National and regional supply/demand balance for agricultural straw in Great Britain

Tags: cereal straw, barley straw, oilseed rape, livestock sector, Great Britain, supply/demand balance, animal diets, biomass energy, tonnes, surplus, James Copeland, Introduction The Central Science Laboratory, Land Use Strategy Team Central Science Laboratory Sand Hutton York, livestock sectors, livestock bedding, Wheat straw, David Turley Agri-Environment, Defra, compensation, Department for Environment, Food and Rural Affairs, oat straw, fertiliser, renewable energy resource, Unitary Authority, Power Station, Scotland and Wales, bedding material, management practice, straw bedding, GB livestock numbers, Nutrient value, beef animals, Regional analysis, biomass power stations, Pig production, Power Stations
Content: National and regional supply/demand balance for agricultural straw in Great Britain James Copeland & David Turley Agri-Environment and Land Use Strategy Team Central science laboratory Sand Hutton York YO41 1LZ November 2008 Report prepared for The National Non-Food Crops Centre
Index Index ................................................................................................................2 Tables ..............................................................................................................2 Figures ............................................................................................................. 2 1. Introduction ..................................................................................................4 2. Methodology ................................................................................................4 2.1 Straw production ....................................................................................4 2.2 Current demands on the straw resource ................................................5 3. Results and Discussion................................................................................7 3.1 Straw Availability in Great Britain ...........................................................7 3.2 Impacts of other markets on straw availability in GB regions .................9 3.3 Straw Value .......................................................................................... 13 4. Conclusion ................................................................................................. 15 5. References ................................................................................................ 17 Tables Table 1: Breakdown of GB straw production (tonnes) by region in 2007 .........8 Table 2: Potential cereal and oilseeds straw availability (tonnes) by GB region after deduction of current requirements for animal bedding......................9 Table 3: Value of fertiliser removed in wheat, barley and oilseed rape straw at typical rates of straw removal (ADAS, 2008) .......................................... 14 Table 4: operating costs for handling straw...................................................14 Table 5: Average weekly farm gate prices for wheat and barley straw in 2007 ................................................................................................................ 15 Figures Figure 1: Proportion of GB straw production by crop type (2007) ....................7 Figure 2: The impact of livestock bedding requirements on regional cereal straw supply/demand balance ................................................................ 11 2
Figure 3: The impact of existing straw-fired biomass power stations upon regional cereal straw supply/demand balance ........................................ 11 Figure 4: The impact of livestock bedding requirements in regional cereal and oilseed straw supply/demand balance .................................................................... 12 Figure 5: The impact of existing straw-fired biomass power stations upon regional cereal and oilseed straw supply/demand balance.....................12 3
1. Introduction The Central Science Laboratory were commissioned by the National NonFood Crops Centre to undertake a simple mass balance analysis of the current production and use of agricultural straw sources in Great Britain Recoverable cereal straw biomass on UK farms typically ranges from 2.75 ­ 4 t/ha depending upon crop type. Any remaining straw stubble is incorporated back into soil. Currently, the main reason for baling and removing straw from fields is for use in the livestock sector. Barley and oat straw is typically baled and removed from fields for use as a source of roughage in livestock feed rations. Wheat straw has a lower feed-value than barley or oat straw but is widely used for animal bedding for cattle, pigs and horses. Other smaller markets for wheat straw include use as fuel for heat and power generation and small volumes are used in the mushroom industry. Due to its relatively low bulk density, transport costs for hauling straw any significant distance are high. So, in the absence of nearby livestock or other markets for straw, it is typically more cost effective to plough straw back into soil. The developing renewable heat and power sector is looking to source biomass and for opportunities to site facilities in areas where biomass supply can be confidently secured. Hence, there is growing interest relating to information on the availability of cereal straw that would otherwise be ploughed back into soil. Additional sources of straw could also be derived from oilseed rape and linseed crops, although only very small volumes are currently collected. 2. Methodology 2.1 Straw production The production of cereal, oilseed rape and linseed straw in Great Britain (GB) was calculated on a regional basis by sourcing data from Defra on regional Crop production areas in 2007 for cereals and oilseeds (wheat, spring barley, winter barley, spring oats, winter oats, triticale, other grains, oilseed rape and linseed). A range of data sources were reviewed to identify typical harvestable straw yields for each of these crops (data on harvestable straw yields and harvest indices (grain to total biomass ratios) were sourced from Defra, scientific reports and industry representatives). Typically around 60% of the straw produced in-field can be recovered for other uses. The calculated GB and regional straw production figures derived by this study represent potential straw production (t/ha @ 85% dry matter) assuming that all straw is harvestable. However, wet weather before baling can significantly reduce straw availability in affected regions due to difficulties in mechanical recovery and risk of spoilage during storage. 4
2.2 Current demands on the straw resource 2.2.1 Straw use in the livestock sector Straw is currently fed to livestock as a source of long fibre, which is essential as part of a ruminant's diet and such roughage (which could be straw, hay or silage) should comprise a minimum of 10% of the feed ration. Although this is well known within the livestock sector, it is virtually impossible to calculate the exact quantities used due to the different feeding systems and feed rations adopted by individual farmers. As the annual usage of straw by different livestock sectors is unreported, current use of straw for bedding material by the GB livestock sector was calculated on a regional basis. Data on GB livestock numbers (diary, beef, pigs and horses) were sourced from Defra, along with information on basic straw use for bedding (tonnes per livestock unit) (Defra 2002). However, as with straw use for feed, use of straw bedding varies depending upon livestock age, management/housing practice and intensity of production in different livestock sectors. This was taken into account in the analysis, reflecting the current GB livestock structure and management practice for each livestock type. A number of assumptions relating to estimated use have been made to derive straw use figures for each livestock sector. Dairy The type of housing varies considerably throughout the country, with cubicles becoming very popular, but these do not use straw for bedding. In parts of the UK they account for more than 90% of the housing. However, not all dairy holdings have cubicles and most still retain straw (loose) yards. This study assumes that 20% of dairy cows over 1 year old are housed on straw for 180days/ year, and that livestock less than 1 year old are permanently housed on straw. Beef This study assumes that all female beef animals over 1 year old are housed for half a year. Both male and female beef animals less than 1 year old are permanently housed. Male beef animals over 1 year old are divided into intensive (13%), which are housed all year, and extensive (73%) which are only housed for half a year. Pigs Pig production within the UK is based upon many different finishing systems. An average annual straw use for pigs was assumed for all adult breeding stock. Horses Based upon discussions with industry, it was assumed that the majority of horses are stabled for approximately 20 weeks of the year, with 50% of the sector using straw. 5
Poultry The British Poultry Council was consulted on straw use within the poultry sector. It was concluded that only small volumes of straw are used for duck, geese and turkey bedding, so straw use by poultry was not included within this study. 2.2.2 Straw-fuelled Power Stations This study has only included an estimate of straw demand for the existing EPR, Ely Biomass Power Station in Cambridgeshire; although additional straw-powered Power Stations are currently proposed for Lincolnshire and Yorkshire. individual company representatives were consulted to obtain estimates of the likely straw demand for each straw-fired Power Station. 2.2.3 Regional analysis of straw availability To examine the available straw resource on a regional basis (after accounting for removal by other markets) data was collated by NUTS (Nomenclature of Territorial Units for Statistics) classifications as used by English and Devolved Administrations in Scotland and Wales for statistical data collation. Collation at NUTS level 3 (and 4 for Scotland and Wales) was adopted in this study, which correlates with Unitary Authority level data in England (NUTS level 3) and Unitary Authority and District level data for Wales and Scotland [at higher levels of detail, issues of confidentiality affect the ability to present data in publicly accessible documents]. The results of the analysis of available straw resource for each NUTS region were imported into a geographic information System (GIS) using ArcGIS, 9.2 to enable spatial presentation, in this case using categorisation steps of 50,000 tonnes in assessment of straw resource availability. A colour `ramp' is used to aid interpretation with straw deficit values for a region identified in red, to increasing surplus figures in dark green. In accounting for the impacts of existing market uses for straw in the above regional analysis, it was assumed that due to the high cost of transporting straw, supplies would be sourced predominantly within each NUTS region ­ creating a range of surpluses and deficits. Clearly creation of market opportunities through deficits will result in straw being drawn-in from neighbouring regions. The impacts of this are discussed in more detail later in the report. 6
3. Results and Discussion 3.1 Straw Availability in Great Britain The majority of agricultural straw production in GB is currently derived from wheat, which accounts for 54%, followed by oilseed rape (21%), barley (20%), oats (4%), other cereals (1%,) and linseed (0.1%) (see Figure 1). Based on 2007 data, the potential total straw yield in GB from both cereals and oilseeds is approximately 11.9 million tonnes (Table 1). Figure 1: Proportion of GB straw production by crop type (2007) Cereal and oilseed straw production is concentrated in the arable Eastern parts of GB (Table 1). Around 70% of GB wheat straw and 55% of winter barley straw is produced in a combination of the Yorkshire and the Humber region, East Midlands, Eastern Regions and South East Regions. Spring barley straw is predominately produced in the North and South East of Scotland (35%) and Eastern Regions and the South West Regions of England (22%). Oat straw production in the West Midlands, South East Regions and South West Regions accounted for 49% of total oat straw production in 2007. A significant proportion of cereal straw is used in the livestock sector. Although only a very small amount of oilseed rape straw is currently utilised for livestock feed, it has a potentially large market as an energy source. 7
Table 1: Breakdown of GB straw production (tonnes) by region in 20071
Region North East Region North West Region Yorkshire and Humber Region East Midlands Region West Midlands Region Eastern Region South East Region South West Region North West Scotland North East Scotland South East Scotland South West Scotland Carmarthenshire Ceredigion North East Wales North West Wales Pembrokeshire Powys South Wales Total Total GB Straw
Wheat 229,865 104,999 794,980 1,201,806 536,523 1,645,860 802,254 602,158 5,918,444 13,495 56,474 270,004 19,630 359,603 392 1,189 7,099 794 7,798 10,052 18,137 45,462 6,323,508 11,884,259
Winter Barley Spring Barley
69,379 39,651 184,893 116,899 81,431 208,703 65,408 110,416 876,780 4,270 62,538 61,775 16,135 144,719 464 520 3,953 476 4,915 3,075 5,159 18,563 1,040,061
29,616 57,641 96,815 72,157 49,792 149,353 104,431 149,948 709,753 64,424 241,156 243,384 72,588 621,553 2,276 3,464 4,303 4,420 12,747 3,527 4,367 35,104 1,366,409 Total Cereals 9,348,142
Oats 24,812 20,526 27,034 49,843 76,566 40,364 84,928 85,772 409,844 11,070 19,354 42,951 10,097 83,472 857 1,164 1,923 1,634 2,311 3,984 4,200 16,072 509,388
Other Cereals 1,952 7,628 7,313 9,544 7,821 17,198 9,982 29,389 90,828 600 1,385 2,379 2,204 6,567 1,167 778 1,388 441 2,648 870 4,088 11,380 108,775
Linseed
Oilseed Rape
*
111,636
*
17,006
*
320,205
2,457
582,097
*
179,585
2,086
544,949
2,422
386,005
2,365
219,144
10,720
2,360,627
*
7,433
*
57,734
*
84,022
*
3,414
356
152,602
0
*
0
*
0
*
0
*
0
2,592
0
*
0
6,049
0
11,811
11,076
2,525,040
Total Oilseeds
2,536,117
1 Asterisk (*) have been used to prevent disclosure of information about individual holdings, entries relating to less than 5 holdings, or those where two or less account for 85% or more of the information available. 8
3.2 Impacts of other markets on straw availability in GB regions 3.2.1 Livestock market impacts on straw resource The use of straw in the livestock sector was calculated and collated on a regional basis (as described earlier) to match data collated on straw production. Subtraction of regional livestock demand from regional cereal straw supply (Figure 2) and cereal plus oilseed straw supply (Table 2 and Figure 4) identified a range of estimated straw supply/demand deficits and surpluses existing across the regions of GB. Overall there was a net GB surplus over livestock demand of 5.7 million tonnes of straw in 2007. Wales had a 704,000 tonne deficit of straw and was a net importer of straw in 2007. Although the North and South East of Scotland had a 584,000 tonne surplus of straw in 2007, overall Scotland had a deficit of 33,000 tonnes of straw in 2007. England had 6.5 million tonnes of surplus straw in 2007 and was a net exporter of straw to both Wales and Scotland.
Table 2: Potential cereal and oilseeds straw availability (tonnes) by GB region after deduction of current requirements for animal bedding
GB Region North East Region North West Region Yorkshire and the Humber Region East Midlands Region West Midlands Region Eastern Region South East Region (inc London region) South West Region North West Scotland North East Scotland South East Scotland South West Scotland Carmarthenshire Ceredigion North East Wales North West Wales Pembrokeshire Powys South Wales
Straw balance (tonnes) 273,357 -394,200 1,019,999 1,674,402 416,822 2,429,242 1,101,518 -15,139 6,506,001 -80,146 161,894 422,371 -537,275 -33,157 -135,848 -72,262 -105,207 -93,688 -99,074 -134,980 -63,005 -704,064
9
3.2.2 Mushrooms Based upon discussion with industry, it is currently estimated that 40,000 tonnes of straw is supplied to UK mushroom growers. 3.2.3 Energy Demand Impacts Based upon reported existing use of straw for energy production, 200,000 tonnes of straw are currently used by the EPR Ely Power Station. The impacts of this on the regional straw supply/demand balance are shown in Figure 3 and Figure 5. This has a relatively small impact upon national straw availability reducing the GB net straw surplus to 5.5 million tonnes. In addition to the EPR Ely Power Station, there are proposals for two additional straw-fired power stations in Lincolnshire at Sleaford and Brigg, each proposing to use up to 240,000 tonnes per year. A further proposal for a straw-fired power station at Holderness in East Yorkshire plans to use 64,000 tonnes of straw per year and a proposed CHP plant at Tesco's distribution site at Goole in East Yorkshire plans to use 43,000 tonnes of straw per year. In total these additional power and CHP stations, if commissioned, would require an additional 587,000 tonnes of straw, reducing the GB net surplus to 4.9 million tonnes. 3.2.4 Straw movement These regional supply/demand balance maps do not take into account the movement of straw between regions across GB. Currently, a large volume of straw is moved from the Eastern Counties of England to the South West, Wales and Scotland to meet the market demands of the livestock sector. 10
Figure 2: The impact of livestock bedding requirements on regional Figure 3: The impact of livestock bedding requirements and
cereal straw supply/demand balance
existing straw-fired biomass power stations upon regional cereal
straw supply/demand balance
11
Figure 4: The impact of livestock bedding requirements on regional Figure 5: The impact of livestock bedding requirements and
cereal and oilseed straw supply/demand balance
existing straw-fired biomass power stations upon regional cereal
and oilseed straw supply/demand balance
12
3.3 Straw Value The livestock sector is clearly an important existing competitor market outlet, for any use of agricultural straw particularly for wheat and barley. However, there is clearly a surplus of cereal straw in GB that could provide a useful renewable energy resource, plus there are additional oilseed straw resources that could be recovered. As discussed earlier, it is difficult to assess how much straw is used in animal diets, though clearly there are alternatives available to the livestock sector or opportunities to modify dietary rations. Even if a significant proportion of the barley straw goes into animal feed (and this is not certain) it's likely that around 2-3 million tonnes of straw are surplus to current animal and biomass energy demands, with the potential for this to be used for further biomass or liquid biofuel energy developments. However, irrespective of demand from the livestock market, straw itself has a value in-terms of its nutrient content, which can be significant, particularly at current fertiliser prices. In order to access this surplus straw farmers need to be compensated for both the cost of baling and removal and for replacement of nutrients forgone in removed straw. The following analysis provides an indication of the price of straw that must be met before farmers are likely to consider going to the effort of retaining straw for sale. A report prepared by ADAS for the NNFCC recently quantified the fertiliser value of different straw types (Ј/t) (ADAS, 2008), which were used to derive fertiliser values per hectare (Table 3). It is difficult for the fertiliser market to give a prediction on fertiliser prices over a period greater than three months; but the straw nutrient values in Table 3 are predicted to rise as both fertiliser Raw Materials and fuel values increase. The operating costs for baling and removing straw (Table 4) include a saving in the cost of straw chopping to offset against the costs of bailing. The majority of cereal straw is chopped as part of the harvesting operation before soil incorporation. Farmers need to be compensated for the value of the nutrients exported, the costs of straw bailing and removal, offset by the saving in operations forgone (e.g. straw chopping), which in this case, and at current high fertiliser values, indicates a wheat straw value of around Ј113/ha or Ј32/tonne, which is around 18% higher than that currently offered in the market place (Table 5). Clearly margins on sale of cereal straw currently offer little opportunity of return on the cost invested, unless costs can be reduced somewhere in the equation. However, the farming industry is quick to capitalise on any opportunities offered by a rise in the price of straw. 13
Table 3: Value of nutrients removed in wheat, barley and oilseed rape straw at typical rates of straw removal and current fertiliser prices (ADAS, 2008)
Nutrient content (per tonne of straw) Wheat N ­ 5.0 kg P2O5 ­ 1.3 kg K2O ­ 9.3 kg Total Barley N ­ 6.0 kg P2O5 ­ 1.5 kg K2O ­ 12.3 kg Total Oilseed Rape N ­ 7.0 kg P2O5 ­ 2.2 kg K2O ­ 11.5 kg Total
Nutrient value per tonne of straw (Ј)
Total nutrient value of removed straw (Ј/ha)
5.65 1.89 9.30 16.84
19.78 6.62 32.55 58.94
6.78 2.18 12.60 21.56
18.65 6.00 34.65 59.29
8.70 3.19 11.50 23.39
36.54 13.40 48.30 98.24
Table 4: Operating costs for handling straw
Operation Costs
Ј/ha
Straw chopping (on harvester) (Nix, 2008) Straw chopping (separate operation) (Nix, 2008) Baling (517 kg/bale) (Newman, 2003) Moving bales from field to stack (Newman, 2003)
4.00 40.00 48.36 9.67
14
Table 5: Average weekly farm gate prices for wheat and barley straw in 2007
Commodity Value (ex farm) (2007)
Ј/t
Ј/ha
Big square bales (Wheat) (Defra, 2008) Big square bales (Barley) (Defra, 2008)
27.41 38.13
95.92 104.85
4. Conclusion An estimated 11.9 million tonnes of straw was produced from cereals and oilseeds in Great Britain in 2007. Wheat is the predominant straw source, accounting some 54% of potential straw, followed by oilseed rape (21%), barley (20%), oats (4%), other cereals (1%), and linseed (0.1%). After accounting for use in animal bedding, the overall GB net straw surplus in 2007 was 5.7 million tonnes. Deductions for straw use by the mushroom sector and EPR Ely Biomass Power Station reduced this to just under 5.5 million tonnes. If the additional straw powered power and CHP stations currently under consideration are commissioned, they would require an additional 587,000 tonnes of straw, reducing the GB net surplus to just below 4.9 million tonnes. It was not possible to quantify the additional amounts of straw going into animal diets, which could reduce this above figure further. However, there are alternatives available to the livestock sector or opportunities to modify dietary rations to reduce the need for straw, should availability decrease or costs rise. Even if a significant proportion of the available barley straw went into animal diets (and this is not certain) it's likely that around 2-3 million tonnes of straw are surplus to current animal and biomass energy demands, with the potential for this to be used for further biomass or liquid biofuel energy developments. Both Wales and Scotland are net importers of straw from England. This will initially be sourced from the nearest neighbouring regions with surplus supplies to keep costs down. The highest straw surpluses are seen in the East of England ­ Yorkshire and the Humber, East Midlands and Eastern England and South East England and these are in most cases some distance from the areas of high demand in Scotland, Wales and the South West of England, and are therefore likely to be seen as last a last resort for straw supply, but some will still travel from these regions. There is clearly a surplus of cereal straw in GB that could provide a useful renewable energy resource, plus there are additional oilseed straw resources (2.5 million tonnes) that could be recovered. However this straw resource should not be viewed as a cheap waste by-product from agriculture, as straw has value in its nutrient content and in providing organic amendment to soil to
15
maintain good soil condition. Farmers will need compensation for this and for the costs invested in recovering straw. Taking into consideration the current cost of buying-in replacement fertiliser for the nutrients exported in straw and the balance of costs in bailing and removing wheat straw, a minimum wheat straw value of around Ј113/ha or Ј32/tonne is likely to be required to persuade most farmers to part with their straw. Current spot farm-gate prices for straw are only around 84% of this value but there is no slump in supply. Some farmers may be able to reduce costs in the chain to compensate or more likely most currently fail to recognise its additional fertiliser value. 16
5. References ADAS. (2008). Addressing the land use issues for non-food crops, in response to increasing fuel and energy generation opportunities. [Online] http://www.nnfcc.co.uk/metadot/index.pl?id=8253;isa=DBRow;op=show;dbvie w_id=2539 (verified 20/11/2008). Department for Environment, Food and Rural Affairs (Defra). (2002). The Water Code: Code of Good Agricultural Practice for the Protection of Water. [Online] http://www.defra.gov.uk/farm/environment/cogap/pdf/watercod.pdf (verified 26/11/2008). Department for Environment, Food and Rural Affairs (Defra). (2008). Derived from Defra Statistics. [Online] https://statistics.defra.gov.uk/esg/publications/amr/default.asp (verified 20/11/2008). Newman R. (2003). A trial burn of rape straw and wholecrop harvested for energy use to assess efficiency implications. [Online] http://www.berr.gov.uk/files/file14920.pdf (verified 20/11/2008). NIX J. (2008). Farm management pocketbook. Ashford, Kent, UK; Wye College. Ed.38, 256pp. 17

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