T A T I O Np R Æ S E N

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Optimal application of slurry –use of implements

Tavs Nyord - Aarhus University, Denmark

Background as a farmer

Agronomist

Ph.D. at DIAS

Assistant professor at AU

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Da nish a griculture

› 62 % of the la nd is fa rmed

› Very intensive a nima l production

› Vulnera ble wa ter bodies: Ba ltic Sea a nd inner Da nish wa ters

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Legisla tion

› NPO-a ction pla n ~1985

› W a ter Environment Action Pla n 1 ~ 1987

› W a ter Environment Action Pla n 4 ~ 2012?

› Ma in focus on lea ching of Nitra te

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Nitra te lea ching

C la y soils Sa ndy soils

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How wa s nitra te lea ching reduced?

› Reduced N a pplica tion ~ 10 (20? ) % under economica lly optimum

› Timing of a pplica tion of a nima l ma nure› Increa sed stora ge ca pa city for a nima l ma nure› a pplica tion when the crops need the fertilizer› Required ca pa city for stora ge of a nima l ma nure - 9 month

› W inter sown crops a nd pa rtly ca tch crops

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Effect of timing of la ndsprea ding on nitra te lea ching

(Misselbrook et a l 2004)

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Ammonia deposition

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Legisla tion focussing on a mmonia

› Ammonia emission a ction pla n – 2001› required covering of stora ge fa cilities

› Broa d sprea ding ba nned

› Incorpora tion ba nned (direct injection ha s to be used) - 2011

› Obliga tion to use soil injection or a cidifica tion of slurry when slurry is a pplied to gra ss or ba re soil -2011

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Splash plate Trailing hose ~ 75 %

Incorporation Injection ~ 25 %

Applica tion techniques

Ma nda tory from 2011!

Unless slurry pH is reduced < 6.4

Splash plate ~ 20-50 % loss Trialing hose ~ 5-30 % loss

Incorporation 5-10 % loss Injection 0-5 % loss

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W hy soil injection/ incorpora tion?

› Legisla tion

› C ommon pra ctise before the legisla tion!

› The reduced N-quota system gives fa rmers economica lly incitement to reduce a mmonia emission

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AARHUSUNIVERSITY Ba re soil injection of a nima l slurry

Before sowing in the spring1st Februa ry to 1st Ma y

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Ba re soil injection of a nima l slurry with spring tine (deep injection)

Wa gner et a l. 2015)

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Ba re soil injection with spring tine injectors (reference)

› W ith out a ny spill – reduction of a mmonia emission by 90-100 % (C hen 2002; W a gner et a l. 2015)

› Extra cost: energy, ma intena nce, reduced ca pa city compa red to tra iling hoses ~ 1 Euro/ m3

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Alterna tives

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Experiment design

› Va ria bles:

› Injection tool (Reference, W ing tine, Discs)

› Tra vel speed (2, 6, 10 km/ h)

› Opera tions depth:

Treatment \ Operation depthDeep (mm) Medium (mm) Shallow (mm)

Reference150 110 80

Disc80 55 30

Wing tine100 70 40 17

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Q ua ntifica tion of hea ted a rea

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Results

Reference Discs Wing tine

Ave

rage

tem

pera

ture

of d

efin

ed a

rea

(o C)

0

2

4

6

8

10

12

14

16

18

Speed

Deep

Medium

Sha llow

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C onclusion a bout soil injection implements

› If there is a correla tion between a rea of hea ted soil a nd NH3 emission – this method could be va lua ble› disc coulters a t a sufficiently forwa rd speed ca n ensure the

incorpora tion of slurry into soil› injection of slurry with a wing tine should be done by a

minimum of 6 km/ h.› At a forwa rd speed of 10 km/ h slurry ca n be injected into

soil with a ll three methods

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Ba re soil injection/ incirpora tion with disc coulter

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Experiments ca rried out in Denma rk 2014 a nd 2015

Experiment on sa ndy soil Dyna mic emission cha mbers (wind tunnels) used a s

mea suring technique Experiment rea peted two times (2*2 replica tions

per trea tment) Experiment ca rried out November 2014 Air tempera ture va ried between 1 a nd 12 degrees

celcius24

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Two types of disc coulters

Slurry pla ced

in front of the

discs

Slurry

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Two types of disc coulters

Slurry pla ced

behind the

discs

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Trail hose (surface)

In front between discs

In front of discs

Behind the discs

Loss

of a

mm

onia

(% o

f app

lied

NH

4 -N)

0

2

4

6

8

10

12

100

55 45

16

Experiments ca rried out in Denma rk 2014 a nd 2015

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C onclusion

› Direct injection of a nima l slurry into ba re soil ca n be done in severa l wa ys with “good” results

› Injection with disc coulter ca n be done, a s long the tra vel speed exceeds 6 km/ h a nd the a pplica tion ra te is below 45 ton/ ha

› Using disc injector, slurry ha s to be pla ced behind the discs –reducing the a mmonia emission with more tha n 50 %

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