Irrigation Technology and Farm Management Information

Irrigation Fact Sheets

The Tasmanian Institute of Agriculture (TIA) works with farmers, agricultural advisers, service providers, industry groups and natural resource management groups to provide excellence in agricultural research, development, extension and education.

Find resources to unlock the full economic, social and environmental potential of investment in irrigation infrastructure.

Tasmanian Institute of Agriculture - Water for Profit Resources

Soil Texture

Soil Texture relates to the "feel" of a moist soil when it is manipulated between thumb and forefinger. It depends on the relative amounts of sand, silt and clay particles in a soil.

Some soils are sticky, others will not stick together at all, some feel "doughy" or "spongy" and other soils can be manipulated like plasticine.

Soil texture affects the movement and availability of air, nutrients and water in a soil and is often used to estimate other soil properties, particularly soil water properties.

Soil Texture (1Mb)

Water available in soil

Efficient irrigation requires the minimising of time the soil is either saturated or dry, and maximising the time when water is readily available to the plant. Soil is like a big sponge, it can only soak up a certain amount of water, and it can only do it at a certain rate (infiltration rate). When soil is saturated there is no benefit in applying more water. Excess water produces plant stress through waterlogging, drainage to the water table below the root zone, run-off and leaching of fertilisers.

Water Available in Soil (1Mb)

Waterlogging in soil

Waterlogging can limit agricultural productivity in many areas of Tasmania. Many soils experience parts of the year when they are saturated. Waterlogging occurs when the soil is so wet that there is insufficient oxygen in the pore space (anaerobic) for plant roots to be able to adequately breathe.

Waterlogging in Soil (PDF 1Mb)

Soil and Plant Testing

Adequate nutrition is a vital part of profitable cropping. Irrigation increases the stakes. Crop yields and nutrient removal are higher under irrigation than for dryland crops, and fertiliser rates need to be adjusted accordingly to maximise returns on your irrigation investment. Soil and plant tests are important tools to help you decide (a) whether fertiliser is needed, and if so, (b) how much to apply.

Soil and Plant Testing (968Kb)

Water Requirements of Annual Crops

The amount of water that you need will depend on the crop you are growing, on whether you are farming in the hotter and dryer areas of the State rather than the cooler wetter districts, and will vary from season to season. The time of planting also an important factor.

Water Requirements of Annual Crops (942Kb)