Environmental parameters affecting the species diversity along the Aliakmon River, North Greece

The annual distribution of aquatic and coastal macrophytes in five selected sites along the Aliakmon River was studied from January 2005 to December 2005 in Northern Greece. Soil and water chemical parameters in these sites were also evaluated. A total of 75 taxa were recorded belonging to 37 families and 53 genera. The majority of the macrophytes belonged to coastal plants (76%), whereas the rest of the macrophytes belonged to aquatic plants (24%). Species of the family Asteraceae were dominant among coastal plants, whereas species of the family Potamogetonaceae were dominant among aquatic plants. Soil samples from the site of Dam of Veria had higher pH and electric conductivity (80-100 cm depth), whereas CaCO3 contents were significantly higher in soil samples from the area of P. Prodromos (60-80 cm depth). Most physicochemical water parameters as well as selected soil nutrients and major ionic components showed an increase during the low charge period (fall) compared to with the high charge period (spring), especially in parameters associated with agricultural activity. Furthermore, there was an increase in most examined values moving towards the delta of the river.     

Investigating Soil Factors Responsible for the Problematic Growth Of 51 Olive (Olea Europαea L.) Cultivars in an Alluvial Soil of Northern Greece

Fifty-one (51) olive cultivars (six trees per cultivar) were planted in an alluvial soil of an experimental field in Northern Greece for study of their growth. Soil is sandy loam (SL) - loamy sand (LS), moderately alkaline and presents no salinity or alkalinity. Despite the applied agronomic practices, i.e., soil fertilization, irrigation, and pest control, about half of the trees did not respond positively to the field conditions, while the remaining ones showed low to moderate growth based on measurements of height and crown diameter. Soil and leaf tissues analysis as well as penetration resistance (PR) measurements showed that olive trees' growth problems could be attributed to a combination of high PR values (>3 MPa) and to a certain degree to low fertility (especially nitrogen and potassium deficiencies). Under the prevailing soil conditions, the most resistant olive cultivars proved to be Dafnolia, Maronia, Oblonca, Ascolana, and Frantoio.     

中国生猪生产结构、成本和效益比较研究

本文采用两个主要的数据资源,对中国近来生猪产业的结构、成本、效益、饲料用途等状况作了一定的分析研究。分析推断出中国生猪生产在向规模化发展过程中,综合效益最高、最适宜的是中等养殖规模。对未来饲料和畜牧业的发展及畜牧业的结构变化趋势进行分析和预测。