Identification of microbial species present in a pesticide dissipation process in biobed systems using typical substrates from southeastern Mexico as a biomixture at a laboratory scale.

The objective of this work was investigation of the growth dynamics of proteolytic bacteria and the enzymatic activity in soil for the cultivation of maize (Zea mays L.), as well as the maize yield under application of some selected organic fertilizers. Intensity and the direction of the developed changes in the soil depended on the type of applied organic fertilizer, the size of its dose introduced into the soil and on the developmental phase of the grown plant (maize). On the basis of obtained results it was found that all tested organic substances stimulated the activity of proteases. Yields of maize as raw material for silages obtained from soil fertilized with sewage sludge were similar to those obtained after the application of pig slurry and they exceeded maize yields harvested from other fertilization objects.

Effect of organic fertilization on development of proteolytic bacteria and activity of proteases in the soil for cultivation of maize (Zea mays L.)

Microbiological characteristics of sewage sludge from a mechanical-and-biological sewage treatment plant composted in controlled conditions with straw and sawdust are presented. Prepared composts were placed in four bioreactors with airflow of 4 l air·min. In bioreactor K1, K2 and K3 the composted mass consisted of 65% sewage sludge (K1–sewage sludge 1, K2 – sludge 2, K3 – sludge 3) + 30% sawdust + 5% straw; while in bioreactor K4 the proportion was: 45% sludge 2 + 50% sawdust + 5% straw. Compost samples were taken from all chambers at the same time, depending on actual temperature. Microbiological analyses consisted in the determination (by plate method) on selective media of the numbers of mesophilic and thermophilic bacteria, fungi and pathogenic bacteria Salmonella sp. Clostridium perfringens and Enterobacteriaceae. Furthermore, in the experiment, the activity levels of dehydrogenase were determined using 1% triphenyltetrazole chloride as substratum. Studies have indicated that the composting process caused a decrease of the number of fungi and pathogenic bacteria from Enterobacteriaceae family and Clostridium perfringens in all composted matters, as well as an increase in the number of thermophilic bacteria. Changes in the number of mesophilic bacteria depended on the compost type. In composts K1 and K2, the composting process caused an increased proliferation of cells, while in the composts K3 and K4 the number of mesophilic bacteria decreased. On the basis of the obtained results, it was also found that in the majority of analysis terms, the lowest activity of dehydrogenases occurred in compost K3, while their level of its activity, in the majority of the studied composts, correlated most intensively with the number of thermophilic bacteria.

Estimation of microbiological status of sewage sludge subject to composting process in controlled conditions

Our studies utilize enzymatic indicators and microorganism numbers for the estimation of soil environment reaction to the applied differentiation of organic fertilizers and maize (Zea mays L.) cultivation. The experiment had a field character. In different terms connected with the development of maize, the activities of, dehydrogenases and acid phosphatase were determined in the soil. The number of microorganisms (bacteria, actinomyces, fungi, oligotrophic, copiotrophic microorganisms) was determined by the plate method, on adequate agar substrates. Activity levels of the selected enzymes were defined using the spectrometrical method. The obtained results show that applied organic fertilization, as well as the cultivation of soil, had a significant effect on the activity of the analyzed soil enzymes. It was found that dehydrogenases and acid phosphatase activity at the time of the experiment was the highest after the introduction into the soil of sewage sludge (5 tons d.m.·ha -1 ·year -1

Biological Activity of Grey-Brown Podzolic Soil Organically Fertilized for Maize Cultivation in Monoculture

Our study was conducted on a podzolic soil from a field experiment, fertilized with increasing doses of

Microbial Populations and Activity of Biochemical Processes Related to Carbon and Nitrogen Transformations in Podzolic Soil under Willow Culture in Fifth Year from Treatment with Sewage Sludge

The authors investigated the impact of different sewage sludge doses on the developmental dynamics of soil microorganisms as well as on soil respiration activity. The following soil combinations were employed: control (soil + nPk), 2 t d.m. of sewage sludge·ha-1·year-1 + nPk, 4 t d.m. sewage sludge·ha-1·year-1 + nPk and 8 t d.m. sewage sludge·ha-1·year-1 + nPk. The experiments were carried out in field conditions. during the first year of analyses, winter rye was used as the test plant, while in the second year rye was replaced by potatoes as test plants. Soil samples for analyses were collected during the consecutive plant developmental stages and, using the plate method, the total numbers of bacteria, fungi as well as pathogenic bacteria from the Salmonella, Clostridium perfringens and Escherichia coli genera were determined. in addition, using the absorption method, the amount of Co2 released from the soil was also ascertained. on the basis of the obtained results it was found that the introduction into the soil of organic matter in the form of sewage sludge failed to cause any statistically significant changes in the total counts of bacteria and fungi. moreover, pathogenic bacteria were found in the examined soils (Salmonella sp., Clostridium perfringens and Escherichia coli) and they persisted in the soils even after 66 (Salmonella sp.) and 94 days (Clostridium perfringens and Escherichia coli) of analyses. The analysis of the Co2 released on the control plot and on other soil treatments showed that the fertilization of soils with sewage sludge resulted in a slight increase of their respiration activities in relation

A Wolna-Maruwka

Papers

Size of Selected Groups of Microorganisms and Soil Respiration Activity Fertilized by Municipal Sewage Sludge