Break Crop Vetch as a brown manure: Michael Pfitzner
Overview: The Pfitzner family has been farming in the Rankins Springs district since the 1960’s. They originally ran a mixed farm enterprise with cropping and sheep.
They farm 2800 hectares of red sandy loam country with a pH of 5.2 with an average yearly rainfall of 350 – 400mm.
Their cropping program once involved committing a third of the cropping country to crop, a third to fallow and a third to pasture but since the millennium drought their farming system has changed to full cropping with retained stubble and no livestock.
They use a disc seeder on 12 metre controlled farming system and grow vetch, peas and lupins as break crops in their crop rotation; but their main focus is vetch as a brown manure, hay and seed. Initially vetch was grown to provide fodder for sheep but has evolved into an important strategy within their cropping program.
Sowing: The vetch seed is slurry inoculated before sowing through an agri-vac as it’s put into the grouper. Using a disc seeder allows them to sow through the brown manured vetch biomass much more effectively than a tyned implement.
Weed Control: Although weed control isn’t just a one year fix, Michael says the use of brown manuring plays a strong role in controlling weed populations simply by not letting weeds grow to maturity during the brown manuring phase.
Nitrogen: Michael feels there is an increase in soil nitrogen through growing vetch but to what degree is difficult to quantify.
Disease: Yellow leaf spot has been an issue as after growing vetch and returning the paddocks to wheat as stubble from the previous cereal crop is still evident. The Pfitzners have found that applying timely urea is a better option than fungicides when the situation occurs.
Soil Health, profitability and sustainability: Although by brown manuring the vetch the Pfitzners are denied income from seed, the increase in soil nitrogen and protein and moisture retention offer more benefits in the longer term.
Since moving to a stubble retained system with legume break crops Michael has noticed an improvement in soil health; with a noticeable increase in soil microbial and insect activity. Part of this he feels is due to the large root system of the vetch.
In areas where there are still compaction issues Michael now sows safflower with the vetch as a companion for extra root penetration or bio-cultivation.