| Abstract | Unatoč tome što se u poljoprivrednoj i šumarskoj praksi najčešće smatra da bujad raste na tlima siromašnim hranivim elementima, mnoga istraživanja su pokazala da tla nakon zarastanja bujadnicama imaju više hranivih elemenata od onih u susjednim kontrolnim biljnim zajednicama. Ipak, takva istraživanja do sada su provedena pretežito u vrištniskim staništima Sjeverne Europe. U ovome radu istražen je utjecaj bujadi na promjene u kemijskim značajkama tla nakon zarastanja livada vunenaste medunike čija je funkcionalna raznolikost znatno drukčija od one u vrištinama.
Istraživanje je provedeno u sjeverozapadnoj Hrvatskoj, a cilj istraživanja bio je iz perspektive botanike, pedologije i ishrane biljaka istražiti ekološku pozadinu zarastanja spomenutih livada bujadnicama. Istraživano je: (i) da li nakon zarastanja livada s bujadnicama dolazi do promjena u reakciji tla te sadržaju humusa, C, N, P2O5, K2O, S, Fe, Cu, Al, Si, Zn, Co; (ii) sadržaj C, N, P, K i S u liskama i podancima bujadi; (iii) florni sastav livada i bujadnica izradom fitocenološih snimaka. Analiza navedenih kemijskih značajki tla i biljnog materijala provedena je uobičajenim standadrnim analitičkim postupcima. Razlike u kemijskim značajkama tla između biljnih zajednica utvrđene su analizom varijanci. Međusobni odnosi kemijskih značajki tla utvrđeni su analizom principalnih komponenti te Pearsonovim korelacijskim koeficijentima. Pearsonovim korelacijskim koeficijentima također su istraženi i linearni odnosi hranivih elemenata u biljnom materijalu sa značajkama u tlu. Odnosi vegetacije i tla istraženi su kanoničnom korespondencijskom analizom.
Tla bujadnica imala su više humusa, C i P2O5 te širi odnos C/N, C/S i N/S od tla livada. Tla livada sadržavala su više Fe i Co od tla bujadnica. Pri vrhuncu rasta biomase bujadi, prosječni sadržaji C, N, P, K i S u liskama redom su iznosili 47,9 %, 1,97 %, 0,65 %, 1,38 % i 0,29 %, a u podancima 41,2 %, 0,51 %, 0,16 %, 0,68 % i 0,15 % u S.T. Sadržaji hranivih elemenata u liskama bujadi nisu pokazali značajanu povezanost s kemijskim značajkama tla dok su oni u podancima pokazali određene povezanosti. Od karakterističnih vrsta istraživanih livada samo Centaurea jacea, Erigeron annus, Fragaria vesca i Clinopodium vulgare pokazale su mogućnost opstanka u bujadnicama te su ove vrste rasle i pri niskim i pri visokim sadržajima N, P2O5, humusa, Al, Fe i Ni. Osim navedenih, česte vrste bujadnica bile su Frangula alnus, Potentilla erecta, Cornus sanguinea, Euphorbia cyparissias i Rubus caesius. Optimum rasta ovih vrsta bio je općenito pri visokom sadržaju P2O5, N i humusa, a zadnje dvije vrste optimum rasta su pokazale pri najvećem sadržaju P2O5. Nakon zarastanja s bujadi florni se sastav livada potpuno izmijenio. |
| Abstract (english) | Despite the fact that in agricultural and forestry practice, bracken is considered to grow in nutrient poor soils, many studies have shown that soils after overgrowing with bracken stands have higher nutrient content than those in neighboring control plant communities. Still, to date, this type of research has mostly been carried out in heathland habitats of Northern Europe. In this study, I investigated the influence of bracken on the changes in soil chemical properties after overgrowing of Holchus lanatus meadows, whose functional diversity is considerably different than that in heathlands.
The study was carried out in northeastern Croatia, and its aim was to investigate the ecology of H. lanatus meadows overgrowing by bracken fern (Pteridium aquilinum) from the botanical, pedological, and plant nutrition perspective. The following topics were investigated: (i) whether after overgrowing of H. lanatus meadows by bracken fern there are changes in soil reaction or in the content of humus, C, N, P2O5, K2O, S, Fe, Cu, Al, Si, Zn, Co; (ii) the content of C, N, P, K and S in the leaf blades and rhizomes of bracken fern; (iii) floral composition of meadows and bracken stands by conducting phytosociological research. Differences in soil chemical properties between plant communities were assessed by variance analysis. The relationships among different soil chemical properties were investigated by principal component analysis and Pearson correlation coefficients, and the latter were also used to investigate the linear relationships between soil properties and plant nutrients. The relationships between soil and vegetation were studied using canonical correspondence analysis.
In bracken stands, the soil contained more humus, C and P2O5, and a higher C/N, C/S and N/S ratio than those in the meadows, whereas the soil in the meadows contained more Fe and Co than the soil in bracken stands. At the peak of bracken fern biomass increase, the average contents of C, N, P, K and S in the dry matter of the leaf blades were 47,9 %, 1,97 %, 0,65 %, 1,38 % and 0,29 %, and those of the rhizomes were 41,2 %, 0,51 %, 0,16 %, 0,68 % and 0,15 %, respectively. The nutrient contents in bracken blades did not show a significant correlation with soil chemical properties, whereas those in bracken rhizomes did show certain correlations. Among the characteristic species of the investigated meadows, only Centaurea jacea, Erigeron annus, Fragaria vesca and Clinopodium vulgare were able to survive in bracken stands, and they exhibited the ability of growing under conditions of both high and low N, P2O5, humus, Al, Fe and Ni contents. Except these four species, five other species were commonly found in bracken stands: Frangula alnus, Potentilla erecta, Cornus sanguinea, Euphorbia cyparissias and Rubus caesius. The optimal growth conditions of these species included high contents of P2O5, N and humus, and the optimal growth of the latter two species was observed at the highest P2O5 content. After overgrowing with bracken stands, the floristic composition of the investigated meadows was completely changed. |
