2 Energy inputs in production agriculture: Life cycle analysis Fuel(for tractors, powered implements, running irrigation etc.)FertiliserAgrochemicals(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:ApplesSome crops are annual.Conduct an annual life cycle analysisSome 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/ha200 kg CO2 per ha
6 Agrochemical use: Orchard case study Fungicides25kg a.i./ha/yr.Embodied energy 210MJ/kg a.i.Insecticides1kg a.i./ha/yr.Embodied energy 310MJ/kg a.i.Herbicides5kg a.i./ha/yr.Total energy =(25x210)+(1x310)+(5x310) = 3963MJ/haTotal kg CO2 =3963x0.06 = 238kg/haCO2 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 orchardMachinery shedStorage of empty fruit binsAssumed to be a galvanised steel barn590MJ/m2 in constructionAssumed to need replacement after 20 yearsEmbodied energy:590x5/20 = MJ/haCO2 emitted:147.5 x 0.1 = 14.75kg/haCO2 use per MJ energy in steel manufacture is higher than in agrochemicals
8 Machinery & equipment: Orchard Case Study Tractor1 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/yrEnergy used in manufacture and maintenance of farm machineryTypeEnergy in materials MJ/kgEnergy consumption for manufacture MJ/kg% energy consumption for repairsTotal MJ/kgPowered361432%66Trailed32828%51.2
9 Machinery & equipment: Orchard Case Study Other machinerySprayer, 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/yrEnergy used in manufacture and maintenance of farm machineryTypeEnergy in materials MJ/kgEnergy consumption for manufacture MJ/kg% energy consumption for repairsTotal MJ/kgPowered361432%66Trailed32828%51.2
10 Total energy and CO2: Orchard Case Study Total energy and carbon dioxide for organic and conventional apple production in IrelandItemMJ/ha OrganicMJ/ha ConventionalKg CO2/ha OrganicKg CO2/ha ConventionalFuel189001050Fertiliser380380020200Chemicals1800396395238Buildings147.514.75Tractor1518144.21Farm equipment1809180.9Total245553013815061818Yields (kg/ha)2000050000Energy/CO2 per kg fruit1.2MJ/kg0.6MJ/kg75g CO2/kg36gCO2/kg
11 Completing the life cycle: Orchard Case Study (conv.) Energy embodied in fruit eaten2.5MJ per kgCarbonSequesterisation into orchard soil: 2000kg carbon/ha/yr.In woody plant tissue: 500kg carbon/ha/yr.Also in fruit, approx kg carbon/ha/yr.CO2 equivalent2500 /12*44 = ~ 9200 kg/ha/yr.Five times more CO2 taken from air than released in a single growing cycle.1800kg CO2 per ha inputs9200kg CO2 sequesterisation
12 Life cycle beyond the orchard: Cold storage:Average storage period = 6 months.1-2MJ/kg (operating)Transport:By ship from New Zealand2MJ/kgBy road from Italy to IrelandPackaging:O.5kg cardboard per kg fruit@8MJ/kg cardboard = 4MJI have not mentioned Air Transport of foods.E.g. strawberries flown from USA to Ireland. 500MJ of food energy takes ~15,000MJ of air fuel alone.@30MJ/kg transported.
13 Life cycle beyond the orchard: Transport from shop to home:A car using 10l/100km uses about 1kW power per km travelledA 3 mile trip to the shop and back (6 miles or 10km total):10kWAssume you collect 10kg of groceries, 1kg of which is a bag of applesThen 1 kg of apples required 1kW to collect.Equivalent to 3.6MJ per kg collectedQuestion:What about if you drive 6 miles to town for a take-away Pizza?Goodfellas 400g ~ 4MJRemember 1 watt hour = 3600 joules1 watt hour = 3600 joules20kW x 3600 = 72MJYou 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?
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