Tuesday, June 30, 2009

Organic Undervine Weed Suppression




These photos (above), from a Sellicks Foothills vineyard, show a good example of organic weed control and how mulches can improve your soil. This vineyard has been applying mulches for three seasons. The undervine area has now got a thick covering of mulch made from waste plant material and tree barks. No significant weeds grow through it only some patches of clover and other 'soft' plants.

The owners have also been adding complex organic matter (in the form of Lawrie and Co's Biologic Blend). This is to help increase the amount of soil organic matter.

Wednesday, June 24, 2009

Spotlight - Important to read the label closely

Just a note about Spotlight plus tm (a Group G Herbicide) the replacement for Hammer as a spike for broadleaf weed control.

Looking at the Spotlight tm label the first rate you see is 300ml/100ltsThis is for de-suckering grapevines!

Do not use that rate when spraying weeds!

The spike herbicide rate is similar to Goal an alternative spike herbicide also commonly used.

Spotlight = 40ml/100lts
This gives a recommended per hectare usage of between 100ml to 300ml/hectare.

Derek Cameron says, "Use 4 x the previous Hammer rate." Derek also says, "be careful using Spotlight as a spike with Jaguar (a Group C/F Broadleaf Selective Herbicide) as the Spotlight makes the Jaguar work too well and begin to affect your covercrop."

As always read the label for more information.

Tuesday, June 16, 2009

Mains water price rises.

Irrigators with mains water - olives, grapevines and other commercial uses will pay $1.88 kilolitre after their initial 120 Kilolitres at $0.97.

See the text from the government gazette below.

WATERWORKS ACT 1932
Water Rates in Respect of Commercial Land
AFTER consultation with the South Australian Water Corporation, I fix the water rate under section 65C (1) (d) of the Waterworks Act
1932, in respect of water supplied to commercial land for the financial year commencing on 1 July 2009 and ending on 30 June 2010:
(i) for each kilolitre supplied up to, and including, 120 kilolitres—$0.97 per kilolitre;
(ii) for each kilolitre supplied over 120 kilolitres—$1.88 per kilolitre.
Dated 4 December 2008.
KARLENE MAYWALD, Minister for Water Security

Monday, June 15, 2009

Mycorrhizal Fungi

Secret weapon in soil.


Mycorrhizal Fungi form a symbiotic relationship with over 90% of all plant species including grapevines. They form a huge extension of the plants root system allowing it to access far more soil volume. In return for sugar from the plant roots mycorrhizal fungi provide the plant with predominantly Phosphorus and Zinc but have also been associated with increased levels of all nutrients, improved water uptake and decreased salt uptake. Mycorrhizal fungi achieve this by increasing the volume of soil the plant can access by 100-1000 times. Add to this the mycorrhizal fungi’s ability to produce chemicals and enzymes to release tied up nutrients and you have a relationship that you really want to encourage.

The American Journal of Enology and Viticulture has published a number of papers (both glasshouse and field trials) showing improved plant function when vines are associated with mycorrhizal fungi.

The picture above shows how VAM are able to access soil nutrients on a much greater scale than plant roots can alone. DJ's has developed our own range of fungi stimulating soil amendments.

In Australian soils mycorrhizal fungi have depleted over time through use of fertilisers, pesticides and tillage. They have now reached levels where they no longer provide benefit to the grapevine or other plants. You can increase your mycorrhizal numbers by inoculating your vineyard using mycorrhizal spores. It is important to look after your fungi once you have started to promote them.

Using natural sources of Phosphorus such as Rock Phosphates or Guano provides slow release fertiliser that encourages mycorrhizal colonization’s. Highly soluble, inorganic sources of phosphorus trick plants, so that they no longer need to feed the mycorrhizal fungi to access soil phosphorus. Over time this decreases the population of mycorrhizal fungi forcing the plant to be more reliant on inorganic phosphorus and other applied nutrients.

In vineyards the other reason for the reduction in mycorrhizal fungi is due to the use of some systemic fungicides. Follow the links at the website www.mycorrhizae.com for more up to date information about which systemic fungicides suppress mycorrhizal colonization. They can help make decision about which fungicides will help you look after the fungi you are trying to promote.

Excessive cultivation also discourages mycorrhizal fungi because every time you cultivate you break the fungal hyphae. This is like continually pruning your vines,there is only so much you can remove before they die. Fortunately most vineyards have very little cultivation and provide an environment that encourages mycorrhizal colonization.

In recent years the research into mycorrhizal fungi has been on their ability to increase soil organic carbon levels. Dr. Sara Wright from the USDA has estimated that 33% of soil organic carbon is from mycorrhizal fungi. This is predominantly due to Glomalin which is the “skin” of the mycorrhizal filaments. As the fungal hyphae live and die they continue to increase soil organic carbon. Increases insoil organic carbon reduces your need to irrigate, as soil water holding capacity increases also.

A photo of a corn plant root colonized with mycorrhizal fungi. The tiny filaments are the mycorrhizal (VAM) hyphae and the round bodies are the VAM spores.

The best time to inoculate your vines with mycorrhizal fungi is at planting. Using a watering can you can drench the vines with mycorrhizal fungal spores. It is the contact with the roots that allows colonization to happen and this easily achieved at planting. Other options including dressing the seed of a covercrop with mycorrhizal spores or applying a solid blend to the soil undervine which contains mycorrhizal spores in it.

Increasing your mycorrhizal colonization will decrease your inputs into the vineyard and improve your vine and soil health. Vineyards actively encouraging mycorrhizal fungi are financially and environmentally more sustainable.

References


If you would like to lean more about mycorrhizal fungi please visit www.mycorrhizae.com or for the more scientifically minded www.mycorrhizas.org.

This is the link to the USDA for more information about Glomalin www.ars.usda.gov.

Friday, June 12, 2009

Soil Moisture Monitoring Data

This graph was produced this week. The vineyard is a heavy red brown clay in the Sellicks Foothills (Colville Rd - west).

It shows that water has infiltrated 100cm depth on this soil. The profile is not yet full and more rain is needed to push moisture into the subsurface and flush salts from the soil.

Thursday, June 4, 2009

Winter Blues

The Range - 29th 5th 2009.
Mist, frost and fog blue the pasture while the winter chill drops the last of the vine leaves.