Friday, May 29, 2009

Nutrition and Drought Effects Workshop

Background.


McLaren Vale has had two very dry Winter/Spring Periods in the last three years.

In 2006/07 and 2008/09 vineyard yields (and to some extent Olive yields were reduced). Some vineyards were less than 50% of typical yields. Yields were reduced by a combination of reduced berry set (% flowers turned into bunches) and reduced berry size (berry weight).

Additionally the summers of both 2008 and 2009 had extended periods of heat which had a serious effect on vine and tree health.

With this is mind, Lucia Grimmer, researcher and agronomist with Agrichem visited McLaren Vale to give her thoughts on nutrition during droughts and heatwaves.

Forty grape growers joined us at the Willunga Football Club.


Problems during droughts.

Lucia notes the problems with drought are caused by dry soil. Limited soil moisture causes;

- Limited uptake of nutrients.

- Plant stress. Symptoms like early leaf drop, increased sunburn, increased splitting, thin cell walls and phenolic wine.

- Reduced soil mircobes activity.

- Higher disease in some cases (nematodes; insect damage; fungal disease).

Solutions

Ask dry soil is the problem she suggested working on the soil is the best place to start.

It is suggested growers start to drought proof their soil by;

- increasing organic matter.

- increasing water holding capacity.

- increasing root growth.

Products that can help.

Humates - Seaweeds - Silica

Humic acid is the most effective way to boost organic matter. Humic acid is the remnants of old coal and leaf litter which has been stable in the soil for eons.

Humates are very stable in the soil compared to other inputs - especially when compared to raw manures. Manures have the added negative affect on plants as they draw down nitrogen. Soil microbes take nitrogen away from plants to break down the manure. Raw manures and green waste can actually plant growth by robbing from the vines. There have been some notable cases where poorly composted, cheap chicken manure has been used in McLaren Vale this year. Ironically this might reduce vine growth - the very thing it is being applied for.
Humates have their positive effect on soil because of their shape. Humates are long chain molecules full of oxygen. These oxygen atoms lock onto water, nutrients and carbon. Plants can then easily take these nutrients up.

Humates can be applied in winter in a granular in a similar way to spreading super. Application rates are 100 to 300kg/ha. The highest rate is recommended on sand.

Cost of applying at the lower rates are $230/ha - comparable with chemical fertiliser rates.

Humic acid is also available in a liquid form. A small amount can be applied as a fertigation product.

Lucia recommends small frequent doses of 1Lt/ha per week. The cost of this application would be $5 per hectare. Therefore repeated ten times it would cost $50 per hectare.

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Seaweeds.

Kelp based products stimulate root growth. More root growth equals more nutrient uptake. Seaweeds contain auxin - a plant hormone for root growth.

As with Humic Acid small frequent applications are ideal. Kelp products can also be applied as foilar fertilisers with your normal applications.

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Silica is recommended to be applied to lessen drought effects because it helps strengthen plant cell walls. This helps lessen stress and also has the effect of making insects

Matthew Wilson is looking to trial Silica as a preventative for Phythophtora root rot. It is also likely to help with nematodes control. Silica fertilisers when applied to the roots as fertigation are supposed to be taken into the root and ‘sharpen’ it. It forms glass like plates inside cell walls. Chewing insects have greater difficulty in attacking the roots. Apparently they wear out their mouth pieces. Chetin (crab shells can have the same effect).

For more information visit www.agrichem.com.au

Thursday, May 28, 2009

Albarino still on nursey price lists... They are wrong!

All 'Albarino' that is commercially planted in Australia is in fact Savagnin. Everything comes from the same source and is the same clone (Galicia; or sometimes called SAVII 01). Remember whatever name the grape has it is still showing as a promising wine.

Some growers from other regions we have heard are preparing to remove their Savagnin and graft 'Albarino' back on top.

Bad news. There is no Albarino comercially available in Australia. While you will see 'Albarino' listed in many nursery adverts and product list - look closely and you will notice they are either SAVII 01 or Galicia.

These adverts should be changed to prevent confusion!

Don't buy Albarino cuttings and buds thinking you are getting something different that what has already been planted.

Over the next 2-4 years ‘real’ Albarino will become available directly from stock from overseas. This has already been DNA tested as part of the importation process. South Australian Vine Improvement has real Albarino planted in its Generation 1 rows - shown below - and will be looking to establish.

Vine nursery extension rows at Kapunda, SA.

Friday, May 15, 2009

On the Look Out for Resistant Ryegrass

The first cases of resistant annual ryegrass from McLaren Vale were collected by myself and confirmed by Dr Angela Baker of the CRC-weeds based at the University of Adelaide in 2005. Since that time these ‘super weeds’ have been spreading and many cases remain undocumented and unnoticed.

Resistant annual ryegrass shows up where farmers have been applying glyphosate herbicides, commonly known as Roundup. This is particularly the case in vineyards and olive groves that were planted in old almond orchards.

When glyphosate first came onto the market in the 1960’s it was used heavily by almond growers with many sprays applied without rotation with another herbicide group. After frequent herbicide applications these grass populations evolved from being susceptible, to being resistant to the glyphosate herbicides. Once resistance was established the plants began to spread.

This vineyard has herbicide resistant annual ryegrass growing undervine.
Now when glyphosate is used on resistant ryegrass it is not controlled well and it multiplied becoming a weed. In many cases they keep growing and start to smother other plants.

These ‘super weeds’ first appear as a scattering of single plants or small patches of plants that survived after a glyphosate application.

If you have seen this problem on your farm last year, seek advice. It is important to stop this ryegrass from seeding and increasing next year. If you continue to use glyphosate you only make the problem worse. Increasing the rate of application does not help, as the ryegrass continues to thrive.

This is a serious problem for farmers and action needs to be taken to prevent these weeds from taking over large patches of the district.

The only solution is to used alternative control measures, like cultivation or knifing or by using other groups of herbicide, like Alliance (a combination of the Amitrole and Paraquat herbicides), or grass selective herbicides (Fulisade).

For more information contact me at DJ’s – 8323 8339.