The Natural Development of Nutrients in Soils (216 KB)
Nutrient recycling within natural vegetation inevitably involves losses and such losses are compounded by harvesting in agriculture. The sustainability of vegetative systems therefore depends on obtaining new replacement nutrients. Mineral fertilisers are usually applied in agriculture but in natural systems the replacement nutrients arise through micro-organisms extracting nutrients from the atmosphere and the mineral component of soils. The paper addresses the interaction between micro-organisms and plants in the provision of new nutrients from soil minerals, and the sustainability of agricultural systems that attempt to directly replace lost nutrients rather than develop the biological health of soils.

Possibilities for Increasing and Measuring Soil Carbon (80 KB)
Environmental and management factors affecting the accumulation of soil organic matter are summarised and used to identify conditions best suited to increasing sequestration of carbon in soils. Several management systems that increase soil organic matter are listed. A new initiative designed to aid the implementation of these approaches to management is identified.

Changes in Australia Grasslands: Report by Squatter, John Robertson 1854 (32 KB)
Grasslands and soil health underwent considerable change within a very brief period of time as a result of the squatting occupation in the 1800's. The deterioration of soil health was commented upon in the squatters' journals. One squatter, John G. Robertson, who took up land in the Casterton (Victoria) area in 1840 and remained there until 1854, gave a vivid description of how the land had changed.

A Soil Structural Degradation Model for Dryland Salinity (540 KB)
The applicability of rising groundwater model for dryland salinity is examined by way of applications where it can't apply, observed salinity outcomes discordant with the model and the physical invalidity of usual representations of the model. A hypothesis involving dryland salinity being caused by soil structural degradation is discussed by way of the impacts of land use on soils, observed salinity outcomes, and the ability to reverse the adverse salinity. The implications are discussed by way of the general degradation of the system that leads to the localised salinity impacts and the appropriate remedial actions.