Agronomy V - Oil Crops

Learn to Grow Oil Crops

Arable Farming

Lesson Structure

There are 9 lessons in this course:

1. Nature & scope of oil crops
   • What are plant oils?
   • Essential oils
   • Plant oil crops & uses
   • Vegetable oil uses
   • Essential oil uses
   • Economic value of oil crops
   • What crops can be grown where?
2. Oil extraction
   • Introduction
   • Oil seed processing
   • Mechanical processing
   • Chemical processing
   • Other processing methods
   • Distillation
   • Simple distillation
   • Steam distillation
   • Fractional distillation
   • Vacuum distillation
   • Molecular distillation
   • Extractive distillation
   • Membrane distillation
3. Canola and rapeseed
   • Characteristics of canola
   • World production
   • Growing canola
   • Using seed
   • Soil types
   • Soil preparation
   • Sowing
   • Growth stages
   • Environmental stresses
   • Nutrition
   • Irrigation management
   • Weeds
   • Pest control
   • Diseases
   • Harvesting
   • Storage
   • Processing
4. Olive oil
   • Characteristics of olive oil
   • World production
   • Growing olives
   • Using seedlings
   • Soil types
   • Soil preparation
   • Planting
   • Pruning
   • Growing conditions
   • Varieties
   • Nutrition
   • Irrigation management
   • Weeds
   • Pest control
   • Diseases
   • Organic production
   • Harvesting
   • Storage
   • Processing
5. Other edible oils
   • Growing conditions
   • Organic matter
   • Soil texture
   • Subsoil PH
   • Soil water available to plants
   • Slope of the topography
   • Natural soil drainage
   • Maintaining good soil structure
   • Growing edible oil crops
   • Sunflowers (helianthus annuus)
   • Flax/linseed (linum usitatissimum)
   • Soybean/soya bean (glycine max)
   • Peanuts (arachis hypogaea)
6. Herbal and pharmaceutical oils
   • Introduction
   • Pros and cons of herbal medicine & nutraceuticals
   • Essential oils
   • General guidelines for growing herbs for essential oils
   • Planting
   • Agronomy
   • Improved herbs and essential oils
   • Growing select crops for cosmetic or pharmaceutical oils
   • Avocado (persea americana)
   • Mint (mentha arvensis)
   • Tea tree (melaleuca alternifolia)
   • Blackcurrant (ribes nigrum)
   • Passionfruit (passiflora edulis)
7. Biofuel and other industrial oils
   • Biofuel production
   • Vegetable oils and genetic modification
   • Extraction of oils from plants
   • GMO crops
   • Oleic acid
   • Oil palm trees
   • Novel fatty acids
   • Chemical and biotechnological transformations of basic industrial oils
   • Key targets for future industrial oil crops
   • Unusual fatty acids
   • Industrial importance
   • Growing select crops for biofuels and other industrial uses
   • Poppy (papaver somniferum)
   • Castor bean (ricinus communis)
   • Camelina (camelina sativa)
   • Crambe (crambe abyssinica)
8. Issues, Risks, Optimising success
   • Successful farming
   • Capital
   • Profitability
   • Risk management
   • Succession
   • Entrepreneurial skills of farmers
   • Production management
   • Developing a farming business plan
   • Goals and mission
   • Asset planning
   • Land
   • Irrigation water
   • Livestock
   • Farm management
   • Labour and machinery
   • Capital
   • Soil testing
   • Produce selection
   • Integrated pest management
   • Integrated weed management
   • Grain storage
9. Product development and management
   • Oilseed production and extraction yields
   • Oil fatty acid composition and biodiesel
   • Oil extraction and biodiesel processing
   • On-farm oil seed processing

Why Study Plant Oils?

There are many different uses for plant oils, most oil crops may be grown because they provide oils in one of the following groups:  
1. Edible oils – human food, and livestock or pet animal feed
2. Biofuels – biodiesel, vegetable oil fuel, alternative fuels
3. Industrial oils – pharmaceuticals, cosmetics, toiletries, paints, lubricants

Plant oils are any oils which can be extracted from plants, and oils are essentially fats. The name ‘plant oil’ is interchangeable with ‘vegetable oil’ and vegetable oil is the term most widely used. They are mainly extracted from seeds (hence they are often referred to as oilseed crops) but can come from fleshy parts of fruits. Although most plants contain oils, some contain a better quantity or quality of oil than others and are therefore considered the main oil crops. A small amount come from other plant parts like leaves, stems, or roots - such as burdock oil which comes from roots of the burdock plant. 

The name vegetable oil can also refer to the liquid oils such as those used in cooking. These oils are liquid at room temperature but can become solid if cooled. Most, but not all, vegetable oils are edible. On the other hand, mineral oils which are the other main group of oils, are inedible. These are mostly derived from petroleum. Whilst plant oils can replace mineral oils for some industrial uses, each oil group has specific advantages and disadvantages which makes them more, or less, preferable.  

Plant oils share the same characteristics as animal oils or fats. That is, they are comprised of triglycerides. Triglycerides are esters of glycerol and three fatty acids. They are often classified on the basis of being saturated or unsaturated. Saturated fats contain mostly saturated fatty acids and unsaturated fats contain mostly unsaturated acids. Saturated fats are so-called because they are ‘saturated’ with more hydrogen atoms. Unsaturated fats can be further divided into polyunsaturated and monounsaturated fats. 

Most vegetable oils contain a combination of saturated and unsaturated acids. Those which are higher in saturated fats tend to be solid at room temperature whereas unsaturated ones tend to be liquid. However, these unsaturated fats can be made into semi-solids or solids though the process of hydrogenation where they are combined with hydrogen effectively making them more saturated. Margarine is an example of a hydrogenated vegetable oil. One of the drawbacks of unsaturated fats is that they tend to become rancid more quickly. This is a reason why they are not preferred over mineral oils for machinery lubrication, for example. Also, in terms of nutrition, unsaturated fats have less energy, or calorific value, compared to saturated fats. So, if you wanted to lose weight you might prefer to fry your food in olive oil, but if you wanted to put weight on you could select margarine (or butter for an animal fat).   

Another type of oil which comes from plants are those known as ‘essential oil’. Unlike vegetable oils, essential oils are not oils in the true chemical sense. They are not triglycerides but are volatile aromatic liquids that often contain hundreds of different aroma compounds. However, like vegetable oils, essential oils do not dissolve in water. They are termed ‘essential’ not because they are essential for a plant’s metabolic processes or for some other reason. Instead, essential refers to the fact that essential oils always contain an essence of the plant’s fragrance.