1. 1.5 - Describe the environmental impact of primary production management
11 Ag/Hort

2. Unit Overview

3. Over-Cultivation Describe the circumstances of over-cultivation?
break up of soil to a particle size less than crumb size
What is its impact on the environment?
Destroys soil structure
Fine soil is easily eroded by wind
Soil compaction causes poor aeration/drainage

4. Solving The Over Cultivation Problems
Minimum tillage – use herbicides to kill weeds, minimal cultivation to control weeds and reduce soil structure damage, direct sowing of seeds into uncultivated seed bed
Add lots of organic matter to decrease loss of soil structure
Quickly re-establish plant cover to reduce soil erosion. Plant roots hold soil together
Cover bare ground with a mulch to reduce soil erosion

5. Disposal of Animal Manures
Describe the circumstances of the disposal of animal manures.
Animal manure from dairy farm milking sheds or piggeries can be: sprayed onto paddocks, placed into settling ponds (best)
What is its impact on the environment?
The effluent is rich in Nitrogen
Spraying effluent onto paddocks can contaminate soil water
The effluent can leach through the topsoil and enter the groundwater used for drinking water OR
drain into waterways which will then be rich in nutrients

6. Solving the Effluent Disposal Problems
Put effluent into settling ponds. Once settled then apply the liquid to paddocks
Monitor the water status of the soil to avoid runoff

7. Indiscriminate Use of Chemicals
Describe the circumstances of the use of chemicals.
Chemicals can be used to kill insects, plants, diseases
What is its negative impact on the environment?
Chemicals can harm other organisms eg plants, humans, animals, natural enemies of the pest
Chemical residues can be left in the soil
Chemicals in the soil can wash into waterways and harm fish
Pests can become resistant to the chemicals, and no longer be killed
Spray drift harms non-targeted organisms

8. Solving the Indiscriminate Use of Chemicals problems
Use of Integrated Pest Management (IPM) to reduce the use of chemicals
Use environmentally friendly organic sprays instead of more toxic conventional sprays
Use biological control to manage pests ‘naturally’

9. Indiscriminate Fertiliser Application
Describe the circumstances of fertiliser application.
Fertiliser is added to soil to improve plant health or growth
Indiscriminate means fertiliser is applied without care
What is its impact on the environment?
Heavy applications of fertiliser increase the chances of fertiliser runoff
Fertilisers feed nuisance plants (weeds) and algae in waterways
Algae and nuisance plants affect stream life and drains, making water unpleasant for swimming and drinking

10. Solving the Indiscriminate Fertiliser Application Problems
Correct application timing depending on the weather and time of year to minimise leaching
Reduced rates of fertiliser applied to the land which requires good monitoring of soil nutrient status
Changing the type of fertiliser from a fine material to pelletised fertiliser that will not be too easily leached away
Apply away from waterways so they do not become nutrient rich

11. Burning Waste Describe the circumstances of burning waste.
Burning is a method of disposing of plant stubble, hedge trimmings, fallen trees, tree stumps, rubbish
What is its impact on the environment?
Burning creates smoke, ash, carbon dioxide which pollutes the air
Other dangerous chemicals can be released when rubbish is burnt, which can harm people and animals
Loss of control of the fire leads to damage of non-targeted plants, habitats, animals

12. Solving the Burning of Waste Problems
Compost plant material and use as a fertiliser or soil conditioner
Chip plant material and use as a mulch

13. High Density Sheep Grazing
Describe the circumstances of high density sheep grazing.
Pasture is grazed at a high density during rotational grazing
Sheep graze close to the soil surface leaving only a little plant cover
What is its impact on the environment?
Increases the risk of erosion by killing pasture plants and so increasing the exposure of soil
Increased erosion causes water to be murky and affects plant life
Poor water clarity makes water unsafe for swimming

14. Solving the High Density Sheep Grazing Problems
Reduce stock numbers so there are fewer animals grazing the same area
Move stock faster so less intensive grazing occurs
Change the type of pasture to one that can tolerate harsher conditions
Increase plant health by fertilising the soil. This will allow more animals to graze the same area because the feed supply will be increased

15. Use of Compost Describe the circumstances of the use of compost.
Decomposition of organic waste material
What is its positive impact on the environment?
When added to soil, micro-organisms breakdown organic matter, improving the soil structure (ie aeration, drainage, water holding ability)
Nutrients are added to soil so nutrients from another environment are not imported
Organic matter is broken down by micro-organisms releasing nutrients for plant uptake, requiring less mining of fertilisers
Nutrients are re-cycled

16. Treatment and Recycling of Effluent
Describe the circumstances of the treatment and recycling of effluent.
How, what, when, where, why
What is its impact on the environment?

17. Biological Control Of Insects
Describe the circumstances of the biological control of insects.
The natural enemy of a pest is used to kill the pest
What is its positive impact on the environment?
It does not kill other organisms
A lot of chemicals are not needed to control the pest

18. Crop Rotation Describe the circumstances of crop rotation.
What is its positive impact on the environment?
Write an answer involving Fertiliser
Write an answer involving Pesticides

19. Use of Resistant/Tolerant plants
Describe the circumstances of resistant or tolerant plants.
What is its positive impact on the environment?

20. Pest Monitoring Describe the circumstances of pest monitoring.
This involves observing and recording pest numbers
What is its positive impact on the environment?
Spraying occurs when the pest population reaches a particular level, reducing excessive quantities of chemicals entering the environment

21. Use of Riparian Strips Describe the circumstances of riparian strips.
These are strips of land either side of a waterway that are fenced off. The strips are planted with shrubs and trees
What are there positive impact on the environment?
Stock don’t enter the waterway and excrete /urinate in it so water quality is improved
The plant roots bind the soil, reducing erosion
Fertiliser is not applied to this area so less fertiliser runs off into the waterway

22. The End of the Year