The impact of spring wheat species and sowing density on soil biochemical properties, content of secondary plant metabolites and the presence of Oulema ssp.

The physical and chemical properties of the soil are important factors influencing the yield of crops. One of the agrotechnical factors influencing the biochemical properties of soil is sowing density. It affects the yield components, light, moisture and thermal conditions in the canopy and the pressure of pests. Secondary metabolites, many of which are known to act as a defense mechanism against insects, are of importance in the interaction between the crop and abiotic and biotic factors of the habitat. To the best of our knowledge, the studies conducted so far do not sufficiently reveal the impacts of the wheat species and the sowing density, together with the biochemical properties of the soil, on the accumulation of bioactive ingredients in the crop plants, and the subsequent impacts on the occurrence of phytophagic entomofauna in various management systems. Explaining these processes creates an opportunity for more sustainable development of agriculture. The study aimed to determine the effect of wheat species and sowing density on the biochemical properties of the soil, concentrations of biologically active compounds in the plant and the occurrence of insect pests in organic (OPS) and conventional (CPS) production systems. The research was conducted on spring wheat species (Indian dwarf wheat-Triticum sphaerococcum Percival and Persian wheat-Triticum persicum Vavilov) grown in OPS and CPS at sowing densities 400, 500, 600 (seeds m-2). The following analyzes were performed: (i) soil analysis: the activity of catalases (CAT), dehydrogenases (DEH), peroxidases (PER); (ii) plant analysis: total phenolic compounds (TP), chlorogenic acid (CA), antioxidant capacity (FRAP); (iii) entomological analysis of the number of insects-Oulema spp. adults and larvae. Performing analyzes in such a wide (interdisciplinary) scope will allow for a comprehensive understanding of the soil-plant-insect biological transformation evaluation. Our results showed that an increase in soil enzyme activity caused a decrease in TP contents in the wheat grown the OPS. Despite this, both the content of TP and the anti-oxidative activity of the ferric reducing ability of plasma (FRAP) were higher in these wheats. Bioactive compound contents and FRAP were most favoured by the lowest sowing density. Regardless of the production system, the occurrence of the Oulema spp. adults on T. sphaerococcum was the lowest at a sowing density of 500 seeds m-2. The occurrence of this pest's larvae was lowest at a sowing density of 400 seeds m-2. Research on bioactive compounds in plants, biochemical properties of soil and the occurrence of pests make it possible to comprehensively assess the impact of the sowing density of ancient wheat in the ecological and conventional production system, which is necessary for the development of environmentally sustainable agriculture.

The role of an urban park's tree stand in shaping the enzymatic activity, glomalin content and physicochemical properties of soil.

Soil enzymes play a key role in the circulation of nutrients and the functioning of the ecosystem. The aim of the study was to assess how the tree species of urban agglomerations affect soil quality and enzymatic activity (dehydrogenases DEH, catalase CAT, alkaline AlP and acid AcP phosphatase, protease PR, ß-glucosidase GLU, and urease UR). To this end, soil samples were taken from beneath nine park trees. The risk of soil contamination by selected heavy metals (Pb, Ni, Cd) was also investigated against the background of the selected physicochemical properties. Enzyme activity results were used to calculate multi-parametric indices of soil quality: availability factor (AF), enzymatic pH indicator (AlP/AcP), biological index of fertility (BIF), geometric mean (GMea), alternation index (Al3), biochemical soil activity (BA16 and BA17). The results showed statistically significant differences in physicochemical and enzymatic properties of soil depending on tree species. Correlation analysis showed that the content of total organic carbon (TOC), total nirogen (TN), total phosphorus (TP) and humus (OM) in soil significantly influenced the activity of the studied enzymes and glomalin content. AF coefficient values (1.84%-18.19%) suggest that the bioavailability of available phosphorus (AP) was sufficient. The Pb, Ni, Cd content results were found to be low and did not exceed the permissible concentrations. DEH, CAT and AlP activity were highest under common hawthorn, and AcP, GLU and PR under northern white cedar. The calculated enzymatic indicators proved to be a sensitive and accurate indicator of the dynamics of changes taking place in the city park soil. Based on the results, an attempt can be made to assess the planning of sustainable development of studied areas of urban parks.

Assessment of selected heavy metals and enzyme activity in soils within the zone of influence of various tree species.

The study aimed to evaluate the total content and bioavailable forms of Zn, Cu, Pb and Ni and enzymatic activity (nitro reductase and peroxidases) in the mineral levels of surface soils within the zone of influence of various tree species. The conducted variance analysis confirmed the significant impact of the studied tree habitats on the total content and bioavailable forms of metals and on enzymatic activity. The total content of analysed metals were low and in no case exceeded the possible concentrations. The high bioavailability (AF %) values calculated for habitats of different species compositions (of 53.78% for Zn, 76.82% for Cu, 60.81% for Pb and 44.72% for Ni) may pose a risk of accumulation of these metals in plants. A significant correlation was found between nitrate reduction activity and Pb content (r = 0.510) and Cu (r = 0.678). Principal component analysis allowed two principal components to be distinguished (PC1 and PC2) that accounted for 60.95% of the total change in variance.

Activity of selected enzymes and phosphorus content in soils of former sulphur mines.

This paper presents phosphorus content, the activity of enzymes, and relationships between chemical properties in former sulphur mine soil ecosystems. Soil sampled 16 years after the completion of open-pit mining works at Machów, and 7 years after sulphur mining by the "melting" method was abandoned in the Jeziórko mine. In these soil samples were determined content of total (TP), mineral (MP), organic (OP), available (AP) phosphorus, the activity of catalase (CAT), dehydrogenases (DHA), alkaline (AlP) and acid (AcP) phosphatase, and metabolic metabolic quotient (qCO2). Total phosphorus content in samples from the Machów mine ranged from 0.297 to 0.392 g kg-1. In the soil from the vicinity Jeziórko, TP content was in the range 0.329-0.460 g kg-1. The content of AP in soil from the vicinity of Machów range from 10.77 to 43.44 mg kg-1, and near the Jeziórko mine from 5.73 to 18.03 mg kg-1. Availability factor (AF) for phosphorus was calculated, which was higher in soil under the impact of the Machów mine compared to the soil near the of Jeziórko mine. The activity of AlP in soil around the Jeziórko mine was lower than in soils sampled near the Machów mine. Enzymatic activity and total carbon content were used to calculate the biochemical activity index (BA12), which was higher in soils under the impact of the Machów mine. The value of metabolic quotient (qCO2) was low in the upper layers of the clarifier (Machów) and also 10 and 40 m from the borehole Jeziórko. The highest value of this parameter was observed in soil from the post-process waste dump at Machów (3.6 µgCO2 [µgC mic]-1 h-1). A long-term human impact significantly affected the soil phosphorus under study and the physico-chemical properties, which led to a change in the enzymatic activity of soil.

Heavy metal contents and enzymatic activity in soils exposed to the impact of road traffic.

The aim of the research was to evaluate the influence of car traffic on the content of selected heavy metals in soil from a park area, and to define the dependency between their content and enzyme activity. Soil samples were collected from 13 points located along a communication route, each 100 m from the next and 50 m from the border of the road. Soil material was obtained from two depths (0-20 cm and 20-40 cm) and analysed for: pH in H2O and in KCl, OC, and texture by laser method. Total content of heavy metals (Pb, Cd, Zn, Cu, Ni), available phosphorus and the activity of selected enzymes: catalase, dehydrogenase, acidic and alkaline phosphatase were all determined. The examined soils have the texture of loamy sands or sands (USDA 2012), slightly acidic or neutral pH, Organic Carbon (OC) content in the range from 3.50 to 13.80 g kg-1. The total contents of elements in surface horizons were, in order of decreasing concentrations: Pb>Zn>Cu>Ni>Cd, although in subsurface horizons it was Zn>Pb>Cu>Ni>Cd. Contamination Factor (CF) determined for Ni, Pb, Cd, Zn, Cu reaches higher values in samples from subsurface horizons, which confirms the influence of car traffic on the content of heavy metals in the surrounding soils. The calculated CF shows contamination is moderate for Ni, Cd, Zn and Cu and high for Pb and Cu. The investigated soils may be classified as class IV (low) in terms of available phosphorus. The activity of the examined enzymes was higher in soil samples collected from the 0-20 cm layer than from 20-40 cm. The correlation analysis indicates a significant positive dependency between OC content in soils and enzymatic activity. Principal Component Analysis (PCA) was also performed. Two principal components PC1 and PC2 account for 66.57% of the variability.

Activity of selected enzymes as markers of ecotoxicity in technogenic salinization soils.

The activity of enzymes in soil is sensitive to the changes in soil properties affected by biotic and abiotic factors. This study investigates the influence of salinity on some enzymes (catalase CAT, dehydrogenases DEH, alkaline AlP, and acid AcP phosphatase) and pH in 0.01 M CaCl2, ECe, the content of total organic carbon, and total nitrogen in technogenic salinization soil next to the soda plant. Seven soil sampling sites were selected (S1-S6) in the area close to the soda plant and C (the control). Based on the enzyme activity, also soil indicators were calculated: the resistance index (RS), enzymatic pH indicator [Formula: see text], the factor of the impact of anthropopressure (IF), the biological index of fertility (BIF), and the indices of biochemical soil activity (BA12 and BA13). The above study did not show one-way changes of the parameters investigated. The relations between the parameters and the activity of catalase, dehydrogenase, alkaline, and acid phosphatase show that they are mostly determined by the state of salinity of the soil environment. The calculated index of resistance (RS), as an effective means of the enzymatic response to environmental stress, facilitated putting the enzymes in the following series: CAT>DEH>AlP>AcP. It shows that catalase and dehydrogenases are most resistant to the anthropogenic factor. The calculated values of BA12 and BA13 indices showed the differences between technogenic salinization soils and the soil sampled from the control. The lowest BIF values were observed at S6 and S3, S4, and C.

Dynamics of phosphorus content and the activity of phosphatase in forest soil in the sustained nitrogen compounds emissions zone.

This paper summarizes research work on the seasonal and profile dynamics of phosphorus content and the activity of phosphatase in soil next to the nitrogen industry. The results are presented of the total phosphorus (TP) and available phosphorus (AP) content and the alkaline phosphatase (AlP) and acid phosphatase (AcP) against the basic physicochemical properties (clay, pH, total organic carbon, total nitrogen). Three soil profiles were sampled from Brunic Arenosols 0.8, 2.0, and 2.5 km away from the nitrogen plant. The control profile was taken from the Tuchola Forest. The soil was collected in both spring and autumn. The results showed that the total phosphorus content was higher in spring than in autumn (the value of index of changes in time TI < 0) contrary to available phosphorus (TI > 0) and in both seasons in surface soils, the lowest, in profile I. Both total and available phosphorus decreased with depth along the soil profiles. The distribution index (DI) calculated for total phosphorus in surface soils demonstrated a rather moderate accumulation, while DI value for available phosphorus for profile III, a considerable accumulation. The availability factor (AF) for all the soil samples was above the threshold of phosphorus load (2%) in the two seasons in this study (from 2.00 to 10.13% for spring and from 3.92 to 21.19% for autumn), suggesting that the transformation rate from TP to AP was high, and AP supply for plant growth was sufficient. The correlation analysis showed a significant and positive correlation of available phosphorus with soil properties such as total organic carbon (r = 0.577), total nitrogen (r = 0.512), and clay (r = 0.493); however, there was no correlation with the activity of phosphatases.

Ecological risk assessment of heavy metals in salt-affected soils in the Natura 2000 area (Ciechocinek, north-central Poland).

This paper aimed to evaluate the ecological risk posed by the accumulation of heavy metals in the salt-affected soils of the habitat covered by the EU Natura 2000 program in relation to the activity of soil redox enzymes. The research was carried out in the halophyte reserve in Ciechocinek (north-central Poland) which is a very specific habitat as it undergoes a long-term human impact related to both the operation of the medical spa town and the agricultural use of soils in the adjacent areas. The obtained results showed that the content of Zn, Cu, Pb, and Cd in the studied soils exceeded the Polish standards. Based on the obtained data and statistical analysis, it was found that metals may come from two different sources: emission from household boiler rooms (Pb, Cd) and corroded brine sewage pipeline (Zn, Cu).They are characterized by limited mobility due to alkaline environment and strong sorption properties of the clay fraction and organic matter. The correlation analysis indicates that the dehydrogenase activities were negatively correlated with soil electrical conductivity (EC1:5) (r = - 0.665, P < 0.05). Taking into account the protective status of the area, it is difficult to indicate definitely the solution concerning the land management. However, according to the authors, one should pay special attention to a possibility of using halophytes which occur within the reserve for phytoremediation.

Evaluation of the content of Zn, Cu, Ni and Pb as well as the enzymatic activity of forest soils exposed to the effect of road traffic pollution.

The paper evaluates the contents of total forms of selected heavy metals (Zn, Cu, Ni and Pb) as well as the activity of catalase (CAT), dehydrogenases (DEH), alkaline phosphatase (AlP) and acid phosphatase (AcP) in mineral surface horizons of forest soils exposed to the effect of road traffic pollutions. The sampling locations (n = 24) were determined in the area covered by the Szubin Forest along the exit road from Bydgoszcz to Poznan (provincial road no. 223). Soil was sampled 25 m away from the traffic lane, from two depths, 5-20 cm (humus horizons) and 20-50 cm (eluvial horizons). The contents of the heavy metals analysed were in the order of Pb > Zn > Cu > Ni. Despite intensive road traffic, with the Integrated Pollution Index (IPI) calculated, there was found a low pollution with nickel, average with zinc and copper and high with lead only. However, under the Regulation of the Minister of Environment, heavy metal values recorded allow for classifying the soils analysed as soils unpolluted with those metals. In the soil samples analysed, there were found significant positive dependencies between the content of clay fraction and zinc (r = 0.455; P < 0.05) and copper (r = 0.430; P < 0.05). With the enzyme activity results, values of the soil resistance index (RS) were calculated. The enzymes analysed were classified in the following decreasing order in terms of their resistance to traffic pollution: catalase > acid phosphatase > alkaline phosphatase > dehydrogenases (humus horizons) and catalase > dehydrogenases > alkaline phosphatase > acid phosphatase (eluvial horizons). Organic carbon showed a significant positive correlation with the activities of alkaline (r = 0.668; P < 0.05) and acid phosphatase (r = 0.668; P < 0.05) however not with catalase and dehydrogenases.