Melioidosis in intensive piggeries in south eastern Queensland

The epidemiology of melioidosis was investigated in 8 intensive piggery units which used water from the same river in south eastern Queensland. In 3 consecutive years cases of disease followed heavy rainfall and flooding. Although Pseudomonas pseudomallei was not isolated from water or soil samples the water supply was suspected as the source of infection. Affected pigs were detected at slaughter by the presence of abscesses most commonly in the bronchial lymph nodes (40%) and spleen (34%). One hundred and fifty nine cases were observed at slaughter from a total of 17,397 animals at risk. Infection by inhalation of water aerosols derived from nipple drinkers, hose sprays and a water misting cooler was considered to be responsible for the bronchial lymph node lesions. These outbreaks occurred outside the area in which melioidosis is generally regarded as being endemic.     

Field degradation of the herbicide metribuzin and its degradation products in a Manitoba sandy loam soil*

The degradation of the herbicide metribuzin (4-amino-6 r-butyl-3-(methylthio)-1, 2, 4-tnazin-5-(4H)one) applied at 1 and 2 kg/ha at times equivalent to pre-emergence (12 June), post-emergence (5 July), and pre-harvest (15 August), has been investigated in Almasippi very line sandy loam at Carman, Manitoba. Gas-liquid chromatographic analytical results showed that metribuzin degraded during the growing season, and that residue levels immediately prior to freeze-up (25 October) were in general less than 10% of applied metribuzin independent of application date, and were largely unchanged the following spring. The metabolites and photoproduct of metribuzin were present in maximum amounts near 13 July for the first two treatment dates, a time closely following maximum soil temperature readings, and these compounds in turn degraded almost completely by freeze-up. The following spring only very low levels were detected. Under the conditions described, metribuzin and its degradation products degraded to low levels and should not provide a carryover problem the next growing season.     

The Spatial Impact of Reaganomics: A Test of Six Models

Recent analyses of the Reagan budget reallocations suggest that the spatial distribution of public expenditures among the American states have undergone a major change. What remains unclear, however, is why the Reagan budget reallocations generated these clearly defined spatial effects. In trying to answer this question, we identify five explanations of the spatial impacts, explanations focusing on electoral, partisan, wealth, urban-rural, and expenditure base effects. Along with controls for regional effects, these explanations are tested by OLS regression analysis of data on the state allocations of federal expenditures from the last Carter to the first Reagan budgets.     

Evaluating soil maps for prediction of soil water properties

Conventional soil survey stratifies a region into mapping classes and characterizes each by a representative soil profile within it. The efficacy of the procedure for predicting particle-size fractions, bulk density, water retention, and available water capacity (AWC) of the soil at previously unvisited sites on the Plain of Languedoc in southern France is evaluated for three scales of survey (1/10 000, 1/25 000 and 1/100 000) and is compared to that of prediction from stratified random and simple random samples. Data from 85 soil profiles on a random transect were used for evaluation. Classification partitioned the variation of the measured properties, except for AWC, well at the 1/10 000 and 1/25 000 scales, whereas classification at the 1/100 000 scale was less effective. At the 1/10 000 and 1/25 000 scales both classification and stratified random sampling were better for prediction than simple random sampling for the same total sample. On average the representative profiles proved substantially better predictors than the stratified random samples, but in most situations where soil stratification performed well efficiencies of the two predictors were similar. In essence, the more successful the classification was the more difficult it was to improve prediction by selecting representatives instead of sampling randomly within classes. These results confirmed statistically that the soil surveyor can exercise intuition and judgement to classify and select representatives.     

The topology of pore structure in cracking clay soil. II. Connectivity density and its estimation

Pores in soil, especially in cracking clays, interconnect in more or less complex patterns. The complexity of the pattern can be represented by its connectivity. The connectivity of a network of cracks is the number of loops in it, and the number of loops per unit volume of soil is the connectivity density (G_v) .
The patterns of cracks wider than 60 μm were exposed in parallel sections 50 μm apart, photographed and skeletonized. Loops were tracked from one section to another and counted. Other loops completed in three dimensions but not apparent in horizontal sections were recognized and added to the count. The counts were linearly related to the number of sections examined, and by regression analysis stable and precise estimates of G_v were obtained for the clay subsoils of Windsor and Swanwick soil series from as few as eight sections. The connectivity density of the crack pattern in the Windsor subsoil was approximately 300 cm⁻³ and that of the Swanwick series about 195 cm⁻³.     

Denitrification losses of nitrogen fertilizer applied to winter wheat following ley and arable rotations as estimated by acetylene inhibition and 15N balance

We studied the fate of 222 kg N ha^?1 applied in spring as K¹⁵NO₃ to winter wheat test crops which followed either continuous arable cropping (Arable) or a rotation in which a 3-year grass/clover ley preceded the wheat (Ley). Denitrification losses (measured by an acetylene-inhibition method) of over 1 kg N ha^?1 d^?1 were measured for short periods following heavy rain in mid-May. However the generally dry and cool weather resulted in accumulated losses by denitrification between fertilizer application and anthesis equivalent to only 5.3% and 3.6% (±2%) of the applied N for the arable and ley treatments respectively. The smaller loss from the ley was despite this treatment containing more inorganic N and available carbon. ¹⁵N balance indicated that, at anthesis, 1.5% and 11.5% (± 7%) of the labelled N was lost from the arable and ley treatments respectively. Given the precision of the 15N and the acetylene-inhibition methods, the results are not significantly different. However, the larger difference between methods for losses from the ley treatment may be an underestimate because ¹⁵N balance does not measure losses of unlabelled N. These were probably very small on the arable treatment but could have increased total N loss by 25% to c. 32 kg ha^?1 on the ley treatment compared with the 8 kg ha-1 measured as denitrified. Such a large difference is unlikely to be an error but was probably due to ammonia volatilization from this crop which was severely infected by mildew. The results were thus a poor test of the acetylene-inhibition method, but revealed another loss process which could be significant in some situations.     

SOIL SEGMENT OVERLAP IN CHARACTER SPACE AND ITS IMPLICATIONS FOR SOIL CLASSIFICATION

A major problem in soil classification for soil survey is the lack, or uncertainty, of correspondence between mapping units in different localities. The problem is examined using multivariate soil data recorded at short regular intervals along transects in Oxfordshire and Aberdeenshire. The data for each transect were transformed to canonical variates, the first two of which were then used to locate soil boundaries and to show the relationships among the sampling points in that projection of the character space. With few exceptions, the sampling points in adjacent segments on all three transects lay in different parts of the canonical variate (CV) plane, showing that the boundaries were well defined. On the transect near Witney, Oxfordshire, distant segments either occupied distinct parts of the CV plane, or were superimposed on it. For the other two transects the portions of the CV plane occupied by some segments overlapped only partially the space occupied by one or more other segments that were not contiguous on the transects. The results show that on two of the three examples, lack of correspondence between mapping classes in different localities is already present in small tracts of country.     

Improved estimation of micro nutrients in hectare plots of the Sonning Series

The form and degree of spatial dependence in readily extractable iron, manganese, copper and zinc in the topsoil of 1 ha plots on the Sonning Series near Reading have been determined. The results have been used to calculate the sampling effort required to estimate mean values with specified precision. They show that two- to three-fold economies can be achieved for iron and manganese, at least, by taking account of the known spatial dependence and optimally configuring the sampling.