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Growing SRC

by smerle — last modified jui 07, 2009 12:27

1/ Planting

The plantation is realized with a specific planter (step planter) and selected cuttings. Four varieties of willows were selected for their productivity and their resistance to the rust (Björn, Tora, Torhild and Oluf). The density of plantation is 16 000 cuttings per hectare.

planteusestep.jpg

2/ Weed control

Maintain clean surface on the first two years is the most important thing to make a successful planting of the SRC. A good preparation of soil allows to limit the development of weeds.

For cutting the vegetation cover, a prototype machine which is specially adapted to the row spacing has been developed.

 

protogyro.jpg

3/ Manuring

The superficial sewage sludge spreading can be realized with a classical spreading equipment after the cutback or the harvest. In the second year of growth of the SRC, it's better to readjust the height of the spreading ramp and to protect the carrier and the tank to prenvent willows peeling or material damaging.

 protoepandage.jpg

4/ Harvesting methods

The SRC crop requires agricultural-type mechanical harvesting. Short Rotation Coppice cannot be justified if manual or forestry methods are used.

The most commonly used harvesting method in Europe is the forage harvester. This method has the advantage of cutting and chopping at the same time, which optimises the operating costs for the harvest. To date, rod harvesters (whole stems harvesters) have proved insufficiently robust to cut 3-year old stems, in Brittany. A new rod harvester was designed early in 2007 and tested in Brittany. The advantages/disadvantages of the two methods are as follows:

Forage harvester with special harvesting header

Rod harvester

récolte_ensileuse

Particularly suitable for large plots with good load-bearing capacity

récolte tiges entières

Particularly suitable for small or damper plots

 
  •  Autumn and winter harvesting must be outside the growing season

  • High forward speed: 0.3-1 ha/hour

     

  • Requires soil with good load-bearing capacity
  • High forward speed: 0.3-1 ha/hour
  • Investment: 85 000€ for the header, 160 000€ for the forage harvester
  • Operating cost: around 250€/ha (estimate for harvesting 50 hectares per year, maintenance, fuel, labour)
  • Flexibility in planning the harvest: until spring
  • Forward speed 0.2- 0.5 ha/h
  • May be used on relatively wet land
  • Skidding is necessary if the rows are longer than 300m
  • Rods can be left to dry on site in the open air
  • Rods are chopped elsewhere
  • Investment: 180 000€

  • Operating costs: Around 350€/ha (for 50 hectares per year, tractor hire, maintenance, fuel, labour)

 

 

Given the climatic conditions in Brittany, it was considered wiser and more reliable to choose two-stage harvesting. Planning of the harvest is more flexible because work can start once the sap starts to fall and can continue until several weeks after the start of re-growth. Leaves left on the stems will dry and fall before the willow is chopped.This machine can harvest up to 250 hectares in a single winter and can therefore harvest all the SRC sites in western France.

 

 

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