- To sort through this complicated question, researchers with the Department of Environment and Primary Industries (DEPI) Victoria are leading a national project �Accounting for Nutrients on
Australian Dairy Farms�, whose main aim is to provide dairy farmers and their
advisors with simple tools to help them make more profitable nutrient decisions and
minimize nutrient losses
- Managing nutrient flow is one of the most complex jobs that dairy farmers have to deal
with
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- Soil testing to identify paddocks with high soil nutrient levels can results in large savings
on fertiliser
- Soil nutrient concentrations are typically in excess of those required for optimal plant
growth and may represent an environmental and animal health risk
- Organic fertilisers could be considered to complement inorganic fertiliser inputs
- Farmers should consult external help in attempting to resolve this question
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| Why is it important to me as a farmer?
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- An enterprise using too few nutrients may be losing milk production, however, using too
much and you build up excess nutrients and perhaps damage the environment
- Nutrient imports onto dairy farms are generally much higher than those exported in
products
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- These nutrient surpluses, particularly phosphorus, potassium and sulphur, may
represent an opportunity to reduce expenditure on fertiliser
- If reducing inorganic fertilisers is a priority, organic fertilisers such as composted green waste and manures may be used to substitute or complement inorganic inputs
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| How can you get the balance right?
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- Review the Accounting for Nutrients on Australian Dairy Farms� project
- The main aim of this project is to provide dairy farmers and their advisors
with simple tools to help them make more profitable nutrient decisions and
minimize nutrient losses
- The project is working closely with 44 commercial dairy farms around Australia.
This involves measuring all inputs and outputs, as well as the amount and
form of nutrients recycled around the farm. There are 14 regional research
teams working across all states of Australia
- Tools are also provided to help farmers better understand what happens to
nutrients on dairy farms and what can be done to get maximum benefits from
these nutrients
- Completing a nutrient balance
- This provides a description of the imports and exports of nutrients on dairy farms
and quantifies the balance (either surplus or deficit). When used in combination
with soil testing it can be a very useful tool for informing decisions about fertiliser
purchases. A nutrient balance will help explain why the soil test values are what
they are, and indicate whether they are likely to increase or decrease in the
future
- The nutrient budget for your farm will be different than your neighbours for many
reasons. It is unlikely that you import and export exactly the same amount of
nutrients in products so the balance of your budgets will be different
- Determine nutrient values of feed types
- Feed types vary in nutrient status but an average value could be used if it is
difficult to source the actual value of the feed. Knowing the nutrient values of feed
types allows for more accurate feed budgeting
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- Undertake soil testing
- Soil testing your paddocks will tell you what your soil nutrient levels are. Seek
advice from DEPI extension staff or your farm consultant on how and where to soil
test so that your soil test results accurate
- The main nutrients to consider when doing a nutrient budget are the
macronutrients which are those that are imported in large amounts in feed and
fertiliser. The main nutrients to consider are nitrogen (N), phosphorus (P),
potassium (K), sulphur (S), calcium (Ca) and magnesium (Mg)
- Seek advice
- Once you know what your soil test levels are you can seek advice from your farm
consultant or another reputable source about what the agronomic
recommendations for your soil would be
- Where do I go for more information?
- Farm consultants, feed consultants and fertiliser company representatives are
available to deliver further information on the topic relevant to their industries
- Dairy farming colleagues are likely to readily recommend particular consultants
and company representatives
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| Alternative fertiliser options
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- There is growing farmer interest in using alternative nutrient sources such as natural or organic fertilisers and soil conditioners instead of traditional manufactured fertiliser to improve productivity and soil �health�
- Organic fertilisers provide nutrients to promote plant growth (fertiliser), whilst also improving the physical and biological composition of the soil (conditions the soil)
- Inorganic fertilisers generally do not have the ability to condition the soil
- Nutrients in organic fertilisers are available more slowly, over a longer period, than those in most manufactured fertilisers. This may be a disadvantage when plants have an immediate need for nutrients, but it can be an advantage under high leaching conditions, in that nutrient loss from the soil is reduced
- The benefits of improved soil health using these natural alternative sources are widely accepted, however there are numerous questions around whether the products being sold to improve soil health actually change soil biological activity and ultimately are cost effective in maintaining or increasing production
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- Uncomposted animal manures have a higher proportion of immediately available nutrients than composted materials. Consequently, the plant production benefits of compost may not be as be apparent until several years after application
- A good compromise that is becoming increasingly popular with farmers is to use a combination of manufactured and organic fertilisers, to gain the benefits offered by both types. For example, an application of organic fertiliser such as poultry manure can be supplemented later with dressings of manufactured nitrogen (N) fertiliser. This not only provides some nitrogen (N) in a quick release form, but also means that lower rates of organic fertiliser can be used
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Other related questions in the Brown Book
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Brown Book content has been based on published information listed in the Resources and References sections below
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- Gourley C, Powell J, Dougherty W, Weaver D. Nutrient budgeting as an approach to
improving nutrient management on Australian dairy farms. (2007) - Australian Journal of
Experimental Agriculture.
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- Getting Value from Nutrient Accounting on Dairy Farms. Accounting for Nutrients -
Technical Information and Tools - Technotes.
- Better Use of Effluent & Fertilisers in Dryland Dairy Farms, Future Ready Dairy Systems Project Case Study. Dairy Australia.
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