Site selection:

Perennial biomass crops are likely to be in the ground for a number of years and reach 3-8 metres in height prior to harvest, depending on crop species. Its impact on the local landscape, ecology, archaeology and public access must, therefore, be taken into consideration.

All the biomass crops (SRC and perennial grasses) can successfully grow on a wide range of soil types. For optimum yield production, however, it is best if very wet or very dry soils are avoided. Sites that remain waterlogged for much of the year and sites on steep slopes should also be avoided, since they can hinder mechanised planting and harvesting operations. Biomass crops are normally harvested in winter, so in the Welsh climate careful consideration must be given to machinery operations to avoid soil compaction. Areas planted with SRC and miscanthus in upland Wales might also be at a greater risk to soil erosion in the first year due to wide plant spacing and slow establishment until complete crop cover. The risk of soil erosion is greatly reduced from the second year onwards. The use of a sown ground cover crop such as white or red clover during the establishment phase may also help reduce the risk of soil erosion as well as reducing weed competition. However, it is important that the cover crop be selected carefully to avoid competition for water, nutrient and light resources with the biomass crop (Lowthe-Thomas, 2002).

It is also recommended when planting willow SRC they should be planted at least 30 metres from any field drains, since their roots can potentially penetrate down to the drainage system.

Environmental impact assessments:

Any site chosen for biomass crop production, particularly SRWC and miscanthus, must meet the requirements of Environmental Impact Assessments. A proposed SRC or miscanthus site is assessed to ensure there will be no significant adverse impact on the environment. Interested growers should contact organisations that may be regulate the plantation of biomass crops e.g. Forestry Commission for SRWC. These organisations may include local councils for matters relating to public rights of way; or county archaeologists to check the records for any important archaeological remains; or if the proposed site is adjacent to a river or on a floodplain, the Environment Agency.

Site layout, rides, hedgerows and other features:

The site layout of willow and poplar SRC should fit in with the surrounding landscape and must conform to the UK Forestry Standard including landscape design. Guidance on SRC landscape design can be found in Forestry Commission Guideline Note 2 - Short rotation coppice in the landscape (Bell and McIntosh, 2001). Related operational requirements must also be taken into consideration. For example, headlands of 8m or more in width are necessary at both ends of the rows to allow for farm machinery and vehicles turning. If only one trailer is available at harvest or the harvester has an integral trailer, row lengths should be restricted to a maximum of 200m to avoid the need to reverse along the rows to off-load. But if two or more trailers are available, row lengths can be longer. However, if liquid sludge is to be applied using an umbilical system, the maximum row length should be 400 metres. Rides of 4 metres should be left along the edges of the crop to allow machinery access for willow beetle control if required. A maximum of 20% open ground could be allowed within a SRC plantation (as is the case under the Energy Crops Scheme in England).

Headlands and rides should be planted with grasses and cut twice a year, as they provide some support for vehicle movements at harvest. The presence of headlands and hedgerows also provide additional habitat opportunities for a wide range of plants and animals. Field margins surrounding willow SRC, miscanthus and reed canary grass crop fields recorded high diversity of plant species, provided a habitat for invertebrates and a food resource for small-mammals and birds. The majority of the bird species and small-mammals were found within the field margin. However, some pests detrimental to agricultural crops (e.g. willow leaf beetle) can also migrate into the crop fields and cause crop damage.

Agrochemical usage and good agricultural practice guidelines:

Since the primary aim of biomass crop production is to provide bioenergy and contribute to the reduction of CO2 emissions, the overall agrochemical usage in biomass crops must be minimal. The DEFRA Code of Good Agricultural Practice for the Protection of Water (1998) must be adhered to when applying organic manures. Under this Code, no more than 250kg organic nitrogen/ha/year can be applied to agricultural land. Where the soil has high residual nitrogen levels from previous cropping or a high soil organic matter level, these rates should be reduced. In SRC willow, no fertiliser should be applied during the establishment year, i.e. from planting until after the post-cutback herbicide application has had time to be effective.

In order to obtain maximum yield from SRC, areas with low soil moisture availability should be avoided. In low rainfall areas water conservation should be considered before planting, since water yield can be reduced by as much as 50% if SRC is planted instead of a grass or arable crop.

Maximising environmental benefits, for example in protecting or enhancing biodiversity, can rarely be achieved without sustaining low-input management systems. Even modest applications of nitrogen, phosphate or potash can alter the weed species composition and consequently associated fauna within the biomass crop fields. Minor changes to farming practice often cost very little, but can potentially make a great difference to wildlife. Giving some consideration to the agronomic management of biomass crops can save money by reducing agro-chemical inputs as well as benefiting biodiversity and the environment.

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Bell SE, McIntosh E. Short rotation coppice in the landscape. Forestry Commission Guideline Note 2, August 2001.

Lowthe-Thomas SC. Ground cover management for short rotation willow coppice in the uplands of mid-Wales. PhD Thesis. Cardiff: University of Wales (Cardiff University); 2003.