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Report On Phosphorus And Potassium Experiments Conducted On Partner Farms Of The Greener Pastures Project, Mike Bolland, Ian Guthridge, Graham Blincow, Peter Needs

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Dairy production in south-western Australia occurs predominantly on sandy soils in the greater than 800 mm annual average rainfall areas of the region. The climate is Mediterranean-type, typically with cool, wet May-October growing seasons and hot, dry November-April. Most dairy pastures are rain-fed and comprise the annual species Subterranean Clover (clover, Trifolium subterraneum L.), Annual Ryegrass (Lolium rigidum Gaud.) and Italian Ryegrass (L. multiflorum Lam.).

Paddock grown pasture is the cheapest source of feed for dairy production in the region (Dilley and Howes 1998). To remain profitable in the face of diminishing returns, dairy farmers have modified their grazing management …

Phosphorus For High Rainfall Pastures, Mike Bolland, Bill Russell, David Weaver

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Soil testing for phosphorus provides a reliable indication of when the level of phosphorus in a soil is likely to be adequate for pasture production in the next growing season. It is a waste of money to apply phosphorus fertiliser when soil testing indicates none is required, or to acidified soils, or to undergrazed pastures, or to pastures dominated by poorly productive species.

Legumes have higher phosphorus requirement than grasses.

Critical soil test phosphorus values do not change when nitrogen fertiliser is applied.