Variation in the relative abundance of the large pine weevil among Sitka spruce plantation sites

Between 1993 and 1994 over 160 forest sites were sampled toobtain indices of pine weevil (Hylobius abietisL.) densities.Overall 48 variables were tested for their ability to explainvariation in weevil numbers between compartments. The modelsgenerated from the sample data identified 14 variables as significantin influencing weevil densities. In this research note the variablesare identified, and their relationship to forest managementdiscussed     

CROSS POLARISATION 13C-N.M.R. SPECTROSCOPY OF SOME GENETICALLY RELATED NEW ZEALAND SOILS

Cross polarisation ¹³C-n.m.r. spectra of seven New Zealand soils have been determined. Some of the soils are genetically related. The results show that the aromaticity of a soil may vary widely from soil to soil even when the parent material and vegetation are similar. The youngest of the soils examined (Hokitika, 300 years), was highly aromatic, and the oldest soil (Okarito, 22,000 years) was more aliphatic.     

Soil organic matter maps by nuclear magnetic resonance

Preliminary studies are reported on a soil and a litter fraction which have the aim of exploring the potential of two-dimensional ¹³C nuclear magnetic resonance spectroscopy for the analysis of soil organic matter structure. It has been shown that contour plots can be obtained in which one co-ordinate gives chemical shift information and the other the magnitude of the dipolar interaction. For aromatic and oxygenated aliphatic carbon, the latter parameter is a measure of the degree of protonation. Hence the method is useful for distinguishing between soils containing highly substituted and condensed aromatic structures and those with protonated aromatic carbon. Likewise, it is possible to distinguish between soils containing dioxygenated carbon which is. protonated (e.g. ketal).     

AMORPHOUS CONSTITUENTS OF SOME HIGH ALTITUDE SOILS OF THE SOUTH ISLAND OF NEW ZEALAND

Soils developed at high altitudes in the South Island, New Zealand have several pedological properties similar to the volcanic allophane soils of the North Island. Their clay fractions consist of finely divided parent material with some degree of ordering and some oxidation of ferrous to ferric iron, but because they are so finely divided they give no X-ray diffraction patterns, and their IR spectra are typical of amorphous aluminosilicates. They are shown to have structure by electron microscopy and thermal analysis. It is suggested that the clays have been produced by the grinding together of stonesby frost action, and that similar material probably exists in other alpine areas and in polar regions where frost action is common.     

铵、钾同时存在时, 土壤对铵的优先吸附

The water stability of aggregates in various size classes separated from 18 samples of red soils under different managements, and the mechanisms responsible for the formation of water-stable soil aggregates were studied. The results showed that the water stability of soil aggregates declined with increasing size, especially for the low organic matter soils. Organic matter plays a key role in the formation of water-stable soil aggregates. The larger the soil aggregate size, the greater the impact of organic matter on the water stability of soil aggregates. Removal of organic matter markedly disintegrated the large water-stable aggregates (> 2.0 mm) and increased the small ones (< 0.25-0.5mm) to some extent, whereas removal of free iron(aluminium) oxides considerably destroyed aggregates of all sizes, especially the < 0.25-0.5 mm classes. The contents of organic matter in water-stable aggregates increased with aggregate sizes. It is concluded from this study that small water-stable aggregates (< 0.25-0.5 mm) were chiefly cemented by Fe and Al oxides whilst the large ones (> 2.0 mm) were mainly glued up by organic matter. Both free oxides and organic matter contribute to the formation and water stability of aggregates in red soils.     

CLAY MINERALS IN SOILS DERIVED FROM LOWER OLD RED SANDSTONE TILL: EFFECTS OF INHERITANCE AND PEDOGENESIS

The clay mineralogy of thirty-two profiles located mainly in the Vale of Strathmore and developed on glacial till derived from Lower Red Sandstone sediments and lavas has been investigated by X-ray diffraction. The soils were selected so that the parent material was related predominantly to one of the rock types common in the Lower Old Red Sandstone succession—namely, marl, sandstone, lava, or conglomerate. Comparison of the < 1.4μm fractions separated from fresh rock samples with those separated from the C horizons of the soils clearly established the dominant influence of parent rock on the soil-clay mineralogy. The clay minerals inherited by the soil often include unusual trioctahedral expansible minerals such as saponite, interstratified vermiculite-chlorite, and smectite-vermiculite, as well as more common types like mica, montmorillonite, and chlorite. Kaolinite is also found but it is not certain that it is only of inherited origin. Weathering of the clays during soil formation brings about complete degradation of the expansible trioctahedral minerals, a process usually well advanced in the B or even at the top of the C horizon, and vermiculitization of mica. The latter process occurs mainly in the A horizon, with concomitant precipitation of interlayer aquohydroxy-aluminium ions thereby forming a vermiculite-chlorite intergrade. Chlorite and kaolinite appear to be little affected by weathering. The weathering transformations are most pronounced in freely drained acid soils (pH < s) and are at a minimum in poorly drained soils and where the pH remains above 6. The susceptibility to weathering of the trioctahedral expansible minerals results in relatively high values for exchangeable magnesium at the base of the profile.     

The effect of training on stride parameters in a cohort of National Hunt racing Thoroughbreds: A preliminary study

Reasons for performing study: The influence of training on stride parameters is controversial and to date there is no information on how training influences stride parameters during high‐speed locomotion in the field. Objective: To determine the influence of training on stride variables during high‐speed locomotion in Thoroughbred racehorses. Methods: Speed, stride frequency, stance and protraction times were quantified in 8 Thoroughbreds with foot mounted accelerometers and GPS sensors during their first week of canter after the summer break and 6 months into training. Results: At a speed of 11 m/s, stride frequency was (mean ± s.d.) 2.160 ± 0.120 strides/s pre‐ and 2.167 ± 0.083 strides/s post training; mean stance time was 125.3 ± 9 ms pre‐ and 125.9 ± 7 ms post training; protraction time was 340.7 ± 20.4 ms pre‐ and 337.2 ± 14.3 ms post training. The increase in stride frequency and the decrease in protraction time after training were significant. There was no statistically significant difference in the maximum speed reached by each horse pre‐ and post training. Conclusions: Stance time stayed constant throughout the training season in the tested horses. A significant decrease in protraction time and a corresponding significant increase in stride frequency were observed after training. Potential relevance: Training of racehorses could be adapted to maximise the effect on modifiable parameters and reduce the risk of training‐induced pathologies. Further research will be conducted to investigate the effect of different training protocols on a large number of horses.     

Pharmacokinetics of an immediate and extended release oral morphine formulation utilizing the spheroidal oral drug absorption system in dogs

This study investigated the pharmacokinetics of a human-labeled oral morphine formulation consisting of both immediate and extended release components in dogs. In a randomized design, 14 dogs were administered either 1 or 2 mg/kg morphine orally. Blood samples were collected up to 24 h post drug administration. Plasma concentrations of morphine were measured using high-pressure liquid chromatography with electrochemical coulometric detection. For both groups, maximal concentration occurred at 3 h post drug administration followed by a gradual decrease in morphine concentration over 24 h. There was substantial variability in morphine concentrations among dogs. The higher dose group produced a greater exposure (higher area-under-the-curve), higher peak concentration, longer half-life and a shorter time to peak concentration ( t _max). The specific oral morphine formulation used in this study produced sustained plasma morphine concentrations over 24 h compared with previous intravenous dosing and immediate-release oral morphine studies. However, the low morphine plasma concentrations and high variability produced from this formulation, suggest that the clinical application of this formulation at the doses evaluated in this study are limited.     

CLAY AND SILT MINERALOGY OF SOME SOILS FROM QASIM, SAUDI ARABIA

Qasim, some 500 km north-west of Riyadh, is one of the agriculturally important areas of Saudi Arabia. Silt fractions of the soils of the Wadi ar Rimah and side wadis, classified as Torrifluvents, are characterized by high quartz contents and the universal occurrence of kaolinite and felspar, generally with plagioclase predominant; mica, chlorite and hornblende also generally occur. The clay fractions contain mainly palygorskite and a smectite-mica interstratification with smaller amounts of kaolinite, traces of quartz and occasionally chlorite. Palygorskite generally increases in content with depth. Variations in mineralogy probably reflect changes in depositional conditions rather than pedogenic processes; possible reasons for the high palygorskite content are discussed. Sedentary soils (Torriorthents) reflect the mineralogy of the rock from which they were derived. In clay fractions from salt-marsh soils (Salorthids) calcite reacts strongly with smectite-mica during DTA.     

APPLICATIONS OF NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY TO THE STUDY OF THE STRUCTURE OF SOIL ORGANIC MATTER

Recent developments in the application of nuclear magnetic resonance (n.m.r.) spectroscopy to soil science are reviewed. Progress in ¹H, ¹³C and CP-¹³C n.m.r. spectroscopy of humic substances is reported. Methods of determining the fraction of aromatic carbon in soil organic matter extracts are discussed, and methods by which structural group analysis can be carried out on in situ organic matter of whole soils are reviewed.