Zur Anreicherung von Schwermetallen in Böden und Kulturpflanzen durch praktische Klärschlammdüngung

The accumulation of heavy metals in soils and crops by practical sewage sludge application An accumulation of cadmium, lead, zinc and copper was found in some soils and crops after sewage sludge application as compared with same soils and plants not fertilized with sewage sludge. In the soils the heavy metals mainly were accumulated in the Ap-horizons. The displacement into subsoils was small, in spite of the good permeability of the sandy soils investigated. Relatively the mobility of zinc and cadmium in soils was most distinct. Within the plants the accumulation of the heavy metals was strongest in the roots, however also evident in the shoots of rye, barley and oats. Zinc and copper was concentrated in the grains, too. On the meadow-land an accumulation of the elements investigated was found in the blades of rye grass (Lolium perenne L.).     

Ahornschmierlaus Phenaccocus aceris als ��bertr?ger des Little Cherry Virus-2 an S��?kirsche in Baden-W��rttemberg nachgewiesen

The Apple mealybug Phenacoccus aceris was verified as the vector of the Little Cherry Virus-2 (LChV-2) in Baden-Württemberg. However, this does not exclude the participation of even more different vectors. Because the Apple mealybug is more spread than presumed as of yet, this vector should be specifically controlled as well as fought in cherry orchards. If planting new cherry orchards it must be strictly adhered to virus-free, certificated plant matter, so that in areas free from Little cherry an epidemic as in the ??Altes Land?? can be avoided.     

Seasonal development of above‐ and below‐ground organs of Trifolium pratense in grass–legume mixture on different soils

Grass–legume mixtures are suitable for crop rotations in organic farming. However, seasonal development of below‐ground organs of Trifolium pratense in mixtures and on different soils was neglected. We asked (1) how the diameter of the root neck, the maximum order of branching as well as (2) the nodule traits are affected by locality and time, and (3) how above‐ground plant traits of red clover vary in space and time. Red clover was investigated in grass–legume mixtures in the first year of vegetation. Five sites in S Germany were sampled at the day of cut at the end of May, the beginning of July, and at the end of August, respectively. Under similar climatic conditions root traits (diameter of the root neck, order of root branching, size of nodules, and proportion of senescent nodules) differed with soil conditions and time within the season. Root diameter increased during the season. Higher sand content fostered root branching and branched roots developed more nodules. Thinner roots had more active nodules (pink). Root diameter and non‐active senescent (green) or moribund (brown) nodules increased at the end of season. Nodule activity differed more according to season than to soil conditions. The number of nodules per plant (12.5–19.5) decreased from May to August. Cylindrical nodules were found on 85–100% of the plants and branched nodules only on 0–25%. The height of plants was lowest in May and increased in July. The mean number of stems per plant (3.3–6.3) was highest in August. Understanding red clover traits and N₂ fixation is interesting scientifically as well as agronomical. Organic and conventional farmers can both benefit of our findings.     

Taxonomy and evolution of cultivated plants: Literature review 1982/1983

Summary Important papers on taxonomy and evolution of cultivated plants published in 1982 and 1983 were compiled and briefly discussed.

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Taxonomie und Evolution der Kulturpflanzen: Literaturübersicht 1982/1983

Zusammenfassung Wichtige Arbeiten über Taxonomie und Evolution der Kulturpflanzen aus den Jahren 1982 und 1983 wurden zusammengestellt und kurz kommentiert.

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: 1982–1983

, 1982 1983 . .

     

Reproductive failure in goats in Norway: an investigation in 24 herds.

Twenty-four flocks comprising 2370 breeding goats were examined. Three hundred-and-sixty-nine (15.6%) of the goats either aborted or delivered dead kids at full term, or were barren. In 23 of the herds the rate of reproductive loss ranged from 2% to 36%, whereas in one herd all of 54 mated goats had live kids. A loss of greater than or equal to 20% was found in 9 herds comprising 799 goats. In 11 herds comprising 946 goats the rate of reproductive failure was less than or equal to 10%. The incidence of reproductive failure was higher in older goats than in those in their first or second pregnancy. The causes were identified in only about 3% of the goats that aborted. It is concluded that reproductive failure in many flocks probably is associated with non-infectious causes such as nutritional and environmental factors.     

Simulated long-term effects of different soil management regimes on the water balance in the Loess Plateau, China

A soil management regime that improves water use efficiency (WUE) is urgently required to increase the sustainability of the winter wheat-summer fallow system in the Loess Plateau, China. However, the long-term partitioning of the water balance must be understood in order to evaluate the viability of possible soil management regimes. Therefore, an ecosystem model (CoupModel) was used to explore the effects on components of the water balance of five types of soil management regimes: conventional practice, wheat straw mulching, incorporation of high organic matter contents, compaction, and use of a harvested fallow crop. Three variants of the fallow crop approach were also considered, in which the crop was harvested 15, 30 and 45 days before sowing the wheat (designated Fallow-15d, Fallow-30d and Fallow-45d, respectively). Simulations were used to identify the relative magnitude of soil evaporation, wheat transpiration and deep percolation and to elucidate the temporal variability in these components for a selected location using climate records spanning 45 years. However, the soil management regime significantly influenced the magnitude of every component of the water balance (in terms of minimum, maximum and mean values) over the long periods considered. Consequently, wheat yield and WUE differed significantly among the simulated treatments. Mulching led to significantly lower soil evaporation, higher transpiration, and more frequent and extensive deep percolation than other regimes, thereby improving fallow efficiency (percentage of rainfall stored in the soil during the fallow period at the end of the fallow period), wheat yields and WUE. In contrast, soil compaction gave the opposite results, leading to the most unfavourable partitioning of the water balance reflected in the lowest wheat yield and WUE values of all the regimes. In 90% of the years no deep percolation occurred in the soil compaction simulations. Use of a fallow crop with optimal harvest timing (Fallow-30d) improved partitioning of the water balance (decreased soil evaporation) and did not significantly reduce wheat yield compared with conventional practice. High organic matter contents in the soil also had a positive influence on the water balance and improved wheat yield and WUE relative to conventional practice. Therefore, mulching appears to be the best management practice for the winter wheat-summer fallow system in the Loess Plateau, according to the simulations. Increasing soil organic matter may be the best option if mulching cannot be implemented. The ideal time for harvesting a fallow crop for use as green manure or fodder appears to be ca. 30 days before sowing the winter wheat.     

Existing sediment management guidelines: an overview

At the inaugural conference of SedNet WG 4 in April 2002 in Venice it was decided that a survey of existing sediment management guidelines was an important pre-requisite to elaborate on the opportunities for river basin planning of sediment management. This article discusses the existing programmes, decision support system, and conventions and concludes that there is presently no comprehensive river basin sediment management guideline at an international (European) or national level. Management guidelines which are of high relevance for sediment management exist mostly for the purpose of environmentally sound handling for navigation. For the maintenance of waterways and harbours sediments have to be handled in an environmentally sound and economical way. There are some special international and national regulations for dredged material which have different legal and technical backgrounds, purposes and limited competence. The way to find the appropriate regulation within legislation is to ask the question: What will happen with the sediment/dredged material?     

Estimating the age–diameter relationship of oak species in Switzerland using nonlinear mixed-effects models

Tree growth plays a key role in forest dynamics, yet little attention has been paid to quantifying tree age–diameter relationships. Predicting diameter growth of oaks is especially important due to their role in nature conservation and adaptive forest management under climate change. Thus, we (1) identified environmental variables that shape age–diameter relationships of oaks and (2) quantified the accuracy of predictions based on these variables. We determined the age–diameter relationship of 243 oaks (Quercus spp.) growing in Switzerland by using tree-ring samples. Nonlinear mixed-effects models based on a modified Chapman-Richards equation were fitted with environmental variables included as covariates. The fixed effects elevation, slope and water-holding capacity were most important in shaping the age–diameter relationships. Lower elevations, steeper slopes, north-facing aspects, higher water-holding capacities and moister summers resulted in larger maximum diameters. For 75 % of the oaks, age–diameter relationships predicted by the fixed effects matched fairly well the observations (root mean square error between predictions and observations <6 cm); the inclusion of random effects reduced root mean square errors for 86 % of the trees. These results suggest that water runoff plays a key role for the age–diameter relationships, accompanied by limiting temperature effects at higher elevations. The fixed effects covered variability in site quality, whereas the random effects included tree-specific deviations from expected age–diameter relationships, potentially due to neighbourhood effects such as stand density and competition.     

Impacts of changing climate and land use on vegetation dynamics in a Mediterranean ecosystem: insights from paleoecology and dynamic modeling

Forests near the Mediterranean coast have been shaped by millennia of human disturbance. Consequently, ecological studies relying on modern observations or historical records may have difficulty assessing natural vegetation dynamics under current and future climate. We combined a sedimentary pollen record from Lago di Massacciucoli, Tuscany, Italy with simulations from the LandClim dynamic vegetation model to determine what vegetation preceded intense human disturbance, how past changes in vegetation relate to fire and browsing, and the potential of an extinct vegetation type under present climate. We simulated vegetation dynamics near Lago di Massaciucoli for the last 7,000 years using a local chironomid-inferred temperature reconstruction with combinations of three fire regimes (small infrequent, large infrequent, small frequent) and three browsing intensities (no browsing, light browsing, and moderate browsing), and compared model output to pollen data. Simulations with low disturbance support pollen-inferred evidence for a mixed forest dominated by Quercus ilex (a Mediterranean species) and Abies alba (a montane species). Whereas pollen data record the collapse of A. alba after 6000 cal yr bp, simulated populations expanded with declining summer temperatures during the late Holocene. Simulations with increased fire and browsing are consistent with evidence for expansion by deciduous species after A. alba collapsed. According to our combined paleo-environmental and modeling evidence, mixed Q. ilex and A. alba forests remain possible with current climate and limited disturbance, and provide a viable management objective for ecosystems near the Mediterranean coast and in regions that are expected to experience a mediterranean-type climate in the future.