Effect of phosphorus addition on onion plants grown in 13 soils of varying degree of weathering

Phosphorus (P) phytoavailability decreases with soil weathering, however P dynamics in high-P soils with relatively narrow differences in weathering and further addition of P is not known. In the present study, P dynamics and availability in soils varying in their chemical properties and P availability were examined. Onion plants were grown in 13 high-P soils at two P levels [Ρ0 and Ρ1]. Extractable P was assessed with Olsen, Mechlich-3, ammonium oxalate, and water soluble methods, as well as plant tissues P content and morphological features. Despite the initial high P content, all the measured parameters, including soil P, plant morphology, and P content, further increased at P1 compared to P0. Moreover, water soluble P, bulb weight, and plant P content exhibited greater differences between P0 and P1 in Alfisols. In conclusion, for high-P soils, P application could increase traits, such as onion bulb weight, especially for soils with higher weathering.     

A cross-sectional study of Leishmania spp. infection in clinically healthy dogs with polymerase chain reaction and serology in Greece

The prevalence of gastrointestinal parasites in stray dogs, and dogs with owners was investigated by fecal examinations from 271 dogs employing sedimentation, simple flotation and centrifugation-flotation methods. The centrifugation-flotation method, when compared to simple flotation or sedimentation methods was generally more accurate in the diagnosis of all intestinal parasites, but statistical differences were detected only in relation to Giardia spp. and Cystoisospora spp. (synonym Isospora spp.). The following parasites, with their respective prevalence, were diagnosed in the fecal samples: Ancylostoma spp. (23.6%); Toxocara canis (5.5%); Trichuris vulpis (4.8%); Spirocerca lupi (1.9%); Dipylidium caninum (0.7%); Giardia spp. (12.2%); Hammondia heydorni (2.6%); Cystoisospora spp. (8.5%); and Sarcocystis spp. (2.2%). The prevalence of most parasites was similar for dogs of mixed-breed and for dogs of a defined-breed, except for Cystoisospora spp. and T. canis which showed a significantly higher prevalence in mixed-breed dogs. The prevalence of Ancylostoma spp. (17.1%) was significantly lower in stray dogs than in those with an owner (31.9%) and the prevalence of Giardia spp. and Cystoisospora spp. was higher in stray dogs (P < 0.05). No effect of season on the occurrence of the different parasite genera could be observed, except for Ancylostoma spp., for which an increase in the percentage of dogs shedding eggs was observed at the beginning of Summer with a peak occurrence during April and May (Autumn). The prevalence of Ancylostoma spp., T. canis, T. vulpis, Giardia spp. and Cystoisospora spp. was higher in adult males than in adult females, but significant differences between the two groups occurred only with Giardia spp. Young animals were found to more frequently shed Nematode eggs in feces than adult animals.     

Effects of age and frequency of cutting on productivity of Mediterranean deciduous fodder tree and shrub plantations

Deciduous fodder trees and shrubs are important feed resources for the critical summer period in semi-arid and sub-humid Mediterranean environments. Eleven such species were established in central Macedonia, Greece as 1-year old seedlings in 1987 and studied through 1994. Height and biomass were statistically different among species and tended to increase with the age of plants. Common Robinia pseudoacacia was the tallest and the most productive species, reaching more than 3 m height and 4 kg DM/plant 8 years since planting; it was followed by Ostrya carpinifolia, the variety monophylla of Robinia, Colutea arborescens and Amorpha fruticosa. Grazeable proportion of total biomass was about 50% and decreased as the age of plants increased. Repeated annual cutting resulted in significant reduction of both height and total biomass by 51% and 88%, respectively as compared with uncut plants at the end of the eighth year while frequent cutting tended to increase the grazeable proportion of biomass after the fourth year. To attain an optimum combination of quantity and quality of biomass in deciduous fodder tree and shrub plantations cutting or grazing should not start earlier than the third year since establishment.