now some science to back claims for nitrogen fixers
http://phys.org/news/2014-12-legume-potential-sandy-soils-productive.html
Legume has potential to turn sandy soils into productive
land
Dec 19, 2014 by Hayley Mayne
After a decade of research, scientists from Murdoch University are excited by a
perennial legume that has the potential to turn poor soils into profitable areas suitable for farming.
Professor John Howieson from the Centre of Rhizobium Studies at Murdoch University said scientists had been searching for a something to treat deep sandy soils for 20 years and that Lebeckia, a shrub legume, has had the most exciting results to date.
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"Our research has shown that Lebeckia improves
carbon content, phosphorus, nitrogen and potassium nutrition and soil fertility to the point where it can be much more profitable for cropping or grazing enterprises," Professor Howieson said.
"Our discovery is significant. We believe it has the potential to turn one million hectares of land in Western Australia and also New South Wales into usable farming land."
Lebeckia is a herbaceous plant which is woody below the soil and research has shown it has a number of benefits.