A simple filter paper method for estimating a wide range of moisture potentials has been tested for fifteen soils ranging in texture from sands to heavy clays. The method has given estimates of moisture potential from -0.1 to -900 bars with an accuracy that should be acceptable for many types of field experimentation. Relationships between 15-bar percentages determined by both the filter paper and pressure membrane methods, and biologically determined permanent wilting percentages for wheat, are discussed.

A study of the effect of soil-water stress and phosphorus level on the efficiency of phosphorus absorption (micrograms phosphorus per milligram oven-dry root per day) and growth by young wheat plants grown on a lateritic podzolic soil showed that absorption was not affected by increasing soil-water stress, provided the plants were not damaged by wilting. In experiments where the water-stress treatment was imposed for only a few days it was found that the rate of phosphorus absorption was reduced after the plants had been subjected to a period of wilting. The results indicate that available soil phosphorus was derived mainly from fine pores undrained at suctions approaching 15 atm. The concentration of available phosphate in these pores may have been considerably higher than earlier estimates of the phosphate concentration in the soil solution. The absorption of phosphorus increased with increasing soil phosphorus potential for all levels of water stress.

The environment, duplex soil types and trends in crop production in South Australia, southern New South Wales, north-eastern and north-central Victoria, the southern Wimmera and the Victorian Western District are reviewed. In the latter 2 regions, pastoral industries dominate and crop production is curtailed by regular and severe soil waterlogging, except for limited areas of lower rainfall. Subsurface drainage can eliminate waterlogging, but is feasible only for the Western District where subsoils are sufficiently stable. The other regions all have a long history of soil degradation due to cropping practices, but these effects can now be minimised with the use of direct drilling and stubble retention cropping methods. A vigorous pasture ley phase is still considered necessary to maintain nitrogen levels and to restore soil structure to adequate levels for sustainable farming. Future productivity improvements will require increased root growth in the subsoils. Deep ripping, 'slotting' of gypsum, and crop species capable of opening up subsoils are techniques which may hold promise in this regard. The inclusion of lucerne, a perennial species, in annual pastures and intercropping at intervals is a technique being pioneered in north-central and western Victoria and may provide the best opportunity to crop duplex soils successfully without associated land degradation.

A collaborative study was carried out on one of the methods submitted to the Joint Economic Commission for Europe (ECE)/Codex Alimentarius Commission Group of Experts on the Standardization of Quick Frozen Foods for the determination of moisture in quick frozen french (fried potatoes. The method was based on the determination of loss of mass of the sample on drying in a convection oven 16 h at 103±2°C. Two samples of uncooked quick frozen french fried potatoes and 2 samples of oven quick frozen french fried potatoes were analyzed by 14 and 13 laboratories, respectively. The method is simple and was found to be analytically satisfactory with repeatability and reproducibility values of 0.21 and 2.00 g/100 g french fried potatoes, and 0.29 and 3.00 g/100 g oven french fried potatoes, respectively. The method was adopted by the Group of Experts in preference to other proposed procedures for this determination. The method has been adopted official first action by AOAC.

A study was made of the effects of plant density, time-of-sowing and level of fallow water on profile changes in soil water content and potential during the growing season of spring wheat. The pattern of soil moisture extraction was affected by all treatments although water depletion occurred chiefly in the 0-90 cm zone. The results are discussed in relation to limitations of a simple soil water budget model and to wheat cropping on the north-west slopes and plains of New South Wales.