Bert%F.%Quin%and%Geoff%J.%BatesPastoral%Robotics%LtdPO%Box%125>122%%%%%%%%%%%%%%%%%%%%%%%%%%%St%HeliersAuckland%1740New%Zealandwww.groupone.co.nz

REDUCING%ENVIRONMENTAL%NITRATE%LOSSES%AND%INCREASING%PASTURE%N%UPTAKE%ON%GRAZED%DAIRY%FARMS%via$DETECTION%AND%TREATMENT%OF%FRESH%URINE%PATCHES

Presented$to$“Toward$Sustainable$Groundwater$in$Agriculture$– An$International$Conference$Linking$Science$and$Policy”,$San$Francisco$28D30$June$2016

A%brief%description%of%dairy%farming%in%NZ

• Over%the%period%1995>2016%the%number%of%dairy%cows%in%New%Zealand%(NZ)%has%increased%from%1.5%to%5.5%million.

• This%has%occurred%through%a%combination%of%within>farm%intensification%and%the%conversion%of%other%land%uses%(mainly%sheep%and%beef%farming%and%forestry).

• Over%98%%of%stock%are%grazing%all>year%round,%with%typically%less%than%10%%of%the%feed%intake%supplied%as%bought>in%grain%and%other%feeds%(fed%out%both%in%the%dairy%shed%and%on%the%pasture).

• Most%cows%are%sent%to%specialist%winter%grazing%farms%during%the%colder%months%prior%to%returning%to%calve.

• Typical%pasture%has%changed%from%the%traditional%perennial%ryegrass/white%clover%mix,%receiving%only%1%or%2%strategic%applications%of%fertilizer%N,%to%higher>producing%diploid%and%tetraploid%ryegrass>dominant%pastures%which%have%a%high%fertilizer%N%requirement%(typically%200>300%kg%N/ha%annually%spread%over%6%applications)%and%have%to%be%resown every%3>4%years.

• While%these%pastures%typically%have%a%slightly%lower%N%content%than%the%old%perennial%ryegrass/clover%pastures,%the%quantity%of%N%being%ingested%and%excreted%per%ha%has%massively%increased.

Trend%in%nitrate%levels%in%Canterbury%New%Zealand

(Carl&Hanson,&Environment&Canterbury&2013)

l:::::50&miles:::::l

Cause%of%the%problem

• Once%the%feed%N%content%increases%beyond%the%cow’s%diet%requirement%of%13%%protein%(2%N%of%DM),%much%of%the%excess%is%voided%in%the%urine.

• This%typically%results%in%urine>N%deposition%rates%of%600>1000%kgN/ha%in%the%urine%‘patch’%of%typically%25cm%diameter.%80>90%%is%present%as%urea.

• So%although%the%‘effective’%urine%patch%size%effectively%doubles%in%size%due%to%lateral%movement%of%N%and%ingress%of%roots%from%neighbouring%plants,%urine>N%recovery%by%pasture%plants%is%usually%less%than%40%.

• Another%20>40%%is%lost%as%nitrate%leaching,%with%ammonia%volatilisation,%nitrous%oxide%and%N2%emissions,%and%incorporation%into%soil%organic%matter%accounting%for%the%rest.

• This%leaching%of%nitrate%has%led%to%increasing%frequency%of%levels%above%10%ppm%nitrate>N%in%groundwater%reservoirs,%and%increasing%eutrophication%of%streams,%rivers%and%lakes.%Increasing%levels%of%E.Coli,%phosphorus%and%turbidity%are%also%causing%concern.

Once%the%urine%patch%is%visible,%it%is%too%late%%to%reduce%nitrate%leaching

Solutions%being%investigated%and/or%promoted

Solution Advantages Disadvantages Assessment

Reduce%stocking Easy&to&achieve Reduction&in&profit Not&often&viable

Cow%housing Allows&excreta&to&be&collected,&spread

High&capital,&running&&&depreciation&costs;&greatly&increased&NH3&losses;&not&‘brand&NZ’

Not&likely&to&be&widely&adopted

Use%of%stand>off%pads

Reduces&time&on&pasture;&excreta&collected and&spread&evenly&over&the&farm

Capital&and&waste&management&costs;&reduced&profitability&&&&&

Will&be&part&of&solution&in&areas&with&cold&winters

Solutions&being&investigated&and/or&promoted&cont.

Solution Advantages Disadvantages Assessment

Pads%combined%with%use%of%forages%and%cut%&%carry%%%%%%%%%%%%%

Reduces&time&on&pasture;&excreta&collected and&spread&evenly&over&the&farm

Capital&and&waste&management&costs;&upskilling&&required&

Likely&to&be&a&widely&used&but&partial&solution

Breeding%of%higher%energy,%low%protein%ryegrasses%

Better&utilisation&of&N&content;&less&excreted&in&urine&&&&&

Previous&attempts&lower&yields;&success&likely&to&require&GM

Use&of&GMOs&not&allowed;&risk&to&value&of&&‘brand&NZ’&&

Put%salt%in%drinking%water%to%encourage%cow%consumption

Urine:N&is&diluted;&15%&less&nitrate&leaching

More&sodium&in&milk;&potential&ethics&issues

Possibly&a&small&part&of&the&solution?

None%of%these%really%work…

None%of%the%solutions%listed%are%individually%or%collectively%capable%any%time%soon%of%bringing%about%the%required%reductions%in%nitrate%leaching.%As%it%stands,%a%significant%proportion%of%dairying%land%is%going%to%have%to%be%converted%back%to%some%other%use,%unless%a%low>cost,%practical%solution%is%found;%one%which%achieves%the%required%reductions%in%nitrate%leaching%and%produces%tangible%economic%benefits%for%the%farmer.

Finding%a%solutionApproach:&we&first&looked&at&the&processes&occurring&in&the&urine&patch,&and&investigated&what&we&could&do&about&these&to&reduce&losses

nitrate%leaching%and%other%N%losses

grass%growth

urease&enzymefast&(2:3days)

soil&bacteria&quite&fast&(1:2weeks)

nitrate

urineurea

ammonium

The&inherent&problem&is&that&the&urine:urea&is&converted&to&ammonium:N&very&quickly&(typically&2:3&days),&and&then&on&to&nitrate:N;&too&quickly&for&the&pasture&to&recover&much&of&the&application&rate&in&urine&patches&of&600:1000&kg&N/ha,&before&much&is&lost&as&ammonia&volatilisation,&nitrate&leaching&and&N2O&and&N2&emissions.&

The%Spikey®%solution…

• We%decided%we%had%to%be%able%to%DETECT%the%fresh%urine%patches,%while%the%bulk%of%the%urine>N%was%still%present%as%urea

• We%achieved%this%by%developing%Spikey®,%a%tow>behind%device%which%detects%fresh%urine%patches%by%measuring%the%increase%in%electrical%conductivity%in%the%near>surface%soil

The%‘Spikey®’%solution

The&changes&in&electrical&conductivity&are&measured&by&the&array&of&spiked&wheels&as&they&pass&over&the&urine&patches

Soil%EC%data%from%Spikey®

:1000

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

0 2 4 6 8 10 12 14 16

Mark&*2000 dVa dVb dVc dVd dVe dVf dVg

Deposition&time9:40&&&&&&&&&&&&&&&10:40&&&&&&&&&&&11:40&&&&&&&12:40&&&&&&&&&13:40&&&&&&&&14:40&&&&&&&15:40

Time&[s]

more%grass%growth

urine

ammonium

Recovering%more%urine>derived%nitrate%with%ORUN®

less%nitrate%leaching%and%other%N%losses

nitrate

urease&conversion&inhibited&for&5:10&days slower&as&a&

consequence&(2:4&weeks)

Detect%+%Treatwith%ORUN®

Now%that%we%can%detect%the%urine%patches,%what%do%we%treat%them%with?

• Once&we&could&detect&the&fresh&urine&patches,&we&had&to&decide&what&to&simultaneously&treat&them&with,&to&reduce&nitrate&leaching.

• We&initially&intended&to&use&the&denitrification&inhibitor&dicyandiamide&(DCD),&which&had&been&shown&to&be&effective&in&reducing&nitrate&leaching&from&urine&patches&in&NZ&and&elsewhere&when&applied&(albeit'with&massive&inefficiency)&to&the&entire&pasture&after&grazing.

• However,&DCD,&being&essentially&non:toxic,&&has&never&been&required&to&have&CODEX&registration,&so&when&trace&amounts&of&DCD&were&detected&in&milk&from&pasture&that&had&been&treated&with&DCD,&there&was&no&actual&‘safe&maximum’&concentration&to&fall&back&on.&Given&the&recent&melamine&milk&powder&scandal&in&China,&the&NZ&dairy&industry&decided&not&to&take&the&risk&of&DCD&traces&in&milk&powder&causing&concern,&and&it&was&withdrawn&for&use&on&dairy&pastures.

• We&therefore&returned&to&consideration&of&the&soil&N&processes&in&the&urine&patch,&and&came&up&with&ORUN®&(Optimised&Recovery&of&Urine&Nitrogen).

What%is%ORUN?

• ORUN®%is%a%mix%of%the%urease%inhibitor%n>(N)>butyl%thiophosphorictriamide (nbpt)%and%the%growth%promotant gibberellic%acid%(GA3).

• The%nbpt inhibits%the%conversion%of%urine>urea%to%ammonium>N%for%5>10%days,%by%blocking%the%activity%of%the%enzyme%urease.

• This%allows%the%urine>urea%to%move%laterally%in%the%soil,%producing%a%much%bigger%‘patch’%of%enhanced%N%content,%allowing%much%more%of%the%urine>N%to%be%recovered%by%the%pasture.

• The%GA3%works%synergistically%with%the%nbpt by%triggering%cell%expansion%in%the%affected%pasture.

Some%results%with%ORUN®

(Quin'et'al'2016)

N2O%fluxg%N2O>N/ha/d

Cumulative%N2O>N%emissionsg%N2O>N/Ha

Fig&2&Comparison&of&nitrous&oxide&flux&and&cumulative&emissions&with&and&without&ORUN®

Some%results%with%ORUN®%cont.

Detailed%data%on%the%reduction%of%nitrate%leaching%available%Oct%2016%– preliminary%results%show%reductions%of%30>48%.

2016%> on>farm%use%of%Spikey®%and%ORUN®%spray%commences

• Spikey®&is&used&on&a&‘follow:the:cows’&basis,&at&least&during&the&periods&of&the&year&at&most&at&risk&from&nitrate&leaching

• Each&day&or&second&day,&Spikey®&is&towed&over&the&areas&grazed&in&the&previous&day&or&two,&detecting&fresh&urine&patches&and&spraying&them&with&ORUN®

• The&current&pre:production&Spikey®&has&a&width&of&8m&and,&when&towed&by&a&quad&bike&or&small&tractor,&takes&10&minutes&to&treat&a&hectare.&The&average&dairy&farm&in&NZ&is&grazing&3:4&ha&per&day.

• A&much&larger&‘contractor’&version&is&being&designed&for&situations&where&farmers&want&to&contract&out&the&urine&detection&and&treatment.

• A&smaller&‘Research&Spikey®’&with&far&more&spiked&wheel&electrodes&will&be&capable&of&mapping&the&location&and&size&of&urine&patches,&and&tracking&them&over&time.

• The&full&costs&of&operating&Spikey®&(capital,&depreciation,&labor and&ORUN®)&to&the&farmer&is&estimated&at&US$10,000/pa&(($83/ha).&Increased&pasture&production,&at&70%&per&individual&urine&patch&and&valuing&pasture&at&10c/kg,&is&$30,000&per&ha.

• Hence&Spikey®&is&fully&cost:effective&for&the&farmer&in&its&own&right,&and&the&environmental&benefits&solve&the&farmer’s&looming&deadline&to&substantially&reduce&nitrate&leaching.

2017%> Simultaneous%same>pass%tasks%to%be%offered

Simultaneous&ONEsystem® Optimised&

N&application&

Simultaneous&residual&pasture&measurement

Also:&dung&harrowing&and&soil&moisture&measurement

2018%and%beyond

Which&leads&to:&• Full&pasture&growth&&measurement&• Pasture&management• Individual&weed&control• pH&measurement• Leaf&analysis• Soil&analysis

‘Mini:ME®’&robotised&tow

vehicle

2015 and beyond2018

http://www.groupone.co.nz/www.groupone.co.nz

Thank%you%for%listening