Above ground herbage yield and chemical composition of the understorey vegetation in a silvopastoral system in northern Greece
In the present research aboveground herbage yield and N, P, K, Ca and Mg concentrations in the understorey vegetation were investigated in a silvopastoral system in northern Greece. The experimental design was a split-split plot with three replications and included: three understorey treatments (Lolium perenne, Trifolium repens and control), two tree species (Acer pseudoplatanus and Pinus sylvestris) and two spacings (2.5m x 2.5m and 3.5m x 3.5m). During the early stages of establishment, the influence of trees on aboveground herbage yield and on chemical composition of the understorey vegetation neither by plant species or spacing was not significant. N and Ca concentrations were found significantly higher in white clover tissues.
Effect of grazing and phenological stage on gross energy content of herbaceous and woody forage in a silvopastoral system
Gross energy content of forage of herbaceous and woody species in relation to grazing and phenological stage was studied in a silvopastoral system. The study was conducted in a semi arid grassland with poor sandy soil in Northern Greece. Moderate grazing (1.1sheep/ha/year) was applied twice in the summer period (early July and late August) of 1992. The calorific content of the woody species forage increased during the summer period, when grazing was applied in comparison to the control (4.71 kcal/g and 4.04 kcal/g respectively). Legume species forage had higher calorific content in comparison to Morus. Gross energy of herbage was maintained stable during the summer period.
Study on the mite fauna of vegetation and soil of a natural pasture in Co. Ioannina, Greece
A two year’s study on the acarofauna of a natural pasture in Co. Ioannina, Greece, showed that species richness of Prostigmata was higher in the aerial part (herbage) than in soil, whereas the opposite was true for Cryptostigmata. The evaluation of taxa using the criteria of dominance and frequency showed that the most characteristic taxa were the following: a) for the vegetation Ceratozetoidea, Peloptulus sp., immature stages of Cryptostigmata and Triophtydeus sp. b) for the soil Ceratozetoidea, Galumnoidea, Oppiidae(a), Oppiidae(b), Oribatuloidea(a), Oribatuloidea(b), Tectocepheus sp., immature stages of Cryptostigmata, Lorryia sp. and Triophtydeus sp. The study of seasonal fluctuation of the most important of them for the two years showed that immature stages of Cryptostigmata developed higher population densities during summer for the vegetation while for the soil the higher densities occurred during autumn. The adult Cryptostigmata showed higher densities during winter for the vegetation while during summer for the soil. The taxon Triophtydeus sp. developed higher population densities during summer and autumn for both the vegetation and soil.
Effect of cutting frequency on forage production and quality of Dactylis glomerata L. during winter
Improved cultivars of cool-season grasses could increase forage production and reduce the imbalance between supply and demand in Mediterranean grasslands during the winter. However, the optimum production of the improved cultivars could be achieved by applying an efficient management system. The objective of this study was to compare forage production and quality of an improved population of Dactylis glomerata under three cutting frequencies during the winter (October-March). Forage production was significantly higher in the high cutting frequency (every 30 days) in comparison to medium (every 45 days), low (every 75 days) and the undefoliated plants during the first year of the experiment. On the contrary, the rare cutting frequency exceeded in forage production during the second year of the experiment. At this time forage production of the high and medium cutting frequency was reduced by 38% and 33% respectively. As far as the forage quality is concerned, the NDF content was significantly lower to the high cutting frequency compared to medium, rare and undefoliated plants (control), whereas there were no significant differences in ADF and ADL content. Crude protein content was significantly higher in cutting frequencies compared to undefoliated plants. It can be concluded that clipping of the above ground biomass twice during the winter (low cutting frequency) secures sustainable production of the system.
Relation between biomass and height in open pollinated families and selected clones of black locust
Black locust (Robinia pseudoacacia L.) is a fast growing, nitrogen-fixing leguminous tree, exhibiting an outstanding adaptability in a wide range of pedoclimatic conditions. It is native to southeastern North America, but it was also extensively naturalized in the temperate regions of Europe and Asia, while in Greece it was introduced 150 years ago. Widely used as multi-purpose species, black locust is ideally suited for forage production of high quality and quantity. The biomass produced, however, is not stable from one year to next and is also influenced by genetic factors. In this paper, aboveground biomass was harvested and measured from 9 open pollinated families and 13 selected clones of the monophylla variety at the end of the growing season for 6 consecutive years. Subsequently, this biomass was correlated with annual height by means of a regression analysis, involving four types of equations: linear, quadratic, exponential and power. It was found that annual biomass can be predicted with relatively high accuracy by using the easily measured annual height for both open pollinated families and clones of the monophylla variety and employing an exponential or, preferably, a power equation.
