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Harvest & post-harvest Harvest & post-harvest Physiology and Physiology and Preservation Preservation

Harvest & post-harvest Physiology and Preservation

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Page 1: Harvest & post-harvest Physiology and Preservation

Harvest & post-harvest Harvest & post-harvest Physiology and Physiology and

PreservationPreservation

Page 2: Harvest & post-harvest Physiology and Preservation

Forage Harvest LossesForage Harvest Losses

Fresh ForageFresh Forage

Living, Breathing, Making & Living, Breathing, Making & Using EnergyUsing Energy

Taking up and Losing WaterTaking up and Losing Water

70 ~ 90% Water (10 ~ 30 % DM)70 ~ 90% Water (10 ~ 30 % DM)

Bacteria and Fungus Bacteria and Fungus ContaminationContamination

Page 3: Harvest & post-harvest Physiology and Preservation

Forage Harvest Losses – start in Forage Harvest Losses – start in the fieldthe field

What happens after cuttingWhat happens after cutting Plants continue to ‘live’Plants continue to ‘live’

Using stored energyUsing stored energy Losing water through pores and Losing water through pores and epidermisepidermis

Miner amounts of proteins are Miner amounts of proteins are converted to Non-protein N converted to Non-protein N (0.5% / hour)(0.5% / hour)

< bacteria and fungi are still around >< bacteria and fungi are still around >

Page 4: Harvest & post-harvest Physiology and Preservation

Forage Harvest Losses – start in Forage Harvest Losses – start in the fieldthe field

At about 50 ~ 60 % moistureAt about 50 ~ 60 % moisture

Pores close at about 70 %, water Pores close at about 70 %, water loss rate slows downloss rate slows down

Some part still ‘alive’ using sugarsSome part still ‘alive’ using sugars (until about 30~40% moisture)(until about 30~40% moisture) About 1~4% of DM is lost as non-About 1~4% of DM is lost as non-

structural carbohydrate, up to 16% structural carbohydrate, up to 16% during extended warm, humid during extended warm, humid conditioncondition

< bacteria and fungi still around, using < bacteria and fungi still around, using energy, generating heat >energy, generating heat >

Page 5: Harvest & post-harvest Physiology and Preservation

Forage Harvest Losses – start in Forage Harvest Losses – start in the fieldthe field

Below 40% moisture(26~40%)Below 40% moisture(26~40%)

Plant is dead (no longer Plant is dead (no longer respiring)respiring)

Soluble sugars can leach from Soluble sugars can leach from all damaged and dead cellsall damaged and dead cells

Bacteria, fungi, yeasts etc using Bacteria, fungi, yeasts etc using sugars, generating heatsugars, generating heat

Page 6: Harvest & post-harvest Physiology and Preservation

Forage Harvest Losses – start in Forage Harvest Losses – start in the fieldthe field

Below 25% moistureBelow 25% moisture Most bacteria are ‘inactive’Most bacteria are ‘inactive’ Fungi & yeasts are still active, Fungi & yeasts are still active,

using sugars, generating heatusing sugars, generating heat

Below 10% moistureBelow 10% moisture Bacteria, fungi, yeasts are Bacteria, fungi, yeasts are

inactiveinactive Hay is stable until moisture Hay is stable until moisture

content increasescontent increases

Page 7: Harvest & post-harvest Physiology and Preservation

Post-Harvest PhysiologyPost-Harvest Physiology

Drying processDrying process

Factors which influence drying Factors which influence drying and the quality of forage and the quality of forage during dryingduring drying

MetabolicMetabolic MechanicalMechanical WeatheringWeathering

Page 8: Harvest & post-harvest Physiology and Preservation

Post-Harvest PhysiologyPost-Harvest Physiology

Drying rateDrying rate Methods for increasing drying rateMethods for increasing drying rate

Adequate periods without rainfallAdequate periods without rainfall

(probability of rain-free period)(probability of rain-free period)

Mechanical Conditioning : crush, bendMechanical Conditioning : crush, bend Chemical conditioning : potassium carbonatChemical conditioning : potassium carbonat

e, Organic Acidse, Organic Acids Raking, TeddingRaking, Tedding

Page 9: Harvest & post-harvest Physiology and Preservation

Preservation and StoragePreservation and Storage

Hay and Silage storage Hay and Silage storage systemsystem

Important processes in curing Important processes in curing or fermentationor fermentation

Preservative and additivesPreservative and additives