L. Tyšer

Weed vegetation of arable land in the Czech Republic: environmental a management factors determining weed species composition

This paper reports on the current situation in weed vegetation composition on arable land in selected areas of the Czech Republic, assessment of influence of selected variables: applied management systems (conventional, organic), crops (winter cereals, root crops) and altitude and ranking of the importance of these particular factors. A phytocoenological survey was conducted from 2006 to 2008 during a vegetation period using relevés that were 100 m2 in size, placed in the central part of fields. In total, 202 relevés of agricultural vegetation were recorded. The combined environmental variables explained 10.6% of the variability. Based on the pCCAs, the highest effect was found at altitude, which explains 5.1% of the species composition variability. The second and third most significant factors are crop and management system, which explain 3.3% and 1.8% of the variability, respectively. The lowlands were generally characterised by the thermophilous summer annual weed species. The higher altitudes were populated by species that are typical for colder areas and poor, humid, and acidic soil types, such as cambisoil.

Organic, integrated and conventional management in apple orchards: effect on plant species composition, richness and diversity

The study was conducted to assess the eff ect of conventional, integrated and organic management on diff erences in plant species composition, richness and diversity. The plants were studied in triads of orchards situated in three regions of the Czech Republic. Data about species occurrences were collected on 15 permanent plots in the tree rows and 15 plots between tree rows in each of the apple orchards during 2009. A total of 201 vascular plant species (127 native species, 65 archaeophytes, and 9 neophytes) were found. Management type and also diff erent regional conditions had a signifi cant eff ect on plant species composition and on diversity parameters of orchard spontaneous vegetation. Species richness and species pool was signifi cantly higher in the organic orchards than in the diff erently managed orchards. Management type had signifi cant eff ect on proportions of archaeophytes, and also neophytes in apple orchards.