Sustainable Agriculture

Sustainability in Agriculture has become increasingly important over recent times. It is no longer sufficient to just be productive and the cost of production is no longer just thought of in terms of money.  The environmental resources of a farm as well as the financial must not deteriorate if a farm is to continue to exist into the future.

Lesson Structure

There are 8 lessons in this course:

1. Introduction
   • Scope
   • Nature of Sustainability
2. Soils
3. Water
4. Land care
   • Weed control
   • Tree Management
   • Pest and Disease
   • Fire, etc.
5. Financial Sustainability
6. Broad Management Strategies
7. Enterprise Selection & Management: Plants
8. Enterprise Selection & Management: Animals

Each lesson culminates in an assignment which is submitted to the school, marked by the school's tutors and returned to you with any relevant suggestions, comments, and if necessary, extra reading.

Aims

• Explain the broad possibilities for improving sustainability on farms.
• Explain how to avoid serious degradation of soils on a farm through sustainable management.
• Explain the broad possibilities for improving sustainability on farms.
• Explain how to avoid too serious degradation of soils on a farm through water management.
• Discuss Economic Rules that apply to a farm Enterprise.
• Crop management techniques for sustainability.
• Minimising degradation through planning and management.
• Evaluate the financial viability and potential of animal enterprises.

What You Will Do

• Investigate what is being done for improving agricultural sustainability in your country or region.
• Contact different organisations or farmers and find out what you can about attitudes & resources available to assist with improving sustainability in your chosen area/Country/region.
• Investigate whether an organic certification scheme operates in your country, and if so, find out what is involved currently in attaining that certification for a farm.
• Obtain either literature or advice relating to the management to soil degradation in your locality.
• Identify the most important issues that farmers need to address in a region within approximately 100 km( or 50 miles )of your home; in order to remain financially viable over the next two decades
• Distinguish between hydroponics, permaculture, biodynamics and certified organic farming.
• Identify a farm situation where it might be appropriate to convert to either permaculture, biodynamics or certified organic system.
• What is being done to improve sustainability of agriculture in the region, country or state of your choice.
• Obtain information from your local government department or irrigation supply company.
• Find out what the local water quality is like and how it was measured.
• Explain how you can test your local water supply for contaminants. What contaminants were found? eg. Bacteria, heavy metals, silt etc.
• Outline how can these contaminants be removed from the local water supply eg filtration, chemicals, etc.
• Identify cost effective means by which contamination can be prevented.
• Identify types of water catchment in your local area. eg dams ,stream ,creeks ,etc.
• Find out what types of conservation are being practiced in your local area.
• Outline methods of pest control being practiced in your area
• Describe methods of weed control used in your area.
• Identify and describe any natural control methods being used in your area.
• Research tourism activities are available in your local area.
• Investigate planning and advisory services in your local area.
• Investigate existing animal enterprises in your local area and the economic impact.

The wind velocity reduction effect of a windbreak is felt up to 30 times the height of the windbreak away at the ground level, but is most effective between 2 and 20 times the height of the windbreak, on the down wind side of the windbreak. For example the most protected area behind a 2m (2.1 yd) tall windbreak would be from 4m to 40m (4 to 44 yd)down wind from the windbreak

If you have a living windbreak (e.g. plans) then other plants in the immediate vicinity of the windbreak (on both sides) may have their growth reduced due to competition for light, water and nutrients from the windbreak plants, however for plants at the equivalent of at least 2 times the height of the windbreak in distance downwind from the windbreak then growh rates are increased. A windbreak consisting of dense foliaged plants, or a solid timber or brick wall will deflect wind directly backwards, as well as up and over, creating strong turbulence both in front and behind the windbreak. In comparison, a more permeable windbreak, such as more open foliaged plants, or slatted fences, or windbreaks made from shade cloth, allows the smooth flow of air through, and up over and past the windbreak with little turbulence.

Be careful not to position your plants too close together, or they will self prune (drop branches), and become too open to be effective. This is particularly important for some conifers, which will self prune their lower branches if planted to closely together, creating a gap below the plants, which can allow the wind to be channelled through, actually increasing the problem of strong winds. This is a common occurrence in many farm windbreaks.

• Don’t cut plants back too heavily. It is better to do frequent light trimmings, otherwise they will become too open foliaged to be effective
• Larger windbreaks comprised of plants also have advantages and disadvantages with regards to fire risk.
• If plants are highly flammable (often have high levels of volatile oils) they pose a real risk to buildings and structures downwind
• If they are comprised of fire resistant plants (generally having a high moisture content), and positioned to deflect winds they can provide significant protection downwind, including protection from radiated heat.
• At the end of a windbreak, or where gaps occur (eg. driveways) wind velocity may be actually increased (can create a wind tunnelling effect).
• Increasing the width of a windbreak may actually decrease it’s effectiveness by reducing it’s permeability.

For a windbreak to be most effective it should be:

• As long as possible, with no gaps or breaks. The area protected  by a windbreak varies with the square of the unbroken length of the windbreak. So for example a windbreak of 20m metres (22 yd) will protect an area approximately four times as large as a 10m (11yd) windbreak, while a 40m (44 yd) windbreak will protect an area about 16 times of that protected by a 10m (11 yd) one.
• As high as possible (to protect a bigger area).
• Have no gaps at the bottom (otherwise wind will funnel under the windbreak, actually increasing in velocity, and increasing the likelihood of wind damage).
• To be permeable to air flow (allow the passage of some air through - but reducing it’s velocity).

Have a cross section (the profile of the windbreak looking at it from the end of the windbreak) that results in the smooth passage of some wind up and over the windbreak (known as an aerofoil cross section). To achieve this you would have low growing plants at the front of the windbreak, slightly bigger growing plants behind them, and taller plants behind them.