The Scottish Government

Newer designs for machinery such as tractors, grain dryers and milking parlour equipment and for buildings - particularly heated/lit sheds for intensive livestock - are generally more energy efficient than older designs. Hence replacement of older capital items with modern designs can reduce fuel and energy usage, thereby avoiding some emissions. Regardless of design vintage, regular maintenance and energy-conscious usage can also avoid some emissions.

Energy efficiency is generally a win -win mitigation method since reductions in emissions are associated with reduced energy usage that also saves private costs, even if capital investments are required.

Matching applications of fertilisers and manure/slurry to plant growth conditions to reduce nutrient wastage and thus N ₂O emissions. Technically feasible and generally a cost-saving exercise for producers, but dependent on wider adoption of best practice. Linked to farmer behaviour and attitudes in response to benchmarking-type information and advice regarding the timing, magnitude, mode and spatial precision of applications plus possible barriers to uptake and maintenance of modern equipment. Research is needed to improve water and nutrient acquisition by roots and the efficiency of their use in plants. Possible positive co-benefit effects, largely in form of reduced water pollution.

Bare cultivated soil is prone to erosion and nutrient leaching. Timely cultivations and use of `catch` and `cover` crops can be used to limit extended periods of bare soil. Feasible but may involve significant change to management practice and lead to seasonal workload pressures. Possible co-benefits for biodiversity from over-wintering stubbles and green manures as well as for water quality.

Field operations, especially ploughing, disturb soil organic carbon. Avoiding such disturbance through reduced tillage techniques can thus save some CO ₂ emissions. Technically feasible, although requires some adjustment to management practices and possible capital expenditure on new equipment. Effect on co-benefits depends on mode of uptake: reduced tillage can sometimes lead to increased use of chemicals to control pest/weed/nutrient levels plus increased N ₂O emissions.

Partially linked to improved utilisation of nutrients by facilitating greater flexibility in the timing of manure/slurry utilisation, but also aimed at reducing CH₄ emissions by seeking to reduce the moist surface area of manure/slurry exposed to air. Technically feasible through (e.g.) covered storage facilities or reducing wetness by mixing with drier material but possibly inhibited by capital costs of improved facilities. Relative attractiveness may increase with regulatory (e.g. NVZ) pressure but also rising fertiliser prices making recycling of on-farm resources competitive. Possible positive co-benefit effects, largely in form of reduced water pollution.

Greater usage of concentrates and control over livestock diets can reduce N ₂O and CH₄ emissions. Technically easier for housed livestock, making it perhaps more compatible with dairying than current beef or sheep systems. Contingent on relative feed prices and capital costs of alternative systems. Intensive beef production perhaps at odds with current marketing image of extensive Scotch beef. Possible negative effects on habitats from loss of livestock grazing and possible local pollutant risks from housed systems - and from additional feed production, which may emit other GHGs and cancel any savings.

Rumen efficiency can be enhanced through the use of various feed additives or other stimulants. Many are still under technical development, but others are already available and can deliver CH₄ savings. Perhaps less dependent on housing than other dietary management options, but still more suited to relatively intensive systems due to need for closer management, with possible negative effect on grazing-dependent habitats and biodiversity.

Shifting to larger, faster maturing breeds - both existing ones and future ones arising from continued breeding programmes - would reduce emissions per kilogram of meat or milk. Technically feasible, but compatibility with traditional, extensive livestock rearing in hills and uplands in terms of both practical husbandry and marketing image is questionable.

Destocking is technically straightforward and a direct method of avoiding domestic emissions of (especially) methane. Indeed, under current estimation methodologies for national GHG inventories, this is the only way of achieving significant reductions in headline levels of domestic emission levels. However, such a radical approach to mitigation has implications beyond GHG emissions through commodity production links to up and downstream sectors, to other environmental public goods and to wider rural economy and community vitality. That is, simply focusing on GHG mitigation may risk damaging significant co-benefits, although they might theoretically be delivered by other means.

Substituting, for example, monogastric pig and poultry production for ruminant sheep and beef is technical feasible, albeit with some significant implications for capital expenditure on farm and for supply-chain infrastructure. However, commercial viability is highly contingent on relative prices of different livestock products and consumer responses to changing availability of beef and lamb vs. pig and poultry. In addition, a radical shift in agricultural production patterns has implications for environmental public goods associated with land use and implications for agricultural supply chain adjustments and for rural economy and community vitality.

Liquid bioethanol from (e.g.) wheat or biodiesel from (e.g.) oil seed rape, as direct substitute for petrol and mineral diesel. Relatively straightforward to grow and therefore familiar to farmers, but highly dependent on policy support and processing capacity infrastructure. Domestic and EU legislation may drive market demand, but different crops yield vastly different energy and carbon outputs and imported raw materials may dominate. Possible negative co-benefits (abroad) of imported raw materials, but also domestic effects on land use patterns and input usage e.g. ploughing-up of set-aside, plus knock-on effects of higher commodity prices. So-called "second generation" biofuels may offer greater net benefits.

Biomass: Direct combustion of biological material, either to generate heat and/or electricity. Typically involving timber products, most often in the form of short rotation coppice ( SRC), or short rotation forestry ( SRF), but other more traditional woodland management systems and other types of material can be used. Most effective if used in some form of combined heat and power installation, either for on-farm or nearby usage - although capital outlay and planning controls may inhibit this. Highly dependent on policy support for capital investment and on-going price of "green" energy. Change of land use can change biodiversity and landscapes in some circumstances and the removal of field residues, such as straw, may compromise low input systems such as organic farming.

Collection of CH4 from housed livestock and (more usually) anaerobic digestion of waste products, for generation of heat and/or electricity. High initial capital costs and on-going issues of scale efficiency for size of plant and throughput - the latter may necessitate access to additional material, either off-farm waste and/or specifically-grown on-farm material. As with biomass, highly dependent on policy support for investment and value of "green energy", but also permitted usage of the digestate (i.e. compost) by-product.

Converting potential energy stored in water at height, or from rivers (high and low head systems respectively) increasing in potential as improvements in small turbine and generator technology occur. Capital cost generally high, although very site specific. Assistance from Government support schemes. Economic viability assisted by market liberalisation and increase in bulk price of energy.

Possible difficulties include availability and cost of grid connection and responding to planning and environmental issues.

Steady improvements in technology in recent years. A wide variety of turbines available. Particularly attractive for farms with substantial on farm energy demands, with surplus sold to the grid. Small turbines can be used where no grid supply. Possible government support. Capital costs significant. Potential returns very site specific dependent on wind speeds and proximity to grid. Visual impacts, along with noise and vibration may cause planning issues and the need for local consultation.

Field operations disturb soil organic carbon, both within and across seasons. Removing land from production, either temporarily or permanently (as with set-aside) avoids such disturbance and thus offers some CO ₂ savings. This may have positive effects on habitat and biodiversity co-benefits. Technically feasible, but contingent on existing farming systems (e.g. rotational patterns) and value of output forgone through idling. A less permanent reduction in cultivated area than (e.g.) afforestation or wetland restoration.

Many agricultural soils, both peat-based or mineral-based, contain less organic carbon than their natural potential. Applying appropriate positive management - such as reducing drainage or retaining organic residues, potentially with Scotland Rural Development Programme support - to such soils may have positive effects on habitat and biodiversity and offers the possibility of co- benefits of restoring their capacity to capture and store carbon, thereby enhancing removals. This is technically feasible, but possibly constrained by cost of applying prescriptions to some existing farming systems both in terms of additional effort and lost output.

Tree planting offers an obvious means of sequestering atmospheric carbon in a durable form that remains in situ for decades and even on harvesting may still represent a carbon store. Rates of sequestration depend on tree species, site-specific growing conditions and management prescriptions, as do effects on co-benefits such as habitats, water quality and landscapes. As with other options, diversion of farmland may have knock-on effects for other commodity markets.