Pro­duc­tiv­ity loss in cat­tle in­dus­try

Central and North Rural Weekly - - FROM THE SALEYARDS -

QUEENS­LAND’S $5 bil­lion beef cat­tle in­dus­try is los­ing pro­duc­tiv­ity be­cause of the de­cline in phos­pho­rus avail­abil­ity in briga­low soils and the lack of legume-based pas­tures.

Gavin Peck, se­nior pas­ture agron­o­mist with the Queens­land Depart­ment of Agri­cul­ture and Fish­eries in Toowoomba, told agron­o­mists at an Incitec Pivot Fer­tilis­ers forum last month that pas­ture “run­down”, caused by ni­tro­gen be­ing tied up in soil or­ganic mat­ter, had halved pro­duc­tiv­ity in the briga­low belt, even though the re­gion car­ries 30 per cent of north­ern Aus­tralia’s beef herd.

Pas­ture legumes have been iden­ti­fied as the best long-term op­tion to in­crease the pro­duc­tiv­ity and re­turns from both “run­down” sown grass pas­tures and na­tive pas­tures through di­rectly im­prov­ing the diet qual­ity of cat­tle and in­creas­ing ni­tro­gen sup­ply to grasses, which leads to bet­ter grass growth and feed qual­ity.

“These briga­low soils in south­ern and cen­tral Queens­land were widely thought to have ad­e­quate phos­pho­rus to sup­port crop­ping, sown pas­tures and graz­ing an­i­mals, but our re­search shows con­clu­sively that this is not the case for large ar­eas,” he said.

“The re­al­ity in the briga­low coun­try is that phos­pho­rus lev­els are vari­able with large ar­eas with low soil phos­pho­rus and these de­fi­cien­cies are hav­ing an ad­verse ef­fect on cat­tle pro­duc­tion.

“Our work shows that with a ma­jor change in at­ti­tudes to fer­tiliser use, gra­ziers can im­prove their re­turns by in­cor­po­rat­ing legumes in grass pas­tures and en­sur­ing they are well sup­plied with phos­pho­rus and other key nu­tri­ents.

“This clear­ing and burn­ing ini­tially led to a big re­lease of phos­pho­rus, but when we ex­am­ined more re­cent soil test re­sults, we found that plant avail­able phos­pho­rus lev­els have dropped dra­mat­i­cally, more so in pas­tures than crop­ping, and only one-third of these soils have enough phos­pho­rus to max­imise legume pas­ture growth,” Mr Peck said.

“Across three dif­fer­ent soils data­bases, 20–30 per cent of soils had Col­well P lev­els less than 10mg P/kg, a level where legumes will re­spond to phos­pho­rus fer­tiliser and stock may ben­e­fit from sup­ple­ments,” he said.

A sur­vey of leu­caena grow­ers by the Univer­sity of Queens­land back in 2007 found 58 per cent re­ported de­clin­ing pro­duc­tiv­ity, with only 10 per cent us­ing fer­tiliser at es­tab­lish­ment and 2 per cent ap­ply­ing fer­tiliser in es­tab­lished pas­tures.

How­ever, tri­als at Wan­doan and Moura found that pas­ture growth and liveweight gains in cat­tle im­proved when they grazed legume-based pas­tures sup­plied with ad­e­quate lev­els of phos­pho­rus.

“With ad­e­quate phos­pho­rus lev­els, ni­tro­gen fix­a­tion and cy­cling works bet­ter,” Mr Peck said.

The re­search found that the eco­nomic re­turns from a switch to more legume-based pas­tures were im­pres­sive across a range of soil fer­til­i­ties, legume species, pas­ture sit­u­a­tions and fer­tiliser strate­gies.

“Sow­ing legumes and putting fer­tiliser on those legumes on low P soils are the best thing that gra­ziers in the briga­low belt can in­vest in,” he said.

FEED FORUM: Bede O’Mara from Incitec Pivot Fer­tilis­ers with Gavin Peck from QDAF, who spoke about the run­down in phos­pho­rus in Queens­land’s briga­low belt. PHOTO: ROD GREEN – RU­RAL PICS

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