UNIT 4

ENVIRONMENTAL ISSUES

Environmental issues in food production

Food Production

Environmental issues

Primary Production

Land degradation

(erosion)

Use of chemical products-

Pesticides and Herbicides

Irrigation

Salinity Volume of water used

Secondary production

By-products Wastage Packaging

Primary Production:the sustainable way… Sustainability in Agriculture means using farming

practices that maintain the lands productivity so it is available for future generations.

There are four main ways the land’s productivity can be sustained

Managing the use of water

Managing the use of

chemicalsPreventing

Land Degradation

Implementing Organic Farming

• Irrigation• Salinity

• Herbicides• Pesticides

• Erosion• Improving Soil

health• Benefits to

producer, consumer and environment.

Managing the use of water Irrigation is the artificial application of water to the land or

soil. Australia is the driest inhabited continent, and irrigated

water is needed to supplement low rainfall to assist in growing crops and pasture.

Agriculture uses 65-75 per cent of the water consumed in Australia per annum and irrigation uses 90 per cent of that.

In 2004-05, the value of produce from irrigated agriculture was estimated at $9.1b.

Australia exports around 65% of its agricultural production to international markets.

Sustainable Irrigation systems are implemented so that water can be conscientiously used and used to improve the productivity of farms.

http://www.csiro.au/Outcomes/Water/Water-Book/Chapter-8-Irrigation.aspx

Where does the water for irrigation come from in Australia?

In general, water for irrigation comes from two main sources◦ Surface water- drawn from rivers, lakes, weirs and dams-

e.g Murray Darling system (VIC, WA, NSW)◦ Underground aquifers- e.g Great Artesian Basin. (NT

82%, SA 46%)

• Water taken from river systems (rainfall) or underground

Water used for agriculture

• Too much water us used

• Land clearing of large water using trees.

Water table rises causing salinity in

the earth. • Salty water runs off plants back in to rivers and destroys crops.

Food production and profits are

effected

Where the water comes from in the Murray- Darling basin

How is the water controlled? Through Channels, Locks, Barrages and Pipes

Weir’s- a barrier across a river designed to alter the flow of rivers to prevent flooding, measure discharge, and help render rivers navigable.

Dams- Construction of the Hume Dam, above Albury, was begun by New South Wales and Victoria in 1919. it is a gated concrete gravity dam with four earth embankments and twenty-nine vertical undershot gated concrete overflow spillways. It is estimated to s estimated to hold approximately six times the volume of water in Sydney Harbour.

Barrages and Locks- At times the rivers are closed with constructed to keep the inflow of sea water out of the fresh water or to control the flow.

Channels and canals are built to help move water from natural waterways to supply water to crops.

Water lost?All plants, whether irrigated or rain fed, transpire water from the leaves to reduce the temperature when exposed to the sun. This is called the hydrological cycle - the movement of water from the atmosphere to the earth and back again.

Poor water management = Salinity Salinity is salinisiation of soil, surface water or ground

water due to human activity such as agriculture. ◦ Overuse or poor management of irrigation water on crops

◦ Irrigation on inappropriate soil

◦ Leakage of surface water and the rising water table containing salts

Salinity = Damage Inefficient irrigation and drainage systems are a major

cause of excess leakage and increase the risk of salinity and waterlogging in irrigation areas.

The build up of salts in the soil profile reduces the plant’s ability to take up water, limiting plant growth. Plants absorb water by osmosis, taking in salt particles to draw water from the soil. If the salt content of the surrounding soil/water medium is too high, water can no longer move into the plant roots.

SALINISATION-

 Salinity one of the greatest

challenges facing agriculture today.

Irrigation systems provide an input of water too quickly for drainage systems result in dissolved mineral salts being brought to surface of soil.

Salinity (total concentration of water soluble salts in soil) makes it hard for plants to withdraw water from the soil, making them wilted, retarding growth and product yield.

Salinity = The costsDirect costs of increasing salinity to agricultural producers include:

◦ reduced farm income

◦ reduced water quality for stock, domestic and irrigation use

◦ reduced productivity of agricultural land

◦ animal health problems e.g. saline water supply

◦ breakdown of soil structure, increased erosion and nutrient loss

◦ loss of beneficial native flora and fauna

◦ decreased land value

Strategies to effectively use irrigated water

Laser Leveling- This is where GPS

technology is used to ensure the correct level or slope is created. It results in better irrigation and reduced water use. This allows the farmer to flood irrigate.

Maintain and repair breaks and channels and pipes- Seepage and leaks can cause a great water loss and channels that are kept maintained will not lose water. Channels that are concrete lined lose much less water.

Capturing irrigation water and reusing it- Draining the surface or

subsurface movement of excess water from the paddock or farm. When capturing irrigation water in channels and dams, it can then be cleaned and reused.

Strategies to effectively use irrigated water

Monitoring water quality- Salinity and any ion in large quantities can be toxic to plants and has potential to cause soil structural problems. Awareness and management of water quality issues can lead to improvement in production levels.

Monitoring moisture in the soil- Seepage and leaks can cause a great water loss and

channels that are kept maintained will not lose water. Channels that are concrete lined lose much less water.

Using just enough water (e.g drip irrigation)- drip irrigation is

far more controlled. Water is slowly provided to a very specific area, close to the roots of the plant, by a network of drip emitters.. This method of irrigation is precise an d economical. The flow of water is so slow that it is easily absorbed into the ground. In a well-tuned system there is little opportunity for excess water running off and being wasted.

ActivitiesReview the two case studies and the

strategies used for using irrigated water for farming. Conduct a Pluses, Minuses and ∆ Delta (things you would change) on both approaches.

1. What happens to the land if water is not managed properly?

2. Explain how Salinity occurs (use a diagram)3. What impact does salinity have on the land

and its ability to grow crops?4. List some strategies that farmers can

undertake to prevent salinity form occurring.

◦ https://www.youtube.com/watch?v=403sT9CGRl0&list=PLMBtu4eImXJgpilF8vURg1xwRqb45m2BN

◦ https://www.youtube.com/watch?v=a1nqiOpz1Xc

◦Deterioration to land whereby quality is no longer useful.

◦Problem in Australia, due to loss of nutrients, salts and acids and soil erosion.

◦Soil erosion due to wind and water leads to loss of

Land Degradation

◦ Soil erosion due to extreme weather conditions such as drought and poor land management.

◦ It is also caused by deforestation and clearing.

How can erosion be minimised?◦ Minimising the amount of tillage so the soil is

not dug up and exposed to water and the wind.

◦ Leaving stubble to cover and protect the soil after harvest.

◦ Planting windbreaks or shelter belts ◦ Giving soil nutrients to improve crop growth, ◦ Raising banks to prevent water run off◦ Avoiding crops near rivers and on slopes,

investigating hydroponics (food grown without soil)

◦ Govt’s can reduce soil erosion by controlling urbanisation (land for food production can be lost by building houses)

Soil erosion

Plants hold soil in place and when removed the wind and water can erode or remove the top soil.

Results in soil erosion leading to barren land.

Trees and forests protect soil from rain erosion by providing shade or mulch.

Top level of soil washed away or may dry out from sun damage.

Removing trees for paper production for packaging etc impacts on oxygen in atmosphere as plants take in CO2 and breathe out O2.

 

DEFORESTATION:

Poor Soil HealthSoil Acidification

◦ Occurs when plants take up nutrients and release acidic waste from their roots.

◦ Once acidic crops and pastures do not grow very well

Caused by increased use of fertilisers and manure. Inefficient irrigation

Strategies to improve soil health Undertake reguler pH tests Add lime to the paddocks to help lower the pH and

to counteract high acid levels.

Poor Soil HealthLoss in Nutrients

◦ Occurs when soil is depleted of its nutrients◦ Crops grown in soil with poor nutrients has a

lower yield and therefore less profit for the producers

Caused by Intensive cropping and continually using the same

soil to grow the same crops.

Strategies to improve soil health Using a crop rotation system that includes a

legume crop that fixes the nitrogen in the soil, making it available to assist growth of cereal crops. This also reduces weed and pest problems and the need for artificial chemicals and fertilizers.

Use of Chemicals in Primary productionWhy use Chemicals?

◦To protect the food supply from weeds, pests and disease that may spoil the crop

◦To maximise product yields◦To reduce waste and increase profits

Three main categories◦Fertilisers◦Pesticides◦Herbicides

FertilisersA substance that provides nutrients to grow or improve soil and used to produce more crops

◦ Most commonly applied by aerial spraying◦ Environmental concerns:

Overuse can increase the acidity of the soil If not carefully applied they can cause spray drift

which can contaminate nearby crops and communities.

Can run off paddocks after rain and contaminate waterways and threaten the life of birds and animals.

◦ Strategies for better use: Aerial spraying should be done on days with little

wind to prevent spray drifting on to other paddocks.

Aerial spraying should fly low to prevent spray drift. Use land-based spraying methods such as hand or

tractor spraying. Crop rotation

Herbicides

A chemical substance used to kill plants or inhibit their growth.

◦Biodegradable◦Can leave residues on foods and are

rigorously tested to ensure they are not harmful (FSANZ)

◦Environmental concerns: can lead to run off in the waterways that kill fish or encourage growth of algae.

◦Strategies for better management: reducing amount used.

PesticidesA chemical substance used to kill specific pests on specific crops.

◦ Varying toxicity level◦ Can leave residues on foods and are

rigorously tested to ensure they are not harmful (controls)

Environmental concerns: can lead to run off in the waterways that kill fish

or encourage growth of algae. Nitrogen from products may be released into the

atmosphere and become a major pollutant as well as contributing to acid rain.

◦Strategies for better management: reducing amount used, crop rotation, regular monitoring to determine necessity of use.

Controls:Strict controls include- NRA (National Registration Authority)

which assesses and registers all chemicals used in agriculture and animal farming.

AQIS(Australian Quarantine and Inspection Service) inspects, monitors and investigates imported and exported foods according to govt regulations.

Commonwealth Dept. of Primary Industries and Energy surveys foods to test for residues of chemicals and contaminants.

USE OF CHEMICALS: USE OF PESTICIDES- Chemicals such as

fungicides (kill fungi in crops), herbicides

(kill plants or hinder growth and poisonous to humans) and insecticides (to kill pests which harm crops) absorbed into soil can be harmful and difficult to remove.

  USE OF FERTILISERS- Added to soil to increase

productivity however excess amounts harmful eg. nitrogen enhances plant growth but run off into waterways kills marine life such as algae.

Watch this…https://www.youtube.com/watch?

v=MqrbFdJChzM

Extra resources for better understanding A 14 minute advertisement documentary of the

pesticide DDT (one of the major pesticides introduced in 1945.) DDT is still used today to control malaria in some countries however it has now been banned in many countries due to its very deadly effects. https://www.youtube.com/watch?v=RmeqHs4svbQ

An article about the still existent damaging effects of DDT in Australia, since its ban in 1987.

http://www.abc.net.au/local/stories/2007/10/09/2054547.htm

Organic farming- going back to the traditional… Organic farming as we know it came about as a

reaction to the wide adoption of intensive farming around the time of WWII as a result of technological advances made earlier in the century and food shortages experienced during the war.

Conventional farming relies on chemical inputs and a highly mechanised approach, whereas organics is about farming the natural way.

Conventional VS Organic Farming

Use of chemicals on crops and soil- ◦ Conventional farming uses chemical fertilisers made

from fossil fuel derivatives that are used to add nutrients to the soil.

◦ Conventional farming uses chemical pesticides, herbicides and fungicides to control pests and weeds.

◦ Organic farming controls invasive species through a mixture of companion planting, crop rotation, use of cover crops, natural pest control, hand weeding and animal grazing.

Environment- ◦ Conventional farming is often intensive and farmers

try to get the most productivity out of the ground with little regard to its environmental impact.

◦ Organic farming aims to balance productivity with environmental impacts.

Conventional VS Organic Farming

Seeds◦ Conventional farming may include the use of genetically

modified (GM) seeds. GM seeds have had their genetic makeup changed in a lab to create foods that have certain desirable characteristics such as vegetables that take longer to go brown or are pest resistant.

◦ Organic farming does not allow GM seeds and requires seeds to be organically grown. Organic farmers will often save seeds from previous crops and use rare seed varieties, preserving the biodiversity of our food.

Animals◦ Conventional animal farming allows the use of antibiotics and

hormones, residues of which end up being consumed by humans. Conventional farming also allows factory farming and practices that compromise animal welfare

◦ Organic animal farming uses organic feed for the animals and does not allow the use of antibiotics or hormones. Organic certification also includes strict animal welfare regulations

It’s issues such as these that people are starting to care more about… Organic Products!$655M industry (2013-2014) in

Australia and projected to grow 12% over the next 5 years.

Global demand for organic products is rising with increasing health consciousness, growing concern for the environment, income growth and the increased convenience of organic food.

How do you know who really does organic? There are currently no laws or regulations in Australia

to protect the use of the word 'organic' being used on product labels.

You can only be certain that you are purchasing truly organic or biodynamic produce and products if it has been certified organic by one of the seven recognised certification bodies that are accredited and audited by the Australian Quarantine Inspection Service (AQIS). –

Products have been produced in accordance with specific organic standards.

Farmers have to prove organic strategies, e.g crop rotations, weed control, pest management, biodiversity, water management, animal health etc.

Why Change? Why change from traditional to

organic? What are the benefits? Why

people care? Benefits Disadvantages

Producer

Consumer

Environment