The initial part summarizes current knowledge about impact of pesticides on microorganisms and their activity. It also deals with a description and effects of organic fertilization used in the experiment (compost and composted biochar). Based on the literature, we determined the hypothesis: Pesticides have negative effect on soil microbial activity, which was tested in the experimental part. In the experimental part, we carried out a pot experiment. We made two basic versions: a control soil without pesticides and a soil after the application of pesticides. We growed specimens of lettuce (Lactuca sativa) in pots. One version was without organic fertilization, next with amended compost and the last one with composted biochar. In total, we prepared six variants of pots, which were subjected to various measurements. We determined the production of aboveground and underground biomass and the root/shoot ratio. This measurement showed that the variants with pesticides are more suitable for plant growth, plants were bigger in both, aboveground and underground biomass, so they can probably uptake nutrients from soil degraded by pollutants, which can´t hold them back. We also monitored activity of microbial respiration by two methods: by measuring the absorbance of CO2 at soda lime and by the substrate induced respiration. The results showed a decrease in respiration of microorganisms in polluted soil in both of these measurements. Results of mineral nitrogen leaching suprisingly determined, that less nitrogen escaped in soil with pesticides in both forms, amonnia and nitrate, but its amount was generally very low. Cellulose test showed worse total breakdown of cellulose in contaminated variants. Phytotoxicity test revealed, that pesticides may have inhibiting effect on plant germination, but the active substances of pesticides can stimulate growth and development of plant sprouts.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:430431 |
| Date | January 2017 |
| Creators | Šafránková, Anna |
| Source Sets | Czech ETDs |
| Language | Czech |
| Detected Language | English |
| Type | info:eu-repo/semantics/masterThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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