bluuebunny/crossref_metadata_2025 huggingface dataset:
Potassium supplying capacity of soils from Minas Gerais-Brazil .
Authors: Mattiello Mattiello Edson Marcio , Alvarez V. Vitor Hugo , de Barros Nairam Felix , Faria Arlindo Arlindo Ferreira , Lima Neves Julio Cesar , Nogueira de Paiva Haroldo
Published: September 2021

Potassium is present in distinct forms in the soil. The K forms in the soil are characterized by reversible exchanges between compartments and they have different characteristics in regards to availability for plant uptake. The soil's capacity to supply or restrict K to plants is different for each soil and it determines the sustainability of agricultural production and fertilization management. Thus, the goal of this study was to evaluate the K supplying capacity of soils of different mineralogies from Minas Gerais (Brazil), under successive corn cultivation. A greenhouse experiment was carried out in factorial 7 x 6 (seven soils and six rates of K), in a randomized complete block design, with four replications. The corn plants were cultivated during 45 days for seven successive crop cycles in pots. The potassium availability in the soil was evaluated at the beginning and at the end of each crop cycle using Mehlich-1 and Mehlich-3 extractors. All treatments showed significant decreases in soil K content, which affected corn dry matter accumulation. The reserve of K was highest in Ultisols followed by Inceptisols and Oxisols. Contribution of non-exchangeable potassium to the plant nutrition was observed. The K availability in soil measured by Mehlich-1 represented 40% of K uptake by plants, and 61% of K uptake when Mehlich-3 was used.
Wildfires, soil carbon balance and resilient organic matter in Mediterranean ecosystems. A review .
Authors: Almendros Gonzalo , González-Vila Francisco Javier
Published: September 2021

A review of the effects of wildfires on Mediterranean soils was carried out with special emphasis on the biogeochemical processes involved in soil C sequestration. Modifications to the composition and properties of soil humic substances and related resilient C-forms in soil resulting from fires were also discussed. The systematic effects of fires on soil organic matter (SOM) mainly involve changes to its solubility and colloidal properties, selective thermal degradation, structural condensation and the cyclization of soil C and N-forms. These effects represent an increase in the biogeochemical stability and chemical diversity of the SOM after the thermal generation of structures that are not found in soils unless they are affected by fire. Non-systematic effects also depend on local environmental constraints and on the great differences in fire intensities and propagation patterns. The effects of fire were also discussed, taking advantage of the results of laboratory simulation experiments. This approach is indispensable for differentiating fire intrinsic effects on soil from those produced by fire-induced inputs of charred necromass and the subsequent effects of soil erosion. In some cases, the characteristic properties acquired by post-fire soils can be explained in terms of molecular-level features of humic substances and, in particular, those concerning resistance to biodegradation, cation exchange capacity, N-availability, soil water repellence and aggregate stability.
CO2 production in anthropogenic Chinampas soils in Mexico City .
Authors: Ikkonen Elena , Stephan-Otto Ervin , Ibáñez-Huerta Abel , Krasilnikov Pavel , García-Calderón Norma Eugenia , Fuentes-Romero Elisabeth , Martínez-Arroyo Amparo
Published: September 2021

We studied microbial-associated CО2 production in anthropogenic chinampas soils. The soils were constructed by the accumulation of materials such as organic matter and loamy lacustrine sediments in Pre-Hispanic cultures in Mexico. To study the temperature sensitivity of CО2 production related to soil depth, moisture and oxygen availability, soil samples were collected at depths of 0-7, 7-18, 18-30, 30-40 and 40-50 cm. The soil samples were incubated under aerobic and anaerobic conditions at controlled temperatures (-5, 0, 5, 10, 20, 30 °C) and soil moistures of 10, 30, 60 and 90% water-filled pore space. For all the soil depths, incubation temperatures and soil moistures, the mean rate of aerobic CO2 production was 58.0 mg CO2 kg-1 d-1 and that of anaerobic CO2 production 31.2 mg CO2 kg-1 d-1, with the highest rate found in the soil samples collected at a depth of 0-7 cm. A decrease in soil organic carbon content inhibited CO2 production more under anaerobic than aerobic conditions. The dependence of aerobic СО2 production on soil moisture increased at what constituted both unusually high and low temperatures for the study area. Since the response of СО2 production to temperature was lower under anaerobic than aerobic conditions, the increase in soil moisture content led to a decrease in the temperature sensitivity of СО2 production. The response of microbial activity to other factors may be modified under what constitutes the limiting conditions for any of the factors considered, as follows: (i) when anaerobiosis increases in the soil, the limiting effect of substrate availability on microbial activity increases; (ii) the CO2 production rate becomes more dependent on soil moisture under temperature stress; (iii) the sensitivity of CO2 production to temperature is highest under drought stress.
The relationship between available P and selected biological properties in the rhizosphere of ten crop species under glasshouse conditions .
Authors: Safari Sinegani Ali Akbar , Rashidi Tahere
Published: September 2021

The aim of the present study was to evaluate the effect of cultivation of 10 agronomic plant species on selected biological activities and bioavailability of phosphorus (P) in different sampling zones. The lowest available P was measured in the planted soil with Solanum lycopersicum. Helianthus annuus, Zea mays and Phasaeolous vulgaris had a relatively larger effect on the decrease of available P in the rhizosphere soil and in the soil adhering to the root mats. S. lycopersicum and P. vulgaris had the highest P concentration (> 980 mg kg-1) and H. annuus and Z. mays had the highest P uptake (17.62 mg pot-1 and 13.13 mg pot-1, respectively). The mean soil microbial biomass P (MBP) was significantly high in the rhizophere soil and in the soil adhering to root mats of T. aestivum, Z. mays, S. tuberosum and S. lycopersicum (> 16 mg kg-1). The mean spore numbers of glumales (SNG) were significantly high in the rhizophere soil and in the soil adhering to root mats of P. vulgaris, S. lycopersicum, T. aestivum and Z. mays (> 167 N/10 g soil). The negative correlations of available P and soluble P with soil biological properties like SNG and alkaline phosphatase activity and the positive correlation with soil pH shows the importance of rhizomicroorganisms and glumales on P nutrition by plants in calcareous soil. Thus rhizosphere acidification of calcareous soil may not be as important as the improvement of biological properties in P uptake and acquisition by plants.
A preliminary study of the content and distribution of pesticide residues in soil samples from the Kathmandu valley, Nepal .
Authors: Giri Nirita , Sieghardt Monika , Lesueur Celine , Mentler Axel , Blum Winfried E.H.
Published: September 2021

The increasing use of pesticides for agricultural production is causing soil pollution problems in different parts of Nepal. Uncontaminated agricultural soils are of great importance as they have a direct impact on food security and human health. The objective of this study was to investigate the quality and quantity of pesticides in soil samples from districts near the capital city of Kathmandu, from where fruit and vegetables are brought to the city for consumption. A questionnaire survey was carried out in four districts around Kathmandu city to investigate the types of pesticides that are most commonly used in these districts. A total of 15 soil samples were taken at a depth of 10 cm and four complete soil profiles were sampled at three different depths (10 cm, 30 cm and 50 cm) on the farms of those who were interviewed. A total of four replicates of each soil sample were extracted and analyzed. The pH, soil texture and organic carbon content of the soil samples were analyzed to understand the general soil characteristics. The QuEChERS method used for the analysis of food samples was modified and applied to the soil samples. An HPLC-MS/MS was used for the qualification and quantification of the pesticide residues in the soil samples. The questionnaire survey revealed that carbendazim, chlorpyrifos-methyl, parathion-methyl, imidacloprid, metalaxyl, dimethoate, omethoate and dichlorvos were the most commonly used pesticides in the area studied. The chemical analysis showed that soil samples from all the districts except Kathmandu city were contaminated with various pesticides. The soil samples collected at the depth of 10 cm were found to be contaminated with the fungicide carbendazim and the insecticide chlorpyrifos-methyl at rates of up to 0.038 mg kg-1 and the systemic insecticide imidacloprid was found at up to 0.016 mg kg-1. The study of soil samples taken at different depths (10 cm, 30 cm and 50 cm) showed that pesticides were homogenously distributed with soil depth. The recovery between 77.5-112%, linearity between 0.01 mg kg-l - 2 mg kg-l with correlation factors R2 higher than 0.99 and LOQ between 0.2 µg kg-1- 6.25 µg kg-l were found. Some samples were contaminated with parathion-methyl, a highly carcinogenic organophosphorous insecticide, even though these pesticides had already been banned. For the first time, this study provides information about soil contamination levels due to pesticides in Central Nepal and shows that further research and information campaigns for farmers are necessary.
Assessment of arsenic toxicity in spiked soils and water solutions by the use of bioassays .
Authors: Martín Peinado Francisco José , Arco Lázaro Elena , Ortiz Bernad Irene , Romero Freire Ana , Sierra Aragón Manuel , Abbaslou Hakime
Published: September 2021

Arsenic (As) has become a serious environmental problem due to its extensive use and its potential high toxicity. Furthermore, it tends to accumulate in soils because of its low mobility in this medium. In this study, an assessment of potential As toxicity based on bioassays with Vibrio fischeri and Lactuca sativa was made in soil and water solutions of laboratory-contaminated samples. Soils spiked with 100 ppm of arsenic registered a reduction in As solubility in the soil solution over time, while for the longest incubation periods (8 weeks), the toxicity responses in all of the samples proved negligible for these bioassays. In spiked water solutions with increasing concentrations (0, 0.1, 1, 10, 12.5, 25, 50, and100 ppm As), significant reductions in root elongation and luminescence were found in lettuce and bacteria bioassays, respectively. The effective concentrations (EC50) of As were 1.52 ppm for L. sativa and 4.98 ppm for V. fischeri; this indicated that the L. sativa bioassay was more sensitive to arsenic concentrations in spiked solutions.
Soil catena along gypseous woodland in the middle Ebro Basin: soil properties and micromorphology relationships .
Authors: Aznar Javier M , Badía Villas David , Poch Rosa M
Published: September 2021

Gypsisols, mainly distributed in arid lands, support a key economic activity and have attracted a lot of scientific interest due to their particular physical and chemical properties. For example, Gypsisols show a high erodibility, low fertility and a variable water holding capacity that can be attributed to different gypsum particle sizes. This study aims to describe some representative Gypsisols from the middle Ebro Basin. Five representative soil profiles (mainly Gypsisols by WRB) were selected and sampled at different positions along a hillside where soils where developed on gyprock. Furthemore, it links micromorphological properties with soil water retention. Soils have a dominant loamy texture, more rarely stoney. Gypsum is abundant in all soil profiles, ranging from 6 to 84% with minimum values in Ah horizons and maximum in By and Cy. The soils have a low level of salinity and a very low cation exchange capacity (CEC). The soil organic matter (SOM) is medium or abundant in the Ah horizons, otherwise it is low. Soil aggregate stability (SAS) is related significantly and positively with SOM and porosity, which is also positively related with moisture retention at field capacity and saturation humidity. However, there is no significant correlation between porosity and permanent wilting point (PWP). Soil water retention is dependant on the gypsum percentage and textural class. Low levels of gypsum have no influence on water retention, but high gypsum levels (> 60%) enhance the field capacity (FC) and decrease PWP, especially when the gypsum is microcrystalline. Gypsum levels between 40 and 60% also increase available water contents (AWC) due to a decrease in PWP. There is a positive and significant correlation between PWP and FC in Gypsisols, except for those which are loamy and have gypsum values over 40%. The higher available water capacity (AWC) than expected is related to microcrystalline gypsum, predominant in the studied soils. These high AWC values are counteracted by an increasingly irregular pore space not suitable for root growth. All these cited characteristics result in a low fertility, influenced by the weather and the human impact, which deforested the highest part of these mountains in the Middle Ages.
Soil micromorphology and the Anthropocene—Cross-scale connections and technology trends .
Authors: Monger Curtis , Cooke Peter H.
Published: September 2021

The Anthropocene is a proposed geologic time period used to convey the profound influence humanity is having on the environmental systems of Earth. The term is controversial because of uncertainties about when to designate its beginning and whether a diagnostic feature of this era survive millions of years into the future. Still, the Anthropocene has captured the imagination of many scientists and provides a framework for analyzing the broad-scale impacts of humanity. The purpose of this paper is to explore how soil micromorphology can contribute to a deeper understanding of the Anthropocene. We approached this issue by systematically examining how data gathered at the micromorphology scale is connected to data obtained at the soil profile, landscape, and global scales. In particular we look at world food production, climate change, groundwater pollution, and plastic decomposition. From this cross-scale analysis it becomes apparent that micromorphology (1) contributes to an understanding of feedbacks operating in complex adaptive systems and (2) provides evidence otherwise invisible for making inferences about climate change. As the human footprint increases, soil micromorphology, using both traditional and emerging technologies, can make a unique contribution to understanding the Anthropocene.
Soil micromorphogenesis and Early Holocene paleoclimate at the desert margin of Southern Arabia .
Authors: Kühn Peter , Pietsch Dana
Published: September 2021

The Ramlat as-Sab’atayn desert margin near Ma’rib, Yemen, displays well-preserved Early Holocene paleosols that are documented by micromorphological and pedological data. The buried soils, which are represented by Ahb horizons, indicate soil formation mostly before 8.3 cal ka BP. In contrast, sandy cover sediments without signs of pedogenesis appeared between 8.3 and 6.6 cal ka BP due to increasing aridity. Characteristic micromorphological features of the cover sediments are a single grain microstructure, crystallitic b-fabric, predominant occurrence of fresh sideromelane, and remnants of microlayers. Micromorphological pedogenic features in the buried Ah horizons include a subangular blocky microstructure, undifferentiated b-fabric as a result of enrichment of organic matter and decalcification, and the predominant occurrence of completely altered sideromelane. Most of these horizons appeared to be nearly completely decalcified so that in parts a stipple speckled b-fabric and neoformed clay coatings could be detected as a result of stronger weathering and soil formation. Pedogenic data provide important information about Holocene climate fluctuations, including the amount of precipitation, which was calculated on the basis of geochemical data from buried A, AB and B horizons. The buried paleosols represent moist climate conditions with precipitation ranging from 400 to 600 mm a-1.
Micromorphological analysis on the influence of the soil mineral composition on short-term aggregation in semi-arid Mediterranean soils .
Authors: Virto Inigo , Barré Pierre , Enrique Alberto , Poch Rosa María , Fernández-Ugalde Oihane , Imaz Maria José , Bescansa Paloma
Published: September 2021

Aggregation in soils is the result of the interaction of the soil organic components and soil minerals. The reactivity of the mineral phase is acknowledged to interfere with aggregates formation and stabilization, but its influence on aggregation in semi-arid Mediterranean soils remains mostly unknown. In this study, we used micromorphological analysis of aggregates formed in a 28-d incubation in two agricultural soils differing only in the composition of the mineral phase in the upper Ap horizon (a carbonate-depleted Palexeralf with 21.5% clay, and a contiguous carbonate-rich Typic Calcixerept with 20.9% clay before decarbonation which was reduced to 10.4% upon decarbonation). The two soils belong to the same agricultural field and have had similar management for decades. Soil samples were completely disaggregated into their fractions < 250 μm, and incubated with fresh organic matter to stimulate re-aggregation. Macroaggregates (> 2 mm) formed during the incubation were separated at days 3, 7, 14, 21 and 28 and used to prepare thin sections. Macroaggregates were more abundant at day 3, and then decreased in number in the two soils, which indicates a dependency between organic matter decomposition and stable macroaggregates formation. They contained a greater proportion of smaller aggregates in the decarbonated soil. Micromorphological analysis revealed significant differences in the fabric and physical characteristics of these macroaggregates, in which bonds among primary particles were observed to be led by clays in the Palexeralf while the coarse fraction appeared embedded in a micromass with crystallitic b-fabric corresponding to carbonates in the Calcixerept. This resulted in a more compact fabric and less porosity in macroaggregates in the Calcixerept. Image analysis of thin sections was used to quantify and characterize the pore system of macroaggregates. Porosity (pores > 20 μm) was more than double (36.9% for 15.6%) within macroaggregates in the decarbonated soil, with more elongated pores. Although in both soils most pores were 20 to 150-μm in equivalent diameter, some porosity > 150 μm was observed only in macroaggregates from the decarbonated soil. These observations allow hypothesizing that the mechanisms responsible for aggregates stabilization and/or formation are different in the two soils, and that they result in different physical characteristics of soil aggregates. The implications of such differences on air and water flow rates within aggregates, and thus on the soil microbial activity and organic matter decomposition, as well as on soil erodibility, need to be studied and accounted for when evaluating the effect of soil management and other practices on soil quality in semi-arid Mediterranean agrosystems.
Modern and relict features in clayey cryogenic coils: Morphological and micromorphological identification .
Authors: Kovda Irina , Lebedeva Marina
Published: September 2021

The research was performed in the south-eastern part of Russia. Soils were formed on clayey parent materials under an extreme continental climate favorable for the deep freezing and maintenance of permafrost. Based on morphological, micromorphological, physical and chemical attributes, the soils represent a soil complex that includes Vertic Luvic Phaeozems (Clayic and Turbic) and Luvic Phaeozems (Clayic and Turbic). Decomposition, aggregation, eluviation, illuviation, pedoturbation, mineralization and hardening result from accumulation and transformation of organic matter, freeze-thaw, shrink-swell, and translocation processes, and cryoturbation. The soil complex is interpreted as polygenetic. Interpretations were made in order to differentiate modern soil processes from relict ones. The most ancient features correspond to the cold Pleistocene glacial period and include cryogenic wedges, permafrost involutions, disrupted soil horizons, cryogenic sorting of coarse material, and accumulation of the organic matter above the permafrost. A subsequent stage of pedogenesis under a warmer and wetter environment is reflected by black humus crack infillings, black humus aggregates deep in the subsoil, vertical translocation of mobile organic matter, and the formation of clay coatings. Finally, the current climate is a warmer but more arid pedoenvironment. It is recorded in the soil complex by brownish fulvic humus and the formation of vertic features. Even in this last relatively warm climatic stage, vertic features formed by shrinking and swelling processes co-exist with annual deep freezing of the soils and subsoil permafrost at a depth of about ~300 cm.
Evolutive and regressive soil sequences for characterization of soils in laurel forest (Tenerife, Canary Islands) .
Authors: Guerra-García José Asterio , Arbelo Carmen Dolores , Rodríguez-Rodríguez Antonio
Published: September 2021

Soil degradation processes have achieved the recognition of a global environmental problem in recent years. It has been suggested by various international forums and organizations that in order to adequately establish methods to combat land degradation, it is necessary to evaluate this degradation locally and at a detailed scale. The evaluation of soil degradation of natural ecosystems at a detailed scale requires the definition of standards to which to compare this degradation. To define these standards and properly handle the processes that give rise to variations in soil quality and degradation, it is necessary to establish in some detail the pedogenic processes that have or have not taken place in a particular area and which lead to the formation of a mature soil. A mature soil should be considered as standard in these situations and, therefore, a non-degraded soil. This paper presents the possible evolutive and regressive sequences of soil, and provides some examples of using this methodology to evaluate the degradation of the same in the Monteverde of the island of Tenerife. It also presents some physical, chemical and mineralogical properties of climacic mature soils, degraded soils and low quality soils, and examines their similarities and differences in this bioclimatic environment and on different parent materials. Thus it is observed that the main processes of degradation in these areas are related to plant cover modifications that lead to the decreasing protection of the soil surface, which results in the long term, in the onset of degradation processes such as water erosion, biological degradation, loss of andic properties, compaction and sealing and crusting surface, loss of water retention capacity, illuviation, etc. Climacic soils that can be found in areas of steep lava flows are Leptosols, while gently sloping areas are Cambisols and Andosols. On pyroclastic materials there are vitric Andosols and andic Andosols according to their degree of evolution. The most characteristic regressive processes are illuviation/leaching, resulting in Luvisols, Lixisols and Alisols; and water erosion, causing the presence of secondary Leptosols.
Reutilization of granite powder as a component of permeable reactive barriers for the treatment of Cr(VI)-contaminated waters .
Authors: Barral María Teresa , Liste Ángel , Balufo Alejandro , Paradelo Remigio , Cancelo-González Javier , Prieto Diego M.
Published: September 2021

Permeable reactive barriers (PRBs) are efficient and cost-effective systems for groundwater remediation. Different types of material have been tested as reactive media for constructing PRBs. To this purpose, the use of waste materials is of particular interest, provided they meet some permeability and reactivity requirements. In the present study, the use of granite powder, a waste generated during the process of cutting granite, was evaluated as a component of PRB filler, mixed in different proportions with compost. The Cr(VI) adsorption capacity and desorption behaviour of granite powder, pine bark compost, composted municipal solid waste and mixtures containing different proportions of granite powder and compost was compared. Individually, the granite powder was not suitable for use as PRB filler because of its moderate permeability and Cr(VI) adsorption capacity. The addition of pine bark compost increased the hydraulic conductivity and improved the Cr(VI) adsorption capacity of the material, while decreasing Cr desorption. In turn, the addition of compost derived from municipal solid waste did not have the same beneficial effect, as it decreased the hydraulic conductivity of the mixtures and had only slightly improved the adsorption capacity. In summary, mixtures containing 50 or 25% granite powder and 50 or 75% pine bark compost (v/v), respectively, were the best materials for use as a PRB in relation to cost/effectiveness.
Planting trees and amending with waste increases the capacity of mine tailings soils to retain Ni, Pb and Zn
Authors: Asensio Fandiño Verónica , Vega Flora A. , Forján Rubén , Covelo Emma F.
Published: September 2021

The sorption capacity for Ni, Pb and Zn of mine tailings soil with and without reclamation treatment (tree planting and waste amendment) was evaluated using the batch adsorption technique. It is important to determine the capacity of waste-amended soils to retain Ni, Pb and Zn, as the sludges used usually have high concentrations of these metals. The results obtained in the present study showed that the untreated mine tailings soil had a low capacity for Ni, Pb and Zn retention. The sorption capacity for Pb increased significantly in all of the treated soils, without any significant differences between them. The treatment that most increased the sorption capacity for Ni and Zn was planting with trees and amending with waste simultaneously, as this increased the concentration of both organic and inorganic carbon, exchangeable calcium, soil pH and effective cation exchange capacity
Soil crusting and surface runoff in agricultural land in Galicia (NW Spain)
Authors: Taboada-Castro M. Mercedes , Rodríguez-Blanco M. Luz , Palleiro Laura , Taboada-Castro M. Teresa
Published: September 2021

This study discusses the soil surface conditions under which crusting and runoff are generated. A field survey was conducted in three agricultural districts in the province of A Coruña (Galicia, Spain), where the soils, developed over basic schists in a temperate-humid climate, are prone to crusting. A total of 168 freshly tilled surfaces and the cumulative natural rainfall since the last tillage operation were studied. The agricultural situations corresponded to primary and secondary tillage, crop seedbeds and pasture seedbeds. Stages of soil crusting were recorded by visual assessment, based on the estimation of the extent of structural, transitional and sedimentary crusting. The runoff was estimated by measuring the maximum distance reached by soil particles carried by the runoff and then deposited on the soil surface where there were no incisions on soil. Surface crusting was observed in all agricultural situations. The amount of accumulated rainfall required to form a fully sedimentary crust was variable, depending largely on the initial soil surface roughness. On average, 50, 150 and 350 mm of accumulated rainfall were required for soil surfaces with a low, medium and high roughness, respectively. The combination of three soil surface conditions (crusting stage, roughness and vegetation cover) was primarily responsible for the start of runoff formation.
Composition of the organic matter in soils from six pedoclimatic zones of Magdalena (Colombia)
Authors: Vásquez Polo José Rafael , Schellekens Judith , Kaal Joeri
Published: September 2021

The soils in the NE of the Magdalena province (Colombia) are subject to intense degradation primarily because of the low accumulation rate of soil organic matter (SOM) and its fast turnover. Numerous traditional studies have aimed to mitigate this situation, focusing on the analysis of total SOM contents. The present study aimed to determine SOM quality from six areas under humid and dry tropical forest with different pedoclimatic conditions, using molecular characterization. For each area, sites with different current land use were studied, including forest and cultivated sites. We applied analytical pyrolysis (pyrolysis-GC/MS) to aqueous NaOH-extractable SOM from surface soil samples. One-hundred and ten pyrolysis products were identified and quantified, from the following chemical groups: N-containing compounds (34.1 ± 5.1%), carbohydrate markers (21.1% ± 7.1%), monocyclic aromatic compounds (20.0% ± 4.5%), aliphatic compounds (7.7% ± 1.4%), phenols (7.0% ± 5.0%), polycyclic aromatic compounds (3.6% ± 0.9 %), lignin products (0.3% ± 0.3%) and other compounds (0.2% ± 0.1%). SOM of all studied areas showed a large proportion of N-containing products, indicating a high contribution from microbial material to the SOM. Multivariate statistics allowed for the differentiation between microbial-derived and plant-derived SOM (Factor 1) and the relative proportion of burning residues (Factor 2), and indicated that pedoclimatic conditions exert more influence on SOM composition (cool and humid zones were enriched in microbial SOM while dry zones contained more plant-derived SOM) than land use for the studied soils.
Barium content of paleosols from Central Italy
Authors: Magaldi Donatello , Arfaioli Paola
Published: September 2021

A paper published in 2013 concerning the elemental composition of 50 paleosols from Central Italy (Tuscany and Abruzzo) noted that Barium values were exceptionally high, a fact which could be not justified by the presence of neighbouring outcrops of igneous rocks. This current paper aims to explain the origin and significance of barium enrichment in these Pleistocene paleosols (Xerults, Xeralfs, Udalfs and Xerepts) formed on alluvial siliciclastic deposits mainly derived from sandstones and shales and, in a few cases, insoluble residues of Mesozoic carbonate rocks. Ba content was considered in relation to the molecular weathering ratio, soil pH and total Mg content. A qualitative inverse correlation was suggested between Mg and Ba for most soils. Maximum Ba values were found both in acid and alkaline soils, while minimum values were observed in neutral soils. This suggests the existence of different pedoclimatic environments. The acid soil solution supports the Ba release from minerals and soil components and its precipitation in the presence of SO42-, clays and Fe/Mn nodules, whereas other bases are removed. In contrast, the soils during seasonal low humidity periods or extended events of drought have a different pH: the soil solution then has a higher base concentration and therefore a greater likelihood of Ba precipitation bound to clays, metal oxides or even as insoluble sulphate (barite). Thus the soils with higher and lower pH are enriched in Ba both directly and indirectly in relation to ionic strength of the soil solution. The significant enrichment in Ba is ascribed to intense and very long pedogenetic processes during past climatic conditions of a wet- warm subtropical type, which acted on the Italian paleosols of Pleistocene age. The recurring shrink-swell pattern would have increased the rate of chemical weathering, the rate of barium release in the soil solution and its subsequent immobilisation in neoformed complexes as barite and others.
Health cards for the evaluation of agricultural sustainability
Authors: Mijangos Amezaga Iker , Muguerza Elustondo Enaitz , Garbisu Crespo Carlos , Anza Hortala Mikel , Epelde Sierra Lur
Published: September 2021

Agroecosystem Health Cards are handbooks that provide straightforward, practical information on how to assess agroecosystem health through the analysis of a group of aboveground (crop) and, above all, belowground (soil) indicators. In addition, they allow for the assessment of the impact of specific agricultural practices on agroecosystem health. The main objective of these Agroecosystem Health Cards is to provide farmers and other stakeholders related to agroecosystem management (technical staff, scientists and administration staff) with a practical tool that allows them to evaluate the impact of agricultural practices on agroecosystem health by themselves, so that they can choose those management options that prove to be more sustainable. To this purpose, these Agroecosystem Health Cards explain which health indicators can be measured, how to do it properly, the meaning of the different indicators and, finally, the reference values considered “good”, “medium” and “bad”. Indicators are divided into two categories (basic and advanced) in order to carry out a basic and advanced diagnosis of health, respectively, depending on the interests and possibilities of the user.
Pollution and risk assessment of potential hazardous elements in a shooting range soils (NW Spain)
Authors: Rodríguez-Seijo Andrés , Lago-Vila Manoel , Arenas-Lago Daniel , Andrade María Luisa , Vega Flora Alonso
Published: September 2021

Pollution at shooting ranges is an issue of growing importance. Accumulation in soils of potentially harmful elements (PHEs) from ammunitions used is a major environmental risk. The total and available (extraction with 0.01 M CaCl2 and DTPA) content of As, Cd, Cu, Ni, Pb, Sb and Zn were evaluated in 10 soils from a shooting range for military use (León, Spain). The results showed that, among the studied pollutants, Pb is the element present in highest concentration (13.83-4451.57 mg kg-1), followed by Sb (1.80-96.10 mg kg-1), Cu (4.50-88.52 mg kg-1), As (13.24-62.47 mg kg-1), Zn (13.31-46.19 mg kg-1), Ni (11.53-46.30 mg kg-1) and Cd (0.30-1.00 mg kg-1). The strong soil acidity, its medium organic matter content and low proportion of clay, favor a high availability of these PHEs, particularly Pb and Cu. Although impact mitigation measures, such as collecting cartridges whenever a round of shots is fired in the shooting range, the pollution assessment indicates that performances should improve in the berm. The application of organic amendments, or nanomaterials, could help reduce the PHEs availability and avoid the contamination of adjacent areas.
Available phosphorus in the central area of the Argentinean Pampas. 2: Kinetics of adsorption and desorption of phosphorus under different soil and management environments
Authors: Silva Rossi Martín María , Rollán Adriana Ana del Carmen , Bachmeier Omar Antonio
Published: September 2021

The concentration of phosphate ions in solution is critical in defining the ability of a soil to adequately meet crop demand. That concentration is regulated by adsorption/desorption and precipitation/dissolution processes, particularly its kinetics of reaction. This work was developed in order to find the kinetic model describing the sorption/desorption of phosphate in soils of the Argentinean Pampas region, to describe the processes associated with these reactions and to define the effect of temperature on them. A bi-linear model that adequately describes the data obtained in the adsorption and desorption experiments is proposed. Thus, it was possible to clearly differentiate two different kinetic mechanisms, each characterized by different reaction rates. Two very labile pools of phosphorus were determined in these soils. The rate at which these processes occur indicates the occurrence of chemical reactions of precipitation in highly soluble compounds and surface adsorption reactions with very low binding energy, as P is quickly released into the soil solution in the desorption process. However, since the amounts of P released in the desorption process are very much less than the adsorbed, is possible to infer that both processes occur at non-equilibrium conditions and there is a lack of reversibility of the reaction P-Soil – P-Solution in the soils studied. The intensity of these processes is differentially affected by temperature and, in general, there is a positive effect of phosphorus fertilization history, although the effect of this is not clearly seen in the amounts of extractable phosphorus with the classic Bray & Kurtz N°1 method.
Soil – landscape relationships in the Empordà basin (Catalonia, NE Iberian Peninsula)
Authors: Boixadera Jaume , Antúnez Montserrat , Poch Claret Rosa Maria
Published: September 2021

Soils developed in representative landforms, which were previously mapped at a detailed scale in the Empordà Basin, were selected to characterize their main pedogenetic processes and to improve the soil maps through a better understanding of the soil – landscape relationships. This basin is a relatively large region (1,300 km2) in Northeastern Catalonia, where Neogene and Quaternary sediments outcrop. They are alluvial and delta fan deposits that mainly reflect a continental environment. Besides varying degrees of soil rubefaction, we can identify calcium carbonate redistribution, clay illuviation and sodication as the main soil forming processes, together with abrupt textural changes, vertic and redoximorphic features. These processes and features are expressed under different morphologies in the area, depending not only on parent material, landform and age, but also on human action, which allows us to refine the conceptual soil-landscape model. Calcium carbonate redistribution is a key process reflecting both changing general environmental conditions and local chemical soil conditions. The actual soil characteristics and the soil forming processes allow us to propose that (i) aeolian dust inputs in these soils have been low to moderate throughout, and that (ii) the rainfall pattern in the last part of the Holocene was able to remove these dust inputs, but unable to leach carbonates from medium textured, moderately calcareous soils in the area when they are some kilometres from the sea and not directly affected by the dune system.
Urban planning and archeological conscience: The impact of soil sealing on archaeological sites
Authors: García Rodríguez Pilar , Álvarez García Beatriz
Published: September 2021

Soil sealing (permanent covering of an area by impermeable artificial material) is one of the most serious problems affecting ecosystems in Western Europe. Numerous studies have analysed this issue from an ecological approach, but very few take into account its impact on one of soil’s essential functions, namely the preservation of archaeological sites. Spanish laws on historic heritage (1985) and environmental impact (2013) have tackled the matter by legislating measures for the preservation of heritage. Furthermore, in 1992 Spain signed the Valletta Treaty (the European Convention on the Protection of the Archaeological Heritage) of the Council of Europe, and further ratified it in 2011. Historians, archaeologists and soil scientists should respond to this threat using a multidisciplinary approach. The present study analyses the impact that soil sealing has had on the Roman city of Complutum, located on the Henares River plain (Madrid, España) on highly fertile Fluvisols and Calcisols. One of the aims of this study is to show that the combined use of aerial photos and satellite images provides a continuously updated file of urban development processes and therefore makes it possible to foresee the impact on archaeological sites. At present, medium and high spatial resolution images (Spot and Landsat satellites) can be obtained free of charge and digital processing makes it possible to map any variations in these sites. Another aim of the study is to analyse the importance of soil type and quality in establishing settlements in corridors which have served as important communication routes. There is a greater likelihood of urban planning and development processes in the immediate surroundings of these routes over the years, implying that it is highly probable that pre-existing sites will be destroyed.

 
Decomposition from legume and non-legume crop residues: Effects on soil organic carbon fractions under controlled conditions
Authors: Sá Pereira Eduardo de , Duval Matias Ezequiel , Galantini Juan Alberto
Published: September 2021

Cover crop (CC) residues protect the soil from erosion and their permanence on the surface is largely influenced by their biochemical constituents. We performed a study under controlled conditions to investigate the dynamics of legume and non-legume CC residues decomposition and the transformations of the soil labile organic carbon fractions in the surface layer (0-15 cm). The experiment was carried out on a Typic Argiudoll (clay loam, 27.4 g kg-1 soil organic matter, 14 mg kg-1 extractable phosphorus and 6.5 pH) placed in undisturbed pots (1570 cm3) in a greenhouse under controlled conditions of temperature (25 ± 1 °C). We evaluated three CC species (oat, Avena sativa L.; vetch, Vicia sativa L.; Persian clover, Trifolium resupinatum L.) and a no-CC control (fallow). Shoot residues were applied on the soil surface at 5.4, 5.4 and 2.7 g dry matter (equivalent to 6, 6 and 3 Mg ha-1 for oat, vetch and clover, respectively) and incubated for 362-days (eight sampling times). The water content in the pots was maintained periodically by weight at 60% of soil water-holding capacity. The soil samples were analyzed for particulate organic carbon (POC), and total and soluble carbohydrates (CHt and CHs, respectively). Oat and vetch residues decomposed faster than clover, with the decomposition rate constant (k) values of 1.3, 1.4 and 1.9 year-1, respectively. At the end of the experiment, POC concentration was lower in vetch (1.83 g kg-1) and clover (1.96 g kg-1) than in oat (2.21 g kg-1) and fallow (3.00 g kg-1), indicating a loss of 45-64% from their initial values. Soil CHt was influenced by residue quality, where the periods of greatest residue decay (vetch 21-59 days and oat 93-130 days) corresponded to higher soil CHt. Hence, this organic carbon fraction is sensitive to residue decomposition and can be indicators of changes in soil organic matter over short periods of time.
Application of artificial neural networks to estimate soil organic carbon in a high-organic-matter Mollisol
Authors: Moreno Rocío , Irigoyen Andrea Inés , Monterubbianesi María Gloria , Studdert Guillermo Alberto
Published: September 2021

Soil organic carbon (SOC) has a key role in the global carbon (C) cycle. The complex relationships among the components of C cycle makes difficult the modelling of SOC variation. Artificial neural networks (ANN) are models capable to determine interrelationships based on information. The objective was to develop and evaluate models based on the ANN technique to estimate the SOC in Mollisols of the Southeastern of Buenos Aires Province, Argentina (SEBA). Data from three long term experiments was used. Management and meteorological variables were selected as input. Management information included numerical variables (initial SOC (SOCI); number of years from the beginning of the experiment (Year), proportion of soybean in the crop sequence; (Prop soybean); crop yields (Yield), proportion of cropping in the crop rotation (Prop agri), and categorical variables (Crop, Tillage). In addition, two meteorological inputs (minimum (Tmin) and mean air temperature (Tmed)), were selected. The ANNs were adequate to estimate SOC in the upper 0.20 m of Mollisols of the SEBA. The model with the best performance included six management variables (SOCI, Year, Prop soybean, Tillage, Yield, Prop agri) and one meteorological variable (Tmin), all of them easily available and with low level of uncertainty. Soil organic C changes related to soil use in the SEBA could be satisfactorily estimated using an ANN developed with simple and easily available input variables. Artificial neural network technique appears as a valuable tool to develop robust models to help predicting SOC changes.
Assessment and suggestions for improvement of soils with different uses in a sector of Montesinho Natural Park, Portugal
Authors: Gutiérrez Montero Mirian , Fonseca Felícia , Figueiredo Tomas , Sánchez Bellón Ángel
Published: September 2021

The main objective of this study is to evaluate the quality of four soils with distinct uses and managements (pasture, cereal, chestnut and oak) to check whether their use is appropriate and propose improvements. The investigation took place at Vilar de Ossos, a sector of Montesinho Natural Park in northeast Portugal. Results were obtained from field work and laboratory analyses of more than 25 parameters (textural analysis, nitrogen, phosphorous and potassium contents, cation exchange capacity and cation saturation percentage, pH, organic matter, stoniness, useful soil depth, drainage, etc.). An estimation of erosion was also made following the universal soil loss equation. Pasture and oak registered low values on soil erosion while cereal and chestnut had medium values in the same parameter. With the data obtained, we made soil evaluations according to the Agrologic Classes and the Riquier Bramao and Cornet systems. Results indicate that only chestnut soil had low qualities for farming, and that cereal soils needed a change of use. Finally, based on the assessments, recommendations to improve soil quality have been made. For the pasture soil, the proposal is to put the focus on the nutritional values. In the cereal soil, conservation tillage is proposed. In the chestnut soil, stopping the current plowing technique is suggested and, in the oak soil, which is a natural soil, the proposal is to leave it in its current state.
Carbon and nitrogen in forest floor and mineral soil under four forest species in the Mediterranean region
Authors: Fonseca Felícia , Figueiredo Tomás
Published: September 2021

The organic and mineral horizons of soils are of great importance in C and N storage in forest areas. However, knowledge of the effects of forest species on the stocks of these elements is still scarce, especially in Portugal. In order to contribute to this knowledge, a study was carried out in forest stands of Pinus pinaster Aiton (PP), Pinus nigra Arnold (PN), Pseudotsuga menziesii (PM) and Castanea sativa Miller (CS), installed in the 1950s in northern Portugal. Sampling areas with similar topography, lithology and climate were selected, in order to better identify hypothesized differences in C and N storage due to forest species effect. In each stand, 15 sites were selected randomly and the forest floor (organic layers) was collected in a 0.49 m2 area. The layers H, L and F of the forest floor were identified and, for L and F, their components were separated in leaves, pine cones/chestnut husks and branches. At the same sites, soil samples were also collected at 0-10 and 10-20 cm depth. At these depths, undisturbed samples were also collected for bulk density determination. The concentrations of C and N were determined in forest floor and mineral components of the soil, and converted in mass per unit area. The quantity of C storage per unit area followed the sequence PN > PM > CS > PP, while for N the sequence was CS > PM > PN > PP, OM and PP keeping the same relative position in the sequence in both C and N concentrations. The PM and CS species store similar amounts of C and N, and about 90% of these elements is found in the upper 20 cm of the mineral soil. In PN and PP species, the contribution of forest floor to the storage of these elements is more expressive than in the other species, but lower than 30% in all cases.