enables the user to predict soil types, using topography, geomorphology, geology and soil colours, all of which can be derived from aerial photographs. This derived model was later applied to other catchments and validated in the field.     

Efficiency of Phosphogypsum and Mined Gypsum in Reclamation and Productivity of Rice–Wheat Cropping System in Sodic Soil

In this study, efficacies of mined gypsum and phosphogypsum (PG), when applied at equivalent doses, were compared for sodic soil reclamation and productivity of rice–wheat system. Application of PG, followed by karnal grass as first crop, resulted in the greatest reduction of soil pH and exchangeable sodium percentage (ESP) followed by PG applied at 10 Mg ha^?1 alone. Application of PG at 10 Mg ha^?1 resulted in greater yields of both rice and wheat than other treatments. Ditheylenetriaminepentaacetic acid (DTPA)–extractable micronutrients of PG-treated soil were greater than in mined gypsum–treated soil. A greater portion of applied P entered the calcium (Ca)–phosphorus (P) fraction in PG-treated soil, which also resulted in more soluble P than the mined gypsum–treated soil. Phosphogypsum effected greater increase in aggregation, soil organic carbon, microbial biomass carbon, and aggregate associated carbon and decrease in zeta potential, leading to increased hydraulic conductivity and moisture retention capacity in soil over mined gypsum–treated soil.