Capillary Water Capacity Research Articles

Effects of cover crops and nitrogen fertilization on soil physical properties, carbon and nitrogen fractions, and winter wheat yield in the Chinese loess plateau: A 4-year field experiment

Context or problemLone-term application of chemical fertilizers in farmland ensure adequate or profitable crop yields but may damage soil structure. Cover crops (CCs) have great potentials to improve soil quality and promote sustainable crop production. However, the combined impacts of CCs with nitrogen fertilization on soil quality and crop yields are not clear. Objective or research questionWe aimed to examine the effects of CCs combined with N fertilization rates on soil physical properties, C and N fractions in both bulk soils and aggregates, and crop yields, and to find the best management practice that improve both soil quality and crop yields synthetically. MethodsA 4-year summer CCs - winter wheat field experiment was conducted in the Loess Plateau of China. CCs with different species and combinations (CC) were soybean (SB), sudan grass (SG), a mixture of both (SS), and no cover crop (CK) and N fertilizer (NR) were applied to winter wheat at rates of 0 (N0), 60 (N60), and 120 (N120) kg N ha−1. Soil physical properties and C and N fractions in both bulk soils and aggregates were evaluated at 0–10, 10–20, and 20–40 cm soil depths. ResultsSoil total porosity (TP), saturated water content (SWC), capillary water capacity (CWC), and C and N fractions decreased while bulk density (BD) increased with the increase of soil depth. The CC, NR, and their interaction (CC×NR) had significant effects on soil BD, aggregate size distribution and stability (MWD), and C and N fractions and only CC and CC×NR had significant effects on other physical properties. The incorporation of CCs significantly increased the proportions of > 5 mm aggregates and C and N fractions in both bulk soils and aggregates, especially in 0–10 and 10–20 cm. And SB and SS improved soil other physical properties more than SG, especially in 0–10 cm, which decreased BD by 13.2% and 12.6% while increased TP by 6.5% and 8.3%, SWC by 14.3% and 15.3%, CWC by 13.9% and 14.2%, MWD by 16.6% and 14.4%, respectively, compared to CK. Additionally, soil physical properties improved more with N60 while the C and N fractions in both bulk soils and aggregates increased more with N120. However, BD increased by 2.6% and 3.3% in N60 and N120 than N0, respectively. The correlations between the proportion of macro-aggregates and soil C and N fractions at 0–10 and 10–20 cm indicated the positive effects of CCs on improving soil structure and fertility simultaneously. Aggregated-associated C and N fractions decreased firstly and then increased with the reduced aggregate sizes, and were higher in micro-aggregates than in other size classes. N60-SB increased wheat yields by 98.7% compared with N0-CK. ConclusionsOverall, the incorporation of soybean residue was the best management practice for winter wheat yield and soil fertility under the reduced N fertilization. Implications or significanceThe selection of CCs species should depend on farmland managements, and the appropriate CCs with N fertilizer rates would target the improvements in soil quality, the sequestration of soil organic carbon, and crop yields synergistically.

Influence of induced drought on photosynthetic performance in Dactylis glomerata varieties during the early growth stage

Drought significantly impacts the growth and yield of forage grasses, particularly its effect on Dactylis glomerata photosynthetic apparatus during the initial phase of development remains largely unknown. This study investigated the effects of drought on physiological parameters of various D. glomerata varieties. The seedlings obtained after seed germination under optimal and simulated drought conditions by PEG 6000 (three variants) were planted in small pots filled with garden substrate. Over a span of 42 days, the plants were initially kept well-watered (70% capillary water capacity, CWC), after which half of the seedlings from each variant were subjected to drought. This drought stress was applied during the tillering phase for 12 days. Subsequently, the plants were rehydrated (at 70% CWC) and allowed to recover for 14 days. Throughout both drought and recovery periods, measurements were taken. Leaf chlorophyll fluorescence parameters were assessed, and the JIP-test analysis was utilised to provide detailed insights into the functionality of D. glomerata photosynthetic apparatus under drought stress and post-recovery conditions. Several parameters were identified as indicative of the plants’ sensitivity to drought, such as performance indices PI ABS and PI tot, along with quantum yield parameters Ψ E0, φ E0, and φ P0. The results highlighted that var. Minora and Tukan exhibited greater tolerance to water deficit when compared to the other varieties studied. They showed a large increases in PIABS and PItot values after drought stress as well as after the re-watering (recovery period) compared to control plants. This suggests their potential for better adaptation to drought conditions.

Impact of long-term fencing measures on soil physicochemical and stoichiometry characteristics of desert steppe in alpine regions

The effects of different enclosure years on soil physicochemical properties provide scientific basis for soil fertility evaluation and ecological restoration. However, the details on the effects of long-term fencing measures on soil physicochemical properties in alpine regions are still lacking. The soil physicochemical properties, soil nutrient content, and stoichiometric characteristics of desert grassland were examined in the desert steppe of northern Tibetan Plateau, where grazing exclusion using fences has been implemented. This study included conducting experiments on different soil layers during different duration (10, 11, and 12 years) of grazing exclusion using fences; natural plots with no grazing exclusion were used as a control variable. Results showed that several soil physicochemical indexes, such as soil organic matter, soil water content, soil capillary porosity, soil non-capillary porosity, and soil capillary water capacity, in plots under the fencing measures were higher than those in the natural plots. The soil bulk density of the 12- and 11-year grazing exclusion plots was lower than that of the natural plots. The clay content of the 10- and 12-year grazing exclusion plots was higher than that of the natural plots, and the sand content was lower than that of the natural plots. The soil nutrient content was especially low with less than the average level of soil nutrient content in China. The stoichiometric C/N, C/P, N/P, and C/K ratios were 10.28–16.39, 2.74–16.69, 0.24–1.53, and 0.27–0.82, respectively. This result indicates that the degree of organic carbon mineralization was relatively high, and there existed a certain N limitation in the study area. The implementation of enclosure is conducive to the accumulation of C and N. The results provide support for elucidating the physicochemical characteristics, soil nutrients, and nutrient cycling of desert steppe in the northern Tibetan Plateau and for the study of the allotted time of fencing project in the alpine region.

Simultaneous enhancement of soil properties along with water-holding and restriction of Pb–Cd mobility in a soil-plant system by the addition of a phosphorus-modified biochar to the soil

Soil quality deterioration and heavy metal contamination have greatly limited soil productivity in mining areas. As soil is a complex system with various properties and interactions, it is imperative to conduct a comprehensive investigation to understand the amendment's mechanisms at work in the soil in mining areas as well as effective ways to address its deteriorating quality. In this study, a potassium dihydrogen phosphate-modified maize straw-cow dung biochar (PBC) was applied as a soil amendment. Various physicochemical properties of the soil including organic matter, total nitrogen, available phosphorus, and pore characteristics were analyzed. This study also assessed soil-saturated water content and soil moisture characteristic curve. Lettuce biomass was measured and changes in various speciation of Pb and Cd in the soil, and the accumulation of Pb and Cd in lettuce were examined. Results showed that the addition of PBC increased soil organic matter, total nitrogen, and available phosphorus while reducing soil bulk density, it also increased soil porosity, saturated water content, and capillary water capacity. Soil structure analysis using CT scanning revealed that 3% PBC increased the macrospores volume fraction while 5% PBC made the pores more uniform. Lettuce biomass increased by 53.3%. 5% PBC resulted in a 56.79% and 38.30% reduction in Pb and a 44.56% and 16.60% reduction in Cd in roots and shoots of lettuce respectively. PBC facilitated the transformation of Pb and Cd from unstable fractions to stable fractions through complexation and precipitation. Overall, the addition of PBC effectively improved soil nutrients, porosity, and water-holding capacity, promoted plant growth, immobilized Pb and Cd, as well as reduced the bioavailability in contaminated-soil from mining areas. This study provides an effective strategy and a new perspective for the remediation of Pb–Cd-contaminated soils.

Effect of oil and surfactants on changes in some physical properties of soils

The paper shows that oil pollution of gray forest and soddy-podzolic soils led to a decrease in capillary water capacity, plasticity and solid phase of soils. As a result of the introduction of the nonionic surfactant tween-80 into the oil-contaminated soil, these indicators were partially restored, but their values remained lower than in soil samples subjected to oil treatment. The obtained materials allow us to speak about the fundamental possibility of using surfactants for the remediation of oil-contaminated soils.

Effects of mixed substrates of different agricultural and forestry residues on the cutting seedlings of Thuja sutchuenensis.

To screen environment-friendly seedling cultivation substrates which could replace peat and with less cost, we compared the effects of different agricultural and forestry residue mixed substrates on cutting propagation of Thuja sutchuenensis, in an experiment following randomized block design. There were five types of mixed substrates, including peat + vermiculite + perlite (T1), edible mushroom residue (EMR) + vermiculite + perlite (T2), carbo-nized rice husk (CRH) + vermiculite + perlite (T3), EMR + slag + sawdust (T4) and CRH + EMR + slag (T5). The results showed that the bulk density of T3 was the lowest, followed by T2, which significantly differed from other mixed substrates. The non-capillary porosity of T2 was significantly greater than that of T1, while the capillary porosity and the total porosity of T2 was lower than T1 and T3, respectively. T2 had the highest contents of total nitrogen, total phosphorus, total potassium, alkali-hydrolyzed nitrogen, available phosphorus, substrate moisture and the highest pH, which differed significantly from other mixed substrates in most chemical indicators. The membership function values of rooting rate and growth indicators of cuttings with different mixed substrates were in order of T2 > T3 > T1> T5 > T4. Most indicators with larger grey relation values were physical indicators. The top five indicators were capillary water capacity, total potassium, field water capacity, maximum water capacity, and total porosity, with both capillary water capacity and total potassium content ranking first. In general, the physicochemical properties, rooting rate, and growth characteristics of cuttings under T2 were better than those of other mixed substrates. The capillary water capacity and total potassium were the main factors affecting rooting and growth of cuttings. At the early stage of cutting, the physical properties of mixed substrate had greater effect on rooting rate and growth of cuttings than the chemical properties. Overall, our results suggested that T2 should be preferred in the cutting propagation of T. sutchuenensis.

Effects of coal gangue on soil property and plant growth in mining area.

With indoor and outdoor treatments, coal gangue with different ratios (10%, 20%, 30%, 40% and 50%) and different particle sizes (0-2, 2-5, 5-8 and 8-10 mm) were mixed into soil, and formed reconstructed soil with different soil bulk densities (1.3, 1.35, 1.4, 1.45 and 1.5 g·cm-3). The effects of soil reconstruction modes on soil water condition, structure stability of aggregate and the growth of Lolium perenne, Medicago sativa, and Trifolium repens were investigated. Soil saturated water (SW), capillary water (CW), and field water capacity (FC) were decreased with increasing coal gangue ratio, particle size, and bulk density of reconstructed soil. >0.25 mm particle size aggregate (R0.25), mean weight diameter (MWD), and geometric mean diameter (GMD) increased first and then decreased with the increases of coal gangue particle size, reaching the peak at 2-5 mm coal gangue particle size. R0.25, MWD and GMD were significantly and negatively correlated with coal gangue ratio. Based on boosted regression tree (BRT) model, the coal gangue ratio contributed 59.3%, 67.0% and 40.3% to the variation of SW, CW and FC, respectively, which was a main influencing factor of soil water content. The coal gangue particle size contributed 44.7%, 32.3% and 62.1% to the variation of R0.25, MWD, and GMD, respecti-vely, which was the greatest influencing factor. Coal gangue ratio had a great effect on the growth of L. perenne, M. sativa, and T. repens, which contributed to 49.9%, 17.4% and 10.3% of their variations, respectively. Soil reconstruction mode of 30% coal gangue ratio and 5-8 mm coal gangue particle size was the best condition for plant growth, indicating that coal gangue could change soil water content and structure stability of aggregate. The soil reconstruction mode of 30% coal gangue ratio and 5-8 mm coal gangue particle size was recommended.

The interactive effect of reclamation scenario and vegetation types on physical parameters of soils developed on carboniferous mine spoil heap

AbstractBulk density, porosity, and water retention capacity play a key role in limiting root growth and nutrient uptake in developed technogenic soils. Thus, the purpose of this study was to evaluate the impact of reclamation technologies and different vegetation types on vital physical soil properties formed from carboniferous materials. The case study was conducted on Sośnica hard coal post‐mine spoil heaps (Upper Silesian Coal Basin of Southern Poland). Nine experimental combinations of reclamation technologies and vegetation types were tested. For vegetation types and basic physical soil parameters, 120 plots (10 × 10 m) were selected. The texture analysis was done on composite soil samples collected at two uppermost soil depths (0–10 and 10–20 cm). Intact structure samples were collected into 100cm3 cylinders from the middle of each plot at both depths for bulk density (BD), porosity, capillary water capacity (CWC), and soil water storage (SWS). In the comparison of different reclamation scenarios, we noted that topsoiling increased BD, whereas CWC and porosity decreased. Spontaneous succession had the same effect on BD, porosity, and CWC as cultivation. Revegetation of the spoil heap with grasses and forbs resulted in lower BD and higher porosity and CWC in the top layer (0–10 cm), whereas woodland resulted in lower BD and higher porosity and CWC at lower depths (10–20 cm). The decreasing order of the SWS was grassland > forbland > woodland. Thus, forbs and grasses should be followed by tree planting, which is crucial to improving the hostile physical properties of the Carboniferous postmine soils.

Comprehensive evaluation of soil quality of different land use types on the northeastern margin of the Qinghai-Tibet Plateau, China

Soil quality evaluation is an important prerequisite for the rational soil resource utilization. We collected soil samples from forest (n=9), grassland (n=18) and cropland (n=38) in Tianzhu County, Gansu Province, which is located on the northeastern edge of the Qinghai-Tibet Plateau. Soil quality was evaluated based on thirteen soil physical and chemical indicators, including soil bulk density, field capacity, and organic matter. A minimum data set (MDS) was constructed using principal component analysis and correlation analysis to establish a soil qua-lity evaluation index (SQI) system, which was used in the soil quality evaluation for the three land-use types. The results showed that total porosity, capillary porosity, field capacity, capillary water capacity, saturated water content, organic matter, total nitrogen and available potassium content were significantly higher in forest than those in grassland and cropland. The SQI system of forest was based on field capacity, organic matter, total nitrogen, available nitrogen, and available potassium, and the SQI ranged between 0.329 to 0.678, with a mean value of 0.481. Grassland SQI system was based on field capacity and available nitrogen, with the SQI ranging between 0.302 to 0.703 and a mean value of 0.469. Cropland SQI system was based on capillary water capacity, non-capillary porosity, available nitrogen, available phosphorus, and available potassium, and the SQI ranged from 0.337 to 0.616 with a mean value of 0.462. The most important barriers to soil quality improvement in forest, grassland, and cropland were available potassium, field capacity, and capillary water capacity, respectively. The MDS-based SQI enabled an accurate evaluation of soil quality across different land-use types in the study area, which was best in forest followed by grassland and cropland. The evaluation results would provide important reference for sustainable soil management in the local area.

Effect of Coal Gasification Slag on Improving Physical Properties of Acid Soil

Coal gasification slag (CGS) is a coal-based solid waste formed by the transformation of inorganic mineral components and carbon components in raw coal into slag during coal gasification. To explore its influence on the physical characteristics of acid soil and study the influence mechanism on the water holding capacity of acid soil, the coarse and fine CGS were used as materials to mix with acid soil in different proportions. The volume weight, particle size composition, and water retention performance of the mixed soil were tested, and the changes of soil water characteristic curve were analysed. The results showed that, after mixing the acid soil with CGS, the particle size composition of acid soil was significantly improved, the sand content increased by 13.27–195.46%, the clay and silt content decreased by −2.14–38.62% and 3.22–40.06%, respectively; and the soil bulk density decreased significantly (P < 0.05), with a decrease range of 3.38–28.12%. The soil texture also changed from silty loam to sandy loam, and the water retention performance showed an upward trend, which significantly affected the soil saturated water content, capillary water capacity and field water capacity, with an increase range of 2.87–38.09%, 1.73–27.92% and 4.18–22.27%, respectively. The Van Genuchten (VG) model could fit the soil water characteristic curve well, indicating that the water retention of acid soil was significantly improved by adding CGS. In conclusion, CGS could improve the water physical properties effectively, and improve the water retention and water holding properties of acid soil significantly. This feature is conducive to the environmentally friendly utilization of CGS to improve agricultural acid soil.

Determination of water absorption coefficient of unfired earth materials different in used clay and ratio of components

The paper is focused on unfired rammed earth and its water absorption properties. Increasing the utilization of raw natural materials can be one of the approaches towards sustainable development. Different prescriptions were designed and specimens were rammed. Then they were put in the covering of nylon and settled in the box with soft foam that was moistened. The level of moistening was constant. The specimens were regularly weighted. Specimens with montmorillonite clay have the highest values of the water absorption coefficient. Montmorillonite clay has a higher binding capacity. The values are compared to values that were found in the literature. Then the maximal capillary water capacity by area was determined.

Soil water dynamics in drained and undrained meadows

Tile drainage belongs to one of the most important meliorative measures in the Czech Republic. It has been hypothesised that it may improve some soil properties which are influenced by the groundwater and their water regime. In the case of meadows, the used management method may also influence the soil properties. In this study, different physical soil properties (particle and bulk density, total soil porosity, maximum capillary water capacity, minimum air capacity, water retention capacity and saturated water content, volumetric water content and matric potential) at depths of 15, 35 or 40 and 60 cm in differently managed meadows (drained versus undrained) located near the village of Železná in the Czech Republic (mildly cold, humid climatic region) were investigated. The drained meadow is used mainly for grazing (extensively) and the undrained meadow is mown twice a year. In addition, the actual evapotranspiration was estimated for the 2018 vegetation season. The selected physical soil properties were significantly (P < 0.05) different between the experimental meadows, especially at depths of 0–28 versus 0–35 cm (particle and bulk density, total soil porosity, maximum capillary water capacity, water retention capacity and saturated water content) and 28–49 versus 35–45 cm (particle density, water retention capacity and saturated water content). In the case of all the studied soil depths, the volumetric water content and matric potential were significantly (P < 0.05) different between the experimental meadows in the years 2016–2019. The actual evapotranspiration was also significantly different (P < 0.05) between the meadows. The obtained differences in the measured soil properties and estimated actual evapotranspiration were probably influenced by the used tile drainage and also by the type of management of the meadow. It is necessary to obtain more research findings with respect to different types of management in the case of drained meadows and also undrained meadows to understand the role of both treatments (tile drainage, management).

Toprak İşlemesiz Koşullar Altında Agrochernozyemlerin Temel Fiziksel Özelliklerindeki Değişimler

Agriculture is one of the leading branches of the economy in the Republic of Bashkortostan (Russia). Long-term agricultural use of land with the use of plowing led to a decrease in the thickness of humus-accumulation horizon of soils, reduction of organic matter and nutrients. There is also deterioration of water-physical properties, development of water and wind erosion, and decrease in yield. Recently, the use of soil-saving farming systems has started, including the use of No-Till soil tillage system. The paper presents the results of assessment of physical properties of agrochernozems in conditions of No-Till use. Such physical properties as bulk density, humidity, temperature, structural and aggregate composition were studied using methods and instruments adopted in soil science. It is shown that in the top layer of soil (0-20 cm) is the accumulation of soil moisture, but the capillary and total water capacity is lower than that in nature soil. At the same time, in cultivated soils faced to the No-Till system the values of bulk density were increased as well as ranges of resistance to penetration. This fact, porbalby was caused the impact of activity of heavy agricultural machinery. The declining of soil density can be reached by cultivation of sideral cultures and perennial grasses.

Comparison of the physical properties of soils belonging to different reference soil groups

Soil properties can be influenced by long-term agricultural management practices as described in pedological literature. In this study, selected physical properties (particle density and bulk density, total porosity, maximum capillary water capacity, minimum air capacity, field capacity, permanent wilting point and available water capacity) of topsoils from different reference soil groups (Cambisols, Luvisols, Fluvisols, Chernozems and Phaeozems, Leptosols, Stagnosols and Gleysols) were sampled and analysed in the years 2016–2017. The topsoil samples were taken from points of so-called S (specific) soil pits to be sampled from the General Soil Survey of Agricultural Soils (GSSAS) which was accomplished in the years 1961–1970. In addition, some of the properties were also compared with those measured during the GSSAS. Recognising the properties, only the particle density, the maximum capillary water capacity, the permanent wilting point and the available water capacity of the topsoil of the individual soil groups were statistically significantly (P < 0.05) different. A comparison of the physical properties with those analysed after more than 40 years was performed, the bulk density increased and the total porosity decreased in the topsoil of the major part of the studied soil groups.

The Spatial Variability of Soil Physical Properties of Different Sized-gap in a Subtropical Forest, China

Gap areas create heterogeneity in the spatial environment, which is important to plant regeneration and diversity. Soil physical properties (SPP) are factors that affect plant growth. This study aims to assess the spatial variability of SPP in different gap sizes and to determine the effect of gap size on SPP. We used geostatistical analysis to illustrate the spatial patterns of SPP variability within 9 gaps, classified into three sizes (small, medium, and large) and under the canopy at the Castanopsis kawakamii natural reserve forest, the soil samples were collected entire gap area at 20 cm depth with the grid system (resolution: 3 m × 3 m). The following SPPs were determined using soil cores: soil bulk density (SBD), soil water mass content (SWMC), soil volumetric moisture content (SVMC), maximum moisture capacity (MMC), capillary water capacity (CWC), minimum water-holding capacity (MWHC), soil capillary porosity (SCP), and soil total porosity (STP). We found that every SPP, except SCP and STP, significantly differed with gap size. Gap sizes generally improved the SPPs, especially in the small and large gaps, indicating that the soil there was more suitable for plant growth than the soil under the canopy. The highest spatial variability of SPPs was observed in the large gaps. Gap size affected SPP and its spatial variability. The results from this study will be useful for work on forest gap regeneration and conservation, especially around the study site.

Spatial variation of soil physical properties and its relationship with plant biomass in degraded slopes in dry-hot valley region of Southwest China

Soil properties are one of the most important factors affecting the distribution and growth of plants in arid and semi-arid regions, especially in the dry-hot valley of southwest China, where desertification is a serious environmental problem deteriorating the dryland ecosystems. However, the spatial variation of soil physical properties and its relationship with plant productivity in degraded slopes is not yet fully understood. In this study, three parallel downslope transects were built on a typical degraded slope in the dry-hot valley of Jinsha River, and soil physical properties (including soil particle size, bulk density (BD), total porosity (TP), capillary porosity (CP), noncapillary porosity (NP), saturated water capacity (SWC), capillary water capacity (CWC), field water capacity (FWC), and hydraulic conductivity (Ks)) at two soil depths (0–10 cm and 10–20 cm) and plant biomass (reflected by aboveground biomass) were measured. The results indicated that the sand content, TP, NP, SWC, CWC, and Ks increased firstly and then decreased, while the silt content and BD decreased firstly and then increased from upper slope to lower slope. Plant biomass was only observed in middle and lower slopes, and that in the lower slope was decreased significantly to slope foot. Slope position and soil depth had significant effects (P < 0.05) on soil physical properties, indicating that topography and soil depth play a key role in driving the spatial variation in soil physical properties. Simple linear regression analysis showed that Ks, sand, and silt content are the key soil indicators affecting plant growth, and the soil layer differences in BD, CWC, and FWC are also the important factors affecting plant productivity. Our findings highlight the spatial variation of soil physical properties, and plant biomass is attributed to the interactions of topography-soil-plant, which is critical for the healthy function of degraded slopes. Such findings provide an important basis for ecological restoration and management in degraded regions.

Temporal Changes in Community Structure over a 5-Year Successional Stage in a Subtropical Forest

In the context of global warming, the changes of forest structure, diversity, and productivity along with forest succession have always been a topic of interest for many researchers. Studying the changes in community structure, biomass, and diversity of different diameter at breast height (DBH) classes in subtropical mountainous forests during forest succession can provide data in support of future forest succession predictions and forest management. We analyzed the changes of three DBH classes in a 10-ha plot while studying subtropical mountainous forest succession in 2012 and 2017. The results showed that during forest succession, the community abundance and richness significantly decreased while biomass increased slightly. Among the three DBH classes, changes were the greatest in small trees, followed by large trees, and then medium-sized trees. The abundance, biomass, richness, and Shannon–Wiener index of small trees all decreased significantly. In forests with medium-sized trees, biomass decreased significantly and abundance did not change significantly. In large trees, abundance and biomass increased significantly. Changes were observed in environmental driving factors during forest succession. In 2012, driving factors with significant effects included total phosphorus, transmitted direct solar radiation, organic matter, and capillary water capacity. In 2017, two driving factors were total phosphorus and total potassium while the main driving factor was still total phosphorus. The results showed that during forest succession the abundance and diversity of small trees were principal components of community abundance and diversity. A reduction in small-tree abundance and diversity will decrease community abundance and diversity. Large-tree biomass was a principal component of community biomass; accumulation of large-tree biomass will increase community biomass. Schima superba Gardner and Champ. and Castanopsis carlesii (Hemsl.) Hayata are the main dominant species in this area, which can quickly form stable communities. S. superba is also a fire-resistant tree species. Therefore, in natural forest management, planting of S. superba and C. carlesii in the secondary bare land can be considered. In addition, the evergreen broad-leaved forest can be recovered to the forest structure and productivity level before selective cutting, which provides important inspiration for forest management in the region.

Ecotone Dynamics and Stability from Soil Perspective: Forest-Agriculture Land Transition

Topographic and edaphic gradients usually arrange ecotonal boundaries. Although the interrelationships between vegetation and edaphic factors are relevant in most types of ecotones, they are not adequately documented. The clearly defined forest-agriculture land ecotone at the Proklest experimental site of the Training Forest Enterprise (T.F.E), Masaryk Forest Křtiny, Czech Republic presents an opportunity to investigate these inter-relationships. Our aim was to determine ecotone effects reflected by changes in soil reaction and other soil physical properties across this clearly defined forest-agriculture land ecotone. We selected eleven sampling spots: four in the forest zone, four in the agriculture land, and three in the ecotone zone between the forest and agriculture land. Every month from April to November, soil samples were collected at a depth of 5 cm. All the soil samples collected were examined for minimal air capacity, actual and potential soil reaction, and maximum capillary water capacity. The forest soil was slightly more acidic when compared to the agriculture soil, with the ecotone zone recording the lowest pH value. The maximum capillary water capacity was higher in the forest region than in the agriculture land with a sharp decline in the ecotone zone where the lowest value was recorded. The minimum air capacity was much higher in the forest region than in the agriculture land. There was a marked decline in the ecotone region where the lowest value was observed. Our results highlight the importance of soil as a factor affecting the distribution of plant communities along ecotones.

The Role of Compost in Stabilizing the Microbiological and Biochemical Properties of Zinc-Stressed Soil

The progressive development of civilization and intensive industrialization has contributed to the global pollution of the natural environment by heavy metals, especially the soil. Degraded soils generally contain less organic matter, and thus, their homeostasis is more often disturbed, which in turn manifests in changes in biological and physicochemical properties of the soil. Therefore, new possibilities and solutions for possible neutralization of these contaminations are sought, inter alia, through reclamation of degraded land. At present, the use of additives supporting the reclamation process that exhibit heavy metal-sorbing properties is becoming increasingly important in soil recovery. Research was conducted to determine the role of compost in stabilizing the microbial and biochemical balance of the soil due to the significant problem of heavy metal-contaminated areas. The study was conducted on loamy sand, to which zinc was applied at the following doses: 0, 250, 500, 750, 1000, and 1250 mg Zn2+ kg−1 DM of soil. Compost was introduced to the appropriate objects calculated on the basis of organic carbon content in the amount of 0, 10, and 20 g Corg kg−1 DM of soil. The study was conducted over a period of 20 weeks, maintaining soil moisture at 50% capillary water capacity. Zinc significantly modified soil microbiome status. The abundance of microorganisms and their biological diversity and the enzymatic activity of the soil were affected. The negative effects of contaminating zinc doses were alleviated by the introduction of compost into the soil. Organic fertilization led to microbial growth intensification and increased biochemical activity of the soil already 2 weeks after compost application. These effects persisted throughout the experiment. Therefore, it can be stated that the use of compost is an appropriate method for restoring normal functions of soil ecosystems contaminated with zinc.

Physical properties of the soils of Georgia

In article is generalized such indexes as water permeability, bulk density, particle density, total porosity, capillary porosity, non-capillary porosity, capillary water capacity, saturation water content, field capacity, permanent wilting point, hydroscopic water content, productive water, pores with air. This indexes were determined in main soils of Georgia: Red (Ferralic Nitisols, Haplic Nitisols), Yellow (Ferric Luvisols), Bog (Dystric Gleysols, Eutric Gleysols, Histosols), Yellow Yellow podzolicic (Stagnic Acrisols, Ferric Acrisols), Yellow brown forest (Stagnic Luvisols, Mollic Luvisols, Humic Luvisols, Ferric Luvisols), Brown forest (Humic Cambisols, Ferric Cambisols, Eutric Cambisols, Dystric Cambisols), Raw carbonate (Rendzic Leptosols), Grey cinnamonic (Calcic Kastanozems, Vertic Kastanozems), Meadow grey cinnamonic (Haplic Kastanozems, Gleyic Kastanozems, Vertic Kastanozems), Cinnamonic (Chromic Cambisols, Calcaric Cambisols, Humic Cambisols, Eutric Cambisols), Meadow cinnamonic (Chromic Cambisols, Calcaric Cambisols, Gleyic Cambisols, Eutric Cambisols), Black (Haplic Vertisols), Chernozems (Voronic Chernozems, Calcaric Chernozems), Mountain meadow (Hyperdistric Umbrisols), Saline soils (Vetric Solonchaks, Mollic Solonetz), Alluvial (Gleyic Fluvisols, Eurtic Fluvisos, Dystric Fluvisols).