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The biodiversity is a core value in all ecosystems. The nitrogen (N) addition in the form of N fertilizers has effect to a wide variety of fauna living in soils. N losses from arable land should tend not only to cause water eutrophication, but also lower soil nutrient stocks and decreasing soil fertility. This study determined the effect of N soil content in conventional tillage agro-ecosystem on the soil fauna diversity in grass stripes under the sloped arable land. My objective here is to observe soil faunal taxa living in grass filter strips. The goal of this work is to describe the relationship of soil fauna to the nitrate (NO₃⁻) content runoff from fields and captured in grass filter strips. The field work was carried out during period from May until June 2013, for soil fauna investigation the extraction in Berlese — Tullgren funnels were used. Nitratenitrogen (NO₃⁻N) was extracted from air-dried sieved soil using a 2 M KCl solution. Altogether 2,020 specimens representing 19 arthropod groups were found in twenty study sites. Most abundant taxa found practically in each of sampling site were Collembola, Acari and the suborder of Oribatid mites. Statistical evaluations revealed that the effect of NO₃⁻ concentration in the soil on the average value of the total edaphic individual numbers was statistically significant; the same applies for the abundance of Acari mites. No significant results were find for the Oribatid mites and the Collembola family; however, there was a clear trend of increasing abundance with increasing concentrations of NO₃⁻.
Agricultural practices in organic farming theoretically are supposed to lead to higher diversity and activity of soil organisms, which correlates with the stability or resilience of the soil system. In a 3-year study, we tested that hypothesis by comparing the nematode abundance, genera composition and community structure in the soil of winter wheat crop under organic and conventional management. We found the soil type to be a stronger predictor for the total nematodes abundance than the farming system itself. In both systems nematode densities were higher in the sandy than in the clayey soil. Total abundance of nematodes was significantly higher in the organic than conventional farm only in sandy soil and only in the autumn. Significantly more plant feeders was observed in organic than in the conventional crops regardless the soil type. In the clayey soil more bacterial feeders were found in the conventional farm, while in the sandy soil — in the organic one. Nematode generic richness was higher in the organic (a range of 15–35 genera) than in the conventional crops (a range of 15–29) on most sampling dates. Higher generic diversity (H') in the organic crop than in conventional was found for total nematodes in the clayey soil, and for hyphal feeders in sandy soil. H' for plant feeders were higher under organic than conventional system in both types of soil. In both farming systems bacterial feeding genera (Rhabditis, Panagrolaimus, Cephalobus and Acrobeloides) dominated in the communities. Plant feeders and omnivores were found among dominant genera only in the clayey soil, first under both systems, the latter only in the organic crops. The evaluation based on the ecological indices such as Maturity Index, Plant Parasite Index, Enrichment and Structure Index, and ratios between nematode trophic groups, showed that nematode communities under both farming systems most of the time were low matured and the soil food webs strongly disturbed.
Stem base health of spring barley cultivated under organic, integrated and conventional systems and fungal communities were studied. A worst plant health status was observed in the organic system. The macroscopic and subsequent mycological analyses revealed the occurrence of Bipolaris sorokiniana and Fusarium spp. The incidence of B. sorokiniana on stem bases was clearly dependent on a farming system, and the highest incidence of this pathogen was observed in the organic system. Also, in that system, Fusarium spp. were isolated more numerously in the beginning of tillering, but in dough stage B. sorokiniana was the most prevalent pathogen, and Fusarium spp. were more numerous in integrated and conventional systems. It is worth to note that organic conditions could be favourable to Gliocladium spp. Because of growing interest in ecology, excluding the use of pesticides and increasing popularity of biological disease control, these antagonistic fungi could be useful in organic systems.
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