Hydromorphic Soils Research Articles

Poorly Crystalline Fe (III) Oxide excess can to alter the electrochemical paths of soils in the Brazilian Tropical Savannah.

Fe oxides are the one of the major constituents of tropical soils, and have very reactive and binding sites. Under flooding conditions used as electron acceptors in respiration of anaerobic microorganisms. The aim of this study was to present the electrochemical and microbiological behavior of a tropical hydromorphic soil under application of Poorly Crystalline Fe(III) oxide. In this way, an iron gel solution was prepared in three different concentrations (0.001, 0.01, 0.03 M) and distributed in four blocks in a microcosm assay. Electrochemical measurements and assessments of soil microbial biomass was made in four different periods (1, 7, 15 and 30 days). Fe (III) oxide changes the pH, Eh and microbial biomass until 15 days of incubation. The 0.03 M concentration prolonged the buffering system, and apparently was change the microbiota more abruptly, on the other hand, at the final incubation, are suggest the development of specific groups capable to degrade crystalline iron.

Пойменные крупнотравные леса острова Сахалин (класс Salicetea sachalinensis Ohba 1973)

Пойменные крупнотравные леса острова Сахалин (класс Salicetea sachalinensis Ohba 1973)

Причины гибели сосны обыкновенной в старовозрастных культурах Нарынских песков

RUSSIAN JOURNAL OF FOREST SCIENCE, 2018, No. 5, P. 381–388 CAUSES OF MORTALITY OF THE SCOTS PINE IN OLD-GROWTH PLANTATIONS OF THE RYN DESERT M. K. Sapanov, M. L. Sizemskaya Institute of Forest Science, Russian Academy of Sciences Sovetskaya st. 21, Uspenskoe, Odintsovsky District, Moscow Oblast, 143030, Russia E-mail: sapanovm @ mail.ru Received 17 April 2017 Scots pine plantation have been created in blowouts of the Ryn Desert on Volga and Ural interfluve since the late 19 th century. Nowadays they represent unique, uneven aged, clear outliers, mainly with uncovered forest floor. Radial increments of stems, structure of root systems of pine and climate-induced variations of groundwater level were studied to find the reasons of recent mortality of trees. Decline of the trees of all ages and stages of development was followed by the denudation of crowns and lightened needles. The reason was identified as loss of water uptake by the lower layer of roots due to lost contact with upper boundary of capillary aureole of groundwaters following seasonal fluctuation and decreasing trend. During the last decade (since 2006) it fell down by 100 cm. Mortality of trees become irreversible due to losses in water support of the upper layer of roots following covering by sand and disturbance by creeping fires. Another cause was found to be the disturbance of the phloem by trunk pests ( Buprestidae ) and shrinkage of cycle of reserve substances. Keywords: sand dunes, pine outliers, mortality of trees, groundwaters, pests . Acknowledgements: The reported study was funded by RFBR according to the research project № 18-04-00246. DOI: 10.1134/S0024114818050078 REFERENCES: Gael' A.G., Oblesenie bugristykh peskov zasushlivykh oblastei (Afforestation of sand dunes in arid regions), Moscow: Geografgiz, 1952, 219 p. Gael' A.G., Sudnitsyn I.I., Rezhim pochvenno-gruntovykh vod sosnovykh nasazhdenii Dono-Archedinskogo peschanogo massiva (Groundwater regime of pine forests in Don-Archeda sands), Lesovedenie , 1971, No. 5, pp. 46-56. Gael A.G., Smirnova L.F., Peski i peschanye pochvy (Sands and sandy Soils), Moscow: GEOS, 1999, 252 p. Kulik N.F., Rezhim gruntovykh vod v Tersko-Kumskikh peskakh v svyazi s ikh obleseniem (Groundwater regime in the Terek-Kuma sands: issues of afforestation), In: Oblesenie i sel'skokhozyaistvennoe osvoenie peschanykh zemel' Yugo-Vostoka (Afforestation and agriculture in sands of the South-East) Moscow: Izd-vo Minsel'khoza SSSR, 1959, pp. 76-102 (140 p.). Manaenkov A.S., Zyuz' N.S., Zhunisov B.K., Lesorastitel'nye usloviya i lesokul'turnoe osvoenie Urdinskogo peschanogo massiva (Forest sites and silvicultural exploration of Ryn Desert), Lesnoe khozyaistvo , 1995, No. 5, pp. 36-38. Orlov A.Y., Koshel'kov S.P., Pochvennaya ekologiya sosny (Soil ecology of the pine), Moscow: Nauka, 1971, 323 p. Sapanov M.K., Prichiny usykhaniya kul'tur duba chereshchatogo na gidromorfnykh lugovo-kashtanovykh pochvakh Severnogo Prikaspiya (Causes of drying up of Quercus robur plantations on hydromorphic meadow-chestnut soils in the Northern Caspian Sea region), Lesovedenie , 2005, No. 5, pp. 10-17. Sapanov M.K., Vliyanie izmeneniya klimata na obvodnennost' Severnogo Prikaspiya (Influence of climate change on the water resources of Northern Pricaspian Lowland), Aridnye ekosistemy , 2010, Vol. 16, No. 45, pp. 25-30. Sapanov M.K., Water uptake by trees on different soils in the Northern Caspian region, Eurasian Soil Science , 2000, Vol. 33, No. 11, pp. 1157-1165. Sudnitsyn I.I., Shein E.V., Gael' A.G., Vliyanie kontsentratsii kornei sosny na pogloshchenie pochvennoi vlagi (Effect of density of pine roots on soil water uptake), Lesovedenie , 1976, No. 4, pp. 9-17. Voronkov N.A., Pul'satsiya gruntovykh vod i raskhod vlagi iz nikh v Archedinsko-Donskikh peskakh (Pulsation and discharge of groundwaters in Don-Archeda sands), Vestnik Moskovskogo universiteta. Seriya 6: Biologiya, pochvovedenie , 1963, No. 2, pp. 43-52. Voronkov N.A., Vlagooborot i vlagoobespechennost' sosnovykh nasazhdenii (Water cycle and water sufficiensy in pine forests), Moscow: Lesnaya promyshlennost', 1973, 184 p.

WATER-SAVING IRRIGATION REGIMES FOR VEGETABLE CROP PRODUCTION UNDER CONDITIONS OF VOLGA-DON INTERFLUVE

Soils of the southern region of Chad are developed on wind-drawn sand and colluvio-alluvium deposits of two main rivers Logone and Chari. This region of Chad is principal agricultural zone of Chad. Evaluation of physical and chemical properties of sandy soils and their fertility in this region revealed that some soils have very high content of strontium. With aim to locate areas with high content of srontium in soil, and to study its dependence on physical properties of soil and translocation of strontium in soil profile nine pedons were dug on different fields intensively used for agricultural production. Using X-ray spectrometric analysis and radiometric measuring of soil samples it has been revealed that Sr content in soil samples varies from 10 to 270 mg/kg of soil depending on type of soil, depth of soil layers, clay and organic content. Strontium content negatively correlates with total content of calcium and phosphorus in layers of soil. Low CEC of soil may be a reason of translocation of strontium from higher to lower layers of soils. Strontium content in soils do not relates with level of radioactivity of soils under study. The highest content of strontium has been found in soils developed on colluvio-alluviumdeposits. Very wide Ca/St ratioin soil samples of alluvial hydromorphic soils may cause increase of Sr content in vegetable food and drinking water. This may be one of etiological factors which directly or indirectly may cause misbalance in mineral nutrition and severe diseases of a man. It worth of considering necessity of further studies of Sr dynamic in soils under different crop production systems and how to mitigate negative effect of natural pollution of soils with this element.

Ferum concretions in the soils of the Lviv region

It is established that ferum concretions can be observed in 60 % area of Lviv’s oblast’s and represented by brown spots, pseudophybras, ortsteins, ortzanders, nodules, layers of marsh ore. In acidic unsaturated soils of Male Polissya, Nadsanya, Precarpathians ferum concretions is the basis for diagnosing soil-forming processes and their genesis. The main factor of ferum concretions formation is the dynamics of oxidation-reducing potential. Fe-Mn pedofetures (ortsteins) dominated in the sodpodzolic gleyed soils of Malogo Pollisya, Nadsanya and in the sod-podzolic pseudogleyed soils of the Precarpathians. Their profile distribution and morphological features. Were established nodules (solid concretions of a dark brown color with a gray tint, irregular shape and with diffuse outlines) were diagnosed within the EI horizon of the brown-podzolic soil of the Precarpathians. Found features of nodules testify about the genesis of in situ. Sod glesish soils of Male Polissya, Precarpathians, valleys Pasmovogo Pobyzzya are characterized by ferum concretions of a dense consistency, a dark brown color with diffuse outlines, which are formed in horizons with long saturation of water due to cementation with soil material of oxides Fe, Al, Mn, Si. Ferum concretions are characterized by maximum accumulation of iron compound (Кх=7,21). Ortzanders and pseudophybras - glandular hydrogenated cemented neoplasms formed are within the profi les of sod pinewood soils of Male Polissya, Nadsanya which were formed on the water-glacial deposits and sod soils in the Davudiv range, formed on Neogene sands on the conditions of high level ironization of ground water and pulsating regime. Little attention is paid to the study of ferum concretions in the soils, which is a significant disadvantage in the study of the genesis of hydromorphic soils. In order to establish the genetic nature, of ferum concretions it is advisable to use modern methods of scanning electronic microscopy, mineralogical and micromorphological studies. Key words: ferum concretions, Fe-Mn pedofetures, ortsteins, nodules, soils.

DENDROECOLOGIA DE <i>Sebastiania commniana</i> (Baill.) L.B.Sm. & Downs E<i> Hovenia dulcis</i> Thunb. EM UMA ÁREA DEGRersoADADA NA FLORESTA OMBRÓFILA MISTA ALUVIAL, SUL DO BRASIL

Em uma área da Floresta Ombrófila Mista Aluvial impactada por vazamento de óleo bruto no município de Araucária - PR, Brasil, conduziu-se o estudo dendroecológico de Sebastiania commersoniana (Baill.) L.B.Sm. & Downs (Euphorbiaceae) e da espécie exótica Hovenia dulcis Thunb. (Rhamnaceae). Os objetivos do estudo foram avaliar o efeito do alagamento da área a partir da construção de diques como medida de descontaminação de petróleo e de fatores meteorológicos no crescimento em diâmetro do tronco de ambas as espécies. Foram coletadas três séries temporais radiais do lenho de cada indivíduo adulto selecionado com uso de sondas de incremento, em duas condições, ambas com solo hidromórfico (Gleissolo Háplico), tendo como diferença a altura do lençol freático: SHT – saturação hídrica temporária (Sebastiania commersoniana n=12; Hovenia dulcis n= 10) e SHP – saturação hídrica permanente (Sebastiania commersoniana n=6; Hovenia dulcis n= 0). Séries cronológicas foram desenvolvidas, correlacionando-as com dados meteorológicos da região. Os resultados demonstraram que os indivíduos da espécie nativa em ambas as condições apresentaram padrão semelhante de crescimento, com tendência de diminuição ao longo dos anos; diferentemente dos indivíduos da espécie exótica, com tendência de aumento do incremento ao longo dos anos. Os indivíduos da condição SHP tiveram taxas menores de incremento após o ano do derramamento, o que mostra que o alagamento da área a partir da construção de diques como tentativa de descontaminação afetou o crescimento dos indivíduos. O crescimento das espécies correlacionou-se com a precipitação apenas na condição SHT. A temperatura mínima representou ser fator limitante ao crescimento de Sebastiania commersoniana, mostrando que temperaturas mais elevadas são importantes para o crescimento, principalmente no início do período deste. Entretanto, a ocorrência de temperaturas muito altas nos meses mais quentes pode ser limitante ao crescimento. Para Hovenia dulcis, nenhuma correlação significativa foi observada com a temperatura, porém, a precipitação mostrou-se fundamental nos meses em que a espécie mais cresce, sendo, no entanto, prejudicial em meses subsequentes às fortes chuvas devido ao efeito de saturação hídrica do solo.

Vegetation types of the upper Madeira River in Rondônia, Brazil

We characterize the vegetation types of the upper basin of the Madeira River in the Brazilan state of Rondonia, a biodiverse region with elevated rates of habitat loss. Vegetation and environmental parameters were recorded from 37 observation points distributed along and near a 160 km stretch of the Madeira River and representing the range of regional environments. Analysis of structure and floristic variables, as well as associated edaphic attributes and water table fluctuation, permitted recognition of five main vegetation types and seven subtypes. Open Ombrophilous Forest was the most frequently encountered vegetation type and occurred on well-drained, nutrient-poor soils, whereas Dense Ombrophilous Forest was seldom recorded. Alluvial Ombrophilous Forests (varzea) were found along a narrow strip of land along the banks of the Madeira River on the most fertile soils in the study area. Semideciduous Forests were found on small areas of rocky outcrops with shallow soils and reduced water availability during the dry season. Campinaranas, which range from open savanna physiognomies to closed canopy forests, were found to be a key environment in the lowlands south of the Madeira River on silty hydromorphic soils, where they harbor a peculiar flora tolerant of flooding during the rainy season. Our classification of the main vegetation types in the upper Madeira River illuminates a high degree of floristic and environmental heterogeneity in a highly threatened region. Our results will be useful for designing conservation strategies aimed at protecting the full range of floristic diversity present in the region.

A KNIFE-ROLLER EFFECTIVELY SUBSTITUTES SOIL PREPARATION BY PLOUGH-AND-HARROW IN LOWLAND PRODUCTION SYSTEMS

SUMMARYCropping systems in the lowlands of temperate South America have been based on irrigated rice and beef-cattle production. Plough-and-harrow is still the most used method to prepare the soil after a season of irrigated rice, but it causes high soil disturbance and is time- and energy-demanding. To improve the sustainability of a rice–soybean rotation system, we studied an alternative method for soil preparation based on a heavy knife-roller. This method was evaluated during three cropping seasons and compared to the plough-and-harrow, applied after the harvest of irrigated rice in a flat hydromorphic soil in south Brazil. In the subsequent summer, soybean was seeded using a no-tillage seeder. Observations on soybean establishment and grain yield demonstrated that the alternative method performed as well as the plough-based system. Benefits of the roller-based method were a 50% reduction in energy consumption for soil preparation, corresponding to a 22% increase in overall energy use-efficiency of soybean production. Labour time and greenhouse gas emissions for soil preparation were reduced with 29 and 55%, respectively. Next to these savings, the roller-based method can also be performed shortly after rice harvest, creating better opportunities for cover crops or pastures in between rice and soybean. In conclusion, the equivalent agronomic and superior sustainability performance makes the knife-roller method an appealing alternative for seedbed preparation after irrigated rice in lowland production systems.

Soil salinization in different natural zones of intermontane depressions in Tuva

Soil salinization features in semidesert, dry steppe, and chernozemic steppe zones within intermontane depressions in the central part of the Tuva Republic are discussed. Chernozems, chestnut soils, and brown desert-steppe soils of these zones are usually nonsaline. However, salinization of these zonal soils is possible in the case of the presence of salt-bearing parent materials (usually, the derivatives of Devonian deposits). In different natural zones of the intermontane depressions, salt-affected soils are mainly allocated to endorheic lake basins, where they are formed in places of discharge of mineral groundwater, and to river valleys. The composition and content of salts in the natural waters are dictated by the local hydrogeological conditions. The total content of dissolved solids in lake water varies from 1 to 370 g/L; the water is usually of the sulfate–chloride or chloride–sulfate salinity type; in some cases, soda–sulfate water is present. Soil salinity around the lakes is usually of the chloride–sulfate–sodium type; gypsum is often present in the profiles. Chloride salinization rarely predominates in this part of Tuva, because chlorides are easily leached off from the mainly coarse-textured soils. In some cases, the predominance of magnesium over sodium is observed in the composition of dissolved salts, which may be indicative of the cryogenic transformation of soil salts. Soda-saline soils are present in all the considered natural zones on minor areas. It is hardly possible to make unambiguous statements about the dominance of the particular type of salinity in the given natural zones. Zonal salinity patterns are weakly expressed in salinization of hydromorphic soils. However, a tendency for more frequent occurrence of soda-saline soils in steppe landscapes and chloride–sulfate salinization (often, with participation of gypsum) in the dry steppe and semidesert landscapes is observed.

Resistance of mineral soils to Fe(III) reduction

Gleying and enhancement of hydromorphism in wetland soils due to Fe(III) reduction entail a series of degradation processes. The resistance of wetlands to degradation can be calculated from the content of potentially reducible iron, Fe(III)pr, which is found from the van Bodegom equation taking into account the contents of oxalate-soluble iron Feox and dithionite-soluble iron Fedit in the soil. In addition, this makes it possible to distinguish relict and actual gleysols. The van Bodegom equation is applicable to soils from which the oxalate solution extracts only amorphous and poorly crystallized iron compounds, which are quickly reduced by Fe-reducing bacteria. These soils have a low proportion of Fe(II) (no more that 15% of the total iron), as well as an accumulative profile distribution of Feox. The van Bodegom equation is unsuitable for calculating the Fe(III)pr content in soils with a high proportion of Fe(II) and a nonaccumulative profile distribution of Feox.

Suitability of large scale Jatropha curcus cultivation in Edo State: a preliminary assessment using the Analytical Hierarchy Process (AHP) method

The aim of this study is to assess the suitability of agro-ecological regions for Jatropha Curcas cultivation using GIS and Analytical Hierarchy Process (AHP) tools. Rainfall amount and temperature data were collected from the Nigerian Meteorological Agency (NIMET), Federal Ministry of Aviation, Oshodi, Lagos and Climate Prediction Centre of the United States Agency for International Development (USAID) for a period of 3 years (2010 - 2012). Rainfall amounts in Edo state ranges between 1400mm-1500mm in the south most part of the state and decreases to 1200mm-1350mm at the centre of the State and 1000mm-1200mm in the north. These values fall within the optimal range for Jatropha cultivation. There are six (6) to seven (7) months of moisture adequacy in Edo state usually from April/May – September/October. Within this period, there is adequate moisture supply to satisfy the consumptive needs of Jatrophacultivation during its vegetative and flowering/fruiting stages. There are two rainfall peaks in Edo state namely May/June and September/October which guarantees two-times planting seasons, namely April planting season prior to the first rainfall peak in May/June and July/August planting season before the last rainfall peak (September/October). Runoff peaks in Edo state occur between September and October. Within this period soils are at field capacity and not suitable for onset of Jatropha cultivation. Analysis of slope conditions in Edo state showed that vast expanse of land in the state may be categorized as highly suitable with small patches of moderately suitable locations in the north. Soil condition in Edo state showed marginally suitable for soils in the mangrove region, southernmost part of the state and moderately suitable for hydromorphic soils of the Owena Basin west of the State. Finally, the result of multi-criteria analysis showed that Edo state can be grouped into two main classes of suitability namely; moderately and highly.Keywords: Jatropha Curcas, Energy production, Climatic factors, moisture storage, Soil condition

Variability of soil carbon stocks in a mixed deciduous forest on hydromorphic soils

Forests play an important role for carbon (C) storage and a large part of C in forest ecosystems is stored in the soil. Although large-scale inventories of soil C stocks have been published recently, detailed site-specific studies are still needed because C storage depends on various site specific soil, ecological and management factors. Quantification of soil C stocks is hampered by spatial and temporal variability. Here, we assess C stocks in an ancient forest site at a stand which has not been managed for >60years and analyse the spatial variability of C concentrations and stocks to evaluate inter-annual variability and elucidate possible causes. Samples were taken down to 1m depth by auger cores in May of three consecutive years (2013, 2014, 2015) on regular hexagonal grids covering an area of 0.25ha and 19 sampling spots. In addition, to address small scale variability, 36 auger cores were taken in November 2014 using a nested sampling design.C stocks were on average 34kgCm−2 (0–1m depth). This is distinctly higher than soil C stocks reported for most other forest sites in similar climatic conditions, and is likely caused by the interplay of several parameters, i.e., hydromorphic soil conditions, high biomass production due to high soil fertility, stand structure (tree age, species and density), and the management history of the site. The coefficients of variation for C concentrations (>50%) and for C stocks (30–50%) show that spatial variability is high. Geostatistical analysis revealed a larger scale component with ranges of 5–20m and a small scale component represented by high nugget effects in the semivariograms (>50%).As hydromorphic soil types are widespread in NE Germany, large amounts of organic C could be sequestered into soil under unmanaged old forests, thus contributing to alleviating the rise in anthropogenic CO2 concentrations in the atmosphere.

Response of bacterial communities to Pb smelter pollution in contrasting soils

Anthropogenic inputs of trace elements (TE) into soils constitute a major public and environmental health problem. Bioavailability of TE is strongly related to the soil physicochemical parameters and thus to the ecosystem type. In order to test whether soil parameters influence the response of the bacterial community to TE pollution, we collected soil samples across contrasting ecosystems (hardwood, coniferous and hydromorphic soils), which have been contaminated in TE and especially lead (Pb) over several decades due to nearby industrial smelting activities. Bacterial community composition was analysed using high throughput amplicon sequencing and compared to the soil physicochemical parameters. Multivariate analyses of the pedological and biological data revealed that the bacterial community composition was affected by ecosystem type in the first place. An influence of the contamination level was also evidenced within each ecosystem. Despite the important variability in bacterial community structure, we found that specific bacterial groups such as γ-Proteobacteria, Verrucomicrobia and Chlamydiae showed a consistent response to Pb content across contrasting ecosystems. Verrucomicrobia were less abundant at high contamination level whereas Chlamydiae and γ-Proteobacteria were more abundant. We conclude that such groups and ratio's thereof can be considered as relevant bioindicators of Pb contamination.

水成土壌における水の動態とその土壌生成的役割について : 小櫃川流域の例(第5報) : 砂質水田土壌の地下水面上のグライ層と灰色土層の生成

水成土壌における水の動態とその土壌生成的役割について : 小櫃川流域の例(第5報) : 砂質水田土壌の地下水面上のグライ層と灰色土層の生成

Identification of wetland areas in the context of agricultural development using Remote Sensing and GIS

El presente estudio tiene como fin determinar el potencial de humedales a nivel de pixel en la llanura de inundación del Río León, se consideraron aspectos de hidrología, vegetación hidrofítica y suelos hidromórficos. Se utilizaron mediciones en campo y modelos distribuidos espacialmente para modelar la hidrología superficial y los niveles piezométricos. También se utilizaron imágenes de satélite para determinar áreas inundadas y vegetación. Los mapas existentes del instituto geográfico Agustín Codazzi fueron utilizados para definir la distribución espacial de los suelos hidromórficos. Se prestó atención especial a la infraestructura agrícola, donde los diques artificiales y trasvases han sido utilizados para modificar la hidrología superficial con el fin de promover el establecimiento de plantaciones y pastoreo. Un total de 536 km2 cumplieron una o más condiciones de humedal según las variables biofísicas, pero solo 393 km2 fueron seleccionados mediante reglas lógicas como pixeles de humedal. La combinación de variables biofísicas para la definición del potencial de humedal es discutida en términos de la distribución espacial y las implicaciones para el manejo de los recursos naturales.

Salt-affected soils of the Barguzin Depression

Factual materials on salt-affected soils in the Barguzin Depression (Buryat Republic) are generalized. A geomorphic map of the depression has been developed. The distribution of salt-affected soils and the specificity of salinization in different geomorphic regions are characterized. These soils tend to be developed within the low lacustrine–alluvial plain of the depression, on the floodplain of the Barguzin River and its tributaries. Smaller areas of salt-affected soils are found on the river terraces. They are virtually absent on ancient sandy ridged terraces (kuituns). The genesis and chemistry of soil salinization are mainly related to the discharge of slightly saline deep water along tectonic faults and fissures. An additional source of soil salinity is represented by surface water flows. The presence of permafrost preventing the leaching of salts and the cryoarid climate favoring the migration of salts toward the soil surface during the dry spring and early summer periods and during the soil freezing in the winter contribute to the soil salinization. Slightly saline hydromorphic solonchakous soils predominate among salt-affected soils of the depression; the portion of semihydromorphic saline soils is smaller. Automorphic saline soils rarely occur in the depression. Strongly saline soils— solonchaks—are widespread within lacustrine depressions around salt lakes. Soils of the soda and sulfate salinization predominate. The content of chlorides is small; their increased amounts, as well as the presence of sulfates, are indicative of the discharge of dee ground water onto the surface. The soda type of salinization is also related to the discharge of deep stratal water with further transformation of salt solutions during freeze–thaw cycles. Under anaerobic conditions, the formation of soda is favored the processes of sulfate reduction.

The role of large arthropods in the development of halomorphic soils in the south of Siberia

Soil sequences along catenas crossing the peripheral parts of shallow-water drying lakes in the south of Siberia have been studied. They include the sulfidic and typical playa (sor) solonchaks (Gleyic Solonchaks), playa solonchak over the buried solonetz (Gleyic Solonchak Thapto-Solonetz)), shallow solonetz–solonchak (Salic Solonetz), and solonetzic and solonchakous chernozemic-meadow soil (Luvic Gleyic Chernozem (Sodic, Salic)). This spatial sequence also represents a series of historical stages of the development of halomorphic soils: the amphibian, hydromorphic, semihydromorphic, and automorphic–paleohydromorphic stages. During all of them, the biogenic component plays a significant role in the matter budget of halomorphic soils. The diversity, number, and functional activity of large insects and spiders are particularly important. Their total abundance in the course of transformation of the halomorphic soils decreases from several thousand to about 100 specimens/(m2 day), whereas their species diversity increases from 17 to 45 species. Changes in the functional structure of the soil zoocenosis and its impact on the character and intensity of pedogenetic processes can be considered driving forces of the transformation of hydromorphic soils. This is ensured by the sequential alteration of the groups of invertebrates with different types of cenotic strategy and different mechanisms of adaptation to biotic and abiotic components of the soil in the course of the development of the soil zoocenosis.

Performance of soybean in hydromorphic and nonhydromorphic soil under irrigated or rainfed conditions

Abstract: The objective of this work was to evaluate soybean cultivation in a hydromorphic or nonhydromorphic soil, with or without supplemental irrigation. Field experiments were carried out with the TECIRGA 6070RR and A 6411RG cultivars in highlands (nonhydromorphic soils) and lowlands (hydromorphic soils), which are traditionally cultivated with irrigated rice. The following parameters were determined in both soybean cultivars: leaf area index, developmental stages, dry matter partition, and leaf gas exchange. Low water stresses, which commonly occur either by deficit or excess in soybean areas cultivated in hydromorphic soils, do not affect the development and partitioning of dry matter; however, they cause reductions in stomatal conductance, photosynthetic rate, and leaf area evolution. Growing soybean in lowlands exposes plants to water stress, even in years with well-distributed rainfall during the growing season, due to the low water storage capacity of these soils.

Environmental genetic features and diagnosis of alluvial marsh marled soils in the dry-steppe subtropical zone of the Kura floodplain

This article presents the results of the research of the soil-forming process of alluvial hydromorphic soils of the dry-steppe subtropical zone in the Kura River floodplain. It has been established that the nearterrace mineralized spring waters significantly influence the genetic profile of alluvial marsh marled soils. The morphogenetic properties and basic physicochemical parameters of these soils have been described. The group and fractional composition of the humus, which is distinguished by a high mobility of humic acids, has been investigated. The bulk chemical composition of the soils showed that alkaline hydrolysis conditions lead to a significant reduction of aluminum silicates and a growth of CaO carbonate forms. Due to a high carbonate content of alluvial marsh marled soils, the content of the mobile ferric form (Fe2+–Fe3+) is relatively low.

Phosphorus Sorption in Hydromorphic Soils Overlying Alluvium and Coastal Plain Sand Parent Materials in Delta State, Nigeria

ABSTRACTHighly weathered soils of the tropics are known to have great affinity for phosphate sorption with reportedly high values for affinity constant, k. This study evaluated soil samples from profiles dug at Agbor, Kwale, and Otegbo which overly alluvium and coastal plain sand parent materials for their capacities to sorb phosphorus (P). The samples were equilibrated in 30 ml of 0.01 M calcium chloride (CaCl2) containing various amounts of P as monopotassium phosphate (KH2PO4) to give 0, 25, 50, 100, 150, 200, 400, 800, and 1000 μg/L P for 6 days at a temperature of 25 ± 2°C. The rate of P adsorption increased with increased concentrations of P and was generally low in the soils. Affinity constant k was also low and did not compare with values earlier obtained for well-drained soils. P adsorption capacity decreased in the order: Agbor > Otegbo > Kwale. Percent phosphorus sorbed was highest at Agbor with values of 11.33%, 10.8%, and 10.12% for 50, 100, and 150 mg/kg P added, respectively. The adsorption maxima (b) of the soils was significantly correlated with the soils organic carbon with r = 0.817, p < 0.05; r = 0.883, p < 0.05, and r = 0.886, p < 0.05 for Agbor, Kwale, and Otegbo soils, respectively. Proper management of the soils organic matter content coupled with the addition of rock phosphate is recommended for P improvement in these soils for sustained cultivation of crops such as Raphia hookeri that are adapted to hydromorphic environment.