Soil and water are the essence of agriculture for grazing and cropping but these factors can be greatly influenced by you - through your management in maintaining good ground cover.

Ground cover is a very good indicator of both the production and sustainability of pastures and crops, and includes growing and dead plants and litter.

Litter plays a vital role in reducing rainfall runoff, evaporation and minimising extremes of soil temperatures.

Adequate levels of litter can reduce evaporation by 50 per cent and reduce temperatures in the top five centimetres of soil by up to 20°C compared to bare soil in hot summer conditions.

It is also the major food source for micro-organisms, with high levels of microbial activity resulting in increased organic matter, cycling of nutrients and improvements in soil structure and water infiltration.

Most soil organisms are in the top five centimetres of soil and their activity depends on suitable soil temperature and moisture, and adequate litter.

Research on the North West Slopes has shown maintaining adequate ground cover is very important for improving the water cycle for sustainable grazing systems.

The water cycle is a balance between evapotranspiration (water use by plants and evaporation), runoff and deep drainage.

While you cannot control the rainfall you receive, many of your on-farm management decisions can influence the effectiveness of rainfall.

Evapotranspiration represents about 93pc of annual rainfall on the North West Slopes.

In a 700 millimetre rainfall zone with low ground cover, up to 520mm can be lost as evaporation from the ground surface.

Research has shown this evaporation can be halved if ground cover, including plant litter, is increased from 40pc to 70pc.

Also, by increasing ground cover, runoff is reduced (70mm/year), and by using deep rooted perennials a further five millimetres/year is gained by less deep drainage.

Add these figures and it is possible to achieve an extra 300mm of effective rainfall for additional growth, resulting in increased profits from improved pasture or crop production.

With climate change occurring by means of what appears to be lower rainfall, this extra effective rainfall would be worth its weight in gold.

Ground cover is the most effective way to maximise water infiltration by minimising rainfall runoff and soil erosion, with adequate ground cover vital to maintaining healthy soil and vegetation and productive pastures.

Research has shown at least 70pc ground cover is needed on the North West Slopes to minimise soil degradation and sustain production.

This figure increases in steeper slopes and more erodible soils, and in Tablelands grazing it should be at least 95pc.

Contact Bob McGufficke, (02) 6722 1388 or Jeff Lowien, (02) 6730 1927.