Estimating particle-size fractions of soil dominated by silicate minerals from geochemistry

Measuring particle-size distribution (psd) is so time-consuming and expensive that it is rarely affordable for systematic survey. In young soil dominated by silicate minerals the size fractions have characteristic elemental compositions, and so they might be predicted from geochemical analysis. We tested the feasibility of predicting the psd from concentrations of elements in samples of topsoil taken in surveys of two large regions in eastern England and on which the psd had been determined. Of the 35 elements measured we chose eight (a) from our general knowledge of mineral composition, (b) after a principal component analysis to avoid redundancy and (c) experience elsewhere. Of the eight elements, five were used (Al, Fe, Ni, Ti and Zr) to build multiple linear regression models for the predictions. The equations were assessed by their coefficients of determination, R ², and the effectiveness of their predictions, expressed as root-mean-square errors (RMSEs) on validation sets of data of known psd. The models accounted on average for 89% of the variance in the clay size-fraction and 82% for sand. The corresponding median RMSEs were 4.9% and 8.8% on medians of 17% and 58%, respectively. The silt size-fraction was less well predicted; R ² was only 0.58, and the median RMSE was 10.6% on a median of 22%. We judge our approach, in which the regression models may be regarded as pedotransfer functions, to have been moderately successful and to merit attention in similar circumstances in other regions.     

The August 2007 equine influenza response management framework

This section outlines the most important issues addressed in the management of the response in the two infected states, New South Wales and Queensland. There were differences in the management of the response between the states for logistic, geographic and organisation structural reasons. Issues included the use of control centres, information centres, the problems associated with the lack of trained staff to undertake all the roles, legislative issues, controls of horse movements, the availability of resources for adequate surveillance, the challenges of communication between disparate groups and tracing the movements of both humans and horses.     

An observational study on the prevalence and impact of Isospora suis in suckling piglets in southwestern Ontario, and risk factors for shedding oocysts

An observational study was conducted to determine the prevalence of Isospora suis oocysts in fecal samples from suckling piglets in Ontario, and to evaluate the relationship between the presence of I. suis oocysts and diarrhea. Fifty farms and 709 litters of piglets were included in the study. Oocysts were detected on 70% of farms, with 187 litters infected. A litter of pigs that was positive for oocysts was significantly more likely to exhibit diarrhea than a litter that was negative [odds ratio (OR) = 4.0; 95% confidence interval (CI) = 2.8 to 5.8; P < 0.001]. Management and housing factors were examined with respect to risk factors for the presence of I. suis. Farms that did not use a detergent when cleaning farrowing crates were 10-times more likely to be positive for I. suis than those that used a detergent (P = 0.007). It was concluded that coccidiosis is a common problem on Ontario swine farms.     

Tick paralysis in dogs and cats in Australia: treatment and prevention deliverables from 100 years of research

This review of tick paralysis caused by Ixodes holocyclus in Australia addresses the question: What are the key discoveries that have enabled effective treatment and prevention of tick paralysis in dogs and cats? Critical examination of 100 years of literature reveals that arguably only three achievements have advanced treatment and prevention of tick paralysis in animals. First, the most significant treatment advance was the commercial availability of tick antiserum in the 1930s. Hyperimmune serum currently remains the only specific anti-paralysis tick therapy available to veterinarians in Australia. Second, advances in veterinary critical care have increased survival rates of the most severely affected dogs and cats. Critical care advancements have been enabled through specialised veterinary hospitals that can provide appropriate care 24 h a day, and advanced training of veterinarians, veterinary nurses and technicians. Third, perhaps that biggest advance of all in the last 100 years of research has been the commercial availability of the isooxazoline class of acaricidal preventatives in Australia specifically for I. holocyclus. This highly effective class of preventatives offers long duration of action, low cost, spot-on or oral formulations and a low rate of adverse reactions. Animal owners and veterinarians now have the most useful tool of all – a reliable preventative. This review reveals the key events in research over the last 100 years and the tortuous pathway to delivering better treatment and preventative options for this enigmatic Australian parasite.     

Fluctuations in method‐of‐moments variograms caused by clustered sampling and their elimination by declustering and residual maximum likelihood estimation

Soil data accumulated in national and regional archives derive from many sources and tend to be concentrated in zones of particular interest. Experimental variograms computed from such data by the usual method of moments can appear highly erratic, and therefore models fitted to them are likely to be unreliable. We have explored two methods of avoiding the effects, one by computing declustering weights and incorporating them into the method of moments, the other using residual maximum likelihood. The methods are illustrated with data on bulk density, exchangeable magnesium, cation exchange capacity and organic carbon of 4182 samples of soil from numerous soil surveys in the whole of Australia and stored in the CSIRO's national archive. The experimental variograms of all four variables are erratic. Cell declustering produced much smoother sequences of estimates to which plausible models could be fitted with confidence. The residual maximum likelihood models closely matched those models over several hundred km. Finally values were simulated at the same sampling points from the residual maximum likelihood models, reproducing ‘spiky’ experimental variograms such as those computed from the data. The simulation showed that clustered design of sampling causes spiky artefacts. We conclude that where data are clustered experimental variograms should be computed with declustered weighting or variogram models be fitted by residual maximum likelihood.     

Soluble organic nitrogen in agricultural soils

 The existence of soluble organic forms of N in rain and drainage waters has been known for many years, but these have not been generally regarded as significant pools of N in agricultural soils. We review the size and function of both soluble organic N extracted from soils (SON) and dissolved organic N present in soil solution and drainage waters (DON) in arable agricultural soils. SON is of the same order of magnitude as mineral N and of equal size in many cases; 20–30 kg SON-N ha^–1 is present in a wide range of arable agricultural soils from England. Its dynamics are affected by mineralisation, immobilisation, leaching and plant uptake in the same way as those of mineral N, but its pool size is more constant than that of mineral N. DON can be sampled from soil solution using suction cups and collected in drainage waters. Significant amounts of DON are leached, but this comprises only about one-tenth of the SON extracted from the same soil. Leached DON may take with it nutrients, chelated or complexed metals and pesticides. SON/DON is clearly an important pool in N transformations and plant uptake, but there are still many gaps in our understanding. Received: 10 June 1999     

Let's re‐write the scientific paper

The European Journal of Soil Science rapidly established itself as a leader, strong in most branches of soil science. Nevertheless, it would be even more attractive if authors would break away from the misleading formalism and stultifying style of the conventional scientific paper. Let us report our research more nearly as it happened; let us overcome our fear of revealing our humanity, our good luck, even our failings, and acknowledge the contributions from our intuition and imagination as well as the hard graft in the field and at the bench. Let us also liven our prose by writing more in the active voice and so that readers can know who did what and who is responsible. Let us convey the wonder of discovery in our writing without sacrificing scientific rigour; then soil research would be seen to be exciting with a bright future.     

Control of nitrogen export from watersheds by headwater streams

A comparative (15)N-tracer study of nitrogen dynamics in headwater streams from biomes throughout North America demonstrates that streams exert control over nutrient exports to rivers, lakes, and estuaries. The most rapid uptake and transformation of inorganic nitrogen occurred in the smallest streams. Ammonium entering these streams was removed from the water within a few tens to hundreds of meters. Nitrate was also removed from stream water but traveled a distance 5 to 10 times as long, on average, as ammonium. Despite low ammonium concentration in stream water, nitrification rates were high, indicating that small streams are potentially important sources of atmospheric nitrous oxide. During seasons of high biological activity, the reaches of headwater streams typically export downstream less than half of the input of dissolved inorganic nitrogen from their watersheds.