2. Energy inputs in production agriculture: 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)

3. Some crops are perennial.
Sample crop:
Apples
Some crops are annual.
Conduct an annual life cycle analysis
Some crops are perennial.
Take a longer term analysis

4. Fuel use: Orchard case study
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 MJ per ha per year.
This is equivalent to about 1050 kg CO2 per ha per year emissions.
Primary content is different from consumer content of energy, as it costs energy to transport fuel from oil field to the use point. Consumer content for diesel is about 35MJ/litre.

5. Fertiliser use: Orchard Case 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

6. Agrochemical use: Orchard case 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.
Total energy =
(25x210)+(1x310)+(5x310) = 3963MJ/ha
Total kg CO2 =
3963x0.06 = 238kg/ha
CO2 compared to energy input: conversion factor of 0.06kg CO2 emission per MJ energy in chemical production

7. Farm buildings: Orchard Case 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 = MJ/ha
CO2 emitted:
147.5 x 0.1 = 14.75kg/ha
CO2 use per MJ energy in steel manufacture is higher than in agrochemicals

8. Machinery & equipment: Orchard 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.
.095kg per MJ
= kg/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

9. Machinery & equipment: Orchard 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.
.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

10. Total energy and CO2: Orchard Case 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
1050
Fertiliser
380
3800 20
200
Chemicals
1800
3963 95
238
Buildings
147.5
14.75
Tractor
1518
144.21
Farm equipment
1809
180.9
Total
24555
30138
1506
1818
Yields (kg/ha)
20000
50000
Energy/CO2 per kg fruit
1.2MJ/kg
0.6MJ/kg
75g CO2/kg
36gCO2/kg

11. Completing the life cycle: 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 kg 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.
1800kg CO2 per ha inputs
9200kg CO2 sequesterisation

12. 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
Packaging:
O.5kg cardboard per kg fruit
@8MJ/kg cardboard = 4MJ

13. 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:
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
1 watt hour = 3600 joules
20kW x 3600 = 72MJ
You have spent 18 times more energy just collecting the pizza than you will get by eating it.
Assuming that 40MJ already went into producing your 4MJ Pizza, who is worse; the food industry or you?