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Determining the environmental burdens and resource use in the

production of agricultural and horticultural commodities.

Defra project report IS0205

Natural Resource Management Institute

!ranfield "niversit#.

Silsoe Research Institute.

$ugust 200%

&&&.cranfield.ac.u'

Referencing and $c'no&ledgements

For referencing this document should be referred to as:Williams, A.G., Audsley, E. and Sandars, D.L. (!!"# Determining the environmental burdens and

resource use in the production of agricultural and horticultural commodities. $ain %e&ort. Defra

%esearch 'roect )S!!*. +edford: ranfield -niersity and Defra. Aailable on///.silsoe.cranfield.ac.u0 , and ///.defra.go.u0

1he authors are grateful to Defra for funding this /or0, es&ecially the guidance and su&&ort of

Dr Donal $ur&hy2+o0ern. 1he /or0 /as mainly carried out and the re&ort /as /ritten by

staff from S%) (/ho hae since moed to ranfield -niersity:

htt&:33///.silsoe.cranfield.ac.u0 #, but the &roect team included the follo/ing, /hose

considerable in&uts made the &roect &ossible:

%aymond 4ones 5 %ichard Weller ()GE% #, %osie +ryson (6elcourt Ltd#, Lois 'hili&&s (Elm

Farm %esearch entre#, Andy Whitmore, $argaret Glendining and Gordon Dailey

(%othamsted %esearch#, 'aul oo0 (%lconsulting#, 7igel 'enlington ($L# and Gerry

8ayman (8ayman 8orticultural onsultancy#.

We also note the sudden and une9&ected death earlier this year of %aymond 4ones, /hose

contribution to the &roect and the research community /as considerable.

1he editorial in&ut of Dr Daid 'arsons is also gratefully ac0no/ledged.

1his re&ort describes the current state of the L) analysis /hich is no/ being distributed toinde&endent e9&erts for reie/ and assessment.

http://www.silsoe.cranfield.ac.uk/

http://www.defra.gov.uk/

http://www.silsoe.cranfield.ac.uk/iwe/expertise/lca.htm

http://www.silsoe.cranfield.ac.uk/

http://www.defra.gov.uk/

http://www.silsoe.cranfield.ac.uk/iwe/expertise/lca.htm



Final report to Defra on project IS0205:Determining the environmental burdens and resource use in the production of

agricultural and horticultural commodities.

Eecutive Summar!

The research addresses key questions underpinning the development of sustainableproduction and consumption systems that are based on domestically producedagricultural and horticultural commodities. It quantifies the resource use andenvironmental burdens arising from the production of ten key commodities anddelivers accessible models that enable resource use and emissions arising fromvarious production options in England and Wales to be examined in detail. Thecommodities examined are: bread wheat potatoes oilseed rape tomatoes beef pigmeat sheep meat poultry meat milk and eggs.

The overall research aim agreed with !efra was to model the environmental burdensand resource use involved in producing ten agricultural and horticultural commodities

using the principles of "ife #ycle $ssessment %"#$& and to deliver these models in auser'accessible form such as Microsoft Excel. The specific pro(ect ob(ectives were toidentify and define the ma(or productions systems in England and Wales and therelated process flow charts to establish the relevant mass and energy flows andother necessary data and their uncertainties to code the "#$ models in a packagesuch as Microsoft Excel with all the main data readily accessible and published touse the "#$ model to analyse these production systems and demonstrate that themodel can compare production systems and can identify high risk parts the systemsand to publish and publicise the research outputs.

$ll inputs into on'farm production for each commodity were traced back to primaryresources such as coal crude oil and mined ore. $ll activities supporting farmproduction such as feed production and processing machinery and fertiliser manufacture fertility building and cover crops were included. The system includedsoil to a nominal depth of ).* m. Where appropriate %tomatoes potatoes&commodities were defined as national baskets of products for example tomato typessuch as loose and on'the'vine tomatoes each included as their proportion of nationalproduction. $biotic resources used %$+,& were consolidated onto one scale basedon relative scarcity. Individual emissions such as carbon dioxide %#-& and nitrousoxide %/-& were quantified and aggregated into impacts for global warming %0W1&eutrophication %E1& and acidification %$1&. -rganic production systems were

analysed for each commodity as well as variations on non'organic %or contemporaryconventional& production.

Interactions between inputs outputs and emissions were represented by functionalrelationships derived from process models wherever possible so that as systems aremodified they respond holistically to specific changes. 2or example crop yields andnitrogen supply dairy cow diet formulation and milk yield and grass productivityemissions animal gra3ing and fertiliser applications are functionally related. 1rocesssimulation models were also used to derive the long term outcomes of nitrateleaching soil crop type and nitrogen supply.

2inal report to !efra for pro(ect I4))5: Environmental burdens and resource use in agriculture1age of 6



"esults#are is needed in comparing commodities as they have different nutritionalproperties and fill different roles for consumers. The results for plant commoditiesare shown in Table I and those for animal commodities in Table II.

#able I #he main burdens and resources used arising from the production of field and protected crops in the current national proportions of productions!stems $%ith the current organic share sho%n in parenthesis.

Impacts & resources used per t'read %heat

$0.()*+ilseed rape

$0)*,otatoes $-)*

#omatoes$./)*

1rimary energy used 07 .5 5.8 9.8 9*)

0W19)) t #-%9& ).) 9.; ).8 <.8

Eutrophication potential kg 1-8*' *.9 .8 9.* 9.5

$cidification potential kg 4- *. <. . 91esticides used dose'ha .) 8.5 ).6 ).5

$biotic resource used kg antimony %& 9.5 .< ).< 9))"and use %0rade *a& ha ).95 ).** ).)*) ).))*)

Irrigation water m* 9 *<

%9& 0W19)) uses factors to pro(ect global warming potential over 9)) years. %& $+, antimony is the element used to scale

disparate entities.

The relationship between energy use and global warming gas emissions inagriculture contrasts with most other industries. /- from the nitrogen cycledominates 0W1 from field crops contributing about )= in wheat production %bothorganic and non'organic&. In addition methane from livestock production particularlyfrom beef sheep meat and milk is a global warming gas emission not related toenergy use.

$bout <;= of the energy used in tomato production is for heating and lighting toextend the growing season >ecause energy use is almost identical for all tomato

production systems per unit area the highest yielding tomatoes %non'organic looseclassic or beefsteak& incur lower burdens than all other types of tomato.

#able II #he main burdens and resources used in animal production in thecurrent national proportions of production s!stems $%ith the current organicshare sho%n in parenthesis*.Impacts & resources usedper t of carcass per 20000 eggs $about - t* or per-0m mil1 $about - t dm*

'eef $0.)*

,ig meat$0./)*

,oultr!meat

$0.5)*

Sheepmeat$-)*

Eggs$-)*

3il1$-)*

1rimary energy used 07 9; 9 * 98 50W19)) t #- 96 6.8 8.6 9; 5.5 9).6

Eutrophication potential kg 1-8*' 95 9)) 8< )) ;; 68

$cidification potential kg 4- 8;9 *<8 9;* *) *)6 96*1esticides used dose ha ;.9 . ;.; *.) ;.; *.5

$biotic resource use kg antimony *6 *5 *) ; *

4and use $-*

0rade ha ).)8 ).)5 ).

0rade *a ha ).;< ).;8 ).68 ).8< ).6; ).<0rade *b ha ).* ).8

0rade 8 ha ).6; ).*

%9&: 0ra3ing animals use a combination of land types from hill to lowland. "and use for arable feed crops was normalised atgrade *a.

-n the livestock side poultry meat production appears however the mostenvironmentally efficient followed by pig meat and sheep meat %primarily lamb& withbeef the least efficient. This results from several factors including: the very lowoverheads of poultry breeding stock %c . 5) progeny per hen each year vs one calf per cow&? very efficient feed conversion? high daily weight gain of poultry %madepossible by genetic selection and improved dietary understanding&.

2inal report to !efra for pro(ect I4))5: Environmental burdens and resource use in agriculture1age * of 6



1oultry and pigs consume high value feeds and effectively live on arable land astheir nutritional needs are overwhelmingly met by arable crops %produced both hereand overseas&. +uminants can digest cellulose and so make good use of grass bothupland and lowland. @uch of the land in the ,A is not suitable for arable crops butis highly suited to grass. -ne environmental disadvantage however is that

ruminants emit more enteric methane. This contributes to the ratios of 0W1produced to primary energy consumed being about 5)= higher for ruminant than pigor poultry meats.

,nlike most of industry and domestic activity the 0W1 from agriculture %excludingprotected cropping& is dominated by /- not by #- from fuel use. /- contributesabout )= to 0W1 in wheat production %both organic and non'organic&. The /-contribution falls to about 5)= for potatoes as much fossil energy goes into coldstorage. >ecause the underlying driver is the nitrogen cycle the 0W1 of cropproduction is relatively similar across contrasting productions systems includingorganic. In contrast #- from the use of natural gas and electricity in tomato

production is the dominant contribution to 0W1.

The balance of global warming gas emissions and fossil fuel consumption is thusquite different from most industries. In agriculture /- dominates with substantialcontributions too from methane. #onsequently a carbon footprint inadequatelydescribes agriculture? it has a carbon-nitrogen footprint . Indeed the nitrogen fluxesin agriculture %and other types of land& also contribute to eutrophication andacidification. The ma(ority of environmental burdens arising from the production of agricultural food commodities arise either directly or indirectly from the nitrogen cycleand its modification in organic and non'organic systems.

nal!ses of organic and non6organic production $bout ;= less energy was used for organic wheat production compared with non'organic but there was little difference in the case of potatoes. The large reduction inenergy used by avoiding synthetic / production is offset by lower organic yields andhigher inputs into field work. 0W1 is only ';= less for organic than non'organicfield crops reflecting the need for / supply to equal / take'off and the consequentemissions to the environment as nitrous oxide to air and nitrate to water.

@ost organic animal production reduces primary energy use by 95= to 8)= but

organic poultry meat and egg production increase energy use by *)= and 95=respectively. The benefits of the lower energy needs of organic feeds is over'riddenby lower bird performance. @ore of the other environmental burdens were larger from organic production but abiotic resource use was mostly lower %except for poultry meat and eggs& and most pig meat burdens were lower. 0W1 from organicproduction ranged from 8= less for sheep meat to 85= more for poultry meat.

"and use was always higher in organic systems %with lower yields and overheads for fertility building and cover crops& ranging from 65= more for milk and meat to 96)=for potatoes and ))= more for bread wheat but the latter is a special case as onlypart of a crop meets the specified bread'making protein concentration.

-rganic tomato yields are ;5= of non'organic. Thus the lowest yielding organic on'the'vine specialist tomatoes incur about six times the burden of non'organic looseclassic.

2inal report to !efra for pro(ect I4))5: Environmental burdens and resource use in agriculture1age 8 of 6



+ther anal!ses showed that:9. >reeding a new variety of wheat that increases yield by )= could reduce energy

use by <=.. The choice of indoor or outdoor sow housing has a negligible effect on pig meat

burdens.

*. 2ree range %non'organic& poultry increases energy use for meat by )= and for eggs by 95= compared with all housed production.

8. If beef production were to based 9))= on beef cows %i.e. no calves from the dairyherd& energy use would increase by 5)=.

5. Tomato burdens can be reduced by ;)= if the proportion of #B1 used isincreased nationally to 9))= from the current 5=.

The analyses were assembled in Microsoft Excel spreadsheets. These allow usersto change key variables such as: the balance of organic and non'organic productionat a national scale? / supply to crops? balance of housing types in animal production?use of #ombined Beat and 1ower systems %#B1& in greenhouses. $lternative

systems can thus be examined in detail. !efault values representing the currentbalance of production methods in England and Wales for all commodities areincluded e.g . national proportions of main production systems and sub'systems?fertiliser application rates.

3odel access and future developmentsThe "#$ model will be made available on the #ranfield ,niversity website at:http:CCwww.silsoe.cranfield.ac.uk %then search for IS0205 and LC&. ,sers will besupplied with updates and invited to participate in a workshop. !evelopment of themodelling continues under pro(ect I4). The main activities include: developmentof versions suitable for analysis at both farm and regional levels? inclusion of newcommodities such as sugar beet? and analysing the national basket of foodcommodities. The latter implies accounting for interactions between commodityproduction systems %for example crop rotations& and considering land availability.The current model is a life cycle inventory of commodity production and this will beprogressed to produce a life cycle assessment for example viewing the relativeimportance of the burdens of producing commodities.

7onclusions9. /itrous oxide %/-& is the single largest contributor to global warming potential

%0W1& for all commodities except tomatoes exceeding )= in some cases.

. -rganic field crops and animal products generally consume less primary energythan non'organic counterparts owing to the use of legumes to fix / rather thanfuel to make synthetic fertilisers. 1oultry meat and eggs are exceptions resultingfrom the very high efficiency of feed conversion in the non'organic sector.

*. The relative burdens of 0W1 acidification potential %$1& and eutrophicationpotential %E1& between organic and non'organic field'based commodities aremore complex than energy and organic production often incurs greater burdens.

8. @ore land is always required for organic production %65= to ))= extra&.5. $ll arable crops incur smaller burdens per t than meats but all commodities have

different nutritional properties and energy requirements beyond the farm so caremust be taken in comparisons.

6. +uminant meats incur more burdens than pig or poultry meats but ruminants canderive nutrition from land that is unsuitable for the arable crops that pigs andpoultry must eat.




;. Beating and lighting dominate the burdens of tomato production? but maximisingthe national use of #B1 could reduce the primary energy consumption by about;)=.

. /on'organic loose classic tomatoes incur the least burdens and they increaseprogressively and definably towards organic on'the'vine specialist types.

<. The model has been used to inform other research pro(ects and is well placed to

analyse variations in existing production systems as well as being readilydeveloped for new systems or commodities.

9).The model can be accessed via the #ranfield ,niversity web site atwww.cranfield.ac.uk %then search for IS0205 and LC&.


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