The Enrich project started in 2004 with the aims of developing methods of using native perennial shrubs to increase whole-farm productivity in marginal agricultural areas. And they did. Their body of work is rather large at this point and still going, but the key findings of Phase 1 are in this booklet.
A summary from the overview:
The proposition presented here is that, for a ‘typical’ farm in the low–medium rainfall crop-livestock zones of southern Australia, the inclusion of perennial forage shrubs at about 10–20 per cent of farm area can increase whole-farm profit by 15–20 per cent. This is achieved by reduced supplementary feeding during the summer/autumn feed gap and, importantly, by deferring the grazing of other parts of the farm at the break-of-season, allowing better management and more pasture to be grown elsewhere.
Perennial Australian shrubs, grown in a mixture, can provide out-of-season feed, contribute to protein and mineral nutrition, improve the efficiency of livestock digestion, help control gut parasites, and provide shelter and shade. And there is a suite of other NRM benefits, such as controlling dryland salinity, wind erosion and improving biodiversity.
Basically, they’ve gathered several years worth of data that shows that using perennial forage does work, which shrubs work well, and what methods of using them give you the results. The overview booklet is good if you want to read the details in clear language without too much filler. They also have a short video from one of their W.A. demonstration sites here, and videos across several aspects of the Enrich project (as well as a couple of other projects from the Future Farm Industries CRC) here that are worth a watch.