CHOOSING which paddocks to cut for spring silage involves a number of considerations and reaches far beyond the obvious topography, access and feedout issues.
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NSW Department of Primary Industries technical specialist in pasture production Neil Griffiths said the most important considerations should be soil fertility and weed management.
When it comes to managing soil fertility, Mr Griffiths said silage removed large amounts of nutrients including nitrogen, phosphorous, potassium and sulphur, which must be allowed for and monitored using soil tests.
"Deficiencies will limit yield but excess can also be a problem," Mr Griffiths said.
"In particular, nitrogen and potassium will need to be managed in the spring to ensure good growth and yield.
"If potassium is needed, and it often is, then split applications early in spring to allow growth and again after silage harvest to replace nutrients will reduce the risk of luxury uptake.
"This is where the plant absorbs more potassium than it needs meaning you lose fertiliser while the silage has excess potassium with possible associated feed quality issues."
Mr Griffiths said it was important nitrogen was applied sensibly.
"Topdressing early in spring to ensure good growth is usually essential but excess nitrogen can interfere with silage fermentation and nitrate poisoning is a risk," he said.
"Both are unusual in Australian silage but should be considered."
Mr Griffiths said weed management was also a major consideration in paddock selection, both from a silage quality and weed control perspective.
"Using silage for weed control is highly effective and is becoming more important as increasing herbicide resistance issues affect more farmers," he said.
Mr Griffiths will sit on the panel for the Round Bale Silage workshop at the 2014 National Fodder Conference in Adelaide on Monday, August 4.
