Solonetzic Soils Research Articles

Features of the introduced species composition and state in the arboreta of Dzhanybek research station in the Northern Pre-Caspian Semi-Desert

The results of studying introduced species diversity and state under rainfed conditions at the Research station of the Institute of Forest Science of the Russian Academy of Sciences have been presented. The station is located in the clay semi-desert of the Northern Pre-Caspian region between the Volga and Ural rivers. The collections of two arboreta were examined. The first arboretum was established in 1953 on hydromorphic meadow-chestnut soils of large mesodepressions, and the second – in 1974 on solonetzic automorphic soils. The arboreta were originally established with an idea of complete elimination of irrigation. In recent decades, tending and silvicultural treatments were discontinued for a number of reasons. An annotated list of tree and shrub species includes 77 species belonging to 25 families and 44 genus. In the arboretum on the large mesodepression, the number of species surviving for more than half a century is 35% in relation to the number of “core” introduced species. Mostly, the species are represented by the families Rosaceae, Caprifoliaceae, Elaeagnaceae, Fagaceae, Fabacea, Oleaceae, Salicaceae, Sapindaceae, Ulmaceae. Some specimens older than 70 years are in satisfactory condition and produce viable volunteer regrowth. The main stages of their acclimatization, in relation to age, and changes in growing conditions, as affected by plants themselves as well as climate, are distinguished. In arboretum on solonetzic soils, the survival of species is 50%. The composition of tree and shrub vegetation of an unused pond, where spontaneous vegetation formed an intrazonal willow-oleaster-poplar community of quasi-riparian type, and of the overgrowing fallow land, where a specific “savannah-like” landscape was formed, have been studied. This allowed to identify the species whose life strategy contributes to their successful colonization of human-disturbed habitats and, in some cases, manifestation of the features of naturalization and invasiveness. The most promising species for landscaping, parks and other plantings in such harsh natural and climatic conditions were also determined.

Composition and Structure of Soils of the Gobustan Massif

Gobustan district is located in the eastern part of Shamakhi, 101 km from Baku. The relief is abrasion rocky. The soil cover here is varied. In the eastern part of Gobustan, gray brown Solonetz soils are common, in the north-west — gray-brown soils. Soil samples were taken, and individual types of soil cover structures were determined. The discovered soil structures are mainly tree-like in nature. Mechanical analysis data show that the upper arable and subarable horizons of these soils, 0-40 and 0-50 cm deep, are characterized by a clayey-heavy loamy mechanical composition. However, in the upper horizons of these soils the content of physical clay is relatively less and amounts to 46.1-52.8%, and the amount of silt particles does not exceed 22.2-28.4%.

Effective strategies for reclaiming soda-saline soils: Field experimentation and practical applications in Southeast Kazakhstan

Soda-saline soils pose significant challenges to agricultural productivity, particularly in regions like the foothill plain of the Ili Alatau in southeast Kazakhstan. In this study, we examined the effectiveness of different ameliorants, including phosphogypsum, elemental sulfur, and sulfuric acid, in reclaiming soda-saline soils and enhancing crop yields. The study was conducted under real climatic and production conditions at the "Amiran" LLP farm. Using a randomized complete block design, we assessed the impact of these ameliorants on soil composition and alfalfa yield over two cutting cycles. The experiment involved the application of phosphogypsum, elemental sulfur, and sulfuric acid to designated plots within the farm, each covering an area of 15m2. Soil samples were collected before and after treatment to assess changes in soil composition and salinity. Alfalfa, a resilient perennial crop, was selected for cultivation due to its tolerance to adverse soil conditions. Our findings reveal that all tested ameliorants successfully neutralized the toxic environment of soda-saline soils, resulting in improved soil conditions and increased crop productivity. Phosphogypsum treatment led to a reduction in bicarbonate and carbonate ions, an increase in sulfate ion concentration, and improved soil structure. Elemental sulfur incubation decreased bicarbonate and carbonate ions, further reducing absorbed sodium levels and enhancing soil fertility. Sulfuric acid treatment provided rapid results in reducing alkalinity and increasing sulfate ion concentration, leading to significant improvements in soil quality and crop yield. However, the reclamation of soda-saline solonetzes presented challenges related to soil heterogeneity and poor water permeability. To address these challenges, we recommend the implementation of mechanical destruction of the solonetz soil horizon and deep soil loosening, accompanied by the addition of ameliorants. In conclusion, our study demonstrates the potential of phosphogypsum, elemental sulfur, and sulfuric acid as effective ameliorants for reclaiming soda-saline soils and improving agricultural productivity in challenging environments. By adopting recommended reclamation strategies, farmers can overcome soil limitations and achieve sustainable crop production in regions affected by soda-saline soil degradation.

Adaptation potential of Miscanthus in a solonetz agricultural landscape

The aim of the study was to assess the ecological adaptability of Miscanthus cv. Soranovsky to saline agricultural landscapes and the phytomeliorative effect of the plant on saline soils. Location and time of the study. The field experimental part of the research was carried out in 2018-2020 in the central forest-steppe in the Barabinsky agrolandscape region (Experimental Research Station of the Siberian Federal Center for Agrobiotechnologies). Methods. The common methods of field and vegetation experiments, chemical analysis of soils and plant samples were used in the study. Results. Miscanthus can grow on solonetzic soils, providing a biomass yield of up to 5 t/ha under dry growing season conditions. The removal of nutrients from the soil by the biomass of Miscanthus stems was found to be low (8.2 kg/ha of nitrogen, 1.4 kg/ha of phosphorus and 9.7 kg/ha of potassium per year) due to their annual reutilization into rhizomes. This fact allow to avoid the danger of soil depletion during long-term cultivation of crops. Growing Miscanthus on meadow-chernozem solonetz for an average of three years led to changes in soil properties such as a decrease in pH, and changes in salts chemistry in the soil solution, manifested as a decrease in sodium bicarbonate content. Conclusions. Miscanthus as a crop has wide adaptation capabilities in relation to the marginal lands of the solonetz zone of West Siberia. Miscanthus plantings have a beneficial environment-forming effect on solonetz soils, due to the enrichment of soils with mineral nutrition elements and improvement of soil chemical properties.

Features of the mineralogical composition of solod and solod meadow-chestnut soil, the case of soils of the liman depression at Dzhanybek research station of the Institute of Forest Science RAS

The structure of the soil cover at the territory of the clayey semidesert of the Northern Caspian Sea is represented by triparted soil complex and peculiar soils like solod. Solods are formed in relief elements that are constant for this territory – mesodepressions, which are referred to limans. Two soil profiles were studied in the bottom of the liman – solod, and on its peripheral part – solodized meadow-chestnut soil. The formation of the solod profile occurs because of periodic moistening with fresh water and systematic flooding during the snowmelt period. The second soil is in the zone of transit of surface water to the liman. The soil profiles have the same type of eluvialilluvial distribution of the clay fraction, while differentiation is more distinct in solod. Mineralogical analysis established the same type of qualitative composition of clay and clastogenic minerals in both soils. Clay minerals are represented by illite, smectite, mixed-layer illite-smectite, accompanied by kaolinite and chlorite. Clastogenic minerals are represented by quartz, mica, K-feldspar, plagioclase, and chlorite. Quartz and feldspars are accumulated in the solodized horizons of the soil profiles; the content of quartz and feldspars decreases in the textural horizons, while the content of mica and chlorite increases. The distribution of the smectite phase in the solod profile reveals a difference in the ratio of illite-smectite packets, structures with a low content of smectite packets predominate in the solod part of the profile, and the proportion with a swelling packet in mixed-layer minerals increases in textural horizons. The solodized meadow-chestnut soil is distinguished by a smaller thickness of the solodized horizon, a higher content of the smectite component, and a calm character of the profile differentiation of clay and clastogenic minerals. In both soils, labile minerals with signs of superdispersion are recorded in the solodized and textural horizons. The superdispersion of labile minerals has different causes. In solod, it is associated with the action of low-mineralized water and the hydrolysis of soil minerals during the wet seasons of the year, as well as with the intense regime of intrasoil weathering in situ, and in the solodized meadow-chestnut soil, with the passage of the stage of solonetz soils. Differences in the smectite component were also revealed: in the solodized horizons of solod, it is represented by individual smectite and the mixed-layer phase of illitesmectite; and in the meadow-chestnut soil – by mixed-layer illite-smectite.

Ameliorative role of shrub belts on light-chestnut soils of sub-arid agro-landscapes ​

Forest plantings have a positive impact on soils, at the same time, the issues related to the role of shrub belts in the reclamation activities are poorly studied. There is a need to investigate their impact, especially in relation to saline soils. Today, tree plantations are more preferable than shrubs within the framework of steppe afforestation carried out in the arid zone. The purpose of the present study is to determine the reclamation efficiency of field-protective forest plantations, consisting of both tree stands and shrub belts, on solonetz soils. The research was conducted from 2020 to 2022 on the experimental plot laid in 1989-1991 in Kotelnikovsky district of Volgograd region. The experiments were conducted with the use of general research methods applied in agroforestry on a site area of 651.3 hectares. Soil sites were laid out according to the developed and standard methodology. From this study, a detailed evaluation of the forest conditions of the experimental site was determined. In general, they are unfavorable for growing protective forest plantations. The soils are saline to a different extent, the reserves of productive moisture are extremely limited, the positive and negative temperatures are extreme, and the relative air humidity is low. The reclamation efficiency of forest belts with inclusions of shrub belts on solonetz soils shows a positive impact of the shrub phytomass on the agroecology of arable land.

Recovery of dry mixed grass prairie well sites 15 years after reclamation

In the mixed grass prairie region of North America, well sites and their associated infrastructure have many ecological effects, including changes to soil physical, chemical and biological properties, loss of vegetation cover, altered plant species composition and habitat fragmentation. Reclamation of disturbed grassland is a challenge faced by many rangeland and conservation managers. The objective of this research was to examine the effect of time on reclaimed grassland well site soil properties and plant communities in southern Alberta. Seeding with three mixes of different numbers of species and proportions of native wheatgrasses (Triticeae tribe) was compared to natural recovery and undisturbed prairie after 15 years. Chernozemic soil was more similar to undisturbed prairie than Solonetzic soil, where soil chemical properties and plant species composition were less resilient following disturbance in some revegetation treatments. All reclaimed treatments had significantly lower soil organic matter, organic carbon and total nitrogen than undisturbed prairie. Vegetation cover and species richness in reclaimed sites did not usually differ from undisturbed prairie. An increase in the proportion of native wheatgrass cultivars in a seed mix did not result in a community dominated by them. Multivariate analysis showed species compositional differences in seeded and natural recovery relative to undisturbed prairie on Solonetzic soil, with no difference on Chernozemic soil except with the dominant wheatgrass seed mix. Thus recovery may require longer than 15 years for Solonetzic soil and revegetation with a dominant wheatgrass seed mix. Presence of early to late successional species indicated natural recovery could be a potential option for mixed grass prairie well site reclamation.

Реакция семян культур-фитомелиорантов при условии природного и техногенного засоления почв и грунтов

Abstract. The purpose of the study is to establish the optimal and critical values of different chemisms and the degree of salinity and the corresponding indicators of osmotic pressure, pH of the medium for the germination energy and germination of seeds of alfalfa and sweet clover. Objectives of the study are to identify the parameters of 50 and 99 % death of seeds of the studied crops, taking into account the chemistry and degree of salinity, to determine the most toxic water-soluble salts in solonetzic soils and drill cuttings; to identify the degree of participation of osmotic pressure and pH of the medium for the studied options, to conduct a comparative study of chemisms and the degree of their salinity on the germination and germination of seeds of phytomeliorants. Methods. The experiments were carried out in laboratory conditions. Seeds of sweet clover of the Alsheevskiy variety and alfalfa of the Yaroslavna variety were used as the object of the study. The energy and germination of seeds were determined according to GOST 12038-84. Scientific novelty. For the first time, the parameters the average lethal dose and the dose is absolutely lethal for sweet clover and alfalfa seeds were established in relation to different salinity chemisms, represented by one easily soluble salt, identical to soil and technogenic salinization. The parameters of osmotic pressure and pH of the medium for the average lethal dose and the dose is absolutely lethal were determined for each salinity chemistry. Results. It was found that a low concentration of MgSO4 (up to 0.3 %) did not reduce the energy and germination of seeds of sweet clover and alfalfa. Sodium neutral salts (Na2SO4, NaCl) led to the loss of seed germination of sweet clover and alfalfa (the dose is absolutely lethal) at a salinity degree of 2.0–2.9 %, which corresponds to a high osmotic pressure of 8.9–13.9 atm. Sweet clover seeds had a higher capacity for maximum salinity. Under soda salinity (Na2CO3, NaHCO3), 50 % death of sweet clover and alfalfa seeds corresponded to salinity levels of solonetzes and drill cuttings of 0.09 and 0.25 %. The phenomenon corresponding to the dose is absolutely lethal was noted here, respectively, at the level of salinity of soils and drill cuttings of 0.42 and 0.95 %. It is important to take into account the average lethal dose indicator when recultivating solonetzes and drill cuttings in order to establish seeding rates and select phytomeliorant crops.

Enzyme activities and organic matter mineralization in response to application of gypsum, manure and rice straw in saline and sodic soils

Saline and alkaline soils are a challenge for sustainable crop production. The use of organic and inorganic amendments is a common practice to increase the fertility of salt-affected soils that can trigger faster carbon (C) and nitrogen (N) cycling. We examined the effects of gypsum (Gyps), farm manure (Manure) and rice straw (Straw) on enzyme activities, organic matter mineralization and CO2 emissions in two salt-affected soils [Solonchak (saline); pH: 8, electrical conductivity (EC): 6.5, sodium adsorption ratio (SAR): 2.5, and Solonetz (alkaline sodic); pH: 8.9, EC: 1.6, SAR: 17]. Gypsum addition decreased soil pH up to 0.62 and 0.30 units, SAR 1.2 and 5.2 units, and EC 2.9 and 1.4 units in Solonchak and Solonetz, respectively. Dissolved organic C, microbial biomass C, dissolved organic N, mineral N (NO3− and NH4+), enzyme activities (urease, invertase, catalase, phosphatase, phenol-oxidase), alkali extractable phenols, and available phosphorous increased with the application of all amendments in both soils. Solonetz released more CO2 than Solonchak, whereas maximum CO2 emissions were common after manure application (3140 mg kg−1 in Solonchak, and 3890 mg kg−1 in Solonetz). We conclude that high SAR and low EC increase CO2 emissions through accelerated C and N cycling and manure decomposition in Solonetz soils.

IN MEMORIAM OF PROFESSOR NINA VYACHESLAVOVNA SEMENDYAEVA

The article informs about the research and pedagogical activity of the Researcher Emeritus of the Russian Federation, the Doctor of Agricultural Sciences, professor Nina Vyacheslavovna Semendyaeva, describing her work in the Siberian Research Institute of Agriculture and Chemicalization of Agriculture and in the Novosibirsk State Agrarian University. Professor Semendyaeva N.V. made a notable contribution to the studies of the West Siberian solonetzic soils and their transformation due to chemical melioration. Professor Semendyaeva N.V. also devoted much time to educating young scientists in the field of the rational use of soils in solonetz areas. The article also presents other areas of salinized soil research that Semendyaeva N.V. also pursued during her long and productive career.

The Change in the Components of the Ecosystems of Reclaimed Solonetz Soils on the Yergeni Plain during the Vegetation Period (the Republic of Kalmykia)

The Change in the Components of the Ecosystems of Reclaimed Solonetz Soils on the Yergeni Plain during the Vegetation Period (the Republic of Kalmykia)

Bioavailability, Speciation, and Crop Responses to Copper, Zinc, and Boron Fertilization in South-Central Saskatchewan Soil

An appropriate fertilization strategy is essential for improving micronutrient supply, crop nutrition, yield and quality. Comparative effects of different application strategies of micronutrient fertilizer were evaluated in two contrasting sites/soils (upper slope Chernozem and lower slope Solonetz) within a farm field located in the Brown soil zone of Saskatchewan, Canada. The study objective was to examine the impact of Cu, Zn, and B fertilizer application strategies on their mobility, bioavailability and fate in the soil as well as crop yield responses. The application strategies were broadcast, broadcast and incorporation, seed row banding, and foliar application of Cu, Zn, and B on wheat, pea, and canola, respectively. The study was laid out in a randomized complete block design (RCBD) with four treatment replicates for a specific crop and site. Crop biomass yields were not significantly influenced by micronutrient placement strategies at both sites. Pea tissue Zn concentration (35.2 mg Zn kg−1 grain and 5.15 mg Zn kg−1 straw) was increased by broadcast and incorporation of Zn sulfate on the Solonetz soil. Residual levels of soil extractable available Cu were increased significantly to 3.18 mg Cu kg−1 soil at Chernozem and 2.53 mg Cu kg−1 soil Solonetz site with the seed row banding of Cu sulfate. The PRS™-probe supply of Cu (1.84 µm Cu/cm2) and Zn (1.18 µm Zn/cm2) were significantly higher with broadcast application of corresponding micronutrient fertilizer in the Chernozem soil. Both the chemical and spectroscopic speciation revealed that carbonate associated Cu and Zn were dominant species that are likely to control the bioavailability of these micronutrients under field conditions.

Classification in hydrologic groups of soil of Uruguay

Dominant soils of the mapping units of the Reconnaissance Soil Map of Uruguay were tentatively classified in hydrologic groups (GH) following the procedure developed by the U.S. Soil Conservation Service (SCS). Since information on the relationship between precipitation and runoff is not available yet, the classification is mostly based on soil morphology: horizons sequence, their texture and structure, soil matrix color, mottling and presence of Fe-Mn concretions as indications of redoximorphic phenomena. Estimates of soil permeability and drainage on the basis of profile morphology and the knowledge of the hydric regime support the classification in GH. The results show that only very few soils are included in Group A, mainly Arenosols (Psamments) or very gravelly soils. Group B (24 profiles) includes mainly moderately well to well drained Subeutric Brunosols (Udolls). Group C (68 profiles) includes Subeutric and Eutric Brunosols (Udolls) and Argisols (Udolls and Udalfs), mostly moderately well to somewhat poorly drained, with a fine textured subsoil. Group D (63 profiles) includes all Vertisols, Planosols (Albolls and Aqualfs), Gleysols (mostly Aquolls and Udolls) and solonetzic soils (Aqualfs), most Litosols (Lithic Orthents and Udolls) and a few Brunosols (Udolls); drainage range from somewhat excessive to poor. the classification achieved is razonably consistent with available information on infiltration rate and hydraulic conductivity measurements for some soils. The comparison with known soils of USA, classified in GH with a more scientific basis, has not shown any evident contradiction between the classification criteria used both in US and Uruguay to assign each soil to the correct GH.

Changes in the rehabilitation status of irrigated lands in the Volgograd Oblast during 2001–2018

A comparative assessment of the rehabilitation status of irrigated lands, which are located in different natural areas of the Volgograd Oblast, is presented for 2001–2018. It was found that during the specified period there were recorded significant changes in the condition of irrigated lands: the total irrigation area has dramatically decreased since 2001 (-31%), especially at local runoff (-44.5%), the groundwater level has decreased (the level >5 m remains on 78% of the area). Also on this background, the areas of secondary salinized soils were also decreased (-3.9%). The main problems at the present are: the presence of fallow lands and rain-fed lands initially cultivated for irrigation, the lack of drainage on the most of irrigation systems and significant areas of saline soils requiring rehabilitation. Differences in natural conditions have largely determined the current rehabilitation state of irrigated soils and the intensity of their changes. Thus, the largest areas of secondary saline soils are preserved on irrigation systems located on the initially highly saline, poorly drained soils of the Khvalyn clay plain (Pallasovka, Svetloyarsk irrigation systems). Reconstruction of a number of irrigation systems with areas of secondary saline soils gave a positive result, after which secondary saline soils on reclaimed lands were not detected (Large Volgograd, Tyazhin irrigation systems). Significant areas of saline soils can be found on irrigated lands in the distribution areas of natural saline soils and chestnut, light chestnut saline soils – in the south of the Volga Upland, in the area of the Northern Yergeni and on the Khvalyn clay plain (Gorodishуsche, Generalovskoye, Pallasovka, etc. irrigation systems). Inherent research on the Volga-Don irrigation system with the involvement of remote sensing data has shown that this system reflects the general features of the modern rehabilitation condition of irrigated lands of the Volgograd Oblast – fallow lands, lack of drainage, and widespread saline soils are specific for this area. The use of high-resolution multispectral satellite images (Landsat-8, Sentinel-2) for the purposes of detection of fallow and irrigated lands in the current season demonstrates the possibility of clarifying information on this category of land. The determination of the distribution of salinized and solonetzic soils on irrigated lands of the Volgograd Oblast by remote methods can be carried out indirectly, i. e. according to the state of vegetation: when areas of sparse vegetation cover are being identified on images, targeted routes for soil surveys and soil sampling are selected.

Utilizing the Stability of Yield Parameters as a Technique to Select Salinity-Tolerant Wheat Genotypes

Summary Considering that agricultural production needs to be adjusted to global climate changes, it is of particular importance to develop bread wheat germplasm with improved tolerance to abiotic stress conditions. Therefore, the aim of this research was to identify stable wheat genotypes with increased salinity stress tolerance. The experiment was conducted with 27 wheat genotypes, at two localities: Kumane (solonetz soil type) and Rimski Šančevi (chernozem soil type) during two growing seasons. A significant influence of genotype and environment, as well as G × E interaction, on the phenotypic expression of yield components was found. The factor of genotype had the largest effect on the variation in plant height (38.7%) and the smallest effect on the variation in the number of grains per spike (8.24%). The greatest influence of the environment (64.7%) and G × E interaction (17.44%) was found in the variation in the number of grains per spike. Salinity conditions contributed the most to the decrease in the number of grains per spike (30%), which is considered the best indicator of the impact of stress on the plant. The smallest decrease in the number of grains per spike was recorded in the genotypes Šumadija (16.0%) and Harmonija (18.8%). However, AMMI and PCA analyses showed that the genotype Harmonija is characterized by a higher value of the number of grains per spike and greater stability. The genotypes Renesansa, Jugoslavija, Bankut 1205, and Harmonija were characterized by the smallest reduction in plant height under salinity conditions, among which Jugoslavija and Renesansa exhibited high stability and lower trait values. The smallest reduction in spike length was found in the genotypes Jugoslavija and Šumadija, which exhibited the specific adaptability to salinity stress. In terms of salinity tolerance, the genotypes Šumadija, Harmonija, and Renesansa are considered valuable genetic resources in breeding programs.

Ameliorating Effects of Soil Aggregate Promoter on the Physicochemical Properties of Solonetzes in the Songnen Plain of Northeast China

Freeze–thaw cycles cause serious soil erosion, which makes the prevention, control and management of solonetzic lands in the Songnen Plain challenging. The use of soil-aggregate-promoter (SAP) is highly favoured because of its energy-saving and efficient characteristics; however, SAP is rarely used in the improvement of solonetzic soil in cold regions. To fill this gap, we studied the effects of different experimental conditions on the physicochemical properties of solonetzes; the investigated conditions included the number of laboratory-based freeze–thaw cycles (with 0, 1, 3, and 5 cycles), initial moisture content (0%, 18%, 24%, and 30%) and SAP application amount (0 g/m2, 0.75 g/m2, 1.125 g/m2, and 1.5 g/m2). The results showed the following: (1) The soil pH value decreased significantly as the SAP application rate increased, and the effect of the initial moisture content and number of freeze–thaw cycles on soil pH was not significant. (2) SAP effectively reduced the soil electrical conductivity (EC), but a certain threshold was apparent, and the factors studied had significant effects on EC. (3) SAP effectively optimised the soil macroaggregates content and inhibited the damage posed by freeze–thaw cycles to the soil structure. These results provide an important theoretical basis for the effective prevention and control of solonetzes in the Songnen Plain of Northeast China.

Vertical distribution of soil seed bank and the ecological importance of deeply buried seeds in alkaline grasslands.

BackgroundSoil seed banks play a central role in vegetation dynamics and may be an important source of ecological restoration. However, the vast majority of seed bank studies examined only the uppermost soil layers (0–10 cm); hence, our knowledge on the depth distribution of seed bank and the ecological significance of deeply buried seeds is limited. The aim of our study was to examine the fine-scale vertical distribution of soil seed bank to a depth of 80 cm, which is one of the largest studied depth gradients so far. Our model systems were alkaline grasslands in East-Hungary, characterised by harsh environmental conditions, due to Solonetz soil reference group with Vertic horizon. We asked the following questions: (1) How do the seedling density and species richness of soil seed bank change along a vertical gradient and to what depth can germinable seeds be detected? (2) What is the relationship between the depth distribution of the germinable seeds and the species traits?MethodsIn each of the five study sites, four soil cores (4 cm diameter) of 80 cm depth were collected with an auger for soil seed bank analysis. Each sample was divided into sixteen 5-cm segments by depth (320 segments in total). Samples were concentrated by washing over sieves and then germinated in an unheated greenhouse. Soil penetration resistance was measured in situ next to each core location (0–80 cm depth, 1-cm resolution). We tested the number and species richness of seedlings observed in the soil segments (N = 320), using negative binomial generalized linear regression models, in which sampling layer and penetration resistance were the predictor variables. We ran the models for morphological groups (graminoids/forbs), ecological groups (grassland species/weeds) and life-form categories (short-lived/perennial). We also tested whether seed shape index, seed mass, water requirement or salt tolerance of the species influence the vertical distribution of their seed bank.ResultsGerminable seed density and species richness in the seed bank decreased with increasing soil depth and penetration resistance. However, we detected nine germinable seeds of six species even in the deepest soil layer. Forbs, grassland species and short-lived species occurred in large abundance in deep layers, from where graminoids, weeds and perennial species were missing. Round-shaped seeds were more abundant in deeper soil layers compared to elongated ones, but seed mass and ecological indicator values did not influence the vertical seed bank distribution. Our research draws attention to the potential ecological importance of the deeply buried seeds that may be a source of recovery after severe disturbance. As Vertisols cover 335 million hectares worldwide, these findings can be relevant for many regions and ecosystems globally. We highlight the need for similar studies in other soil and habitat types to test whether the presence of deep buried seeds is specific to soils with Vertic characteristics.

Effects of subsoiling tillage on structure, permeability, and crop yields on compacted Solonetzic and Chernozemic dryland soils in Western Canada

Compaction induced by field wheel traffic and dense layers in the subsoil may adversely alter soil structure, impede soil aeration, restrict water infiltration and nutrient uptake, and inhibit plant root development, negatively affecting plant yields. Reclaiming compacted Chernozemic and Solonetzic soils with hardpan B horizons may be possible through subsoiling operations to loosen the soil to depth, e.g. ~0.30 m. The objective of this study was to evaluate the effect of subsoiling on soil physical properties and plant yield in wheel traffic compacted and non-compacted Chernozemic and Solonetzic soils in southern Saskatchewan Canada. Subsoiling increased air permeability in the compacted Chernozemic soil from 4.5x10-7 m sec-1 to 2.9x10-6 m sec-1. In the compacted Solonetzic soil, subsoiling significantly decreased soil cone index to 1579 kPa compared to 2376 kPa in the non-subsoiled treatment. Crop yields (hard red spring wheat, dry peas) in the two years following the treatment were similar among tillage and compaction treatments in the Chernozemic soil. However, subsoiling of the compacted Solonetzic soil resulted in a seed yield increase of canola of ~ 1000 kg ha-1 in the first year of study and no treatment effect in the second year when wheat was grown. Overall, subsoiling of the compacted soils tended to improve soil physical properties, especially in the Solonetzic soils.

Yield of prickly pear cactus irrigated with saline water in soils of the semi-arid region

Knowing the tolerance of plants grown in the Brazilian semi-arid region to salt stress is of paramount importance for the sustainability of regional agriculture. This study was developed to examine the growth and yield of prickly pear cactus ‘Orelha de Elefante Mexicana’ (Opuntia stricta Haw) irrigated with increasing water salinity levels (0.75, 3.0, 5.25 and 7.50 dS m-1 to 25 ºC) and grown on soils representative of the Brazilian semi-arid region (chromic Luvisol, Solonetz and Fluvisol). Total fresh weight decreased linearly, with a 21.42% reduction when we compare the average fresh weight per plant in the lowest and highest saline level treatments. The chromic Luvisol and Solonetz soils showed the best fresh weight and dry matter yields under the present experimental conditions.

Soil solution studies in solonetz soils: review of the results

The article provides an overview of the main results of research devoted to soil solutions of solonetz soils obtained by centrifugation, pressing, displacement by a replacement fluid and lysimetry. Due to the difficulties of extracting soil solution from the dense horizons of solonetz soils, the available publications are few. Nevertheless, recently there has been increasing interest to such research, especially at the interface of pedogenesis and hydrogeology, in order to get a better insight into soil processes as shaped by landscape specifics. Since many aspects of solonetz genesis and melioration are still poorly understood, detailed studies of soil solutions in solonetz soils are urgently needed.