Research from Meat and Livestock Australia confirms maintaining ground cover of at least 70% through pasture species and planned grazing minimises rainfall loss through evaporation and surface run off.
Impact of various ground cover levels
20% ground cover
- Run-off water loss = 160mm/year
- Soil loss = 8.5mm/year
- Poor plant production and sustainability
- Low green leaf and plant vigour
- Low water infiltration
- Plants exposed to temperature extremes
- Low litter levels
- Low microbial activity
- Poor organic matter content
- Poor soil structure and surface sealing of soil
40% ground cover
- Still too low
- Run-off water loss = 90mm/year
- Soil loss = 4.0mm/year
- Poor pasture and soil loss
70% ground cover
- Run-off water loss = 10mm/year
- Soil loss = 0.3 mm/year
- Good plant production and sustainability
- High green leaf and plant vigour
- High water infiltration
- Plants’ bases protected from temperature extremes
- High litter levels
- Good microbial activity
- High organic matter content
- Good soil structure and soft soil surface
Reducing surface run-off minimises the risk of erosion, however, some run-off is essential to fill farm dams and to provide stream-flows for downstream use and to maintain healthy rivers and aquatic ecosystems.
Maintain ground cover of at least 70% with a high perennial component on low slopes, and up to 100% on steep areas, where erosion potential is higher. This will reduce the soil damage due to run-off, particularly under high-intensity storm rain, and improve water quality.
Wheatbelt NRM’s Optimising fodder options in mixed farming systems Project will be investigating how Wheatbelt farmers can use perennial pastures, shrubs and summer cropping to increase summer ground cover with the added benefit of tackling the seasonal feed gap.