The effect of management system and N-fertilization on the N and P content of leys in the Ioannina Prefecture
The use of leys (cultivated grasslands), play an important role on animal nutrition as well as on the protection of the natural environment from degradation, specifically on mountainous and semimountainous areas comprising, mostly, of abandoned or degraded fields. Important factors that need to be considered in establishing lays are species selection, management systems, and grazing animals. This study presents the results from nitrogen (N) fertilization and lay type on N and phosphorus (P) levels of cultivated and indigenous plant species in a field in the Ioannina prefecture. The three-years experiment comprised of two treatments: 1. Three lay types: Trifolium repens with Lolium perenne, T. pratense with Lolium perenne and Lolium perenne (monoculture), and 2. N-fertilization at the levels 0 kg/ha, 40 kg/ha and 80 kg/ha. Sheep grazed the field. Sampling took place at the end of the third year. The results suggested that fertilization and lay type had no effect on N and P levels of perennial ryegrass. On the contrary, the interaction of lay type and N-fertilization differentiated the N and P levels of plant litter. Additionally, lay type influenced the P-levels of the indigenous species. The results indicate the importance of the appropriate species selection for lay management. The use of nitrogen fixing species may positively influence the diversity as well as N and P content of the indigenous species minimizing the need for further fertilization.
Growth pattern of tall fescue and alfalfa mixture under different water regimes
The interspecific interferance in grass – legume mixtures results in growth pattern changes of the above ground part of plants. This pattern was measured in a 1:1 mixture of tall fescue (Festuca arundinacea) and alfalfa (Medicago sativa). A pot experiment was conducted in Drama Nothern Greece, frοm March to July 1994. Two water regimes were applied: irrigation up to the field water capacity and irrigation using the ¼ of the water used in the previous treatment, so that plants are grown under drought conditions. Above ground biomass of each plant, leaf area and LAR of the mixture were measured. Also, the ratio of above ground biomass of tall fescue to alfalfa was calculated. The results showed that the drought decreased above ground biomass, Leaf Area Index (LAI) and Leaf Area Ratio (LAR) of the mixture. The same treatment affected the seasonal changes of production and the species ratio in the mixture as well. In the irrigation treatment, tall fescue participation decreased. On the contrary, in the drought treatment its competitive ability was improved and its participation in the mixture was kept in high levels.
Tolerance of phryganic species to free calcium carbonate of soils
Phryganic rangelands occupy large areas in Greece due to human activities, especially the combined effect of wildfires and overgrazing. It seems though that in addition to those factors the distribution of phryganic species is also affected by soil factors. To test the hypothesis, a controlled experiment was conducted in the Farm of the Forest Research Institute of Thessaloniki at Loutra Thermis. In this experiment, seeds of Phlomis fruticosa L. and Salvia fruticosa Miller (formerly Salvia triloba L.) were grown in pots with different amounts of calcium carbonate. More specifically, three levels of calcium carbonate were established by mixing 0, 20 and 40% of calcareous soil in the soil content of each pot. The seeds were sown in autumn and measurements of the germinated and grown plants were taken at the end of the following spring. They included aboveground height and biomass and root length. The levels of calcium carbonate were 1.5, 13.5 and 25.0% respectively for the three levels. It was found that the aboveground height differed significantly among the three treatments in both species but not biomass. Root length was longer than the aboveground part in both species but only in Salvia the differences were significant among treatments. It is concluded that Phlomis can grow well in soils with and without free calcium carbonate, a fact that explains its wide distribution. Salvia, on the contrary, seems to grow better on soils with abundant calcium carbonate in the soil profile.
The effect of clipping intensity to the allometric relationship of three ligneous species
The effect of different clipping intensity of the current growth (30% and 60%) compared to control (0%) on the allometric relationship of the foliage of a tree Morus alba L. and two legumes shrubs Amorpha fruticosa (L.) and Colutea arborescens (L.) was studied. The clipping conducted at three different periods in the end of May, in the middle of July and in the end of August. The number of leaves, their leaf area (LA) and the weight of leaf (W) were measured as well as the specific leaf weight (SLW) and specific leaf area (SLA) were evaluated. The number of the new leaves of the two legumes was significantly higher than Morus alba. The production of the new leaves of the 60% clipping intensity treatment was significantly higher (P≤ 0.05) compared to the 30% clipping to all species. SLA of the clipped plants was significantly higher in comparison to the control SLA. In the contrary, LA and SLW was significantly lower in the two treatments compared to the control. Clipping ontribute to the higher production of new leaves especially in legumes. That fact is very important since number and size of leaves are correlated with the available photosynthetic area as well as with the forage production.
Comparable study of hydrodynamic behavior in two different provenance population of Dactylis glomerata L.
Two population of Dactylis glomerata L. from different bioclimatic zones were studied under same climatic conditions, in order to investigate their hydrodynamic mechanism of adaptation to drought. One population was from the region of Taxiarchis (North Greece) and the second one was from Crete island. The population was subjected in two water treatments (rain fed and well-watered). The results suggest that Crete’s population had higher relative water content and water potential under rain fed conditions in comparison to Taxiarchis’s population, probably due to the preconditioned adaptation to drier climatic condition of Crete. In addition, the isohydric attitude of Crete’s population indicates that stomata conductance is the main adaptation mechanism to drought for this population. The anisohydric attitude of Taxiarchis population indicates more complicated adaptation mechanisms.
