MYCORRHIZA FOR ENERGETIC WILLOW

Polish Energy Law obliges energy producers (mostly thermal energy producers) to increase their share of renewable energy to 7.5 per cent in 2010. This is to limit gradually the 'greenhouse effect' and utilize ashes according to the ecologic requirements of the EU.

One of such pro-ecologic solutions is growing willow for energy purposes, which results in creating plantations of willow in the EU. Obviously, the owners of such plantations aim at the highest possible crops and possibly the most healthy willows grown, since it directly determines their financial figures.

According to ecologic rules a plantation can give high crops, remaining possibly healthy. Obviously, it is possible only when the cheap, modern technology of mycorrhization is used. Mycorrhizal fungi, growing naturally in forest habitats, can also be used in plantations, with all the effects of a mycorrhizal symbiosis.

In forest habitats willows are inhabited by a few ectomycorrhizal fungi (EM), e.g. Leccinum, as well as endomycorrhizal (VAM). While the VAM-fungi are quite common in post-agricultural soil, the EM-fungi are a rarity and have to be applied, especially in non-forest environment.

The influence of the EM-fungi on leafy trees is exceptionally positive and widely proven scientifically. In the case of willow plantations two effects are most important: crop-creating and bio-protective. As far as the first one is concerned, we can assume, that an average increment of bio-mass is approximately 20 per cent. The second one is equally important and not to be over-estimated. Large plantations of one species of plants, fertilized and watered, create perfect conditions for pathogens, including particularly devastating like Phythophthora sp.. Inhabiting the roots zone, it is practically indestructible on plantations. In the USA some infected areas are burnt with fire 30 cm deep, since this is the only way to eliminate the pathogen
(Juzwik J. 2004 – Jedlnia k/Radomia). Research conducted by MYKOFLOR aims at isolating mycorrhizal fungi and bacterias, which would be highly antagonistic to Phythophthora sp.. Even now we offer inoculants, that can be used on willow plantations. These are fungi isolated from the roots of Salix caprea growing in natural habitats of the Augustów Forest and Żmudź (Lithuania). Our experience so far makes us firmly believe, that these inoculants will prove efficient in intensive willow growing.

A few words concerning the technology of mycorrhization on willow plantations

1. Time

It is best to apply inoculants in the first year after transplanting seedlings, when young sprouts measure just over 20 centimetres.

2. Method and density

The inoculant is injected to the soil using a KWAZAR MIKOR applicator, between every two plants. Growing 30 000 plants on the area of 1 hectare (2.47 acres), this means 15 thousand injections. Consequently, 12 to 15 doses of inoculant are required.

More details are available on the Technology page.

Detailed research into ectomycorrhiza of willows (Estonia)

Two willow clones, Salix viminalis L. and S. dasyclados Wimm., growing in separate blocks in mineral soil in one short-rotation forestry (SRF) plantation in Estonia, were analysed to compare the frequency, structure and species composition of ectomycorrhizal (EM) colonisation on their fine roots.

Salix dasyclados had significantly greater EM colonisation on root tips (94%) than S. viminalis (75%). The development of EM and associated fungal structures in fine roots (Hartig net, mantle, Hartig net and mantle combined. surface hyphae, endophyte) was similar for both Salix clones. Nine groups of ectomycorrhizal tips were distinguished on the basis of morphological characterisation. Due to high variability among samples, no significant differences between the Salix clones could be found with respect to the abundance of these morphological groups. In total, nine fungal taxa were identified as fungal associates of the two Salix clones. Identification was based upon amplifying and sequencing the rDNA-ITS region of the fungal associates of the root tips. Phialophora finlandia was the most common fungal associate. Morphological groups with well-defined features (e.g., Tomentella sp.) showed limited taxonomic variation, while groups with ill-defined features contained wider taxonomic variation, including unrelated species (e.g., Laccaria sp., Hebeloma helodes). EM fungal diversity was low and largely comprised species considered as pioneer or early stage fungi. A tendency towards higher EM levels with higher N and organic matter concentrations, and low pH, P and K concentrations were observed when the mean levels of EM colonisation were compared with soil variables.

It is suggested that EM colonisation level may be primarily determined by the tree species but that local soil nutrient status also influences colonisation. The quality of root litter produced by the Salix clones is known to differ and this may have a role in determining EM colonisation.

Source: Puttsepp, U; Rosling, A; Taylor, AFS. 2004. Ectomycorrhizal fungal communities associated with Salix viminalis L. and S. dasyclados Wimm. clones in a short-rotation forestry plantation. FOREST ECOLOGY AND MANAGEMENT. 196(2-3):413-424. [from:] http://mycorrhiza.ag.utk.edu/latest/latest04/04_8putts1.htm

In May, 2005 we mycorrhizated with the ectomycorrhizal inoculum Salix AU a 1 ha of one-year plantation of energetic willow in Popowo-Ignacewo. This area is known as very dry, so we were worried about the adaptation of mycorrhizal inoculum in the roots of willows.

However, the strength of the mycorrhizal spawn was so enormous, that in spite of the drought mycorrhizated willow had significantly higher increment in growth — 20%, which makes us trust that the crops next year will be much higher, considering the fact that the mycorrhization took place just a year after the willows were sowed.

We can also say, that all the expectations concerning using mycorrhizae in such plantations are justified.

Refering this result to the total amount of crops from this young plantation, one hectare gave about 12-13 tons more, which is not only financially but also ecologically beneficial.

See also: www.lasprywatny.pl