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November 2008

Welcome to the November edition of Fertile Minds, the monthly newsletter of Sydney Environmental & Soil Laboratory.

We often promote the benefits of having a plant tissue analysis performed, but did you know that there are times when it won't help? In this issue we look at when not to rely on a tissue analysis.

If you have any questions you would like answered in Fertile Minds, please write to info@sesl.com.au. Or if you have any special requirements, we would be pleased to talk with you and tailor a package and price. Please contact the office on (02) 9980 6554 or write to us at info@sesl.com.au.

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In this issue

• The Loam Ranger – Soil for winegrapes
• Considerations in using recycled water on crops and turf
• Conserving biodiversity in landscaping
• When plant tissue analysis won't help
• Did you know ... ? – Mycorrhizae

The Loam Ranger – Soil for winegrapes

Dear Loam Ranger,

What do I need to know about the soil in my planned vineyard before I plant the vines?

Before planning a vineyard, organise a site soil survey. Analysis of horizon depth, soil texture, structure, density and chemical composition will support informed decisions about vineyard design and management required to produce consistent grape quality and quantities.

Organise a full soil chemical analysis as well. This will identify nutritional deficiencies.

Click here for information on soil preparation and management (1000 words, 4 minutes)

Considerations in using recycled water on crops and turf

In the driest inhabited continent on Earth (only Antarctica is drier), water is a luxury. As global warming gathers pace and southern Australia dries, it will become precious. So more and more uses will be found for recycled water.

Already, treated domestic effluent is supplied, via a dedicated reticulated pipeline, to new houses in the north-west of Sydney, for toilet flushing and garden watering. The use of recycled water in various industries will eventually become commonplace.

Irrigation of crops and turf is an obvious use for recycled water, particularly where a ready supply of waste water is already available. Intensive animal enterprises such as dairies and piggeries use a lot of water for hosing and cleaning. The water that runs off is replete with nutrients that crops and pastures need. In fact, the careful reuse of dairy, piggery and feedlot effluent can save around half a farm’s fertiliser costs (although this depends on a number of factors).

But the use of recycled water for irrigation requires care. Two factors exert the most control.

Click here to read about salt and nutrients in recycled water (1000 words, 4 minutes)

Conserving biodiversity in landscaping

Most landscaping projects, both small and large, use the same small range of plants. These plant species are typically chosen for several reasons:

• They are available in bulk (because they are easy to propagate).
• They transplant and grow well.
• They are resilient in urban conditions.
• They are familiar, so their characteristics are understood.
• Landscaping is quick and straightforward.

But this practice ultimately diminishes our built environment. We end up with the same plants everywhere: box hedges, lomandra strips, mondo grass borders, dwarf lilly pillies, spiny grevilleas, kikuyu lawns ... and not much else.

What tends to happen in new developments is that maybe a hundred species are cleared from a site – all the way from unnoticed groundcovers, grasses and sedges up to trees – and are eventually replaced with half a dozen species, none of which grows naturally in the area. This has two serious effects: it reduces biodiversity and it robs many animals species of their food source and homes.

Even in redevelopments, although the developers may specify native species, the site ends up with plants that could originate anywhere in Australia and that are genetically identical to those at thousands of other sites.

Click here to see how you can preserve biodoversity in landscaping (1000 words, 4 minutes)

When plant tissue analysis won't help

Plant tissue analysis is an extremely valuable tool for understanding nutrition problems and correcting imbalances to maximise yields. But there are times when it won’t help and may even give you the wrong advice.

The six most common elements in the Earth’s crust are all present in high amounts in soils. Therefore, any soil adhering to a plant tissue sample, in particular one collected close to the ground, is likely to skew laboratory results of those elements. It is important to keep in mind that plant samples are never washed before analysis, because this can wash out highly soluble nutrients, such as potassium and boron, and can add others present in the water. So contaminated samples can give false readings.

Click here to see when not to use plant tissue analysis (500 words, 2 minutes)

Did you know ... ? – Mycorrhizae

The word mycorrhiza comes from the Greek mukes, fungus, and rhiza, root. A mycorrhiza (plural mycorrhizae, which confusingly is Latin, not Greek; or just mycorrhizas) is a “fungal plant root”. It is a fungus that invades a plant root to form a mutually beneficial relationship – a symbiosis.

Most plants have mycorrhizal roots – around 92% of plant families and 80% of plant species.

Fungi from many different groups have developed an association with plant roots, so the origin of the symbiosis appears to have been a common discovery by various fungi and plants because of the benefits it brings both members of the partnership. Indeed, the oldest known fossils showing mycorrhizae are about 400 million years old.

The fungal hyphae (the very fine threads that form the bulk of most fungi) are much finer than plant roots: they can therefore explore much tighter spaces in the soil, and increase the effective root surface area by up to 100 times, maximising the extraction of both nutrients and water. In particular, mycorrhizae are adept at extracting tightly bound phosphorus from soil, using enzymic extraction methods not available to plants.

Click here to read about the benefits of mycorrhizae to crops (400 words, 2 minutes)