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Re: Soil management around trees



Vegetation control around trees is the single most important
factor.  This has been proven to be true in countless
research trials and through decades of experience by tree 
planters and landscapers.  It outweighs fertility and irrigation.  

Grasses and legumes alike will compete with young trees for
water and nutrients.  Some herbaceous species exude
chemicals that inhibit growth of other nearby plants. 

The effect is that young trees struggle to survive and those
that do are stunted in growth in comparison to trees which 
have been maintained vegetation-free. 

The survival phase lasts 3 years, but especially the
first growing season.  The estabishment phase extends 
to 5 years.  Thereafter, landscape trees can compete with vegetation 
adequately, but orchard trees will still need grass control. 
 
Two recent studies on pecan tree establishment in Alabama
provide insights: 

*  A 5' radius from the trunk should be vegetation-free; thus, 
   a 10'x10' square area is needed

*  Legumes, which can be so important in a mature orchard to 
   provide Nitrogen and provide habitat and food prey for 
   beneficial insects, should also be controlled around young
   trees

*  Disking as an alternative-to-herbicides method of weed control
   was comparable to herbicide-treated plots when drip
   irrigation was used.  Yields were reduced by half when
   irrigation was eliminated on disked plots in comparison
   to herbicide-treated plots.  Thus, tillage works when 
   irrigation is available but when trees are dry-farmed,
   the no-till plots worked better.  A mulch--a type of
   no-till--should perform similar to herbicides, and that has 
   been the case in many studies. 

Fabric mulch with water-absorbing gels:   

A heavy-duty fabric weed mulch combined with hydrophyllic 
polymers can provide a no-till, no-weed, no-irrigate mulch
system for upwards of 10 years.  The cost of establishment 
for the fabric pro-rated over 10 years is about $100 per acre.
This is well worth it when you consider the expense and labor 
associated with non-chemical weed control; i.e., tractor cultivation, 
hand hoeing, organic mulch costs, labor, headaches and worries, etc. 

Sheet mulch: 

A good layer of newspapers covered by straw, hay, or grass
to keep the paper from blowing away will provide an
effective sheet mulch of organic composition which will
harbor worms and microbes underneath, especially since the mulch 
decomposes.

 



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