Influence of cutting regime and fertilizer application on the botanical composition,yield and nutritive value of herbage of wet grasslands in Central Europe

The changes in dry matter (DM) yield, botanical composition and nutritive value of herbage to ruminants of two wet grasslands, Arrhenatherum elatius grassland (Experiment 1) and a Molinia caerulea fen meadow (Experiment 2), in which a range of cutting and fertilizer treatments were imposed in 1999, were assessed after 4–7 years of treatment imposition. Both experiments had a split‐plot design with four replicates. In Experiment 1 the three main‐plot cutting treatments were two cuts with a delayed first cut, three cuts and four cuts during the growing season of each year. In Experiment 2 the cutting treatments were two cuts with a traditional harvest time, two cuts with a delayed first cut and three cuts. The four sub‐plot fertilizer treatments were an unfertilized control, application of a phosphorus and potassium (PK) fertilizer, application of a nitrogen (N) and PK fertilizer to the first cut only (N₁PK) and application of PK plus N applied to each of two, three or four cuts (N_c PK). Application of fertilizer influenced yield and botanical composition of herbage more than the cutting treatments while the opposite occurred for nutritive value of the herbage. Application of fertilizer increased the proportion of tall grasses in Experiment 1 and forbs in Experiment 2. The proportion of Equisetum palustre, present only in Experiment 1, was reduced from 0·33 to less than 0·01 by increased cutting frequency together with the NPK fertilizer treatments. In Experiment 1 diversity of vascular plants was negatively affected only by the four‐cuts treatment while on both wet grasslands other cutting and fertilizer application treatments had no effect. Changes in DM yield of herbage caused by the cutting and fertilizer application treatments were similar for both vegetation types with DM yield increased significantly by fertilizer application but only slightly or not reduced by increasing the cutting frequency. Nutritive value of herbage was positively correlated with cutting frequency and was most influenced at the first cut.     

On the genus Bursaphelenchus Fuchs, 1937 (Nematoda: Parasitaphelenchinae) associated with wood and insects from declining forest trees in the Czech Republic

An overview of the genus Bursaphelenchus in the Czech Republic is presented, based on a recent survey for monitoring the presence of the pinewood nematode, Bursaphelenchus xylophilus, as well as on previous reports of this genus in the country. In addition, we provide a morphological and molecular characterization of four Bursaphelenchus species (B. eremus, B. pinophilus, B. vallesianus and B. borealis) found during the monitoring programme for forest pests, conducted during 2006–2010, within the Moravian and Bohemian regions. Nematodes were extracted from over 1917 insects and 1493 wood samples collected from deciduous and coniferous trees exhibiting wilting and declining symptoms. Bursaphelenchus species were found only in 0.73% of insects and 0.47% of the total number of wood samples. Bursaphelenchus borealis and B. pinophilus dauer juveniles were found associated with the insect vectors Dryocetes autographus and Pityogenes bidentatus, respectively. While a total of seven Bursaphelenchus species are now reported from the Czech Republic, the status of B. xylophilus remains as absent.     

Instantaneous and potential radiation effect on underplanted European beech below Norway spruce canopy

In even-aged, 120-year-old Norway spruce stands with underplanted beech (in 1995) four permanent research plots were established, each 100 × 100 m in size. Twelve subplots were selected on each plot along a light gradient from complete canopy closure to open light conditions. On each plot, photon flux density (PFD) was measured continuously, and during same time interval (August 2008, 2009), color digital hemispherical photographs were taken. Cumulative PFD values for measuring points were compared with potential PFD radiation obtained from hemispherical photograph analysis for different angle of hemisphere and different parameters from hemispherical image analysis (gap fraction, total openness and direct, indirect and total amount of radiation). Cumulative and average daily values for the plots were compared; 120° hemispherical photograph angle, gap fraction and total openness were the variables that explained the largest proportion of variance in light transmittance. Determination coefficients between direct and total light component were highest for the total potential radiation and lowest for the diffuse light component. Comparison between potential and instantaneous light measurements for radial, height increment and SLA of young beech showed that instantaneous radiation measurements explained height increment best; 120° of hemisphere proved to be the best explaining angle.     

Effect of zinc chelate and valnemulin for the treatment of swine dysentery in an experimental challenge study

The aim of study was to determine the influence of zinc chelate, valnemulin and it’s combination on Brachyspira hyodysenteriae shedding and morphological changes of colonic mucosa in an experimental model of swine dysentery (SD). The study was performed on pigs coming from a dysentery-free herd. Animals were inoculated by B. hyodysenteriae strain B204. When the clinical signs of SD and B. hyodysenteriae shedding developed, the pigs were divided into four treatment groups. The first group was treated with zinc chelate (250 ml/1000 L in water), second group was given valnemulin in feed at 75 ppm; the third group was given a combination of both and the fourth group was control. The results demonstrated therapeutic effect of valnemulin in pigs with serious SD and did not show therapeutic effect of chelated zinc.     

Field efficacy of three insecticides against cabbage stink bugs (Heteroptera: Pentatomidae) on two cultivars of white cabbage

Abstract

In 2002 – 2003, three insecticidal substances were tested for their ability to reduce the damage inflicted on plants of white cabbage by cabbage stink bugs, Eurydema ventrale and E. oleracea (Heteroptera: Pentatomidae). The two cultivars of cabbage tested were: the early cultivar, ‘Tucana F₁’, which requires about 60 days from transplanting to harvest, and the mid-early cultivar ‘Hinova F₁’, which requires about 120 days. In a field experiment, the growth and damage on cabbage plants sprayed with malathion (two sprays), potassium soap [potassium salts of fatty acids] (five sprays), and refined rape oil (five sprays) were compared to the growth and damage on unsprayed plants. Potassium soap and refined rape oil are considered to be environmentally friendly insecticides. In 2002, plants of the cultivar ‘Tucana’, that were treated with malathion had the highest plant weights [PW], head weights [HW], HW/PW ratio, and the lowest number of frame leaves. In the drier year of 2003, there were no significant differences in damage between the three treatments for either cultivar, except during the last assessment done on 13 August. In 2003, plants of ‘Tucana’, treated with potassium soap, had the highest PW and HW. The significantly lowest PW and HW values were recorded from the untreated plants. For the cultivar ‘Hinova’, the PW and HW were heaviest from the plants treated with malathion. In both years, the HW/PW ratio of Hinova (mid-early cultivar) did not differ between treatments, while the plants of ‘Tucana’ (early cultivar) treated with malathion had the highest ratio. Of the three substances tested, malathion was the most effective at reducing the damage on white cabbage plants caused by cabbage stink bugs. However, in an attempt to reduce the use of synthetic insecticides, instead of malathion, we recommend the use of refined rape oil (49 EUR/ha), as it is as effective as potassium soap (81 EUR/ha), but much cheaper.     

Do recreational fisheries metrics vary on differently sized fishing grounds?

This study aimed to assess the relationship between basic metrics in recreational fishing and the size of the fishing ground. Data were obtained from individual angling logbooks collected by the Czech Fishing Union over 12 years on 212 fishing grounds located in the regions of Prague and Central Bohemia in the Czech Republic. Small fishing grounds had the highest catch, yield, numbers of fishing visits and numbers of angling guard controls per hectare. Medium‐sized fishing grounds had the highest catch, yield, and numbers of both fishing visits and angling guard controls per fishing ground. Anglers returned to medium‐sized fishing grounds most frequently. The percentage of anglers who caught and took home at least one fish decreased with increasing size of the fishing ground. In conclusion, basic metrics in recreational fishing are related to the size of the fishing ground, which thus plays an important role in fisheries management.     

Effect of low‐dose N application and early mowing on plant species composition of mesophilous meadow grassland (Arrhenatherion) in Central Europe

Semi‐natural temperate grasslands in Europe make an important contribution to biodiversity, but their existence has been endangered by both agricultural intensification and abandonment. In the Czech Republic, Arrhenatherion meadows are a typical example, with their conservation made difficult by the scarcity of research on effective management practices. We examined effects of two potentially useful approaches, application of 56 kg N ha^?1 and earlier first mowing (i.e. in the middle of May, about 2 weeks earlier than usual), on species composition of an Arrhenatherion grassland in central Bohemia over a 7‐year period (1998–2004). These treatments did not influence species richness, but resulted in small changes in canopy structure in terms of cover of individual species and particular plant functional groups. N application resulted in increases in nitrophilous species and tall graminoids, especially Alopecurus pratensis, Festuca pratensis, Heracleum sphondylium and Ranunculus acris, and in decreases in short graminoids. Earlier mowing decreased tall herbs, especially H. sphondylium, and might thus be useful in compensating for increases in some nitrophilous species owing to N application. However, earlier mowing had negative impacts on spring‐flowering species in terms of reduced cover.