Woody vegetation thickening occurs in agri-ecosystems worldwide, often with negative consequences for production. Dense Callitris glaucophylla (Joy Thomps. & L.A.S. Johnson) stands affect landscapes across NW NSW, Australia, and strategies to reduce tree density to levels which maintain biodiversity values alongside agricultural production are currently being sought. We investigated soil chemical and groundcover patterns associated with individual small and large C. glaucophylla trees at six sites of variable management history and lithology in NW NSW, Australia. We posed two questions: (1) do individual C. glaucophylla trees impose patterns on soil and groundcover (soil extractable P, C, N, S and pH, litter biomass, litter P and pasture cover), and, (2) if patterns exist, do they differ between tree sizes? Results showed that extractable P, C and pH decreased away from trees of both sizes, but significantly higher values were recorded adjacent to the stem of large trees. Litter biomass exhibited a strong site-related trend independent of soil variables. Positive correlations between litter and soil variables existed for some sites and not others, indicative of processes such as grazing which contribute to the transport of litter away from the tree. Irrespective of tree size ground-storey vegetation cover increased significantly away from the stem, presumably as a consequence of competition for soil water. Further results indicated that single C. glaucophylla trees enrich soils in patterns analogous to other species in similar environments worldwide. However, localised soil improvements must be weighed up against the negative effects of decreased groundcover associated with trees, and the potential for the species to re-seed prolifically into managed paddocks. Future research will discern the impact of individual C. glaucophylla trees at higher densities, where soil patterning may be modified by intense within-stand competition.

In Australia, as elsewhere, there is a growing need for information relating to soil condition, its current status, and the nature and direction of change in response to management pressures. This information is required by land managers, and regional, State and, national agencies to inform modified land-use practices and investment to maintain and improve the soil resource. Here, we present data relating to soils under 3 land-use types at 6 properties the north-western slopes of New South Wales. We aimed to quantify the range of soil condition states that exist across the region and to test a range of potential soil condition indicators and their suitability to detect differences in soil condition between these land-use types. A range of soil properties showed no significant difference between land-uses and could be rejected as indicators. However, significant differences existed between the land-uses and soil depths for a range of the other soil parameters determined (bulk density, C, N, P, EC, and Na). Soil C, N, P, and Na concentration and total soil C were typically higher in woodland soils compared with other land-uses, while bulk density, pH, and EC were lower in the woodland soils. The depth at which these differences existed varied between soil parameters. Correlation and principal components analysis suggested that a minimum dataset of soil parameters including soil bulk density, pH, C, P, and Na would discern much of the difference in soil condition between the land-uses studied. It is proposed that these parameters be used as a minimum dataset of indicators for soil condition assessment on soils of the type across this region. Work continues under the New South Wales Land and Soil Condition Monitoring Program to further refine the selection of appropriate soil indicators in this and other regions of New South Wales.

We describe the principles and practice of computer-assisted telephone interviewing, and its successful deployment in a general practice-based research study into the referral behaviour of general practitioners (GPs) in the Grampian region of Scotland. Participating GPs were interviewed concerning the acceptability of the method. It proved to be an efficient and acceptable method for collecting data from a large number of practitioners in this large geographical area. Our experience confirms that this efficient method of data collection could be much more widely utilized in primary care research.

Objective To derive clinical standards for singleton birthweight in a population based on area of residence.Design Analysis of variables recorded in Aberdeen Maternity and Neonatal Databank, calculating for each birth a standardised birthweight score, taking account of determining factors.Subjects All singleton live births of 32 to 42 weeks gestation to Aberdeen City District residents from 1979 to 1983.Results Basic standards of birthweight are presented correcting for gestational age, sex of the baby and parity of the mother. Birthweight is not normally distributed and empirical data are presented rather than smoothed curves. Adjustment for maternal height is straightforward but adjustment for maternal weight must take account of the gestation at which the woman was weighed. A method of calculating the appropriate correction for height and weight is described in detail.Conclusion Birthweight is not normally distributed at each week of gestation. Standardisation for parity, gestation and sex of the baby is essential, but adjustment for maternal size is complex.