Sugar and the soil food web, very interesting stuff.
Here's a press release from CSU;
Quote:
A sweet end to weeds
12 Dec 2005
Sugar could be an innovative alternative to herbicides and curb one of agriculture?s costly scourges, annual weeds.
In a three year project by researchers from Charles Sturt University?s Institute for Land, Water and Society, sugar spread on plots in central NSW was found to effectively inhibit or ?starve? the growth of annual weeds, making way for the native grasslands to flourish.
?In our trials conducted on a private property and a travelling stock reserve near the NSW town of Young, sugar provided an effective, short-term, ecologically friendly method of weed control,? said a member of the CSU research team and ecologist Dr Ian Lunt.
?Our earlier research has shown that many of our annual weed problems are due to high nutrient levels,? said research leader and Senior Research Fellow at the Institute for Land, Water and Society, Dr Suzanne Prober.
In the project funded by the NSW Environmental Trust, the sugar fed soil micro organisms, which then absorbed soil nutrients. This ?starved? the weed species which need these nutrients to grow.
?We realise that it would not be economical to use the sugar levels we used in our trials,? said Dr Prober. ?However, at the moment we don?t know if we would get similar results if we used less sugar or if we used cheaper alternatives such as molasses or sawdust.?
?We see what we have done so far as only part of the picture,? said Dr Prober. ?Our long term goal is to work out the best methods for re-establishing a native ecosystem that is diverse, self-sustaining and resistant to invasion by weeds.?
The researchers are aware their work could be the basis for other more agriculturally driven studies.
?Annual weeds such as Wild Oats and Paterson?s Curse are the bane of every farmer?s life,? said Dr Lunt. ?Sugar may help land managers to control annual weeds and reintroduce native perennials.?
?Our trials have demonstrated an enormous potential to use sugar to help restore degraded, weedy woodlands. We are now seeking further funds to develop large-scale, cost-effective techniques to tap this potential,? concluded Dr Lunt.
Media Officer : Fiona Halloran
Telephone : 02 6933 2207
Media Note: For photos or to arrange an interview, contact Fiona Halloran, CSU Corporate Communication and Media, telephone (02) 693 32207 or send an email and Margrit Beemster, Institute for Land, Water and Society Communications Coordinator on telephone (02) 60519 653 or send an email.
|
and yes here's a PDF with more detail about the study and some photos;
sweetendtoweeds.pdf
I have reservations when claims are made for any single soil amendment as the answer to problems faced by trees. However the proven role sugars play in the rhizosphere is critical to the health of the bottom trophic level, the micororganisms, bacteria and fungi. The exudation zone around the roots of plants has higher sugar concentrations than the surrounding soil structure, that is extremely attractive to the microorganisms who need those sugars to be able to complete their own metabolic processes...in this way these sugars (simple carbohydrates) are essential to arguably the most important cycle going on (from the plant's perspective) the process of ionisation within the soil profile.
You can find more than enough data at the USDA, Natural Resources Conservation Service website
http://soils.usda.gov/sqi/concepts/s...y/biology.html
There are nine chapters plus lots of links, references etc...
However for those who are less patient here's a paper by Dr Elaine Ingham (from around 1995) that explains the soil food web very well, as Arborists pay particular attention to the explaination of how in the process of predation Nitrogen is accumulated in the soil (around the roots);
The Soil Foodweb ecosys health.doc Quote:
|
Because protozoa require 5 to 10-fold less nitrogen than bacteria, N is released when a protozoan eats a bacterium. That released N is then available for plants to take up. Between 40 and 80% of the N in plants can come from the predator-prey interaction of protozoa with bacteria.
|
Some of our understanding of interrelationships between soil microorganisms has advanced since this paper was written but the general tenents are still valid.
Now having gained (hopefully) much knowledge from that paper, visit this site from the USDA Ag research service and draw on the specfic understanding of the relationship between mycorrhizal fungi and plant roots re sugars;
Quote:
|
Mycorrhizal fungi live within the roots of most plants in a mutually beneficial relationship (symbiosis). They help roots scavenge more nutrients and water from the soil in exchange for sugar to make the molecules they need to live and grow.
|
http://www.ars.usda.gov/is/AR/archiv.../fungi0501.htm
I'm not sure this is enough to get it moved into the Tree Fact Factory, but I'll be honest and say for me the relationship is well proven and although I started out as a skeptic; re the impact of simple sugars on tree health, I have become a true believer,
I don't feed trees, only the sun can do that, but I sure as hell feed the soil trees live in.