Watch fer­tiliser pro­gram as chick­peas use triple potas­sium

Central and North Burnett Times - - RURAL WEEKLY -

AS GROW­ERS con­tinue to re­place wheat in their ro­ta­tions with chick­peas to cap­i­talise on higher mar­ket prices, there’s a grow­ing need to up­date fer­tiliser pro­grams – or face nu­tri­ent run­down.

Bede O’Mara, Incitec Pivot Fer­tilis­ers’ sub-trop­i­cal farm­ing sys­tems agron­o­mist, said one of the ma­jor dif­fer­ences be­tween grow­ing wheat and chick­peas was that chick­peas re­moved sig­nif­i­cantly more potas­sium.

“This in­creased potas­sium re­moval will add up for grow­ers who are now reg­u­larly in­clud­ing chick­peas in the ro­ta­tion, par­tic­u­larly if they are grow­ing the crop year on year with other higher potas­sium re­moval crops, such as cot­ton and high yield­ing sum­mer grains like sorghum or corn,” he said.

Last sea­son, Mr O’Mara ar­ranged grain test­ing to pro­vide up-to-date guid­ance on nu­tri­ent re­moval from chick­pea crops.

The test re­sults showed that one tonne of chick­pea grain re­moved 10.7kg of potas­sium – nearly three times more than one tonne of wheat (3.7kg).

The chick­pea crop also re­moved more ni­tro­gen, phos­pho­rus and zinc per tonne of grain than wheat.

Chick­peas were shown to re­move 37.4kg/t of ni­tro­gen, 4.1kg/t of phos­pho­rus and 35g/t of zinc in the tests, con­ducted by the Nu­tri­ent Ad­van­tage lab­o­ra­tory.

“When you mul­ti­ply these fig­ures by the high yields that many grow­ers achieved last sea­son, it could well have been a high re­moval event for those pad­docks,” Mr O’Mara said.

“If chick­peas be­come more of a pil­lar crop in the ro­ta­tion, they will come at a larger nu­tri­ent re­moval cost.”

He added that there had been some con­firmed and sus­pected cases of potas­sium de­fi­ciency in chick­peas over the past few sea­sons on soil types known for be­ing on the lower side of ad­e­quate.

These in­clude many box soils and other vari­able soil types.

Act­ing on these in­sights, Incitec Pivot Fer­tilis­ers has cre­ated a new fer­tiliser blend for chick­pea crops, called ChicKP SZ.

The new fer­tiliser con­tains 6% ni­tro­gen, 11.4% phos­pho­rus, 19.1% potas­sium, 10.7% sul­phur and 0.7% zinc.

Most of the sul­phur in ChicKP SZ is in the sul­phate sul­phur form for im­me­di­ate avail­abil­ity to the crop.

Mr O’Mara en­cour­aged chick­pea grow­ers to con­sider rates of around 100kg/ha of ChicKP SZ at plant­ing on 50cm or nar­rower rows, rather than us­ing their stan­dard ce­real starter fer­tiliser which con­tains no potas­sium.

On wider rows, he said lower rates of around 60 to 65kg/ha could be ap­plied in con­tact with seed.

“ChicKP SZ will bet­ter meet the nu­tri­ent re­quire­ments of chick­pea crops and en­sure longer term sus­tain­abil­ity in the crop­ping sys­tem,” Mr O’Mara said.

“An­other strat­egy to im­prove potas­sium sup­ply may be to drill 50 to 100kg/ha of muri­ate of potash as a test strip eight or more weeks prior to plant­ing.

“This will al­low the as­sess­ment of potas­sium re­sponses in chick­peas or other ro­ta­tional crops.”

Muri­ate of potash is not rec­om­mended for use at plant­ing in con­tact with the seed.

“Al­ter­na­tive or­ganic sources of potas­sium such as ma­nure and com­post can also be used, but they need to be broad­cast and in­cor­po­rated at the be­gin­ning of the pre­ced­ing fal­low for seed safety and nu­tri­ent avail­abil­ity rea­sons,” Mr O’Mara said.

“If you’re grow­ing chick­peas where you haven’t grown them be­fore, soil test first to de­ter­mine start­ing soil fer­til­ity and check for any sub­soil con­straints.”

When you mul­ti­ply these fig­ures by the high yields that many grow­ers achieved last sea­son, it could well have been a high re­moval event for those pad­docks

— Bede O’Mara


Incitec Pivot agron­o­mist Bede O’Mara.

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