Variationen der Nährstoff-und Schwermetallgehalte in Böden

This article investigates the variations of nutrient (phosphorus (P) and potassium (K)) and heavy metal contents in soils. Therefore, selected regions in Eifel and Hunsrueck (region around Trier) were examined. The data base consists of more than 100.000 existing measurements plus own investigations on the main land use classes —field, grassland, vinicultural areas and forest—with regard to their intensities (conventional und biological). The evaluation of the nutrient contents for P and K was made using the manual adequate fertilization for field and grassland. The creation of heavy metal distribution maps is based on the Kriging method. In the past, soils in the region of Trier received a too large amount of P and K—especially in vinicultural areas. Mineral and organic fertilization has a great influence on the heavy metal contents on farmland. The immission of dust contaminated with heavy met|als is important on forest and grassland locations. On vineyards the use of cupreous plant protection agents is critical. The land use classes have had a substantial influence on the nutrient and heavy metal contents of the soil. In contrast to this, the intensities showed less differences. In order to reduce the anthropogenic impact on heavy metals in soils, it is necessary to create specific reduction strategies for each land use class. For example the fertilization has to be limited to the need of the plant, contaminated secondary raw material fertilizer has to be avoid the comparability of analytical methods has to be ensured.     

Not Only Single Mating in Stingless Bees

Queens of the large, pantropical and fully eusocial taxon Meliponinae (stingless bees) are generally considered to be singly mated. We indirectly estimated queen mating frequency in two meliponids, Melipona beecheii and Scaptotrigona postica, by examining genotypes of workers at microsatellite DNA loci. Microsatellites were highly variable, providing suitable markers with which to assign patrilinial origin of workers within colonies headed by single queens. Queen mating frequency varied between 1 and 3 (M. beecheii) and 1 and 6 (S. postica), representing the first clear documentation of polyandry in the Meliponinae. Effective paternity frequency, m _e , was lower, although above 2 for S. postica. Stingless bees may provide suitable subjects for the testing of recent inclusive fitness arguments describing intracolony kin conflict in social Hymenoptera. Received: 26 August 1998 / Accepted in revised form: 18 November 1998     

Solar- und Windenergie zum Pumpen von Wasser

Water pumping by means of wind and solar energy becomes more and more attractive by reason of increasing energy prices. Water supply for remote villages especially in developing countries needs hydraulic energy of about 1 to 50 kWh per day. The use of renewable energies like solar and wind seems to be technically successfull and has a good chance to be competitive with conventional energy sources like diesel or electricity in regions with mean wind speeds above 4–5 m/s or high insolation of about 5 kWh/day annual average.     

Chemische Reaktionen von Phenylarsinverbindungen

In an equilibrium reaction, phenylarsine dichloride (PFIFFIKUS) reacts rapidly with alcohols at room temperature to yield phenylarsine bisether and phenylarsine chloride ether. The reactions, however, are not quantitative. The derivatives were identified using mass spectrometry.