Cut­ting failed crops can cost nu­tri­ents in soil

North East & Goulburn Murray Farmer - - NEWS -

NORTH East grow­ers who have this year cut crops for hay and silage are be­ing re­minded that they have also re­moved con­sid­er­able nu­tri­ents from their soil.

Crop nutri­tion ex­perts - sup­ported by the Grains Re­search and De­vel­op­ment Cor­po­ra­tion (GRDC) cantly more ni­tro­gen, potas­sium and sul­phur than if the crop was left stand­ing for grain pro­duc­tion.

Ac­cord­ing to re­search, hay can re­move up to two times more ni­tro­gen and up to 10 times more potas­sium than har­vested grain crops.

sul­phur can be lost.

Agri­cul­ture Vic­to­ria re­search sci­en­tist, Roger Arm­strong, said one­off hay cut­ting of a failed crop can prompt changes in crop nutri­tion pro­grams and pad­dock man­age­ment into the next sea­son.

“With nu­tri­ents that would oth­er­wise be re­cy­cled in the soil be­ing lost through the re­moval of crop ma­te­rial in hay and silage, soil tests will be­come more im­por­tant ahead of next year’s sow­ing to in­form nutri­tion pro­grams in 2019,” Dr Arm­strong said.

Dr Arm­strong says re­peated re­moval of hay is con­sid­ered to be one of the most acid­i­fy­ing of agri­cul­tural prac­tices, and on acid soils can ex­ac­er­bate the is­sue in the longer term.

The re­moval of ce­real or canola hay re­quires 25 kilo­grams/hectare of lime for each tonne of biomass re­moved, or 45kg/ha for each tonne of an­nual legume hay re­moved, to neu­tralise the re­sult­ing acid­ity.

Cut­ting hay also re­duces in­puts of or­ganic mat­ter into the soil for that sea­son.

The size of the ef­fect when the hay is cut from a failed crop can be roughly sim­i­lar to or­ganic mat­ter lost from burn­ing stub­ble residues from a good crop, com­pared to re­tained stub­ble.

Fol­low­ing hay cut­ting, lit­tle residue cover - around 0.4t/ha of residue after hay cut­ting ver­sus 2.0t/ha after har­vest - re­mains.

Grow­ers are there­fore ad­vised these pad­docks to min­imise the risk of wind and wa­ter ero­sion which also con­trib­ute to soil nu­tri­ent loss.

To sup­port grow­ers and ad­vis­ers wish­ing to ac­cess tools and re- sources to as­sist with dry sea­son de­ci­sion-mak­ing, and for gen­eral sup­port, the GRDC has de­vel­oped a “Deal­ing With The Dry” web por­tal which con­tains links to use­ful in­for­ma­tion.

In­for­ma­tion on nu­tri­ent re­moval from cut­ting crops can be found on the GRDC Com­mu­ni­ties web­site at and http://

THINK BE­FORE YOU CUT: Cut­ting hay re­moves sig­nif­i­cantly more ni­tro­gen, potas­sium and sul­phur than if the crop was left stand­ing for grain pro­duc­tion.

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