Energy inputs in production agriculture: Life cycle analysis Fuel –(for tractors, powered implements, running irrigation etc.) Fertiliser Agrochemicals.

Energy inputs in production Energy inputs in production agriculture: Life cycle analysisagriculture: Life cycle analysis

• Fuel – (for tractors, powered implements, running irrigation etc.)

• Fertiliser• Agrochemicals

– (sprays mostly)

• Farm buildings – (energy and carbon invested in constructing them)

• Farm vehicles and machinery – (energy and carbon invested in manufacturing them)

• Irrigation– (energy and carbon invested in infrastructure)

Sample crop:Sample crop:ApplesApples

• Some crops are annual.– Conduct an annual life cycle analysis

• Some crops are perennial.– Take a longer term analysis

Fuel use: Orchard case Fuel use: Orchard case studystudy

• Orchard tractor uses 10l diesel fuel per hour.• In one season it operates for 45 hours for each ha it

works on.• This is equivalent to 450 litres per ha per year.• At primary content of 42 MJ/litre of diesel this is

18900 MJ per ha per year.• This is equivalent to about 1050 kg CO2 per ha per

year emissions.

Fertiliser use: Orchard Fertiliser use: Orchard Case StudyCase Study

• Fertilisers, especially nitrogen, are very energy intensive to produce.

• An annual application of 50kg per ha N, 10kg per ha P, and 40kg per ha K would represent: – 3800MJ/ha

– 200 kg CO2 per ha

Agrochemical use: Orchard Agrochemical use: Orchard case studycase study

• Fungicides– 25kg a.i./ha/yr.

– Embodied energy 210MJ/kg a.i.

• Insecticides– 1kg a.i./ha/yr.

– Embodied energy 310MJ/kg a.i.

• Herbicides– 5kg a.i./ha/yr.

– Embodied energy 310MJ/kg a.i.

• Total energy =– (25x210)+(1x310)+(5x310) = 3963MJ/ha

• Total kg CO2 = – 3963x0.06 = 238kg/ha

Farm buildings: Orchard Farm buildings: Orchard Case StudyCase Study

• For basic orchard production:– 5m2 building per ha of orchard

• Machinery shed• Storage of empty fruit bins

• Assumed to be a galvanised steel barn– 590MJ/m2 in construction

– Assumed to need replacement after 20 years

• Embodied energy:– 590x5/20 = 147.5 MJ/ha

• CO2 emitted:– 147.5 x 0.1 = 14.75kg/ha

Machinery & equipment: Machinery & equipment: Orchard Case StudyOrchard Case Study

• Tractor– 1 tractor per 10 ha; typical weight 3500kg, depreciated over 15 years

– = 23kg mass/ha/yr.

• Energy embodied in tractor:– 23 x 66 = 1518MJ/ha/yr.

• CO2 @ .095kg per MJ – = 144.21kg/ha/yr

Energy used in manufacture and maintenance of farm machinery

Type Energy in materials MJ/kg

Energy consumption for manufacture MJ/kg

% energy consumption for repairs

Total MJ/kg

Powered 36 14 32% 66

Trailed 32 8 28% 51.2

Machinery & equipment: Machinery & equipment: Orchard Case StudyOrchard Case Study

• Other machinery– Sprayer, mower, mulcher, fertiliser spreader, forklift etc.

– Total weight 5300kg (for 10 ha, over 15 years)

• Energy embodied in machinery:– 35.3 x 51.2 = 1809MJ/ha/yr.

• CO2 @ .1 kg per MJ – = 180.9kg/ha/yr

Energy used in manufacture and maintenance of farm machinery

Type Energy in materials MJ/kg

Energy consumption for manufacture MJ/kg

% energy consumption for repairs

Total MJ/kg

Powered 36 14 32% 66

Trailed 32 8 28% 51.2

Total energy and CO2: Orchard Total energy and CO2: Orchard Case StudyCase Study

Total energy and carbon dioxide for organic and conventional apple production in Ireland

Item MJ/ha Organic MJ/ha Conventional

Kg CO2/ha Organic

Kg CO2/ha Conventional

Fuel 18900 18900 1050 1050

Fertiliser 380 3800 20 200

Chemicals 1800 3963 95 238

Buildings 147.5 147.5 14.75 14.75

Tractor 1518 1518 144.21 144.21

Farm equipment 1809 1809 180.9 180.9

Total 24555 30138 1506 1818

Yields (kg/ha) 20000 50000 20000 50000

Energy/CO2 per kg fruit

1.2MJ/kg 0.6MJ/kg 75g CO2/kg 36gCO2/kg

Completing the life cycle: Completing the life cycle: Orchard Case Study (conv.)Orchard Case Study (conv.)

• Energy embodied in fruit eaten– 2.5MJ per kg

• Carbon– Sequesterisation into orchard soil: 2000kg carbon/ha/yr.

– In woody plant tissue: 500kg carbon/ha/yr.

– Also in fruit, approx 400-1000kg carbon/ha/yr.

• CO2 equivalent– 2500 /12*44 = ~ 9200 kg/ha/yr.

• Five times more CO2 taken from air than released in a single growing cycle.

Life cycle beyond the orchard:Life cycle beyond the orchard:

• Cold storage:– Average storage period = 6 months.

– 1-2MJ/kg (operating)

• Transport:– By ship from New Zealand

• 2MJ/kg

– By road from Italy to Ireland• 2MJ/kg

• Packaging:– O.5kg cardboard per kg fruit

– @8MJ/kg cardboard = 4MJ

Life cycle beyond the orchard:Life cycle beyond the orchard:

• Transport from shop to home:– A car using 10l/100km uses about 1kW power per km travelled

• A 3 mile trip to the shop and back (6 miles or 10km total):– 10kW

• Assume you collect 10kg of groceries, 1kg of which is a bag of apples– Then 1 kg of apples required 1kW to collect.

– Equivalent to 3.6MJ per kg collected

• Question:– What about if you drive 6 miles to town for a take-away Pizza?

• Goodfellas 400g ~ 4MJ• Remember 1 watt hour = 3600 joules