Monika Tomkiel

Enzyme activity and microorganisms diversity in soil contaminated with the Boreal 58 WG herbicide

ABSTRACT Next-generation herbicides are relatively safe when used properly, but the recommended rates are relatively low, which can lead to overdosing. This study evaluated the responses of soil-dwelling microorganisms and soil enzymes to contamination with the Boreal 58 WG herbicide. The analyzed product contains active ingredients flufenacet and isoxaflutole. All tests were performed under laboratory conditions. The analyzed material was sandy clay. Boreal 58 WG was introduced to soil in four doses. Soil without the addition of the herbicide served as the control. The soil was mixed with the tested herbicide, and its moisture content was maintained at 50% of capillary water capacity. Biochemical and microbiological analyses were performed on experimental days 0, 20, 40, 80 and 160. Accidental contamination of soil with the Boreal 58 WG herbicide led to a relatively minor imbalance in the soil microbiological and biochemical profile. The herbicide dose influenced dehydrogenase activity in only 0.84%, urease activity in 2.04%, β-glucosidase activity in 8.26%, catalase activity in 12.40%, arylsulfatase activity in 12.54%, acid phosphatase activity in 42.11%, numbers of organotrophic bacteria in 18.29%, actinomyces counts in 1.31% and fungi counts in 6.86%.

The effect of carfentrazone-ethyl on soil microorganisms and soil enzymes activity / Wpływ karfentrazonu etylu na mikroorganizmy i aktywność enzymów glebowych

Abstract The aim of this study was to determine the effect of carfentrazone-ethyl (CE) doses of 0.265, 5.280, 10.560, 21.180, 42.240 μg kg-1 soil DM on fungi, Acnomycetes, organotrophic bacteria, total oligotrophic bacteria and spore-forming oligotrophic bacteria, and on the activity of dehydrogenases, catalase, urease, alkaline phosphatase, acid phosphatase, arylsulfatase and β-glucosidase. Carfentrazone-ethyl had a stimulating effect on total oligotrophic bacteria and organotrophic bacteria, but it inhibited the growth of Azotobacter, fungi, spore-forming oligotrophic bacteria and Actinomycetes. The analyzed substance modified the structure of soil microbial communities, and it induced the most profound changes in fungi. The highest values of the colony development (CD) index and the eco-physiological (EP) index were observed in organotrophic bacteria. The optimal dose of carfentrazone-ethyl stimulated the activity of dehydrogenases, catalase, urease, alkaline phosphatase, acid phosphatase and β-glucosidase, but it had no effect on arylsulfatase. The highest doses of the analyzed substance inhibited the activity of dehydrogenases (reduction from 11.835 to 11.381 μmol TPF), urease (reduction from 0.545 to 0.500 mmol N-NH4) and arylosulfatase (reduction from 0.210 to 0.168 mmol PNP). Dehydrogenases were most resistant to CE, whereas acid phosphatase and arylsulfatase were least resistant to the analyzed compound Streszczenie W pracy określono wpływ karfentrazonu etylu zaaplikowanego w dawkach 0,265, 5,280, 10,560, 21,180, 42,2 40 μg kg-1s.m. gleby na grzyby, promieniowce, bakterie organotrofi czne, oligotrofi czne ogółem i oligotrofi czne przetrwalnikujące oraz aktywność dehydrogenaz, katalazy, ureazy, fosfatazy alkalicznej, fosfatazy kwaśnej, arylosulfatazy i β-glukozydazy. W wyniku badań stwierdzono stymulujące działanie karfentrazonu etylu na bakterie oligotrofi czne ogółem i bakterie organotrofi czne, natomiast inhibicyjne na Azotobacter, grzyby, bakterie oligotrofi czne przetrwalnikujące oraz promieniowce. Preparat ten zmieniał strukturę zespołu drobnoustrojów. Największe zmiany wywoływał u grzybów. Najwyższe wartości wskaźników rozwoju kolonii (CD) i ekofi zjologicznej różnorodności (EP) odnotowano u bakterii organotrofi cznych. Karfentrazon etylu w dawce optymalnej zwiększał aktywność dehydrogenaz katalazy, ureazy, fosfatazy alkalicznej, fosfatazy kwaśnej i β-glukozydazy, a nie oddziaływał na arylosulfatazę, natomiast najwyższe dawki zmniejszały aktywność dehydrogenaz (obniżenie z 11,835 do 11,381 μmol TPF), ureazy (obniżenie z 0,545 do 0,500 mmol N-NH4) i arylosulfatazy (obniżenie z 0,210 do 0,168 mmol PNP). Najbardziej opornymi enzymami na działanie KE okazały się dehydrogenazy, a najmniej fosfataza kwaśna i arylosulfataza.

Implication of zinc excess on soil health

ABSTRACT This study was undertaken to evaluate zincs influence on the resistance of organotrophic bacteria, actinomyces, fungi, dehydrogenases, catalase and urease. The experiment was conducted in a greenhouse of the University of Warmia and Mazury (UWM) in Olsztyn, Poland. Plastic pots were filled with 3 kg of sandy loam with pHKCl – 7.0 each. The experimental variables were: zinc applied to soil at six doses: 100, 300, 600, 1,200, 2,400 and 4,800 mg of Zn2+ kg−1 in the form of ZnCl2 (zinc chloride), and species of plant: oat (Avena sativa L.) cv. Chwat and white mustard (Sinapis alba) cv. Rota. Soil without the addition of zinc served as the control. During the growing season, soil samples were subjected to microbiological analyses on experimental days 25 and 50 to determine the abundance of organotrophic bacteria, actinomyces and fungi, and the activity of dehydrogenases, catalase and urease, which provided a basis for determining the soil resistance index (RS). The physicochemical properties of soil were determined after harvest. The results of this study indicate that excessive concentrations of zinc have an adverse impact on microbial growth and the activity of soil enzymes. The resistance of organotrophic bacteria, actinomyces, fungi, dehydrogenases, catalase and urease decreased with an increase in the degree of soil contamination with zinc. Dehydrogenases were most sensitive and urease was least sensitive to soil contamination with zinc. Zinc also exerted an adverse influence on the physicochemical properties of soil and plant development. The growth of oat and white mustard plants was almost completely inhibited in response to the highest zinc doses of 2,400 and 4,800 mg Zn2+ kg−1.

Response of actinomycetes, phosphatases and urease to soil contamination with herbicides

Abstract A laboratory experiment was completed to determine the effect of the herbicides Alister Grande 190 OD, Fuego 500 SC and Lumax 537.5 SE on counts of actinomycetes as well as the activity of enzymes and their resistance to herbicides. Sandy loam was mixed with appropriate doses of the herbicides, such as: 0 - the control, 1 - technological dose and doses 20-, 40-, 80- and 160-fold higher than recommended. On day 20, 40, 80 and 160, counts of actinomycetes and activity of urease, acid phosphatase and alkaline phosphatase were determined. For 160 days, soil was incubated at 25°C and its moisture content was maintained on a constant level equal 50% of water capillary capacity. On days 20 and 80 of the experiment, the ecophysiological (EP) and colony development (CD) indices were computed. Additionally, the resistance (RS) of enzymes to the herbicides was assessed on day 20 and their resilience index (RL) was determined on day 160. It has been found out that soil contamination with herbicides contributed to elevated counts of actinomycetes. The highest number of these microorganisms was observed in soil with Lumax 537.5 SE, and the lowest one appeared in soil with Alister Grande 190 OD. The CD for actinomycetes was the highest in treatments with Fuego 500 SC and the highest EP was determined in soil with Alister Grande 190 OD. Application of the herbicides in doses from 20- to 160-fold higher than recommended by the manufacturer significantly increased the activity of acid and alkaline phosphatases. With respect to the activity of urease, the herbicides produced variable effects. The strongest inhibitory effect on the activity of urease was produced by Fuego 500 SC, which reduced the activity of this enzyme by 13.39% when added to soil in a dose exceeding by 160-fold the recommended rate. The RS of the enzymes to the herbicides ranged from 0.461 to 0.955. Urease was the most tolerant to soil contamination with the herbicides.

The sensitivity of soil enzymes, microorganisms and spring wheat to soil contamination with carfentrazone-ethyl

ABSTRACT Herbicides pose a significant threat to the natural environment, in particular in soils that are most exposed to plant protection agents. Prolonged herbicide use leads to changes in soil metabolism and decreases soil productive potential. In this study, the influence of carfentrazone-ethyl (CE) on the microbiological and biochemical properties of soil and the yield of Triticum aestivum L. was evaluated. Carfentrazone-ethyl was applied to sandy loam (pHKCl – 7.0) in doses of 0.000, 0.264, 5.280, 10.56, 21.18, 42.24, 84.48 and 168.96 µg kg−1 DM soil. Soil samples were subjected to microbiological and biochemical analyses on experimental days 30 and 60. Carfentrazone-ethyl disrupted the biological equilibrium in soil by decreasing the abundance and biodiversity of soil-dwelling microorganisms, the activity of soil enzymes, the values of the biochemical activity indicator and spring wheat yields. Carfentrazone-ethyl had the most adverse effects when applied in doses many fold higher than those recommended by the manufacturer. The toxic effects of CE were also determined by its soil retention time. Soil treated with CE was characterized by higher counts of oligotrophic bacteria, organotrophic bacteria, bacteria of the genus Azotobacter, actinomycetes and fungi on day 60, and spore-forming oligotrophic bacteria on day 30. The activity of dehydrogenases, urease, alkaline phosphatase and β-glucosidase was higher on day 30 than on day 60.