Physical properties of a Luvisol for different long‐term fertilization treatments: I. Mesoscale capacity and intensity parameters

The physical properties of a Luvisol derived from loess near Bonn, Germany, under different long‐term fertilization treatments were examined. For the investigation of the impact of farmyard manure (FYM) on soil strength at the mesoscale (100 to 300 cm³ soil cores), undisturbed samples were taken from two different depths (10 and 40 cm), either with no fertilization at all, with full mineral fertilization, with FYM only, and with both mineral and organic fertilization. We investigated hydraulic and mechanical parameters, namely precompression stress, pore‐size distribution, saturated hydraulic and air conductivity, and calculated pore connectivity. Long‐term organic fertilization resulted in significantly more and coarser pores which in addition were more conductant and mechanically stronger by trend. Mineral fertilization also increased pore volume by trend but not pore functionality. Mechanical strength generally increased with fertilization by trend, however, was reduced again when organic and mineral fertilization were combined. Nonetheless, FYM led to relatively higher soil strength as the FYM‐treated plots with lower bulk density attained similar soil strength as the unfertilized but denser plots and thus supported the soil‐improving impact of organic amendments. The subsoil physical properties were rather unaffected by fertilization, but were dominated by texture.     

Optimisation of amino sugar quantification by HPLC in soil and plant hydrolysates

Amino sugars are increasingly used as indicators for the accumulation of microbial residues in soil and plant material. A reverse-phase high-performance liquid chromatography method was improved for the simultaneous determination of muramic acid, mannosamine, glucosamine and galactosamine in soil and plant hydrolysates via ortho-phthaldialdehyde (OPA) pre-column derivatisation and fluorescence detection. The retention time was reduced, and the separation of muramic acid and mannosamine was optimised by modifying the mobile phase. The effects of excitation wavelength, OPA reaction time, tetrahydrofuran concentration and pH value of the mobile phase on the amino sugar separation were tested. Quantification limits were in the range of 0.13 to 0.90 μg ml⁻¹. No interferences exist from amino acids or other primary amines, occurring in soil and plant hydrolysates.     

Impact of controlled redox conditions on nickel in a serpentine soil

Purpose  

Serpentine soils exist in many regions around the world; they are naturally enriched with nickel (Ni). An adequate understanding of soil processes determining Ni solubility is a special need particularly since less research has been addressed to Ni behavior under dynamic and controlled redox conditions. Our aim was (1) to characterize the properties of a serpentine soil and (2) to determine the impact of predefined redox windows on the mobility and dynamics of Ni in a serpentine soil.     

Effect of cattle faeces with different microbial biomass content on soil properties, gaseous emissions and plant growth

A study was carried out to investigate the effects of different diets for heifers, low- and high-yielding cows on the microbial composition of their faeces and subsequently the impacts of these faeces on CO₂ and N₂O emissions, N mineralisation and plant N uptake. A diet low in N and high in acid detergent fibre offered to heifers resulted in faeces dominated by fungi. These faeces were characterised by a low content in microbial biomass C and N and a high ergosterol concentration in comparison to the faeces of high-yielding cows. Added to soil, faeces of heifers led to lower emission and stronger N immobilisation during a 14-day incubation in comparison to the faeces of high-yielding cows. Total N₂O emission was significantly (P?<?0.05) correlated with faecal microbial biomass N. Rye grass yield and N uptake were lowest in the soil supplemented with faeces from heifers in a 62-day pot experiment. Plant N uptake was influenced by the faecal microbial biomass C/N ratio and the fungal C to bacterial C ratio. In conclusion, the faecal microbial biomass was affected to a high degree by the feeding regime and faecal microbial characteristics revealed higher impacts on plant N uptake than soil microbial properties.     

The distribution and diversity of Collembola in saltmarsh habitats of the German North Sea – a preliminary study

The distribution pattern and diversity of Collembola communities in the soils of low and high intertidal saltmarshes were compared. The intertidal “mud” soils are colonized by Collembola to depth of 30 cm and at a distance of 10 m towards the sea from coastal edge. The communities of Collembola in low intertidal saltmarsh soils are dominated by a population of Archisotoma sp. The contents of organic matter in the intertidal saltmarsh soils influenced the distribution of Archisotoma sp.     

Brachygnathia in a herd of Angus cattle

Seven cases of brachygnathia in a single calf crop (28 calves) were observed in an Angus herd. Two of the affected calves, 1 female and 1 male, were necropsied and anatomically described. Breeding histories and results of pedigree analysis involving the 7 affected calves indicated the cause of the defect to be genetic with the mode of inheritance that of a single autosomal recessive gene.     

Heterotrophic plant cell suspension cultures for monitoring biological activity in agrochemical research. Comparison with screens using algae,germinating seeds and whole plants

Heterotrophically cultured cell suspensions are used increasingly in agrochemical research for screening plant-growth retardants and herbicides which influence plant meristems. For this purpose, a large-scale microscreen has been devised, which permits the objective monitoring of cell division by measuring the conductivity in cell suspensions cultured in test tubes. Comparing the effects of a wide spectrum of growth retardants and herbicides with different primary modes of action, the test was most sensitive to nitrogen-geterocyclic retardants in wheat-cell suspensions and to sulfonylurea > imidazolinone > cyclohexanedione, oxy-phenoxypropionic acid, nitrile > glufosinate, phenoxy acid, bipyridylium and diphenyl ether herbicides in maize and oilseed rape cell cultures. As had been expected, inhibitors of photosynthetic processes were only slightly active. The results of the tests were compared with the effects of the compounds on germinating seeds of cress (Lepidium sativum L.) and on photoautotrophic systems using algal cell suspensions (Scenedesmus acutus) and duckweeds (Lemna paucicostata). It is suggested that heterotrophic cell suspensions, in combination with the series of biotests mentioned above, are a valuable complement to the whole-plant screens used routinely in industrial laboratories. They are particularly useful for identifying compounds whose biological activity is masked by limited penetration or translocation behaviour in whole plants.     

Mapping Spatial Patterns with Morphological Image Processing

We use morphological image processing for classifying spatial patterns at the pixel level on binary land-cover maps. Land-cover pattern is classified as ‘perforated,’ ‘edge,’ ‘patch,’ and ‘core’ with higher spatial precision and thematic accuracy compared to a previous approach based on image convolution, while retaining the capability to label these features at the pixel level for any scale of observation. The implementation of morphological image processing is explained and then demonstrated, with comparisons to results from image convolution, for a forest map of the Val Grande National Park in North Italy.     

Aboveground production and N and P use by Larix occidentalis and Pinus contorta in the Washington Cascades, USA

Aboveground net primary production (ANPP) and N and P use patterns were determined for western larch (Larix occidentalis Nutt.), a deciduous conifer, and lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.), an evergreen conifer, in the Cascade Mountains of Washington, USA. Western larch and lodgepole pine retranslocated 87 and 66% of foliage N and 66 and 78% of foliage P, respectively. At the stand level, N use efficiency of western larch was greater than that of lodgepole pine, whereas P use efficiency of lodgepole pine was greater than that of western larch. Western larch and lodgepole pine were comparable in ANPP and production efficiency (ANPP/foliage mass) if needle longevity is considered. The similarity in ANPP of the evergreen lodgepole pine and the deciduous western larch may be related in part to the lower initial construction cost of the foliage, and the efficient use of nitrogen by western larch.     

Modern forestry vehicles and their impact on soil physical properties

Mechanized harvesting procedures for typical forest vehicles were analysed to examine soil stresses and displacements occurring in soil profiles and to reveal changes in physical properties of forest soils. All field experiments were carried out under traffic lanes of standard forest vehicles in forest stands of the southern Black Forest. The soil stresses were determined using stress state transducers (SST) and displacement transducer systems (DTS) at depths of 20 and 40 cm. Complete harvesting and trunk-logging processes with a total time span of 9 min were observed. The maximum vertical stresses for all experiments exceeded 200 kPa; some experiments showed maximum vertical stresses up to 500 kPa or more at a depth of 20 cm. To evaluate the impact of soil stresses on soil structure, the internal soil strength was determined by predicting the precompression stress. Comparison of soil stress data with the natural bearing capacity of the natural forest soil proves that sustainable traffic is not possible, irrespective of the vehicle type and the working process. Topsoil and subsoil compaction, an increase in the precompression stresses, deep rutting and vertical as well as horizontal soil displacement associated with shearing effects took place and affected the mechanical strength and the physical properties of forest soils. Considering these results, heavy forest machinery has a severe impact on soil physical properties such as air, heat, water fluxes and rootability. In order to sustain the present undamaged soil condition, a change in harvest logistics and organisation is necessary. This can be achieved with a permanent skid-trail system which has already been designed to implement new guidelines in Baden-Württemberg, Germany (Ministerium für Ernährung und ländlichen Raum, Baden-Württemberg 2003, p 27).