Lysimeterstudie zum Einfluss von Düngung und Bewirtschaftung auf die Ertragsbildung,den Wasserhaushalt und die Nährstoffauswaschung im Trockengebiet der Uckermark

Lysimeter study about the effect of fertilization and management on yield, water balance, and solute leaching in the dry region of the Uckermark Results are presented of a lysimeter study on the effects of fertilization and management on yield, seepage rate, and solute leaching in the dry region of the Uckermark (Northeast Germany) from 1992 to 1999. The crop rotation included sugar beet, summer barley, pea, and winter wheat with fertilization of 280 and 400 kg N ha^—1 within the crop rotation. Additionally to the mineral fertilization, sugar beet was fertilized with the sugar beet leaf or slurry. The average annual seepage rate was 13.7 mm, the nitrogen leaching was 4.3 kg N ha^—1, and the phosphorus leaching was 0.008 kg P ha^—1. Differences between the treatments were negligible and insignificant. The amount of the precipitation from April to September had a significant influence on yields. Furthermore, results of water use efficiency and the effect of different nitrogen rates on yields are presented.     

Soil microbial diversity of four German long-term field experiments

Abstract

The understanding of agro-ecosystems is the key to estimating the influence of long-term agricultural production methods on the environment. The present study aimed to improve the knowledge of functional and structural soil microbial diversity influenced by differentiated fertilization at four German long-term field experiments. Soil microbial biomass, β-glucosidase, protease, alkaline phosphatase, DMSO-reduction and TTC-dehydrogenase were evaluated in soils from three different fertilizer treatments (control, farmyard manure, mineral fertilizer) at four sites (Lauterbach, Bad Lauchstädt, Halle, Thyrow). Profiles of 29 identified phospholipid fatty acids were used for the evaluation of structural diversity. The results obtained showed that fertilization applied over several decades or even more than a century has led to distinct alterations of the soil ecosystem. There was a clear separation of the sites by microbial biomass and metabolic activities into dependence of soil properties and fertilization treatments. In contrast to the control, microbial biomass and enzyme activities of the FYM soils increased more strongly than in the NPK plots. The results of PLFA analyses indicate that the community of the autochthonous microflora has differently changed among sites and fertilizer application. Principle component analyses revealed that bacteria especially Gram-positive bacteria and eukaryotes were responsible for these differences.     

Structural changes of microbial transglutaminase during thermal and high-pressure treatment

The activity of microbial transglutaminase (MTG) and the corresponding secondary structure, measured by circular dichroism (CD), was analyzed before and after treatment at different temperatures (40 and 80 degrees C) and pressures (0.1, 200, 400, 600 MPa). Irreversible enzyme inactivation was achieved after 2 min at 80 degrees C and 0.1 MPa. Enzyme inactivation at 0.1, 200, 400, and 600 MPa and 40 degrees C followed first-order kinetics. The enzyme showed residual activity of 50% after 12 min at 600 MPa and 40 degrees C. Mobility of aromatic side chains of the enzyme molecule was observed in all temperature- and/or pressure-treated samples; however, high-pressure treatment at 600 MPa induced a loss of tertiary structure and a significant decrease in the alpha-helix content. The relative content of beta-strand substructures was significantly increased after 30 min at 600 MPa and 40 degrees C or 2 min at 0.1 MPa and 80 degrees C. We conclude that the active center of MTG, which is located in an expanded beta-strand domain, is resistant to high hydrostatic pressure and pressure-induced inactivation is caused by destruction of alpha-helix elements with a corresponding influence on the enzyme stability in solution.     

Comparison of two quantitative soil organic carbon models with a conceptual model using data from an agricultural long‐term experiment

Quantitative soil organic carbon (SOC) models are required for a better understanding of C sequestration in soils and for prognoses at different scenarios. However, it is unclear whether the major C‐stabilization mechanisms are included adequately. Objectives were (1) to test the performance of the CIPS (Carbon turnover In Pore Space) model and the Rothamsted Carbon (RothC) Model for a prediction of the SOC dynamics at the long‐term experiments at Halle (Germany) and (2) to compare the model structures of the quantitative models and a conceptual model in order to identify shortcomings of the quantitative models. Both quantitative models had a similar prediction performance: the C dynamics was predicted satisfactorily for the Halle sites under continuous rye with NPK fertilization or without any fertilization (1878–1953), but larger deviations between modeled and measured C contents were observed for the continuous rye and maize in the entire period from 1878 to 1996. The comparison of the conceptual model with the quantitative models revealed that the neglect of the black C dynamics and the interactions of SOC with mineral surfaces are not included explicitly. Site‐specific calibrations are required where these processes have a significant impact on soil organic matter dynamics. Furthermore, the number of pools and mechanisms in the conceptual model is higher than in the quantitative models independent of their level of abstraction. Despite the neglect of some important mechanisms in the quantitative models, it has to be noted that they reproduce the SOC data generally well in agricultural surface soils. Moreover, they need only few inputs which are generally easily obtainable.     

Improving the efficiency and effectiveness of global phosphorus use: focus on root and rhizosphere levels in the agronomic system

Phosphorus (P) is essential for life and for efficient crop production, but global P use with limited recycling is inefficient in several sectors, including agronomy. Unfortunately, plant physiologists, agronomists, farmers and end users employ different measures for P use efficiency (PUE), which often masks their values at different scales. The term P use effectiveness, which also considers energetic and sustainability measures in addition to P balances, is also a valuable concept. Major physiological and genetic factors for plant P uptake and utilization have been identified, but there has been limited success in genetically improving PUE of modern crop cultivars. In maize, studies on root architectural and morphological traits appear promising. Rhizosphere processes assist in mobilizing and capturing sparingly soluble phosphate from rock phosphate. Combinations of phosphate-solubilizing microorganisms with ammonium-based nitrogen fertilizer, as well as strategies of fertilizer placement near the roots of target crops, can moderately enhance PUE. The desired concentration of P in the products differs, depending on the final use of the crop products as feed, food or for energy conversion, which should be considered during crop production.     

Investigation on Soil Lipid Extraction with Different Organic Solvents

Soil lipid content is an important characteristic of the soil organic matter. One of the commonly used extractants for the determination of soil lipid is benzene/ethanol 1:1(v/v). In this study the toxic solvent mixture benzene/ethanol was substituted with the less harmful one toluene/ethanol 1:2.3 (v/v). Both solvent mixtures give a comparably high recovery of soil lipid and the composition of both lipid fractions are very similar according to their thin layer chromatography (TLC). Further investigations with NMR-spectroscopy confirmed that the extracted lipid fraction consists mainly (7gt;90%) of structure elements of aliphatic hydrocarbons.     

Estimation of clay content from easily measurable water content of air‐dried soil

Soil texture is one of the main factors controlling soil organic carbon (SOC) storage. Accurate soil‐texture analysis is costly and time‐consuming. Therefore, the clay content is frequently not determined within the scope of regional and plot‐scale studies with high sample numbers. Yet it is well known that the clay content strongly affects soil water content. The objective of our study was to evaluate if the clay content can be estimated by a simple and fast measure like the water content of air‐dried soil. The soil samples used for this study originated from four different European regions (Hainich‐Dün, Germany; Schwäbische Alb, Germany; Hesse, France; Bugac, Hungary) and were collected from topsoils and subsoils in forests, grasslands, and croplands. Clay content, water content of air‐dried soil, and SOC content were measured. Clay content was determined either by the Pipette method or by the Sedigraph method. The water content of air‐dried soil samples ranged from 2.8 g kg^–1 to 63.3 g kg^–1 and the corresponding clay contents from 60.0 g kg^–1 to 815.7 g kg^–1. A significant linear relationship was found between clay content and water content. The scaled mean absolute error (SMAE) of the clay estimation from the water content of air‐dried soil was 20% for the dataset using the Pipette method and 28% for the Sedigraph method. The estimation of the clay content was more accurate in fine‐textured than in coarse‐textured soils. In this study, organic‐C content played a subordinate role next to the clay content in explaining the variance of the water content. The water retention of coarse‐textured soils was more sensitive to the amount of organic C than that of fine‐textured soils. The results indicate that in our study the water content of air‐dried soil samples was a good quantitative proxy of clay contents, especially useful for fine‐textured soils.     

Determination of 12 type A and B trichothecenes in cereals by liquid chromatography-electrospray ionization tandem mass spectrometry

A new sensitive method for the simultaneous determination of 12 trichothecenes (deoxynivalenol, nivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, fusarenon X, T-2 toxin, HT-2 toxin, neosolaniol, monoacetoxyscirpenol, diacetoxyscirpenol, T-2 triol, and T-2 tetraol) by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) is presented. The development of the method and investigations on the matrix influence on the MS signal are described in particular. The matrix effect was thereby minimized by using an internal standard, a special mobile phase, and specific fragmentation parameters. The sample was extracted with acetonitrile/water (84:16, v/v), and the extract was cleaned up with a MycoSep 227 column. Quantification was based on the internal standard de-epoxy-deoxynivalenol. Calibration curves were linear between 16 and 1600 ng/g, and the limits of detection ranged from 0.18 to 5.0 ng/g. The developed method was applied for the determination of trichothecenes in 120 naturally contaminated wheat and oat samples.     

非1B/1R类型和1B/1R类型小麦K型雄性不育系比较研究

利用非 1B/ 1R类型小麦 K型不育系 KTSP3314A和 1B/ 1R类型小麦 K型不育系 K3314A,分别与10个普通小麦品种 (系 ) 2 5 9,36 6 5 ,TB90 2 ,F10 7,J18,R2 0 5 ,L783,5 0 3,3380和 78115杂交 ,测定和比较其恢复性、单倍体发生频率和主要农艺性状。结果表明 ,非 1B/ 1R类型小麦 K型不育系比 1B/ 1R类型小麦 K型不育系更易恢复 ;不育系本身不产生单倍体 ,其杂交种 F1 产生极少或不产生单倍体 ;农艺性状除了株高具有明显的优势外 ,其他均无不利的遗传效应。     

A COMPARISON OF NORMAL TISSUE COMPLICATION PROBABILITY OF BRAIN FOR PROTON AND PHOTON THERAPY OF CANINE NASAL TUMORS

This study compared the calculated normal tissue complication probability of brain in dogs with a nasal tumor, which had both photon and proton treatment planning. Nine dogs diagnosed with a variety of histologies, but all with large, caudally located nasal tumors were studied. Three-dimensional (3-D) photon dose distribution, and a proton dose distribution was calculated for each dog. To calculate the normal tissue complication probability (NTCP) for brain, the partial brain volume irradiated with the prescribed dose was determined, then a mathematic model relating complications to partial volume and radiation dose was used. The NTCP was always smaller for proton plans as compared to photon plans, indicating conformation of the dose to the target allows a higher dose to be given. If a 5% NTCP were accepted, the mean applicable dose for this group of dogs was 50.2 Gy for photons, but 58.3 Gy for protons. Not all dogs would benefit the same from proton irradiation. If a large partial brain volume has to be irradiated, the advantage becomes minimal. There is also a minimal advantage if the planning target volume (PTV) includes a small, superficial brain volume. However, for a complex PTV shape the degree of conformation is clearly superior for protons and results in smaller calculated NTCPs.