Management
Provided effective weed control has been achieved at planting, SRWC
requires relatively low maintenance during the growing period. During
the second and third year of growth, weed control should not be required
as canopy closure is achieved. However, if necessary, weeds can be
controlled using contact herbicides (with care) or residual herbicides
after cutback and before bud-burst. It is recommended that advice
be sought for individual sites and different weed types, guidelines
on herbicide applications are available from the Forestry Commission. Mulches or sown cover crops can be beneficial for weed control
and organic mulches may have additional benefits of soil improvement,
increased yields and provide a habitat for invertebrate predators
of pest species.
Cut back
At the end of the first winter the crop is usually cut back with
a clean cut at ground level. This process encourages the formation
of multi-stemmed stools which increase plant productivity. This
cut back allows a residual and contact herbicide mix such as paraquat/pendimethalin
or amitrole/pendimethalin to be safely applied and will control
most weeds until canopy closure is achieved. However, cut back at the end of the first year of growth is not
always recommended, particularly at sites where weeds have caused
a problem or when growth is slower due to poor growing conditions.
In addition, the newer varieties do not always create a multi-stem
stool after this cutback period but can be harvested on a 3 year
rotation instead.
Fertilisation
Results from research on SRWC in upland Wales suggest that for
good establishment and competitive yields, fertilisation in the
first year may be beneficial and that where soil are acidic, lime
application is essential. At sites with more nutrient rich soil
fertilisation is less important since the willows translocate nutrients
back to the stool during the winter (Bollmark et al 1999) and drop
their leaves, which adds organic matter to the soil, increasing
the soil nutrient status. To reduce the fertilisation costs and environmental impacts, organic
waste such as cattle slurry and sewage sludge can be applied to
SRWC with the additional benefit of disposal of this waste. Guidelines
for the fertiliser rates are available from DEFRA and the Environment
Agency and should be consulted prior to application to avoid potential
pollution problems.
Pests and diseases – see specific sheet on willow pests in
the Crop Damage section.
Bollmark. L., Sennerby-Forsse, L. & Ericsson, T. (1999) Seasonal
dynamics and effects of nitrogen supply rate on nitrogen and carbohydrate
reserves in cutting-derived Salix viminalis plants. Can. J. For.
Res. 29(1): 85-94
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