Running a profitable light, acidic-soil farm, is perhaps a fitting topic to highlight in the 1800th issue of this column, published weekly throughout the past 35 years. There have been many other major agricultural developments during this time, but perhaps the transformation of country once regarded as near useless, to highly profitable land, stands out.
Prior to the 1970s, not a lot was widely understood about these soils, despite efforts by previous generations.
Through the years, research has found a range of pastures and crops that can thrive in these acid soils, provided soil fertility issues are addressed, pastures are well established and well managed. These include many oat and triticale varieties, narrow leaf lupins, cowpeas, serradella and biserrula, and perennial grasses like premier digit.
A good example of what research has achieved, when matched with innovative risk takers, is George and Maree Avendano’s operation on “Towri”, Boggabri. Nearly 30 years ago they borrowed to purchase a largely acid soil property with many predicting they would be lucky to last more than a year or so. Today they have extensively developed the original property, plus several new purchases, all financed via profits from their so-called second- or third-rate country.
Our farm is another example and has returned gross margins (variable costs deducted from gross returns) of around $350 a hectare per year in recent years. Our business is different from the Avendano’s, but our pasture types and winter dual purpose crops are similar. They run about 1000 breeders and sell their stock as finished, generally heavier than 500 kilograms. We trade steers, purchasing at around 250kg and sell at around 500kg, the bulk of them mainly going to Woolworths or Coles.
Tropical grasses comprise 40 per cent of our property, native grasses 40pc and dual purpose cereals 20pc. This mixture aims to maximise quality feed production throughout the year. Like the Avendanos, we are conservative stockers, running seven to eight dry sheep equivalents (DSE) a hectare, but with gross margins per DSE currently around $50.
Serradella is our and the Avendano’s main winter legume in both native and tropical pastures. While it does require grazing management a little different from sub clover (aerial seeder), it has proven long term persistent across medium and lighter textured soils, including deep acid soils. Serradella is high quality, non-bloating, has good aphid tolerance, hard seeded and is productive. Other legumes on both properties include biserrula, gland, rose and sub clover.
Tropical grasses, especially but not only premier digit, are persistent (over 25 years on the Avendano property and 15 years so far on ours), as well as productive from spring through to late autumn. A key factor has been almost total annual success with establishment, despite dry years, largely because of pre-sowing weed control, shallow sowing and early spring sowing. Annual legumes are mainly added the following autumn.
Critical to good pasture legume production, and accumulation of soil nitrogen for the grasses, has been soil fertility correction; mainly phosphorus and sulphur. Prior to the discovery of acid soil tolerant pasture legumes, fertiliser responses had been poor. But acid soil tolerant species respond to nutrient deficiency correction in a major way.
Winter dual purpose crops have several purposes on both farms. To clean up summer weeds during the fallow (as preparation before sowing tropical grasses), to clean up winter weeds in-crop, and to provide winter feed, especially critical when autumn breaks are late. Fallow moisture storage is critical as is early sowing.
Next week: Realistic options for control of African lovegrass and Coolatai grass.
- Bob Freebairn is an agricultural consultant based at Coonabarabran. Email robert.freebairn@bigpond.com or contact (0428) 752 149.
