Soil Catalase Activity Research Articles

Differential effects of various reclamation treatments on soil characteristics: an experimental study of newly reclaimed tidal mudflats on the east China coast

Reclamation of coastal land is increasingly being used as a means of raising agricultural productivity and improving food security in China. Applications of organic and inorganic supplements on reclaimed soils can significantly adjust a range of soil properties, C, N, P content and stoichiometry, and extracellular enzyme activities. However, the linkages between soil C꞉N꞉P stoichiometry and extracellular enzyme activities following reclamation of coastal saline soil remain largely unclear. In this experimental study, treatments included control (CK), chicken manure (OM), polyacrylamide plus chicken manure (PAM+OM), straw mulching plus chicken manure (SM + OM), buried straw plus chicken manure (BS + OM), and bio-organic manure plus chicken manure (BM + OM) were conducted to explore the linkages between soil physicochemical characteristics in reclaimed soils under different treatments and to evaluate their impact on oat yield. Soils under all reclamation treatments exhibited higher moisture content and, with the exception of SM + OM, lower soil pH compared to the control. The reclamation treatments also significantly decreased soil bulk density (BD) and soil salt content (SSC), and increased soil organic carbon (SOC), total nitrogen (TN) and organic phosphorus (OP). Our study of soil C꞉N꞉P stoichiometry revealed that newly reclaimed soils in the study area are N limited. Additionally, soil invertase (INV), urease (URE) and alkaline phosphatase (ALP) activity under different reclamation treatments were significantly enhanced compared with CK in surface soil, while soil catalase (CAT) activity was observed to be much higher in BM + OM than in other treatments. Mean oat yields for each of the treatments were ranked as follows: BM + OM > SM + OM > PAM + OM > BS + OM > OM > CK treatment. Our results also indicate that TN (12.1% and 12.4%) was the main factor affecting URE and ALP, whereas BD (13.5%) and pH (8.5) were key factors affecting INV and CAT activity, respectively.

Изменение активности каталазы в почвах Черноморского побережья Кавказа при загрязнении тяжелыми металлами и нефтью

Изменение активности каталазы в почвах Черноморского побережья Кавказа при загрязнении тяжелыми металлами и нефтью

Effects of Two Types of Straw Biochar on the Mineralization of Soil Organic Carbon in Farmland

To investigate the effects of biochar on soil carbon composition and transformation, the effects of 1%, 2%, and 5% mass ratios of banana and cassava straw biochar on carbon dioxide release, total organic carbon (TOC), soluble organic carbon (SOC), and enzyme activity in soil were studied in incubation experiments at a constant temperature in the laboratory. The results showed that the cumulative CO2 emissions from cassava straw were 15.82 (1% addition ratio) and 28.14 μg·kg−1 (2%), which were lower than those from banana straw, i.e., 46.77 (1%) and 59.26 μg·kg−1 (2%). After culture, the total organic carbon contents of cassava straw were 8.55 (5%), 5.27 (2%), and 3.98 μg·kg−1 (1%), which were higher than those of banana straw, i.e., 6.31 (5%), 4.23 (2%), and 3.16 μg·kg−1 (1%). The organic carbon mineralization rate in each treatment showed a trend of increasing first, then decreasing, and finally stabilizing. There was a very significant positive correlation between catalase and urease activity in soil with cassava straw biochar and between catalase activity and SOC mineralization with banana straw biochar. It plays an important role in the transformation and decomposition of organic carbon. These results show that the application of biomass carbon can significantly improve the organic carbon content and enzyme activity of farmland soil, increase the cumulative mineralization amount and mineralization rate of SOC, and thus increase the carbon sequestration capacity of soil.

Estimation the impact of the linear form of recreation on the properties of brown forest soils (for example NPP «Skolivski Beskydy», Ukrainian Carpathians)

The article analyses the impact of recreational loading on brown forest soils by physical, water-physical, agrochemical and biotic properties. It was found that the density of soil structure on the trails increased by 1.1-1.9 times and field soil moisture decreases by 1.8-1.9 times. In the initial stages of recreational degression, the humus content is recorded slightly higher compared to the control area, while on trails with a higher recreational load, on the contrary, decreases by more than 50%. Indicators of biotic activity is catalase activity of soil and biomass of soil biota. Depending on the stage of recreational regression, the indicators of biotic activity decreased by 25-60% compared with the control. As the criteria for estimating the impact of recreation activities on the soil: the width of the trail, the parallels trails, the density of the soil structure and the forest litter. Аccording to the results of field and laboratory studies: trail «Starovikovi lisy» are included in the I category and the trail «Dolynoyu richky Kamyanka» to the IV category, route «Skole-Parashka» – ІІІ category.

Iron-modified biochar and water management regime-induced changes in plant growth, enzyme activities, and phytoavailability of arsenic, cadmium and lead in a paddy soil

The aim of this study was to evaluate the effect of raw (RawBC) and iron (Fe)-modified biochar (FeBC) derived from Platanus orientalis Linn branches on the plant growth, enzyme activity, and bioavailability and uptake of As, Cd, and Pb by rice in a paddy soil with continuously flooded (CF) or alternately wet and dry (AWD) irrigation in a pot experiment. Application of RawBC (3%, w/w) significantly increased soil pH, while FeBC decreased it. The FeBC was more effective in reducing As and Pb bioavailability, particularly under the AWD water regime, while RawBC was more conducive in reducing Cd bioavailability under the CF water regime. The FeBC decreased As concentration, but increased concentrations of Cd and Pb in the straw and brown rice, as compared to the untreated soil. Soil catalase and urease activities were enhanced by RawBC, but decreased by FeBC treatment. The FeBC increased the grain yield by 60% and 32% in CF and AWD treatments, respectively. The FeBC can be recommended for immobilization of As in paddy soils, but a potential human health risk from Cd and Pb in FeBC-treated soils should be considered due to increased uptake and translocation of the metals to brown rice.

The effects of whey application on the soil biological properties and plant growth

Whey is an industrial dairy by-product. Whey proteins present in whey are valuable functional ingredients with a variety of applications. Because of high investment and management costs, many medium and small-scale cheese manufacturing plants choose the way to waste whey by discharging it to land without refining while large companies prefer to evaluate it. In this experiment were investigated the effects of whey application on some growth parameters of test plant and soil biological properties. For this purpose, greenhouse experiment was conducted to determine the effects of different whey powder solution (6% dry matter) such as no demineralized whey powder (NDWP), 50% demineralized whey powder (50% DWP) and whey protein powder (WPP) on maize growth and biological properties of soils using increasing application rates (0, 50, 100, 150 and 200 ml/kg) as three replication. At the end of the study generally, all whey treatments influenced the soil microbiological properties in comparison with the control, indicating activation by microorganisms. The addition of different doses of different whey solutions caused a rapid and significant increase in microbial biomass C, soil respiration, dehydrogenase activity and catalase activity in soil; this increase was especially noticeable in soils treated with NDWP and 50% DWP. Similarly, addition of 50% DWP to the soil increased values of plant height, fresh plant weight and fresh root weight compared to the control and other whey. Whey has a positive effect on soil biological properties. In conclusion, we can say that this waste product, which has high nutrient element content, could be used in fertilization practices especially as a nitrogen source and multi-perspective studies need to be carried out on this topic.

Evaluation of soil enzyme activities as soil biological activity indicators in desert-oasis transition zone soils in China

The seasonal and spatial variations (desert, desert-oasis, and oasis) in some enzyme activities (urease, alkaline phosphatase, nitrate reductase, dehydrogenase, and catalase) in the 0–20 cm and 20–40 cm soil layers were evaluated along a typical desert-oasis transition zone in the Shule River basin in China. The results showed that there was a significant positive correlation of soil urease, alkaline phosphatase, dehydrogenase, and catalase activities with vegetation coverage and available phosphorus while they had a negative correlation with soil pH and EC. Nitrate reductase activity was positively correlated with soil pH and EC but was negatively correlated with elevation and vegetation coverage. According to the redundancy analysis, environmental factors (elevation, vegetation coverage, soil moisture contents, pH, EC, OM, AP and AK) in this study explained 89.8% of the soil enzymatic activity variations when combined (p < 0.01). The Monte Carlo simulation showed that the order of importance of environmental factors on soil enzyme activities was as follows: vegetation coverage (42.5%) > elevation (38.0%) > EC (30.7%) > AP (18.1%) > pH (15.4%). Accordingly, catalase activity exhibited sensitivity to changes in land use intensity and no seasonal variation, suggesting that it is the soil biological activity indicator best suited for measuring existing conditions and potential changes in the desert-oasis transition zone soils.

Effects of straw returning and fertilization on soil fertility and yield and quality of edible sweetpotato

Two-year field experiments were conducted in 2017-2018 to examine the effects of wheat straw returning and fertilization on soil fertility and enzyme activities, as well as the yield and qua-lity of edible sweetpoato. There were five treatments, including conventional fertilization+zero straw (CK), conventional fertilization+50% straw returning (50%S), zero fertilization+100% straw returning (100%S-F), conventional fertilization+100% straw returning (100%S), conventional fertilization+100% straw retuning+150 kg N·hm-2 (100%S+N). The treatments of straw returning and fertilization significantly increased the contents of available phosphorus (P), hydroly-zable nitrogen (N), total N, and organic matter in soils, and increased the activities of soil catalase, alkaline phosphorylase, urease, and invertase. The storage root yield, single root fresh weight and commodity potato rate were significantly increased under the treatments of straw returning and fertilization. The storage root yield was the lowest under the treatment of 50%S. After two years of straw returning, storage root yield and commodity potato rate were the highest under the treatment of 100%S. In general, the contents of starch and protein in sweetpotato were increased after two years of straw returning and fertilization, but the contents of reducing sugar and soluble sugar were decreased under 100%S and 100%S+N treatments. Our results suggested that straw returning in full quantity was better than straw returning in half quantity. The storage root yield and commodity potato rate was the highest under the combination of full quantity straw returning and conventional fertilization, with the taste of sweetpotato being changed. Thus, the amount of nitrogen fertilizer should be appropriately reduced in actual practice.

Effects of polymer modifiers on the bacterial communities in cadmium-contaminated alkaline soil

Polymer modifiers are widely used in the remediation of cadmium-contaminated soil. However, little is known about how polymer modifiers affect soil bacterial communities. The purpose of this study was to measure the effects of polymer modifiers (polyacrylate polymer and organic polymer) on the composition and network structure of bacterial communities in cadmium-contaminated soils combined with phloem girdling of cotton. The results showed that polyacrylate polymer increased soil urease, sucrase, and alkaline phosphatase activities (P < 0.05), while organic polymer increased soil catalase and urease activities (P < 0.05). Polymer modifiers decreased soil Ex-Cd (exchangeable Cd) concentration (P < 0.05) but increased Carb-Cd (carbonate-bound Cd), Ox-Cd (FeMn oxides-bound Cd), Org-Cd (organic Cd), and Res-Cd (residuals Cd) concentrations. Polyacrylate polymer increased the relative abundances of Proteobacteria, Gemmatimonadetes, and Chloroflexi (P < 0.05), while organic polymer only increased the relative abundance of Chloroflexi (P < 0.05). Co-occurrence network analysis showed that polymer modifiers decreased the relative abundances of rhizosphere bacteria, negatively affected the symbiosis, and triggered the competition among the key bacterial species. Polymer modifiers has good effects on reducing the bioavailability of soil cadmium and increasing soil pH, enzyme activities, and relative abundances of dominant bacteria, which changes the relationships of rhizosphere bacteria and may be help for the remediation of cadmium-contaminated alkaline soil.

Effects of wheat straw incorporation and nitrogen application on sweetpotato yield and quality and soil fertility

ABSTRACT The study was aimed to determine the effect of wheat straw incorporation and nitrogen (N) fertilization on soil fertility and enzyme activity, as well as sweetpoato yield and quality. Field experiment was conducted in the summer seasons of 2017 and 2018, and four treatments were set: zero straw +50 kg·ha−1N (S0N50), 50% straw return +50 kg ha−1N (S1N50), 100% straw return +50 kg·ha−1N (S2N50), 100% straw return+150 kg ha−1N (S2N150). The aboveground yield, storage roots yield and single root fresh weight increased with the increase of straw returning quantity(S2N50> S1N50> S0N50). The storage root yield ofS2N150in 2017 was higher than that ofS2N50,but lower than that ofS2N50in 2018. Two years of nitrogen/straw incorporation also increased the starch content of sweetpotato, but decreased the reducing sugar, soluble sugar and protein content. The available N, total N, available P, available K and organic matter content, as well as catalase, alkaline phosphorylase, urease and invertase activity in soil were enhanced by nitrogen/straw incorporation. The results indicated that the conjoint application of full amount of straw and appropriate amount of N had the best effect on increasing the yield and starch content of sweetpotato.

The effects of four cadmium tolerant plant straws on the growth and cadmium content of jujube seedlings

To study the effects of four cadmium-tolerant plant straws on the growth and cadmium content of Zizyphus acidojujuba seedlings, Zizyphus acidojujuba seedlings were planted in cadmium-contaminated soil (5mg ⋅ kg−1) with cadmium-tolerant plants straws such as Ranunculus sieboldii, Clinopodium confine, Plantago asistica and Mazus pumilus through pot experiments. Results showed that the biomass, photosynthetic pigment content, peroxidase (POD) activity and soluble protein content of Zizyphus acidojujuba seedlings could be improved by applying four kinds of plant straws with cadmium tolerance to cadmium-contaminated soil. At the same time, the catalase (CAT) activity in cadmium-contaminated soil was increased, the growth of Zizyphus acidojujuba seedlings was promoted, and the cadmium content in root and overground parts of Zizyphus acidojujuba seedlings was reduced. The cadmium transfer coefficient of Zizyphus acidojujuba seedlings could be increased by only applying the straw of the Clinopodium confine, while the cadmium transfer coefficient of Zizyphus acidojujuba seedlings could be reduced by all the other straw treatments Therefore, the four kinds of cadmium-tolerant plant straws are all suitable for the restoration of cadmium-polluted Zizyphus acidojujuba gardens, among which the Ranunculus sieboldii, Plantago asistica and Mazus pumilus straws are better.

Soil properties, bacterial and fungal community compositions and the key factors after 5-year continuous monocropping of three minor crops.

Minor grain crops are widely cultivated in northwest China and played important roles in local economic. Soil microbes play a central role in ecological function and biological stability and related to soil quality. In order to uncover the soil microbial composition differences and the factors under 5-year continuous monocropping of three minor crops (Proso millet, Common bean and Common buckwheat) in Guan-Zhong Plain, six soil nutrimental parameters, soil pH, soil moisture content, and four soil enzyme activities were analyzed and soil microbial composition were sequenced. The results showed that after 5-years of continuous monocropping, different cover crops influenced most of soil physicochemical properties, expect soil moisture content (P < 0.05), the available nutrients were significant higher in proso millet soil, and the pH was significantly higher in common buckwheat soil. soil ALP, catalase and urease activities were significantly different between soils (P< 0.01), in which soil catalase activities were significantly lower and soil ALP and urease activities were significantly higher than that of proso millet and common buckwheat. A total of 171439 sequences, 9468 OTUs and 29 phylum for bacteria, 128920 sequences, 544 OTUs and 27 phylum for fungi were obtained. In addition, no significantly difference obtained in diversity and richness between soils (P < 0.05). According to relative abundance, Proteobacteria, Chloroflexi, Gemmatimonadetes and Acidobacteria were the dominant bacterial phylum in all samples, moreover, the relative abundance of Caldiserica was significantly different between soils (P < 0.05). Ascomycota (79.04%-90.21%) was dominant phylum in fungal community and phylum Phragmoplastophyta (P < 0.01) and Glomeromycota (P < 0.05) were significantly different between soils. Redundancy analysis indicated that available nutrients Nitrogen and Potassium are the strongest predictors in both bacterial and fungal community. In conclusion, different cover crops influenced soil nutrient properties, soil pH and soil microbial composition, and continuous monocropping decreased soil fertility condition. Moreover, Common bean and Common buckwheat were more sensitive to monocropping treatment.

Effect of biochar addition on CO2 exchange in paddy fields under water-saving irrigation in Southeast China

Biochar has been widely applied to paddy fields to improve soil fertility, crop productivity and carbon sequestration, thereby leading to variations in the CO2 exchange between the paddy fields under flooding irrigation and the atmosphere, as indicated by many previous reports. However, few relevant reports have focused on paddy fields under water-saving irrigation. This study conducted a field experiment to investigate the effects of three biochar addition rates (0, 20 and 40 t ha−1) on the CO2 exchange between paddy fields under controlled irrigation (CI, a water-saving irrigation technique) and the atmosphere in the Taihu Lake region of Southeast China. Our results showed that biochar addition increased the paddy field ecosystem respiration (Reco) and the soil respiration rate (Rs) in the CI paddy fields. And biochar application increased the total CO2 emissions and the total soil CO2 emissions, especially at a rate of 40 t ha−1. In contrast, gross primary productivity (GPP) was decreased and the net ecosystem exchange of CO2 (NEE) was increased with biochar addition. However, biochar addition at a rate of 20 t ha−1 significantly increased the total CO2 absorption and the net CO2 absorption of the CI paddy fields (p < 0.05), whereas biochar addition at a rate of 40 t ha−1 had no effect on the total CO2 absorption and decreased the total net CO2 absorption. At the same time, biochar addition significantly increased soil catalase, invertase and urease activities and contributed substantially to the increase in soil invertase activity. In addition, the soil bacterial, fungal and actinomycetal abundances were evidently increased with biochar addition, of which the soil fungal abundance showed the greatest increase. A high correlation was observed between soil catalase and invertase activities and soil microbial abundance. Reco was highly correlated with air and soil temperatures and soil enzyme activity. A significant quadratic polynomial correlation was observed between GPP and leaf area index (p < 0.01). The combination of biochar addition at a rate of 20 t ha−1 and water-saving irrigation has the potential to increase the size of the carbon sink and promote soil enzyme and microbial activities in paddy field ecosystems.

Postagrogenic Changes in the Enzyme Activity and Organic Carbon Content in Chernozem during the First Three Years of Fallow Regime

Comprehensive studies of the biological status of ordinary chernozem (Haplic Chernozem (Loamic)) were carried out in the early years of the fallow regime in comparison with its arable analogue, old fallow, and the reference virgin steppe soils. They included a field experiment on the conversion of an old-arable plot with the ordinary chernozem in Botanical Garden of the Southern Federal University to a fallow. In this experiment, organic carbon and the activity of two classes of enzymes, oxidoreductases (catalases and dehydrogenases) and hydrolases (β-fructofuranosidase) were compared for soils under land-use variants. The organic carbon content in the soil of the young fallow increased already in the first year; it did not change significantly in subsequent years of plant cover restoration, and varied depending on the observation period during the growing season. The activity of the enzymes also increased in the first year of the fallow regime and continued to restore throughout the time after the cessation of agricultural use. The catalase activity in the young fallow soil was 9% higher (p < 0.05) than in the first year of research, the activity of dehydrogenases increased by 20% (p < 0.05), and β-fructofuranosidase by 10% (p < 0.05). However, the enzymatic activity was significantly lower than in the case of old fallow and, especially, of the reference soil in the virgin steppe.

Effect of Chinese Milk Vetch (Astragalus sinicus L.) and Rice Straw Incorporated in Paddy Soil on Greenhouse Gas Emission and Soil Properties

Paddy soil is an important emission source of agricultural greenhouse gases. The excessive application of chemical fertilizer to paddy soil is one of the important reasons for high greenhouse gas emissions. Emissions can be reduced through optimized agricultural management measures. The incorporation of Chinese milk vetch (CMV) and rice straw in the field to replace some of the chemical fertilizer can reduce the emissions of greenhouse gases, but the relationship between these emissions and soil properties after the incorporation of CMV and rice straw is unclear. Through the continuous determination of greenhouse gases and the physical and chemical properties of soil, it was found that the addition of CMV and straw could increase the emissions of methane (CH4) and carbon dioxide (CO2), but nitrous oxide (N2O) emissions were lower. The effect of the combined incorporating of CMV and rice straw on soil properties was more significant than CMV alone. It was also found that CH4 and CO2 emissions were positively correlated with microbial biomass carbon and nitrogen, pH, and soil catalase and β-xylosidase activities. In practice, we can reduce greenhouse gas emissions by water and fertilizer management.

The mechanism of polystyrene microplastics to affect arsenic volatilization in arsenic-contaminated paddy soils

Different concentrations and sizes of polystyrene microplastics (PS-MP) were added to low (25.9) and high (56.8) mg kg−1 As-contaminated soil to investigate the effects of PS-MP on soil As volatilization. Either S1 (10 μm) or S2 (0.1–1 μm) PS-MP was added to As-contaminated soil at 0.8%, which increased As volatilization by 13.7% and 7.4% in low As-contaminated soil; and 21.8% and 16.5% in high As-contaminated soil, respectively. The addition of PS-MP reduced the water-soluble (WS) As content, increased the non-specifically-sorbed (NSS), specifically-sorbed (SS) As content, soil catalase (CAT) and urease (UE) activities. The abundance of Proteobacteria and Firmicutes showed opposite trends to As volatilization, while the abundance of Bacteroidetes and arsM gene expression exhibited similar variability to As volatilization over the 7-week experiment. Therefore, we postulate that in As-contaminated soil, As volatilization was enhanced in the presence of PS-MP due to two possible mechanisms: 1) PS-MP affects the abundance of Proteobacteria, Firmicutes, Bacteroidetes, and arsM gene in soil; 2) PS-MP increases As volatilization via reducing soil nutrient and increasing the content of SS As. Our results highlighted the importance of investigating impacts of microplastics on the volatility of specific contaminants to implement effective environmental remediation strategies in polluted farmlands.

Responses of soil enzyme activities and plant growth in a eucalyptus seedling plantation amended with bacterial fertilizers.

Plant growth-promoting rhizobacteria (PGPR) are widely used to improve plant nutrient uptake and assimilation and soil physicochemical properties. We investigated the effects of bacterial (Bacillus megaterium strain DU07) fertilizer applications in a eucalyptus (clone DH32-29) plantation in Guangxi, China in February 2011. We used two types of organic matter, i.e., fermented tapioca residue ("FTR") and filtered sludge from a sugar factory ("FS"). The following treatments were evaluated: (1) no PGPR and no organic matter applied (control), (2) 3 × 109CFU/g (colony forming unit per gram) PGPR plus FS (bacterial fertilizer 1, hereafter referred to as BF1), (3) 4 × 109CFU/g plus FS (BF2), (4) 9 × 109CFU/g plus FS (BF3), (5) 9 × 109CFU/g broth plus FTR (BF4). Soil and plant samples were collected 3months (M3) and 6months (M6) after the seedlings were planted. In general, bacterial fertilizer amendments significantly increased plant foliar total nitrogen (TN) and soil catalase activity in the short term (month 3, M3); whereas, it significantly increased foliar TN, chlorophyll concentration (Chl-ab), proline; plant height, diameter, and volume of timber; and soil urease activity, STN, and available N (Avail N) concentrations in the long term (month 6, M6). Redundancy analysis showed that soil available phosphorus was significantly positively correlated with plant growth in M3, and soil Avail N was negatively correlated with plant growth in M6. In M3, soil catalase was more closely correlated with plant parameters than other enzyme activities and soil nutrients, and in M6, soil urease, polyphenol oxidase, and peroxidase were more closely correlated with plant parameters than other environmental factors and soil enzyme activities. PCA results showed that soil enzyme activities were significantly improved under all treatments relative to the control. Hence, photosynthesis, plant growth, and soil N retention were positively affected by bacterial fertilizer in M6, and bacterial fertilizer applications had positive and significant influence on soil enzyme activities during the trial period. Thus, bacterial fertilizer is attractive for use as an environmentally friendly fertilizer in Eucalyptus plantations following proper field evaluation.

Influence of Suaeda heteroptera – microorganisms – Nereis succinea on soil enzyme activities in oil-contaminated soil

ABSTRACT Oil is an important industrial raw material used as both a fuel and energy source and is the pillar of national economies. With the development of the petroleum industry, oil pollution is becoming increasingly serious and is one of the major pollutants. Bioremediation has become the main remediation method for the treatment of environmental pollutants owing to its advantages such as low resource consumption, high efficiency, absence of secondary pollution, environment-friendly, etc. The aim of this study was to determine the influence of Suaeda heteroptera–microorganisms–Nereis succinea on the activities of soil enzymes (including dehydrogenase, catalase, urease, and amylase) in petroleum-contaminated soil. A pot experiment was performed to determine the effects of Suaeda heteroptera, Suaeda heteroptera – microorganisms, and Suaeda heteroptera –microorganisms – Nereis succinea on oil pollution. While petroleum contamination decreased the soil dehydrogenase, catalase, urease, and amylase activities, Suaeda heteroptera –microorganisms – Nereis succinea improved the activities of these enzymes. Thus, Suaeda heteroptera – microorganisms – Nereis succinea could be employed to recover the soil polluted by oil.

Effects of Biochar on Soil Water-Soluble Sodium, Calcium, Magnesium and Soil Enzyme Activity of Peach Seedlings

The effects of biochar (rape straw, paddy straw, wheat straw and corn straw) on soil water-soluble sodium (Na), calcium (Ca), magnesium (Mn) and soil enzyme activity of peach seedlings was studied by pot experiment. The experimental result indicated that the effect of paddy straw biochar on soil water-soluble Na content was not significant compared with control, but caused a significant increase in the content of soil water-soluble Ca and Mn. Corn straw biochar significantly increased the content of soil water-soluble Na, and the content of soil water-soluble Ca and Mg were little different from that of control. The soil water-soluble Ca content under wheat straw biochar treatments was significant lower than that of other treatments. Soil enzyme activity is a comprehensive index of soil fertility, and all the biochar treatments led to a significant increase in soil urease activity, which significantly decreased the soil invertase and acid phosphatase activities, and the soil catalase activity between biochar treatments and control had no obviously difference. In conclusion, paddy straw biochar and corn straw biochar have a better effect on soil water-soluble mineral elements such as Ca and Mg, and biochar can promote or inhibit soil enzyme activity under planting peach seedlings.

ВЛИЯНИЕ ЗАГРЯЗНЕНИЯ СЕРЕБРОМ НА АКТИВНОСТЬ КАТАЛАЗЫ ЧЕРНОЗЕМОВ, БУРЫХ ЛЕСНЫХ ПОЧВ И СЕРОПЕСКОВ

Due to the widespread use of products based on silver nanoparticles, the risk of contamination of the soil cover and surface water increases, since an element in this form can leach out of the material. The amount of silver emissions into the environment is increasing every year. There is growing evidence of silver toxicity for living organisms of not only aquatic, but also terrestrial ecosystems. Silver, accumulating in soil in large quantities, like other heavy metals, can have a toxic effect on the physical, chemical and biological properties of the soil.High doses of the element can have a significant effect on the biological properties and ecological condition of soils. The study of enzyme activity can be used to identify major changes in the soil under the influence of silver. In this regard, it is relevant to study the effect of silver on catalase activity, since this enzyme is an indicator of the potential biological activity of the soil and reflects the intensity of mineralization processes in it. The aim of the work was to study the effect of silver pollution on the activity of soil catalase most characteristic of the southern regions of Russia. The object of the study identified soils characteristic of southern Russia: ordinary chernozems, seropesks and brown forest soils. For model studies, soil samples were taken from the upper arable layer (0‑10 cm), since silver accumulates in the surface soil layers. Silver pollution was modeled in a laboratory. Used silver nitrate at a concentration of 1 mg / kg, 10 mg / kg and 100 mg / kg, the experiment was 3 times biological repetition. The choice of biological indicators is due to the fact that oxidoreductases are most sensitive to chemical pollution among enzymes. This enzyme is an indicator of the biological activity of the soil and reflects the intensity of the mineralization processes in it. Laboratory and analytical studies were carried out using generally accepted methods in biology, soil science and ecology. Catalase activity was determined by the volumetric method according to A.Sh. Galstyan. As a result of the study of the effect of silver on three types of soils, the most characteristic of the southern regions of Russia, a decrease in catalase activity was noted. The degree of reduction of this indicator depended on the dose of the element introduced into the soil. The degree of resistance to silver contamination has the following sequence: common chernozem&gt; sulfur sands ≥ brown forest soil. This is probably due to the light particle size distribution of sulfur sand and the acidic reaction of the environment of brown forest soils (pH = 5.8), as well as a low content of organic matter (1.8 % and 2.3 %, respectively), which contributes to high mobility, and therefore and high ecotoxicity of silver in these soils. A decrease in the activity of catalase of ordinary chernozem was observed for 90 days. At 1 UDC on the 30th and 90th day of the experiment, the same decrease in the studied parameter was observed. A similar pattern was observed at 10 UDC at the same experimental time. At 100 UDC (100 mg / kg) on the 90th day after contamination, a tendency toward restoration of catalase activity was observed, however, control values before silver contamination were not achieved. Chernozems have a high number of microorganisms and their high activity, and pollution tolerance mechanisms provide detoxification of soils from exposure to silver.