Criteria and standards for sustainable agriculture

This paper presents an assessment system which on the basis of quantifiable criteria and appropriate orientation values describes the risk potentials of farming as far as environmental protection and sustainability is concerned. The procedure addresses the most significant risks and suggests ranges for their tolerability. By this way farmers can recognize principal shortcomings of their management and look for appropriate countermeasures to cope with them. The guiding principle is a way of farming which uses the available resources and the production potential as efficiently as possible, while keeping the unfavorable impacts on soils, water, air and biota within acceptable limits. Several years of investigations in about 125 different farms have shown that non‐tolerable impacts of farming on the environment are predominantly due to avoidable managerial mistakes. The suggested assessment system provides criteria for the actual magnitude and the tolerability of the different risk potentials and may thus help to substantiate the compliance with such general principles as ”︁good farming practice”.     

Inversion of TDR signals—revisited

In this study, we discuss the consistence of measured and calculated TDR traces. The calculated traces are solutions of a time domain reflectometry (TDR) forward solver, an algorithm for computing the TDR trace for a given dielectric profile along a transmission line. An unambiguous and efficient forward solver is a prerequisite for a good solution of the inverse problem, i.e., to extract the spatial distribution of the dielectric properties along the transmission line from a TDR trace. To advance our understanding of TDR inversion, we proceeded in two steps: (1) design of a TDR head section with minimal disturbances on the signal and (2) searching for causes why measured and predicted TDR traces differ. Based on a first experiment with a three‐rod TDR probe of 100 cm length, we demonstrated that our TDR forward solver—like others presented in literature—approximate the measured TDR traces apparently well but not precisely enough for signal inversion. In a second experiment, using a two‐rod TDR probe of 70 cm length, we addressed the problem of non‐parallel transmission lines. We found that the influence of a non‐parallel installation is similar to an increase of the electrical conductivity in soil water but can be distinguished from this property. A third experiment reveals that lateral and longitudinal disturbances in the vicinity of a TDR probe are of minor importance. From the analysis of our experiments, we found that neither lateral disturbances nor non‐parallel rods are responsible for the deviations between calculated and measured traces. This analysis showed us that structure in the sampled medium affects the shape of the TDR traces. Since minor deviations are essential for TDR‐signal inversion, we need new concepts to handle the fuzziness between measurements and calculations.     

Anaesthetic properties of Propiscin (Etomidaat) and 2-phenoxyethanol in the common carp (Cyprinus carpio L.), neural and behavioural measures

The objective of the study was to evaluate the anaesthetic effects of Propiscin (2% etomidate) and 2-phenoxyethanol on common carp ( Cyprinus carpio L.) by observing neural and behavioural measures. When exposed to the anaesthetic agent, the carp lost equilibrium after approximately 90 s of exposure. They did not breathe and the controls did not respond to tail pinch or prick or 6 V at the skin of the upper jaw. A shift to lower frequencies on the electroencephalogram (EEG) and computing fast Fourier transformation was observed when exposed to water containing Propiscin or 2-phenoxyethanol. Heart rate was reduced after placement in the water containing an anaesthetic agent. It may be concluded from our results that common carp were immobilized and sedated, when exposed to water containing 2 mL L⁻¹ Propiscin and immobilized and anaesthetized in water containing 0.5 mL L⁻¹ 2-phenoxyethanol. In addition, the use of EEG provides for a sound assessment of exposure of carp to these anaesthetics.     

Purification and characterization of an alpha-mannosidase from the tropical fruit babaco ( Vasconcellea x heilbornii Cv. babaco)

An alpha-mannosidase (EC 3.2.1.24) present in the lyophilized latex of babaco ( Vasconcellea heilbornii ) has been purified to apparent homogeneity by native PAGE. The purification involves a three-step procedure with successive anion exchange with Q Sepharose HP, lectin affinity chromatography using ConA Sepharose 4B, and gel filtration using Superdex 200 prep grade. The molecular mass was determined to be in the range of 260-280 kDa by Superdex 200 prep grade gel filtration, and isoelectric focusing showed a pI range between 5.85 and 6.55, suggesting different glycosylated isoforms. The optimal temperature for the alpha-mannosidase was determined to lie between 50 and 60 degrees C, and the optimal pH was 4.5 at 50 degrees C. The K(m) value for p-nitrophenyl alpha-mannopyranoside (pNPM) was found to be 1.25 mM and the V(max), 2.4 microkat mg(-1) at 50 degrees C and 1.94 microkat mg(-1) at 40 degrees C. The pure alpha-mannosidase was specific for mannose and did not display activity for any other tested synthetic substrates.     

Prof. Dr. SC. Gisela Höflich zum 65 geburtstag

Auch die K‐Werte im Unterboden sind primär durch den unterschiedlichen Tongehalt der Versuchsböden determiniert. Durch differenzierte K‐Düngung verursachte negative bzw. positive K‐Bilanzen führen im Unterboden zu geringeren Veränderungen der K‐Werte als im Oberboden: Der K_t‐Gehalt wird durch K‐Düngung im Mittel der drei Dauerversuche gegenüber K‐Mangel in der Krume um 36 mg/100 g, im Unterboden um 14 mg/100 g erhöht. Dieser Unterschied widerspiegelt sich in allen anderen Werten des K‐Status (K_HCI, K_e, K_w, K_DL) und der K‐Dynamik (K‐Sorption, K‐Desorption, K‐Fixierung). Die relative Veränderung der K‐Kennwerte nimmt mit steigendem Tongehalt ab und ist am deutlichsten bei verschiedenen Werten des labilen Kaliums. Das Verhältnis des K_DL zur Summe des wasserlöslichen plus austauschbaren Kaliums beträgt im Unterboden der K‐Mangelvarianten 34% in Lauchstädt, 56% in Halle und 136% in Thyrow; die entsprechenden Werte in den Volldüngungsvarianten betragen 40, 61 und 200%.     

Einfluss unterschiedlicher ct‐gehalte von Böden des thyrower bodenfruchtbarkeitsversuches auf Ertrag sowie boden‐ und düngerstickstoffaufnahme im gefässversuch

In einem dreijährigen Gefäßversuch wurde der Einfluß unterschiedlicher C‐Gehalte von Böden aus dem “Thyrower Bodenfruchtbarkeitsversuch”; auf den Ertrag von Roggen und Ölrettich sowie deren Boden‐ und Düngerstickstoffaufnahme geprüft. Bei Roggen führte höherer Humusgehalt nur bei Unterlassung einer mineralischen Stickstoffdüngung zu höheren Erträgen, beim nachgebauten Ölrettich auch in der gedüngten Variante. Eine bessere Ausnutzung des Düngerstickstoffs bei höherem Humusgehalt und eine Mehrmobilisation von Bodenstickstoff durch mineralische Stickstoffdüngung konnte nicht festgestellt werden. Von dem nach Versuchsabschluß im Boden verbleibenden Düngerstickstoff wurden zwischen 70 ... 90 % als Bestandteil von Humusfraktionen ermittelt.     

Hydrocarbons Emissions from a Municipal Wastewater Treatment Pilot Plant in Vienna

Hydrocarbons emissions were measured from an aerationtank of a municipal wastewater treatment pilot plant. The collected off-gas samples werecharacterised for C₂–C₇ hydrocarbons usingGC-FID analytical technique while the total volatileorganic compounds (TVOC) were measured using acontinuous hydrocarbon gas analyser. Approximately,the estimated emission rates for 1 m³ of wastewaterfrom this aeration tank were 5 mgC of C₂–C₇hydrocarbons, and an average of 7 gC of TVOC. Withexception to toluene, all other measured hydrocarbonsare emitted less than 1 mgC day^-1. The results supportthe view that a significant reduction in annualemissions of hydrocarbons from wastewater treatmentplants in Vienna has taken place.     

Disturbed Vasopressin Release in 4 Dogs with So-Called Primary Polydipsia

Primary polydipsia is characterized by a marked increase in water intake and secondary polyuria, and in dogs often is described as a behavioral problem or a psychological disorder. We describe 4 dogs with primary polydipsia, diagnosed on the basis of a modified water deprivation test, in which further examination included serial measurements of urine osmolality (UOsm) and plasma vasopressin (VP) measurements during water deprivation and hypertonic saline infusion. The dogs, ranging in age from 4 months to 4 years, all were presented for evaluation of polyuria and polydipsia. Physical examination, routine blood chemistry, and urinalysis disclosed no specific cause for the polyuria and polydipsia. During serial measurements UOsm spontaneously reached high concentrations in 2 dogs, whereas in the other 2 dogs UOsm also fluctuated but on no occasion exceeded 1,000 mosm/kg. Primary polydipsia was diagnosed when UOsm exceeded 1,000 mosm/kg at the end of the modified water deprivation test and plasma osmolality did not exceed the upper limit of the reference range during testing. During water deprivation, plasma VP concentrations remained relatively low. The VP response to hypertonic saline infusion was abnormal, with an increased threshold value in 3 dogs, an increased sensitivity in 2 dogs, and an exaggerated response in 1 dog. It is concluded that some dogs fulfilling current criteria for primary polydipsia produce concentrated urine spontaneously throughout the day in a pattern similar to what has been observed in healthy pet dogs. This finding can be regarded as diagnostic and precludes the need for a water deprivation test. During water deprivation testing, all 4 dogs produced highly concentrated urine in the face of low basal plasma VP concentrations. The observed abnormal VP release in response to hypertonic stimulation may be interpreted as a primary disturbance in the regulation of VP secretion, although it might also be the result of overhydration caused by a primary abnormality in drinking behavior.     

Biostimulation and enrichment of 2,6-dichlorobenzamide-mineralising soil bacterial communities from dichlobenil-exposed soil

Eleven enrichment cultures of 2,6-dichlorobenzamide (BAM)-mineralising bacteria from a dichlobenil-exposed soil were enriched using three different media. Ten of the enriched mixed cultures had stimulated BAM mineralisation only in the presence of supplementary carbon and were able to utilise BAM as the sole nitrogen source, while only one was able to utilise BAM as the sole source of both carbon and nitrogen. Cultivation and DNA-based analysis of the mixed cultures suggested that different bacterial populations were stimulated by the three strategies. Our findings indicate that natural BAM-mineralising populations capable of using BAM as a source of nitrogen can be readily stimulated, enriched and maintained following sub-culturing from dichlobenil-treated soils by adding an alternative carbon source.     

Humus balancing in Central Europe—concepts,state of the art,and further challenges

Humus‐balancing methods are simple tools for the assessment of interactions between agricultural land use and soil organic matter (SOM). Aside from this commonality, approaches for humus balancing differ considerably with regard to their specific aim, scope, and methodical approach. The term “humus balance” covers both simple models to quantify SOM change in arable soils, or soil organic C (SOC) change in particular, and models that refer to the optimization of soil productivity in arable soils by calculating organic‐fertilizer demand, without quantifying SOM or SOC change. This situation naturally has caused much discussion and misunderstandings. Against this background, the aim of this review is to systematically explore the different methodical approaches to humus balancing in order to contribute to a more sophisticated discussion of this model family, its opportunities, and limitations. As humus balancing has long history as well as special actual relevance in Germany, and, lately Switzerland, we focus on these countries and discuss the different approaches that are presently available and applied there. We argue that humus balances can be roughly categorized into “ecological” and “agronomical” approaches based on their specific concepts and methodology. Ecological humus balances comprise a strong link to quantitative SOM change, while humus balances of the agronomical family refer to the maintenance of soil productivity without a quantitative link to SOM change. Lately, some models have been presented that link the two concepts. However, we identify that humus‐balancing methods often are insufficiently validated, partly because the validation of agronomical humus balances is not easily possible without a very comprehensive field‐experimental basis. Further, the comparability of different approaches even within the two concept families is low at present, indicating the need for a comparative model evaluation for a proper assessment of the methods.