Microbial and enzymatic activity of soil contaminated with a mixture of diflufenican + mesosulfuron-methyl + iodosulfuron-methyl-sodium

Abstract

The aim of this study was to determine the effect of three active substances, diflufenican, mesosulfuron-methyl and iodosulfuron-methyl-sodium, applied in combination, on soil microbial counts, the structure of soil microbial communities, activity of soil enzymes and their resistance to the tested product, the biochemical indicator of soil fertility, and spring wheat yield. Soil samples with the granulometric composition of sandy loam with pHKCl 7.0 were used in a pot experiment. The herbicide was applied to soil at seven doses: 0.057 (dose recommended by the manufacturer), 1.140, 2.280, 4.560, 9.120, 18.240 and 36.480 mg kg−1 soil DM. Uncontaminated soil served as the control treatment. It was found that a mixture of the tested active substances increased the counts of total oligotrophic bacteria and spore-forming oligotrophic bacteria, organotrophic bacteria and actinomycetes, decreased the counts of Azotobacter and fungi, and modified the structure of soil microbial communities. The highest values of the colony development (CD) index and the ecophysiological (EP) index were observed in fungi and organotrophic bacteria, respectively. The herbicide applied in the recommended dose stimulated the activity of catalase, urease and acid phosphatase, but it had no effect on the activity of dehydrogenases, alkaline phosphatase, arylsulfatase and β-glucosidase. The highest dose of the analyzed substances (36.480 mg kg−1) significantly inhibited the activity of dehydrogenases, acid phosphatase, alkaline phosphatase and arylsulfatase. The values of the biochemical soil fertility indicator (BA21) decreased in response to high doses of the herbicide. Urease was most resistant and dehydrogenases were least resistant to soil contamination with a mixture of diflufenican + mesosulfuron-methyl + iodosulfuron-methyl-sodium. The analyzed herbicide had an adverse influence on spring wheat yield, and doses of 18.240 and 36.480 mg kg−1 led to eventual death of plants.

Response of microorganisms and enzymes to soil contamination with a mixture of pethoxamid terbuthylazine

“…Atrazine, primextra, paraquat and glyphosate also had a negative effect on the development of bacteria, actinomycetes and fungi, according to Sebiomo et al (2011). In contrast, Baćmaga et al (2015) following the use of a mixture of active substances named diflufenican, mesosulphuron-methyl and iodosulphuron-methyl-sodium observed an increase in the counts of total oligotrophic bacteria and their spore forms, organotrophic bacteria and actinomycetes, and a decrease in the counts of fungi and Azotobacter. Martinez et al (2008) studying sulfentrazone found that this product stimulates the growth of actinomycetes, but it does not have an effect on the count of fungi.…”

“…In five repetitions, the respective dilutions of soil were sown onto Petri dishes. On the media characterised by Baćmaga et al (2015).…”

Enhancement of sediment phosphorus release during a tunnel construction across an urban lake (Lake Donghu, China)

“…Dehydrogenase activity (DHA) from sediment was determined using 2, 3, 5-triphenyltetrazolium chloride (TTC) as substrate (Neto et al 2007;Bacmaga et al 2015). The fresh sediment was diluted with sterilized distilled water to 1:2 (w/ v), adding 2 ml Tris-HCl (pH 7.5) and 2 ml 0.4 % TTC to the 2 ml of the suspension liquid.…”

Imazethapyr Effects on Soil Enzyme Activity and Nutrient Uptake by Weeds and Greengram (Vigna radiata L.)

“…The soil enzyme activity reacts faster than physical activity of soil. Therefore, they can beused as an early warning bioindicator against the changes occur in soil (Baćmaga et al, 2015;Franco-Andreu et al, 2016;Saha Ajoy et al, 2016. So far, contrasting results have been observed by various researchers evaluating the impact of imazethapyr on soil microbial biomass and enzymatic activities.…”