Opening rains have been variable in low rainfall cropping areas of the state this year. Some of these areas have received so little rain a number of farmers have decided not to proceed with sowing a crop.

In lower rainfall cropping areas, when conditions are not suitable for sowing a crop due to late or poor opening rains, it is good to have a productive pasture to fall back on to provide feed for livestock and soil surface cover.

Many  farmers have sown pasture legumes but found it difficult to find a pasture species that persists from season to season, provides a bulk of growth and surface cover, and is good quality stock feed. Oldman saltbush is a handy fodder species in lower rainfall areas but has some nutritional limitations for stock and doesn’t fit well in a crop rotation.

Most of the pasture species in cropping rotations are winter-growing annuals.  These die and break down over summer, more so with summer rains and grazing, leaving little feed and protection from erosion in autumn.

Productive, pasture plants that grow year in, year out, and persist under cropping, grazing, drought and frost, are needed for low rainfall farming areas.

Attention has turned to investigating the potential of growing perennial, native grass species as pastures that can be occasionally cropped. Perennials persist from year to year, and summer-active species respond to rains outside of the annual growing season and compete less with crops in winter time.

Perennial grasses provide more year-round protection from erosion because even as stubby, heavily-grazed plants, they hold the soil together with their deeper root system better than shallow-rooted annual species .

A range of perennial grasses occur naturally in parts of the State and therefore are adapted to local soil and climatic conditions. Large areas, particularly in the northern agricultural districts and on Eyre Peninsula, were grasslands before they were put under the plough.

Finding the right species could lead to the development of a system where summer-active grasses provide feed over summer and into autumn. Crops are sown using no-till if opening rains are sufficient and timely, with herbicides applied to suppress growth of the grasses. The grasses remain suppressed until the crop is harvested. Should the crop fail due to lack of follow up rain, butts of grasses will still provide some protection from erosion and they will respond to summer rains.

Over 2000 years has gone into the development of plants grown today as crops and pastures so there is some catching up to do in the native grass field. Work has begun on the challenge of finding and using productive, perennial, native grass species that can be sown and grown as easily as cereals and pasture legumes.  

AUTHOR: Mary-Anne Young, Soils and Land Management Consultant, Rural Solutions SA
CONTACT: Mary Anne Young, Rural Solutions SA Jamestown office, Telephone: 08 8664 1408, or Email: Young.Mary-Anne@saugov.sa.gov.au