Jan Köbbing

Car­bon foot­prints for indi­vi­du­al nur­se­ries and crops

Klasmann-Deilmann has deve­lo­ped a cal­cu­la­ting tool for deter­mi­ning the car­bon foot­print of a hor­ti­cul­tu­ral com­pa­ny. This mea­su­re dis­c­lo­ses not only emis­si­ons rela­ting to ener­gy con­sump­ti­on, seed, fer­ti­li­sers and pesti­ci­des, as well as pack­a­ging and gro­wing con­tai­ners, but also the pro­por­ti­on ari­sing from sub­stra­te use. The cal­cu­la­ting tool also con­verts a nursery’s emis­si­ons into a figu­re for a given cul­ti­va­ted crop. A num­ber of important fin­dings are pre­sen­ted here.

 It was in 2013 that Klasmann-Deilmann first cal­cu­la­ted a cor­po­ra­te car­bon foot­print (CCF) that fac­tors in all emis­si­ons gene­ra­ted throughout the Group. The CO2 levels deter­mi­ned for this pur­po­se can sub­se­quent­ly be con­ver­ted into a pro­duct car­bon foot­print (PCF) for a given gro­wing medium.

The metho­do­lo­gy under­ly­ing the car­bon foot­print – this foot­print being veri­fied to the ISO 14064 stan­dard – has now been deve­lo­ped fur­ther to crea­te an app­li­ca­ti­on for hor­ti­cul­tu­ral busi­nes­ses. The new cal­cu­la­ting tool can now also be used to deter­mi­ne the CCF for a given nur­s­e­ry and the PCF of each crop cul­ti­va­ted the­re. First­ly, all rele­vant fac­tors are iden­ti­fied in detail and fed into the cal­cu­la­ti­ons. The­se inclu­de con­sump­ti­on of electri­ci­ty, natu­ral gas, petro­le­um and coal, the seed used, fer­ti­li­sers and pesti­ci­des uti­li­sed, and pack­a­ging and gro­wing con­tai­ners. The use of gro­wing media, inclu­ding their trans­port to the nur­s­e­ry, is also pre­cise­ly fac­to­red in.

The CCF sub­se­quent­ly deter­mi­ned by the cal­cu­la­ting tool enab­les a given hor­ti­cul­tu­ral busi­ness to deve­lop its own stra­te­gy for redu­cing emis­si­ons and to assess this over several years. Poten­ti­al para­me­ters here may inclu­de the business’s hea­ting stra­te­gy or the use of substrates with a hig­her pro­por­ti­on of alter­na­ti­ve con­sti­tu­ents. Spe­cia­lists at Klasmann-Deilmann pro­vi­de acti­ve ongo­ing input into the cal­cu­la­ti­on pro­cess for the car­bon foot­print concerned.

Sus­taina­bi­li­ty is play­ing an incre­a­singly important role for the major food cor­po­ra­ti­ons,” comments Moritz Böcking, Mana­ging Direc­tor of Klasmann-Deilmann. “We are keen to equip not only our­sel­ves but also our cus­to­mers for the deman­ds of the future. Tho­se able to account for how envi­ron­ment­al­ly and cli­ma­te-friend­ly their pro­ducts are have an addi­tio­nal com­pe­ti­ti­ve advan­ta­ge, sin­ce retail con­su­mers and who­le­sa­lers are paying incre­a­sing atten­ti­on to respon­si­b­ly pro­du­ced goods and reward sus­tainab­le development.”

Cal­cu­la­ting tool: tri­al­led in coope­ra­ti­on with two nurseries

The cal­cu­la­ting tool was deve­lo­ped in col­la­bo­ra­ti­on with Colo­gne-based Meo Car­bon Solu­ti­ons GmbH, and tri­al­led in clo­se coope­ra­ti­on with two nur­se­ries in Ger­ma­ny. mk jung­pflan­zen gmbH, a pro­pa­ga­tor of young vege­ta­ble plants and part of the Peter Stader group, and orna­men­tal-plant grower Irß­lin­ger GmbH & Co. KG pro­vi­ded ope­ra­tio­nal data that were then pro­ces­sed using the cal­cu­la­ting tool. At the same time, both nur­se­ries hel­ped to design the tool such that it reflec­ted the rea­li­ties of a hor­ti­cul­tu­ral company.

First­ly, cor­po­ra­te car­bon foot­prints were deter­mi­ned for both nur­se­ries. The out­co­me was then con­ver­ted to give pro­duct car­bon foot­prints for the rele­vant indi­vi­du­al crops – let­tuce, leaf let­tuce, lamb’s let­tuce, cab­ba­ge, herbs, leek, cele­ry and poin­set­ti­as – rai­sed in eit­her trays or press pots.

The fol­lowing reci­pes were among tho­se used as substrates (pro­du­ced by Klasmann-Deilmann) in pro­pa­ga­ting the young plants and for cal­cu­la­ting the car­bon footprints.

  • Reci­pe no. 002, con­sis­ting of 100% black peat, pro­du­ced in nort­hern Germany
  • Reci­pe no. 317, con­sis­ting of 90% black peat and 10% of the GreenFibre wood fib­re pro­duct, pro­du­ced in nort­hern Germany

CCF: bulk of emis­si­ons is from ener­gy consumption

All major emis­si­ons fac­tors are inclu­ded in the cor­po­ra­te car­bon foot­print for a hor­ti­cul­tu­ral com­pa­ny. The car­bon foot­print shown in Figu­re 1 was pre­pa­red for the mk jung­pflan­zen gmbH nur­s­e­ry: here, ener­gy con­sump­ti­on accoun­ted for by far the grea­test pro­por­ti­on of emissions.

Peter Stader

We have been addres­sing the issue of sus­taina­bi­li­ty and care­ful use of resour­ces for qui­te some time now. This inclu­des, of cour­se, the deba­te on peat­lands and their explo­ita­ti­on, as peat is – along with ener­gy – the big­gest sin­gle input in the pro­duc­tion of our young plants. It was Klasmann-Deilmann who drew my atten­ti­on to car­bon foot­prin­ting at the 2017 IPM tra­de fair; they gave us the oppor­tu­ni­ty to ana­ly­se our com­pa­ny. We ful­ly appre­cia­te, of cour­se, that the abso­lu­te figu­res – taken indi­vi­du­al­ly – are high­ly abs­tract and not par­ti­cu­lar­ly mea­ning­ful. Howe­ver, what this exer­cise fos­ters wit­hin our com­pa­ny is awa­reness of the issue: what can we achie­ve through the care­ful use of the resour­ces we still have? Apart from the substrates we uti­li­se, the­re are many other aspects that merit consideration.”


PCF: bulk of emis­si­ons is from ener­gy consumption

A pro­duct car­bon foot­print (PCF) fac­tors in all major emis­si­ons sources. Figu­re 2 com­pa­res emis­si­ons for 1,000 young cab­ba­ge plants grown in 4‑cm press pots (cul­ti­va­ted from March) at the mk jung­pflan­zen gmbH nur­s­e­ry with emis­si­ons for 1,000 minia­tu­re poin­set­ti­as (cul­ti­va­ted from August) at the Irß­lin­ger GmbH & Co. KG nur­s­e­ry. Becau­se the crop is grown in a hea­ted green­house, ener­gy con­sump­ti­on accounts for the grea­ter part of emis­si­ons ari­sing from poin­set­tia pro­duc­tion. For young cab­ba­ge plants grown in press pots, howe­ver, just over 50% of emis­si­ons rela­te to the sub­stra­te. For both crops, an appre­cia­ble pro­por­ti­on of emis­si­ons ari­sing from sub­stra­te con­sump­ti­on results from trans­port of substrates to the nursery.

Sea­so­nal effect: emis­si­ons much lower in summer

The PCF per 1,000 plants (e.g. cab­ba­ge, let­tuce) or 1,000 press pots (e.g. lamb’s let­tuce, herbs) depends in part on sea­so­nal fac­tors. Figu­re 3 shows that win­ter crops cau­se hig­her emis­si­on levels than tho­se grown in sum­mer, this being rela­ted to wea­ther con­di­ti­ons ( = grea­ter ener­gy con­sump­ti­on) and light levels ( = lon­ger gro­wing cycle in the cold sea­son). The­re is a rule of thumb which sta­tes that sub­stra­te-rela­ted emis­si­ons account for 45% of the total in win­ter, as ener­gy con­sump­ti­on is rela­tively high. In sum­mer, this pro­por­ti­on incre­a­ses to 75%, sin­ce less ener­gy is used.

Trays redu­ce both amount of sub­stra­te nee­ded and emissions

Figu­re 4 illus­tra­tes that, when plants are sown and pro­pa­ga­ted in press pots, resul­tant emis­si­ons are con­si­der­ab­ly hig­her than for tray-grown crops, as more sub­stra­te is requi­red. Howe­ver, this com­pa­ri­son is depen­dent on the size of the press pots and tray cells used. As sub­stra­te uti­li­sed in press pots is high­ly com­pac­ted, lar­ger amounts are con­su­med per plant, lea­ding in turn to grea­ter sub­stra­te-rela­ted emissions.

In the com­pa­ri­son used for cal­cu­la­ti­on pur­po­ses, tray cells were con­si­der­ab­ly smal­ler than press pots. This means that less sub­stra­te was nee­ded per plant and that the­re were more plants per squa­re met­re of green­house space: tray-cul­ti­va­ted cab­ba­ge plants were grown 295 to a box, com­pa­red with only 140 per box cul­ti­va­ted in press pots. This lowe­red emis­si­ons rela­ting to sub­stra­te and ener­gy. Emis­si­ons rela­ting to the plastic trays used, and the lon­ger gro­wing peri­od, had no appre­cia­ble impact on the over­all calculation.

Tho­mas Hanen­berg and Kat­rin Irßlinger

For us it was a valu­able expe­ri­ence and our first enga­ge­ment with this issue. Perhaps we are some­what ahead of the cur­ve right now; nevertheless, the envi­ron­ment and sus­taina­bi­li­ty are issu­es of gro­wing impor­t­ance for retail con­su­mers – and, the­re­fo­re, hence for our cus­to­mers, the retailers, as well. Pre­sen­ta­ti­on of our green­house gas per­for­mance show­ed it makes sen­se for us to break down this foot­print to the indi­vi­du­al pro­duct level. This enab­les us to use this key per­for­mance indi­ca­tor as a mar­ke­ting asset.”


Alter­na­ti­ves: lower cumu­la­ti­ve end-of-life emissions

In the cal­cu­la­ti­on of both the CCF and the PCF descri­bed here, the focus is on a nursery’s value chain inclu­ding the ope­ra­tio­nal inputs it buys in. This is a crad­le-to-gate sce­n­a­rio cal­cu­la­ti­on ending at the time when crops lea­ve the pre­mi­ses of the nur­s­e­ry and are, for examp­le, resold.

In terms of the PCF for a given crop, howe­ver, broa­der con­si­de­ra­ti­ons are advi­s­able, sin­ce the sub­stra­te used will ful­ly break down over time and release fur­ther quan­ti­ties of CO2. In this regard, it does not mat­ter in which con­text the sub­stra­te decom­po­ses (e.g. on farm­land or in a retail consumer’s gar­den). What is important are the emis­si­ons that must be addi­tio­nal­ly attri­bu­t­ed to a given crop if its ent­i­re life cycle is taken into account (end-of-life approach). For the crop as pro­duct, emis­si­ons accrue along the value chain that have not­hing to do with the nur­s­e­ry its­elf, inclu­ding trans­port-rela­ted emis­si­ons and tho­se rela­ting to the sub­stra­te in which it was grown and in which it may remain until it is composted.

Espe­cial­ly when this all-encom­pas­sing end-of-life approach – which con­si­ders a crop over its ent­i­re life cycle – is adop­ted, alter­na­ti­ve con­sti­tu­ents in a gro­wing medi­um have a posi­ti­ve impact as they help sub­stan­ti­al­ly redu­ce a crop’s PCF. This is becau­se rene­wa­ble sub­stra­te con­sti­tu­ents them­sel­ves gene­ra­te no emis­si­ons sin­ce, in cycli­cal fashion, they first absorb car­bon from the air befo­re sub­se­quent­ly releasing it. The­re­fo­re, emis­si­ons can be attri­bu­t­ed only to the asso­cia­ted pro­duc­tion pro­ces­ses (e.g. pro­du­cing fib­re from wood­chips). Peat, howe­ver, is con­si­de­red a fos­sil resour­ce for which emis­si­ons from its decom­po­si­ti­on are ful­ly taken into account.

In the crad­le-to-gate approach, howe­ver, alter­na­ti­ve con­sti­tu­ents have only a slight impact. This is due to the brief peri­od during which the sub­stra­te is used in the nur­s­e­ry. Accord­in­gly, only a small pro­por­ti­on of emis­si­ons ari­sing from the sub­stra­te are gene­ra­ted in the nur­s­e­ry its­elf. To a lar­ge extent, the actu­al decom­po­si­ti­on pro­cess takes place at the later sta­ges of the value chain. Figu­re 5 depicts this in a sim­pli­fied manner.

In Figu­re 6, addi­tio­nal emis­si­ons based on an end-of-life approach are added to the pro­duct car­bon foot­print of a crop that uses a crad­le-to-gate approach. Lamb’s let­tuce cul­ti­va­ted in 4‑cm press pots, rai­sed in a pure black-peat sub­stra­te, is com­pa­red with lamb’s let­tuce grown in black-peat sub­stra­te to which 10% wood fib­re is added. It is evi­dent that the end-of-life PCF of the crop is alrea­dy decre­a­sing sub­stan­ti­al­ly. Fur­ther emis­si­ons reduc­tions can, accord­in­gly, be achie­ved by using a hig­her pro­por­ti­on of wood fibre.


Sum­ma­ry conclusions

The PCFs deter­mi­ned in this pro­ject for dif­fe­rent crops under dif­fe­rent cul­ti­va­ti­on con­di­ti­ons resul­ted in the fol­lowing main findings:

  • The bulk of emis­si­ons in nur­se­ries results from the use of fos­sil fuels and substrates;
  • Win­ter crops cau­se hig­her emis­si­on levels due to (wea­ther-rela­ted) grea­ter ener­gy consumption;
  • When plants are sown and pro­pa­ga­ted in press pots, this tends to lead to hig­her sub­stra­te-rela­ted emis­si­ons than for tray-grown crops;
  • Cul­ti­va­ti­on of young vege­ta­ble plants under cold-house con­di­ti­ons gives rise to rela­tively high emis­si­ons rela­ting to the sub­stra­te used;
  • The use of a blo­cking sub­stra­te with a share of 10% of the GreenFibre wood fib­re pro­duct can redu­ce PCF (per 1,000 plants) under the end-of-life approach.

The goal is incre­a­sing awa­reness of cli­ma­te issu­es in com­mer­cial hor­ti­cul­tu­re. “We are very keen to see nur­se­ries hol­ding more in-depth dis­cus­sions with our experts,” says Moritz Böcking, “with a view, if pos­si­ble, to swit­ching to substrates that have a lower car­bon footprint.”



Dr Jan Köb­bing, Land Use + Sus­taina­bi­li­ty Manage­ment; Klasmann-Deilmann GmbH

Josef Reh­me, Advi­so­ry Ser­vices + Qua­li­ty Manage­ment, Klasmann-Deilmann Ser­vice GmbH

Dirk Röse, Cor­po­ra­te Com­mu­ni­ca­ti­ons, Klasmann-Deilmann GmbH