The biological activity of soil in Norway spruce forests and in fern Athyrium distentifolium Tausch ex Opiz stands on deforested polluted sites in the Beskydy Mts.

The study is focussed on the biological activity of acid forest soil with aim to characterize some of its parameters. Activity of acidic soil phosphatase, basal and potentional respiration were compared and viable plate counts of microorganism colonies were evaluated. The soils of the Kněhyně region in the Moravian-Silesian Beskids Mts. are intensively influenced by acid deposition. They were sampled from area where often occurrence of fernAthyrium distentifoliumTausch ex Opiz was recorded. Above mentioned characteristics (values of parameters) were determined in soil samples collected in fern stands (close to the periphery of fern individuals with rich root system), from site between individual ferns and from the rest of neighbouring spruce community without distinct herbage layer. In majority of studied cases, increased values of all monitored parameters were found in space ofA. distentifoliumroots accumulated close by fern base. Bare soil between individual fern plants often shows on a lower biological soil activity, however these differences were mostly not statistically significant. On the contrary, values of studied soil parameters recorded in the rest of neighbouring forest community without distinct herbage layer, reached mostly the lowest values and they often differ significantly from values assessed in soil taken near theA. distentifoliumroots.

Plant-wax alkanes as seasonal markers of red deer dietary components

n-Alkanes are long-chain hydrocarbons commonly occurring in plant cuticles that can be recovered in herbivore faeces. Differences among plant species in their content of cuticular wax n-alkanes can be exploited to estimate diet composition of herbivores. n-Alkanes have been used mainly in domesticated herbivores feeding on relatively simple diets over short-term periods. Extending the method to wild herbivores feeding on seasonal complex diets is possible provided that n-alkanes act as effective dietary component markers in different seasons. The n-alkane content of browse species and herbage layer and of faeces of red deer (Cervus elaphus L., 1758) males and females in a region with a Mediterranean climate is described. Information on the n-alkane content of plant species was related to that of faeces to estimate the diet composition of red deer. Plant species had distinct n-alkane contents, some of which varied seasonally. The n-alkane content of faeces also varied seasonally and between red deer sexes. Both red deer males and females had relatively high proportion of browse in their diets during summer and of herbage layer in spring, as shown by other studies in Mediterranean environments.

The response to season, exclosure, and distance from water of three central Australian pasture types grazed by cattle.

Three central Australian pasture types grazed by beef cattle were exdosed for eleven years, and detailed plant measure- ments made over the last seven years. The exclosed land extended out 3.2 km from permanent watering points. Rainfall during this period (1968-1979) varied from well above average for three years to near drought conditions. The series of above average rainfall years had a @eater influence on yield, density and cover of the herbage layer than the experimental treatments of exclosure and distance from water. Dry matter production varied from 217 kg ha-1 to 2377 kg ha-1. Overall, plant density and cover were generally not affected by treatments, although some plant species and species groups were affected. Grazing should continue at present stocking levels and under similar management on the studied landscapes, as no dele terious effects have been found during the study period.

Studies of Central Australian Semidesert Rangelands. II. Range Condition and the Nutrient Dynamics of the Herbage Layer, Litter and Soil.

The levels and turnover of nitrogen, phosphorus and sulfur in the herbage layer: litter and soil of three central Australian plant communities were investigated, following several years of above-average rainfall, and the possibility of a relationship between nutrient levels and range condition assessment was examined. There were only a few positive correlations between range condition and phosphorus levels, and they were not associated with the susceptibility of different soils to erosional losses. There were no positive correlations between range condition and the levels of either nitrogen or sulfur. The herbage and litter layers together, of the three plant communities, contained 30-72 kg ha-1 of total nitrogen, 4 kg ha-1 of total phosphorus and 4-7 kg ha-1 of total sulfur. These quantities were comparable to those of arid regions in other parts of the world, but the levels of nitrogen, phosphorus and sulfur in soils, estimated by incubation or extraction to be available to plants, were comparatively low. Incubated nitrogen in the 0-10 cm depth of soils was 9-14 ppm and extractable phosphorus was 3-1 1 ppm. The 0-4 cm depth of soil contained 0.5-3 ppm extractable sulfur, and concentrations decreased with depth. Total soil nitrogen was lower than that in other arid regions whereas the amount of organic carbon in soil was comparable, so that C:N was relatively high. Substantial withdrawal of nutrients from senescing plant parts and rapid cycling of nutrients through litter appeared to be responsible for maintaining the level of nutrients in the herbage layer.

Studies of Central Australian Semidesert Rangelands. I. Range Condition and the Biomass Dynamics of the Herbage Layer and Litter.

Following a sequence of years of above-average rainfall, standing biomass, rates of production and quantities of litter were high in the ground storey of three central Australian rangeland plant communities. Standing biomass was of the order of 4000 kg ha-1 in Astrebla grasslands, 2600 kg ha-1 in open woodlands and 1300 kg ha-1 in Acacia shrublands, and litter biomass was c. 1300 kg ha-1, 1600 kg ha-1 and 4000 kg ha-1 respectively. Levels of biomass and production rates were comparable with those of some semiarid and temperate sown pastures in average seasons, but they appeared to have reached their natural limit. Total standing biomass, production rates, species diversity, litter biomass and decomposition rates were not correlated with range condition assessments of the experimental sites. Species frequency was the only characteristic measured which was related to range condition other than botanical composition, the basis of site selection.

Chemical and botanical composition of the diets of oesophageally fistulated sheep, cattle and goats in a semi-arid Eucalyptus populnea woodland community.

Diet samples collected from oesophageally fistulated sheep, cattle and goats on six occasions over a 12 month period were analysed for botanical and chemical composition. Angus steers, Merino wethers and feral goats were used in the study which was conducted in a poplar box (Eucalyptus populnea) woodland community near Cobar in northern N.S.W. Over 90 species, including trees and shrubs, were available to the livestock but only 18 species were eaten and of these, only five were of major consequence. These were the grasses, Eragrostis lacunaria and Stipa variabilis and the chenopods, Bassia diacantha, B. convexula and Chenopodium anidiophyllum. Other species to figure prominently in the diet were the composite forbs Calotis spp. and the shrub Acacia aneura. Diet quality was generally low with percent N in the range 0.98-2.10% and in vitro digestibility values ranging from 42-61%. The diet quality varied throughout the year and between animal species at any one time of year. Sheep selected diets which were higher in nitrogen and which were more digestible than those selected by either cattle or goats. Shrubs and trees were a major component of the diets of all three livestock species when the herb layer plants had been reduced to low levels of availability (< 180 kg/ha). Goats ate more trees and shrubs than either sheep or cattle at all times (P < 0.05) and these plants contributed up to 55 per cent of the goat's diet on occasion. The maximum contribution of shrubs to sheep and cattle diets was 22% and 34% respectively. Management implications are discussed in the light of the ephemeral nature of the herbage layer and the nutritional needs of the livestock.