202-203 Soil and Water Resources

202-101 Chemistry for Land and Food Resources, 202-106 Land Resources.

This subject will identify the importance of soil and water in the landscape and as key components of ecosystems, both natural ecosystems and production systems. A basic knowledge of soil properties and behaviour will be applied to understanding the cycling of water and nutrients, the appropriate use of fertilisers, irrigation and drainage, and soil management practices designed to maintain soil and water resources in good condition. The origin of soil variation in the landscape and codification of soil information through classification will be introduced.

The subject will cover areas including:

• the origins of soil variability and how this variability is expressed through the properties and behaviour of soils in the field (builds on the 100-level subject Land Resources);

• soil profile description; an introduction to soil classification (the Australian Soil Classification);

• the physical and chemical nature of soil minerals and organic matter; the main soil organisms and their function; reactions in the soil solution and between the solution and surfaces;

• soil structure, aeration, water retention and movement, availability of water to plants and effects of waterlogging;

• introduction to nutrient cycling and its importance in natural ecosystems and production systems (agriculture, horticulture and forestry); emphasis on N, P, K and S; use of fertilisers and other soil amendments to correct nutritional problems;

• the hydrological cycle, with emphasis on the major processes - precipitation, evaporation, runoff and drainage; catchment processes and water management at the farm scale, including irrigation. Examples of water balances at large (basin) and small (farm) scales;

• land degradation processes and their management - accelerated soil acidification, sodicity, salinity and erosion; understanding the processes and the extent of the problems; remedial measures;

• and the impact of soil management on water quality, especially with respect to nutrients and salts.

Three-hour examination (50%) and two assignments equivalent to 3000 words (each worth 25%).

• R E White, Principles and Practice of Soil Science. 3rd edn, Blackwell Science, 1997.