Hydrophysical Properties Research Articles

The Relationships of Texture and Hydrophysical Properties in Soil Profiles Under Selected Exotic Trees in the Context of Climate Change in Central Europe

The Relationships of Texture and Hydrophysical Properties in Soil Profiles Under Selected Exotic Trees in the Context of Climate Change in Central Europe

Is cassava yield affected by inverting tillage, chiseling or additional compaction of no-till sandy-loam soil?

Defining a suitable soil tillage option that provides adequate soil physical conditions for optimum cassava (Manihot esculenta Crantz) productivity has not been adequately researched in southern Brazil. This study aimed to evaluate, in an Argissolo Vermelho-Amarelo Distrófico (Acrisol or Hapludalf), three tillage methods – conventional (inverting) tillage, chiseling, and long-term no-tillage (without and with, additional soil compaction), as affecting soil hydro-physical properties and cassava yield, in southern Brazil. Undisturbed and disturbed soil samples were collected from row and interrow [...]

Hydro-physical properties of agriculturally used peatlands in Liang Anggang Protected Forest, South Kalimantan, Indonesia

The utilization of peatlands as agricultural areas that do not pay attention to proper water management will result in peatland degradation. To restore the degraded peatlands, it is necessary to explore the peat’s hydrological and physical characteristics. Therefore this study investigates the hydro-physical peat characteristics in the peatlands that have been converted into agricultural use. The research was carried out in the Liang Anggang Protected Forest area, specifically in the area converted to agricultural land. Undisturbed peat samples were collected in both intensive and un-intensive agricultural sites. Peat characteristics were analysed in the laboratory include bulk density, particle density, porosity, total soil water content, and hydraulic conductivity variables. The result shows that peat characteristics in the intensive agricultural land significantly indicate higher bulk density and particle density with the values 0.30 g/cm3 and 0.91 g/cm3, respectively. Still, significantly lower values are found in porosity (66.87%), total soil water content (226.95%), and hydraulic conductivity (0.0025 cm/s). Degraded peatland restoration that functions as a protected forest must be carried out through rewetting activities and maintaining the water table depth. On the other side, the peatland whose function is designated as an agricultural area, wetland farming systems should be applied using adaptive crop species.

Impacts of Olive Waste-Derived Biochar on Hydro-Physical Properties of Sandy Soil

In this study, waste olive leaves and branches were pyrolyzed to produced biochar, and their impacts on physical and chemical properties of a sandy soil were evaluated. Pyrolytic temperatures of 300 °C, 400 °C, and 500 °C were used for biochar production. After evaluating the physio-chemical properties, the produced biochars were added to the top 10 cm layer of the soil at rates of 0%, 1%, 3%, and 5% in a column experiment at 25 °C. Biochar was mixed with a sandy soil into the top 10 cm of the columns. For all treatments, cumulative evaporation was reduced; however, treatments with 5% biochar prepared at the highest temperatures showed the highest impact. The available water contents were increased by 153.33% and 151.11% when olive branch-derived biochar and olive leaves-derived biochars produced at 500 °C were applied at 5% rate, respectively. No impact of available water was observed for 1% biochar contribution. Biochar application decreased both cumulative infiltration and infiltration rate. Biochar pyrolyzed at 500 °C most intensely improved hydro-physical properties of a sandy soil. However, its application as a soil supplement in arid environments should be adopted with constraints due to its high pH (9.69 and 9.29 for biochar pyrolyzed at the highest temperatures) and salinity (up to electrical conductivity = 5.07 dS m−1). However, the salinity of biochar prepared from olive branches (5%, pyrolyzed at 500 °C) was low (0.79 dS m−1); therefore, it can be used safely as a supplement in saline and acidic soils, but with restriction in alkaline soils.

The Use of Apple Pomace as a Soil Amendment Enhances the Activity of Soil Microorganisms and Nitrogen Transformations and Affects Crop Growth

Apple pomace (AP) is an abundant waste causing environmental problems. Therefore, the aim of the study was to evaluate the impact of AP on soil and plant growth under optimum and limited water availability. Two laboratory experiments were conducted to evaluate the impact of AP on: (i) hydrophysical properties, respiration, and N transformations in soil aggregates and (ii) the growth of wheat and faba bean in soil with addition of AP under optimum and limited water availability. The soil respiration rate increased rapidly after the introduction of AP, and the effect was dependent on the aggregate size. The reduction of nitrate and the increase in ammonium content in response to the AP addition were more pronounced in the larger aggregates. Reduced growth of wheat was noted in the dry soil supplemented with AP. Faba bean maintained its unchanged rate of growth after the application of AP, irrespective of water availability. An increase in the chlorophyll content was observed in faba bean grown in the AP-enriched soil. The apple pomace reduced the water wetting rate and increased the repellency index but did not affect the tensile strength of the soil aggregates. Disposal of AP as a soil amendment affects many indicators of soil quality. The application of AP to the soil has an impact on respiration and N transformations in the soil aggregates; moreover, it differently influences the growth of spring wheat and faba bean.

Land-use change affects soil hydro-physical properties in Mollisols of semiarid Central Argentina

The objective of the present study was to describe the relationships between soil physical properties and to identify variables that determine the pore system and hydrological functions which are specifically important in drought prone semiarid marginal croplands. We compared Mollisols under natural vegetation (NV) with their agriculture (AG) pairs in the central Argentinean Dry Pampas to obtain the range of values for variables that characterize the soil pore system. These were total carbon (OC), bulk density (BD), structural instability index (SII), volumetric weight of aggregates (VAW), total porosity (TP), macropores (Ma), saturated hydraulic conductivity (K), infiltration rate (IR), Dexter's S index (S), and least limiting water range (LLWR). To a depth of more than 23 cm, TP and Ma were considerably lower (~ 35% and 50% less, respectively) in AG versus NV. The changes in porosity and pore size resulted in 74% smaller IR and 65% lower K. The S index had mean values of 0.16 and 0.14 for the upper and middle layer respectively in NV; while for AG, these values were significantly lower (0.09 and 0.10, respectively). The LLWR was also lower in AG (21 and 59% less in the upper and middle layer, respectively), due to high soil resistance even at non-limiting BDs (1.17 and 1.32 g cm−3 for AG2 and AG1, respectively). Soil OC was positively correlated with TP, Ma, and S, and negatively correlated with BD and SII. Multiple regression models for S included SII, TP, and clay contents, while for LLWR the variables were OC, TP, and clay plus silt. Thus, these complex soil quality indices can be predicted by using simpler physical parameters, but texture and organic matter also have a strong effect on them. Moreover, our results contribute to a better understanding of the role of texture and organic matter in controlling soil physical quality and for maintaining soil-based ecosystem services.

Small-scale spatial variability of hydro-physical properties of natural and degraded peat soils

The spatial variability of soil properties plays an important role in water and carbon cycles in peatlands. The objectives of this study were to analyze the spatial variation of hydro-physical properties of peat soils and to establish pedotransfer functions (PTFs) to estimate the hydraulic properties of peat using readily available soil properties. We selected three study sites, each representing a different state of peat degradation (natural, degraded and extremely degraded). At each site, 72 undisturbed soil cores were collected from 5 m by 5 m grid cells in an area of 35 m by 40 m. The saturated hydraulic conductivity (Ks), soil water retention curves, total porosity, macroporosity (pore diameter >30 μm), bulk density and soil organic matter content (SOM) were determined for all sampling locations. The Van Genuchten (VG) model parameters (θs, α, and n) were optimized using the RETC software package. A strong positive correlation between macroporosity and Ks was observed irrespective of the degradation stage of the peat. However, the relationships between macroporosity and Ks differed between the natural and the drained peatlands. Adding macroporosity to the PTFs substantially improves the prediction of Ks as well as VG parameters. Results show that the soil physical and hydraulic properties (e.g. Ks and VG model parameters) exhibit different levels of spatial heterogeneity depending on the peat degradation stage. The geostatistical analysis suggests that the spatial dependence of soil hydro-physical properties varies depending on the considered property as well as land management (e.g. drainage). Bulk density and SOM are spatially dependent, whereas Ks and macroporosity are spatially independent if the peat is severely degraded. In conclusion, the peat degradation stage plays an important role and should be generally considered in the spatial analysis of peatlands. The obtained semivariograms may serve as a basis for 2D and 3D hydrological modelling as well as peatland restoration studies.

INFLUENCE OF ANTHROPOGENIC FACTORS ON THE SOIL CONDITION OF THE N.V. TSITSIN MAIN BOTANICAL GARDEN OF RAS

The territory of the N.V. Tsitsin Main Botanical Garden of the Russian Academy of Sciences is subjected to significant anthropogenic stress, which has a negative effect on the state of valuable collections of tree and shrub species. Soil compaction is one of the most dangerous consequences of anthropogenic impact, expressed in increased recreational impact. In this context, the botanical garden was very concerned about the deterioration of the collection of elaeagnus species. Therefore, the soils on which these plants grow were chosen as the object of research. On this territory, three sampling plots with different degrees of anthropogenic impact were laid. Sampling plot No. 1 had the maximum anthropogenic impact. The area of medium anthropogenic impact was represented by the sampling plot No. 2. The sampling plot No. 3 where the anthropogenic impact was minimal was a reference plot. All the studied soils were classified as soddy-slightly podzolic medium loamy soils (Umbric Albeluvisols Abruptic). Fundamental differences in the morphological properties of the studied soils were that the soils located in the area of maximum anthropogenic impact, starting from a depth of 40 cm, showed gley spots, which were not found in other soils. Increased bulk density of soil in undisturbed state corresponded to increased anthropogenic impact. This led to a decrease in total pore space of soil. Soil compaction contributed to a noticeable decrease in gravimetric soil water content in upper horizons. At the same time, worsening of subsurface runoff contributed to gley-forming processes in the illuvial part of the profile. Cluster analysis revealed good grouping of the dependence of the studied indicators on the severity of anthropogenic impact. The studied indicators were separated depending on their type and position in the profile. The conducted study made it possible to assess the essential physical and hydrophysical properties of soils on the part of the territory of the Main Botanical garden of RAS that is occupied by the valuable collection of elaeagnus. Based on the results of the study, a set of measures is proposed that can significantly reduce the identified negative effects and improve the state of both the studied soils and stands growing on them in general.

Modeling the Effect of Fertilizers on the Dynamics of Moisture Contours at Drip Irrigation

Introduction. A review of research on modeling and calculating moisture contours shows that at this stage there is a developed formalized mathematical apparatus connecting physically reasonable parameters and hydro-physical properties of soils. However, to improve the efficiency of drip irrigation and fertigation, it is necessary to determine the effect of fertilizers dissolved in irrigation water on hydrophysic properties of soil, and on the basis of the findings to determine the effect of fertilizers on shapes and sizes of moisture contours. Materials and Methods. To investigate the effect of fertilizers on the dynamics of moisture contours, potassium monophosphate was used, because it has a “bad” mobility in soil and it is cost-efficient to be introduced into irrigation water. Potassium monophosphate effects on density, viscosity, osmotic pressure, moisture contact angle and surface tension of irrigation water. As a result, there are changes in soil water retention curve and its hydraulic conductivity function. Therefore, moisture contours are formed with small, but still significant differences. Results. A software tool has been developed that allows exploring the dynamics of the moisture contours of different soil types and texture with different porosity and with a previously known moisture distribution in depth. Discussion and Сonclusion. When potassium monophosphate or other nutrients are added to water, small changes of the formation of moisture contours are observed. The results obtained enable us to calculate irrigation norms at the design stage of the planning process of fertilizer distribution with irrigation water during drip irrigation for different concentrations.

Changes in soil structure and pore functions under long term/continuous grassland management

Pore size distribution (PSD), and wetting/drying mechanism enable proper understanding of how land management changes influence soil structure and function dynamics as a measure for soil quality. Therefore, the objectives of this study are to: (i) estimate the soil quality index under continuous long term grassland management, and its impacts on soil hydro-physical and functional properties; (ii) differentiate the impact of the grassland age on the PSD curve structure using data obtained from soil water retention and (iii) determine the impact of wetting/drying on soil structure and functional dynamics. Soil hydro-physical, and functional properties of grassland at different ages (1, 2, 8, 13, 19 and 24 years) after renovation by plowing were determined. Data from the soil water retention curves were fitted to van Genuchten’s equation. Three (3) wetting/drying cycles were considered for grassland managed for 2, 13 and 24 years in order to detect further soil structure developments due to assumed climate change impacts. Results showed that total soil porosity and the number of coarse pores increased, while the soil bulk density decreased as sward age increases in all studied depths (0–5, 10–15 and 20–25 cm). Soils at 24 years grassland management showed the most intense changes in pore continuity by an increased hydraulic conductivity and an improved pore size distribution which both support root growth and nutrient as well as water accessibility. Notable (significant) difference in the soil hydro-physical properties occurred as early as 2years after grassland renovation, but a measurable improvement of soil functions down to 30 cm depth lasted 19 years. To test the hypothesis how far could a more intense wetting/drying furthermore enhance the restructuring we carried out extra wetting/drying experiments. It could be shown that the Ksat and air permeability values increased the more pronounced when the matric potential gradients and these cycles occurred more often. Thus, with increase in sward age and cycles these values further increased. However, the formation of macroscopic more homogenous structure can also result in higher values of Ksat and air permeability after shorter periods but the heterogeneity of the data was greater than after 24 years, in all depths. Therefore, results from our study can be used to establish a long-term sustainable grassland management without irregular soil inversion as effective strategy for improving soil structure and functionality.

Long-Term Trial of Tillage Systems for Sugarcane: Effect on Topsoil Hydrophysical Attributes

Seeking to provide essential information about sustainable tillage systems, this work aimed to assess the effects of liming and soil cultivation systems on the soil hydrophysical attributes of a long-term cultivated sugarcane field in the tropical region of southeast Brazil. Infiltration tests and soil sampling down to 0.10 m were performed in order to determine saturated soil hydraulic conductivity, soil bulk density, soil total porosity, macroporosity, microporosity, and soil resistance to penetration. The studied areas include no-tillage (NT) and conventional tillage (CT) systems with 0 (CT0 and NT0) and 4 (CT4 and NT4) Mg ha−1 of lime, and an adjoining area with native forest (NF). The data analysis included an analysis of variance followed by the Tukey test to compare different systems, assessment of the Pearson correlation coefficient between variables, and a principal component analysis of the dataset. The lowest bulk density and highest soil total porosity, macroporosity and saturated hydraulic conductivity were found in the NF. The bulk density in CT4 and NT0 was higher than in other systems, indicating the need for amelioration. NT4 is suggested as the most viable system for conservation agriculture in sugarcane fields, combining the benefits of no-tillage and liming to enhance soil hydrophysical functions.

Effect of Maize Plant Density, Compost and Sulfur on Productivity of Intercropped Maize and Tomato and some Soil Properties

Two field experiments were carried out at the Experimental Farm, EL- Gemmeiza Agricultural Research Station, El-Gharbia Governorate, ARC, during the two seasons 2019 and 2020 to study the effect of maize plant density (10, 12 and 14 thousand plant fed-1), compost and sulfur on some soil physical and hydro physical properties and productivityof intercropped yellow maize with tomato and net economic return. A split- plot design in randomized complete block design with three replicates was used. The main-plots were assigned to the three plant densities (D1, 100% tomato + 50% maize ; D2, 100% tomato + 60% maize ; D3, 100% tomato + 70% maize) under different intercropping patterns. The sub-plots were allocated for soil conditioners (compost, sulfur and compost + sulfur as well as recommended doses of NPK).The results revealed that the maximum values of the all traits of maize and tomato were obtained when high plant density (D3) with compost + sulfur in both seasons. The lowest soil bulk density and settling percentage values and the highest total porosity ,void ratio and pore size distribution values were recorded with the high plant density (D3) and compost + sulfur in both seasons. Soil hydraulic conductivity and soil moisture characters were increased in all treatments at the two soil depths in both seasons compared with the sole planting of maize or tomato. The high plant density (D3) with compost + sulfur gave the highest values of water use efficiency, LER, ATER, LEC, MAI and Net economic return in both seasons.

Dependence of the Photosynthetic Quantum Yield on Phytoplankton Light Absorption: Equations for Assessing Primary Production in the Black Sea

Purpose. Investigations were performed during a scientific cruise to characterize hydrophysical properties, chlorophyll a concentration, photosynthesis-irradiance curves, spectral light absorption coefficients by phytoplankton, and spectral quantum downwelling irradiance. From these results, the dependence of the photosynthetic quantum yield upon environmental factors was studied with the purpose of adapting an algorithm developed for the Baltic Sea so that it can be applied for the Black Sea. Methods and Results. Complex hydrophysical and biological studies were carried out at several depths within the euphotic zone. Spectral bio-optical parameters were measured in accordance with the latest NASA protocols (2018). Experiments to determine the photosynthesis-light relationship were performed under temperature and light conditions similar to those in situ. The quantum yield of photosynthesis was calculated from parameters of photosynthesis-light curves (photosynthesis efficiency, light saturation parameter) and the spectral light absorption coefficients by phytoplankton pigments. It was found out that the main photosynthetic characteristics of phytoplankton, including the maximum photosynthetic quantum yield and the fraction of phytoplankton absorption associated with photoprotective accessory pigments, varied with depth within the euphotic zone, due to phytoplankton acclimation to environment factors during the period of seasonal stratification. The relationship between the photosynthetic quantum yield and the quanta absorbed by photosynthetically active phytoplankton pigments was revealed. The results of this research made it possible to build on the approach developed for other regions and modify the equation for calculating the quantum yield to apply specifically for environmental conditions in the Black Sea. Conclusions. For the first time, comprehensive studies carried out in the Black Sea, including measurements of the photosynthesis-light dependence, spectral light absorption coefficients by phytoplankton and spectral downwelling irradiance as a function of optical depths within the euphotic zone, made it possible to reveal the equation for calculating photosynthetic quantum yield. This new equation can be applied for calculating primary production of the Black Sea using a spectral approach, based both on the results of in situ measurements and remote sensing data.

Indication of Natural Boreo-Continental Pine Sites Through Discrimination Analysis of the Soil Biochemical and Water-Holding Properties

Abstract Natural pine site differentiation is instrumental in the modification of Scots pine cultivation to environmental change. The aim of this study was to distinguish azonal pine sites in prevailing beechwood conditions by the means of soil property interrelationships. The study aimed at verifying assumptions (i) that intrinsic soil properties suggest differences at naturalness among various communities in the same mesoclimate, relief or on same soil group and (ii) whether pines differ from beechwoods uniformly or unevenly among different regional population areas. The verification was carried out by discrimination analysis of the H- and A-horizon forest soil properties at selected pine and beech stands in the Czech Republic between 2006 and 2015. Homogeneous pines were confirmed either on poorly developed or very infertile soils. Mixed pines were found on Cambisols. Complete separability was found between pines and beechwoods on Podzols due to inverse proportions of correlations among acid phosphomonoesterase (APMEA) and urease (UA) activities, Corg, Cmic, base saturation, bulk density and aeration. The inverse proportions among UA, Ntot, Cmic and soil hydrophysical properties conditioned the separability of pines on different soil groups than beechwoods. Soil indications of natural pines are related to phosphorus release by APMEA and site resistance to drought due to soil organic matter and water-holding capacity.

Influence of modifying additives on the structural characteristics and properties of portland cement concretes

The influence of polycarboxylate and naphthalene-sulfone superplasticizers, paraffin hydrophobizator and complex hydrophobic-plasticizing additives on the structural characteristics, physical-mechanical, hydrophysical properties, corrosion resistance and frost resistance of fine-grained Portland cement concretes was studied. Structural parameters of concretes (average and true density; density coefficient; total, open, closed porosity) were compared with compressive strength, water absorption, softening coefficients and salt resistance of materials. It is shown that the introduction of superplasticizers increases the density, softening coefficients and salt resistance, reduces the water absorption of Portland cement structures, and the use of paraffin hydrophobization and complex hydrophobic-plasticizing additives increases the closed porosity as a result of the formation of mosaic hydrophobic films on the surface of solid phases, which have a positive effect on the hydrophysical and physical-mechanical properties of concretes.

Quantifying hydro-physical properties of growing media with the HYPROP and comparison with the DIN EN standard procedure

Quantifying hydro-physical properties of growing media with the HYPROP and comparison with the DIN EN standard procedure

Effects of biochar amendment and reduced irrigation on growth, physiology, water-use efficiency and nutrients uptake of tobacco (Nicotiana tabacum L.) on two different soil types

Biochar has shown beneficial effects in agricultural production, yet the combined effects of biochar and reduced irrigation on crop growth and water-use efficiency (WUE) in diverse soil types have not been fully explored. A split-root pot experiment was conducted to investigate the effects of addition of 2% softwood (SWB) and wheat straw biochar (WSB) on growth, physiology, WUE and nutrients uptake of tobacco (Nicotiana tabacum L.) plants grown in a Ferrosol and an Anthrosol, respectively, under three irrigation treatments. The plants were either irrigated daily to 90% of water-holding capacity (FI), or irrigated with 70% volume of water used for FI to the whole root-zone (DI) or alternately to half root-zone (PRD). The results showed that plants grown in Anthrosol possessed greater leaf gas exchange rates, dry biomass and WUE while lower nutrients content compared to those grown in Ferrosol. Despite a negative effect on plant N content and WUE, WSB addition increased water-holding capacity, consequently improved leaf gas exchange, water uptake, biomass and K content resulting in an improved in the leaf quality of tobacco as exemplified by an increased leaf K content and a more appropriate N to K stoichiometric ratio. However, these effects were not evident upon SWB addition. Moreover, these responses to biochar addition were stronger in Ferrosol than in Anthrosol might be associated with its lower pH. Compared to FI, PRD slightly reduced photosynthetic rate but significantly decreased stomatal conductance, transpiration rate and leaf area, leading to a significant increase in intrinsic, instantaneous and plant WUE. Additionally, PRD was superior over DI in improving yield, WUE, N uptake under a same irrigation volume. It was concluded that WSB combined with PRD could be a promising practice to synergistically improve tobacco yield, quality and WUE by improving soil hydro-physical properties and nutrients bioavailability.

Effects of poly-γ-glutamic acid and poly-γ-glutamic acid super absorbent polymer on the sandy loam soil hydro-physical properties.

The main forms of poly-γ-glutamic acid (γ-PGA) applied in agriculture include agricultural γ-PGA and γ-PGA super absorbent polymer (SAP). Laboratory experiments were conducted with a check treatment CK (no γ-PGA added) and two different forms of γ-PGA added to sandy loam soil (T and TM stand for γ-PGA and γ-PGA SAP) at four different soil mass ratios (0.05% (1), 0.10% (2), 0.15% (3) and 0.20% (4)) to determine their effects on sandy loam soil hydro-physical properties. Both of them could reduce the cumulative infiltration of soil water. The total available water (TAW) which the soil water content (SWC) from field water capacity (FC) to permanent wilting point (PWP) after γ-PGA added into sandy loam soil had no significant different compared with CK, and the TAW was highest at the treatment of γ-PGA with 0.10% addition amount into sandy loam soil. However, the TAW of sandy loam soil increased dramatically with the γ-PGA SAP addition amount increasing. TM3 had the highest soil water absorption among the treatments with γ-PGA SAP. The T1 to T4 treatments with γ-PGA addition slightly prolonged retention time (RT) when SWC varied from FC to PWP compared with CK. For γ-PGA SAP addition treatments, the time for SWC varied from FC to PWP was 1.48 times (TM1), 1.88 times (TM2), 2.01 times (TM3) and 2.87 times (TM4) longer than that of CK, respectively. The results of this study will provide further information for the use of these materials in agricultural application.

ИЗУЧЕНИЕ ГИДРОФИЗИЧЕСКИХ СВОЙСТВ ТЯЖЕЛОГО БЕТОНА, МОДИФИЦИРОВАННОГО ОРГАНОМИНЕРАЛЬНОЙ ДОБАВКОЙ И МИКРОАРМИРУЮЩИМИ ВОЛОКНАМИ

The main task of the implementation of environmental policy is to create a resource-efficient system for the placement and disposal of industrial waste and secondary raw materials, in particular, in the production of building materials and products of specified properties. Within the framework of these studies, issues related to the activation of microsilica, which is a waste of ferroalloy production, and methods of its use for modifying the structure of cement stone, in particular, for heavy concrete, are considered. The mechanism of the structure formation process, the method of introduction and the optimal consumption of the additive for modifying the concrete mixture have been determined. With the help of a comprehensive study, the products of dispersion of microsilica, which is part of the complex modifier, have been determined. It has been established that the process of the chemical activation of mineral particles has not been sufficiently studied, in this regard, the presented studies, which consist in finding solutions to increase the operational characteristics due to the process of pretreatment of microsilica with an alkaline medium pH = 10.2 together with a micro-reinforcing component, are relevant. The aim of the study is to establish the positive effect of the activation process of silica fume together with a micro-reinforcing component on the modification of the structure of heavy concrete to increase the hydrophysical properties. The object of research is a modified heavy concrete based on activated microsilica with a micro-reinforcing component. In this work, the following research methods were used: physicochemical activation of microsilica with water, treated by electrolysis with the Melesta device; determination of the frost resistance grade in the WK3 180/40 climatic chamber; water tightness was determined in the UVB-MG4.01 installation; water absorption was determined using a SNOL electric digital oven. Research results: a positive effect on the hydrophysical properties of heavy concrete was established by reducing the content of the binder (cement) and replacing it with a microdispersed filler previously activated with an alkaline medium with pH = 10.2. Further modification with a complex additive (high-water-reducing additive "MasterGlenium 115" with a consumption of 1% plus a reaction-chemical additive with microsilica grade MKU-95 - 15% of the binder mass) together with basalt fiber, improves the following characteristics: water absorption - 2%; waterproof grade - W14; frost resistance - F600, which makes it possible to apply this composition in practice to obtain building products and structures with specified characteristics in harsh operating conditions.

La acumulación de materia orgánica mejora el suelo en un sistema agroforestal

The study consisted of analyzing the content of organic matter (OM) in the soil and the changes that occurred in some physical properties. Soil properties such as hydrophysical properties, moisture, bulk density (Da), total porosity and field capacity (CC) were evaluated. Between the years (2012 to 2021), the samples were described in the field as the color and type of structure in the laboratory, the mechanical composition was determined presenting a sandy clay loam texture (sand 48.5%, silt 25.1% and clay 26.4%), pH 6.4, MO 1.4%, Da 1.4 g cm-3 and CC 22.3%. The soil was classified as Anthrosols, and samples were taken at a depth of 0 to 20 cm. Thirty samples were analyzed, and the results show a poorly defined A horizon that presents large to medium blocks characteristic of a B horizon, this soil was hosted more than 23 years ago, with prolonged agricultural use and later with agroforestry use at present as an organic orchard, which has a low carbon content of 0.84%, these soils have been preserved with vegetation cover, concluding that the carbon content has not led to soil improvement in 10 years of implantation of the agroforestry system.