Glyphosate is translocated from shoots to roots and later released into the rhizosphere and can be later found in the soil up to one year later. There are plenty of papers that study its effect on mycorrhizal fungi but almos nothing on truffle:
-Chakravarty & Sidhu 2007 [ectomycorrhizalfungi]:Fungal growth was significantly(P = 0.05) reduced particularly at concentrations above 10 ppm.
-Laatikainen & Heinonen-Tanski 2002 [ectomycorrhizalfungi] maneb, glyphosateand terbuthylazin estimulated the growth of some mycorrhizal fungi……
-Pasaribuet al. 2013 [arbuscularmycorrhizalfungi] Glomus growth was unaffected by glyphosate treatments. P intakeincreased.
-Beyrleet al. 2011 [orchidmycorrhizas] Application of glyphosate at0.5 or 1.0 mMhadno effect on fungal growth
– repeated use of glyphosate selects against grasses in favour of dicotyledons, Sourzat(2002
If you have a garden should know how much effort is to keep it without weeds. So to create an brûlé, a “bull fight arena” with no weeds at all it is not free! truffle invests energy to do it and if we help it, truffle will enjoy. Moreover trees will grow better without competition. So we´ve seen like glyphosate and other herbicides had a good effect on truffle mycelium concentration, but we do not want truffles with herbicides on them, right?
Here some tips. One option for the first 3 years is to use a white fabric geo textile:
Trees are first planted, irrigation pipes with e.g. 2 drippers/tree of 4L/h lay over surface and fabric is placed over the trees so they lie down. After that with a cutter we take trees out over the fabric, so they look like the following image:
Once trees start producing, we will need to control weeds out but over brules as well. Offset implements are great for that task so we till over brules but do not drive over them! see this power harrow on a young orchard:
During summer and autumn we will need to control weeds every 4-8 weeks, so power harrows or vibrotillers do a good job just tilling 3-4cm deep. We´ll kill (thin) the top shallow truffles, but won´t disturb the deeper ones or the ones at the spanish wells…
Marcos S. Morcillo