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Land Use Policy 30 (2013) 234– 242

Contents lists available at SciVerse ScienceDirect

Land Use Policy

jou rn al h om epa ge: www.elsev ier .com/ locate / landusepol

etermining the cost of in-field mitigation options to reduce sediment andhosphorus loss

lison Baileya,∗, Clare Deasyb, John Quintonb, Martyn Silgramc, Bob Jacksonc, Carly Stevensb,d

Department of Agriculture, University of Reading, Reading RG6 6AR, UKLancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UKADAS UK Ltd., Woodthorne, Wergs Road, Wolverhampton WV6 8TQ, UKDepartment of Life Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK

r t i c l e i n f o

rticle history:eceived 11 August 2010eceived in revised form 28 March 2012ccepted 31 March 2012

eywords:iffuse pollution controlhosphorus loss mitigationombinable cropsostngland

a b s t r a c t

The Mitigation Options for Phosphorus and Sediment (MOPS) project investigated the effectiveness ofwithin-field control measures (tramline management, straw residue management, type of cultivation anddirection, and vegetative buffers) in terms of mitigating sediment and phosphorus loss from winter-sowncombinable cereal crops using three case study sites. To determine the cost of the approaches, simplefinancial spreadsheet models were constructed at both farm and regional levels. Taking into accountcrop areas, crop rotation margins per hectare were calculated to reflect the costs of crop establish-ment, fertiliser and agro-chemical applications, harvesting, and the associated labour and machinerycosts. Variable and operating costs associated with each mitigation option were then incorporated todemonstrate the impact on the relevant crop enterprise and crop rotation margins. These costs werethen compared to runoff, sediment and phosphorus loss data obtained from monitoring hillslope-lengthscale field plots. Each of the mitigation options explored in this study had potential for reducing sedi-ment and phosphorus losses from arable land under cereal crops. Sediment losses were reduced frombetween 9 kg ha−1 to as much as 4780 kg ha−1 with a corresponding reduction in phosphorus loss from0.03 kg ha−1 to 2.89 kg ha−1. In percentage terms reductions of phosphorus were between 9% and 99%.Impacts on crop rotation margins also varied. Minimum tillage resulted in cost savings (up to £50 ha−1)whilst other options showed increased costs (up to £19 ha−1 for straw residue incorporation). Overall,the results indicate that each of the options has potential for on-farm implementation. However, tram-

line management appeared to have the greatest potential for reducing runoff, sediment, and phosphoruslosses from arable land (between 69% and 99%) and is likely to be considered cost-effective with onlya small additional cost of £2–4 ha−1, although further work is needed to evaluate alternative tramlinemanagement methods. Tramline management is also the only option not incorporated within currentpolicy mechanisms associated with reducing soil erosion and phosphorus loss and in light of its potentialis an approach that should be encouraged once further evidence is available.

ntroduction

The introduction of the European Union (EU) Water Frame-ork Directive in 2003 requires Member State governments to

et water quality objectives based on good ecological statusnd includes specific requirements to control diffuse pollutionEuropean Parliament, 2000; Moss et al., 2003). Two of the prin-ipal diffuse pollutants of concern are sediment and phosphorus

P) (Deasy et al., 2010).

Sediment is indicative of soil erosion and reductions in agri-ultural productivity, and increased fine sediment loadings are

∗ Corresponding author. Tel.: +44 118 378 6270; fax: +44 118 935 2421.E-mail address: a.p.bailey@reading.ac.uk (A. Bailey).

264-8377/$ – see front matter © 2012 Elsevier Ltd. All rights reserved.ttp://dx.doi.org/10.1016/j.landusepol.2012.03.027

© 2012 Elsevier Ltd. All rights reserved.

responsible for a range of off-site environmental problems reducingecosystem function, for example, the siltation of river beds whichhinder fish spawning. There is also increasing evidence for the roleof fine sediment in controlling the transfer and fate of nutrients,particularly P (Jarvie et al., 2005; Collins et al., 2005), and con-taminants such as pesticides and metals (Rees et al., 1999; Collinset al., 2005; Quinton and Catt, 2007). Phosphorus in surface runoffis largely transported in particulate form, bound to sediment par-ticles, but can also be lost as phosphate in solution (Haygarth et al.,2000). Phosphorus contributes to the eutrophic status in freshwa-ters being the key nutrient for plant growth in rivers, lakes and

reservoirs. In most European countries agricultural systems areoperating at an annual P surplus, which for the UK is estimatedto be 6 kg ha−1 yr−1 (Ulén et al., 2007), and the typical loss of P towater from farming land in the UK is in the order of 1 kg ha−1 yr−1

A. Bailey et al. / Land Use Policy 30 (2013) 234– 242 235

Table 1Control and mitigation options at each of the case study sites according to their soil type.a

Harvest year

2006 2007 2008

Control monitoring of sediment and P lossCultivation: conventional plough, up and down the slope All All AllTramline monitoring Silt, sand Silt, sand ClayCereal straw residue: baled and removed Sand

Mitigation options adoptedCultivation: conventional plough, tramline disruptionb Silt Silt, sand Silt, sandCultivation: minimum tillage Clay Clay AllCultivation: minimum tillage with tramline disruption Silt, sandCultivation: contour plough Clay Clay ClayCultivation: contour plough with beetle bankc Clay ClayCultivation: contour minimum tillage Clay Clay ClayCultivation: contour minimum tillage with beetle bank Clay ClayCereal straw residue: chopped and incorporated Sand

a For each harvest year, the options adopted at the three sites are indicated. All, refers to adoption at all sites, silt refers to adoption at Rosemaund, sand refers to adoptionat Old Hattons, and clay refers to adoption at Loddington.

b Tramline disruption involves using a cultivator fitted with a ducksfoot tine used to disrupt the compacted surface of the tramline (tractor) wheeling to a depth of around6

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agers and the project steering group. Other less effective optionswere withdrawn in either the second or third year. The optionsincluded different cultivation techniques, a cereal straw residue

cm.c Beetle bank is located along the contour and across the field centre.

Defra, 2002; Heathwaite et al., 2005). This means that agricultures thought to be responsible for 20% of the P inputs to surface watersn the UK (White and Hammond, 2009).

Controlling the transfer of diffuse pollutants from land to waterepresents a priority task for catchment managers and stakeholdersDefra, 2002; Kronvang et al., 2005), and an understanding of Pnd sediment loss pathways is essential for effective targeting ofitigation methods (McDowell et al., 2001). Although sediment

ields in the UK are relatively low by European and world standardsVanmaercke et al., 2011; Walling and Webb, 1987), a number oftudies investigating the provenance of suspended sediment loadsn UK catchments have reported the significance of cultivated fieldsn this process (Robinson and Naghizadeh, 1992; Chambers et al.,992; Collins et al., 1997; Collins and Walling, 2004; Walling andollins, 2005). Phosphorus is lost from arable systems via a numberf pathways and the most desirable, in environmental terms, is viarop uptake and subsequent removal by harvesting. Less desirable

loss from farming systems can occur from both point and diffuseources. Surface runoff, as a result of the erosion process, representsn important pathway for diffuse P loss from many agriculturalystems and may account for up to 90% of the P transported fromrable land in the UK (Catt et al., 1998; Evans, 2010).

Options which attempt to manage the source of P are typicallymbodied in nutrient management planning and include: regu-ar soil P testing, matching P applications with crop requirements,ncorporation of fertilisers and manures as opposed to broadcast-ng, and better timing of P applications to coincide with periodsf reduced runoff risk (Hart et al., 2004). The timing option alone,owever, cannot be relied upon as a principal method of mitigationecause weather is highly unpredictable (Hart et al., 2004) and inany areas of England and Wales, there are few windows when

ptimal soil and weather conditions coincide (Preedy et al., 2001).Mitigation options focusing upon source control, transport

ontrol or delivery management are relevant to reducing bothediment and P loss and primarily concentrate upon topsoil protec-ion and the interception of surface runoff. Transport managementptions commonly include: the early sowing of winter cereals,elaying tramline establishment, sowing winter cover crops, usingough seed beds, reduced or no-till establishment, and estab-ishment of in-field or riparian buffer strips (see for examples

ierzynski et al., 2000; Cuttle et al., 2007).

Whilst there have been a number of studies internationally intohe effectiveness of mitigation measures for the control of P andn the costs and benefits of soil conservation more generally (see

for example, Kuhlman et al., 2010), the evidence illustrating theeffectiveness of these measures is limited (Deasy et al., 2010) andthere are very few reports in the literature which provide costsfor the practical implementation of sediment and P loss mitigationmeasures at the field level.

The Mitigation Options for Phosphorus and Sediment (MOPS)project (2005–20081), which focused on transport/delivery con-trol measures at the hillslope scale representing different levels offarmer intervention in terms of mitigating sediment and P loss fromcombinable cereal crops addresses this research gap. This paperpresents the field monitoring results from the three years of theMOPS project alongside the cost of the mitigation options at thefarm and regional levels.

Methodology

Field sites, mitigation options and experimental design

Three contrasting case study farms in England covering vulner-able soil types and slope forms were used in the project to explorewhich within-field methods were most effective for reducing sed-iment and P loss. The three field sites were ADAS Rosemaund inHerefordshire (grid reference S0565480) on silty–clay–loam soils(Bromyard and Middleton series), the Severn Trent Water farmat Old Hattons near Wolverhampton (grid reference SJ884055) onsandy soils (Salwick series), both in the West Midlands region of theUK, and the Allerton Trust farm in Loddington, Leicestershire (gridreference SK797010) on clay soils (Hallsworth and Denchworthseries), in the East Midlands region of the UK.

A broad range of practical mitigation options focused on within-field measures were explored based upon literature review, andconsultation with the farm managers and a project steering group.Each option or combination of options was introduced at one ormore sites in the first year. Options which demonstrated mostpotential in terms of reducing sediment and P loss after the firstyear were continued and introduced at other sites in the secondand third years of the project, again in consultation with farm man-

1 See http://www.lec.lancs.ac.uk/research/catchment and aquatic processes/mops.php.

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36 A. Bailey et al. / Land U

anagement comparison, the establishment of a raised within field m vegetative barrier (beetle bank), and tramline management,pecifically ‘tramline disruption’ (see Table 1).

Runoff, sediment and P losses were monitored from unboundedillslope lengths with runoff collection gutters situated at the basef the hillslope. This extended the study scale from the more tradi-ional small bounded plot areas usually used in experimental worko a scale more representative of management practice. The hill-lope lengths were 3 m wide and between 67 m and 270 m long,ith length determined by the nature of the site. Slope angles were

etween 4◦ and 5◦. The hillslope lengths were replicated at eachite, with four replicates typically used for each option at each sitecross the three years. There were 52 lengths monitored in totalver the three years across the three sites.

For all three years of the project, collection of runoff from rain-all events took place from October through to March, when bareoil leads to erosion risk and hence the potential for soil and dif-use P loss is at its highest. A minimum of six rainfall events were

onitored at each site in each winter, with higher rainfall and areater number of events, as recorded by a rain gauge fitted to thequipment, increasing the number of events sampled.

Novel surface runoff flow splitters diverted a sample of at leastne eighth of the total surface runoff to 400 l tanks with the rate ofollection adjusted depending on the runoff volume. The remainderas diverted to waste. The tanks were sampled after each individ-al rainfall event, with a thoroughly mixed water and sedimentample taken for analysis for suspended sediment and total P. Fur-her information on the experimental design and methodology cane found in Deasy et al. (2008, 2009).

inancial analysis

The financial analysis focused on deriving per hectare individualrop enterprise margins and then, taking into account crop areasrown, an overall crop rotation margin. The margins encompassedield and crop price to determine crop revenue; seed, fertiliser andgro-chemical variable costs; and operations that could be directlyssociated with each crop enterprise including crop establishment,ertiliser and agro-chemical applications, and harvesting. This wasndertaken at two levels, one focused on the three individualase study farms and one examined the implications for croppingn the two UK regions within which the case study farms wereocated.

The first stage of the analysis involved the development of sim-le spreadsheet models to determine the overall crop rotationargin per hectare at each case study farm without mitigation.

his was based upon the case study farm crop rotations taking intoccount the major cereal and break crops grown and the area ofhe farm they occupied. Individual enterprise margins for each cropere calculated to reflect the direct costs of crop production. Data

or the models included physical information from the experimen-al work at each case study farm and financial information fromublished sources. Yields were taken as the average for each cropt each of the three farms in each year. Crop prices were takenrom Farmers Weekly (Farmers Weekly, 2006a,b, 2007a,b; Farmers

eekly Interactive, 2007) during the October after harvest. Pricesor seed, fertiliser and agrochemicals were taken from Nix (2005,006, 2007). Similarly, machinery operational costs were also basedpon standard data taken from Nix, linked to field records as appro-riate, to reflect the number and type of operations, and the lengthf time required to undertake them, including the differences inork rate that occurred on the light and medium/heavy soils

ound at each of the case study farms. The costs encompassed fuel,abour requirement, repairs and depreciation which are all directlynfluenced by machinery use. An overall crop rotation marginer hectare was then derived from the individual crop enterprise

cy 30 (2013) 234– 242

margins using the data on the areas of the different crops grown ateach of the case study farms.

The second stage of the analysis was to incorporate the finan-cial impact of the adoption of the different mitigation optionswithin these spreadsheet models. The calculations used the datafrom the case study farm field records for each of the identifiedmitigation options to revise the original data set. The costs associ-ated with tramline disruption and crop straw residue incorporationare additional operational costs within the individual cereal cropoperating margins. The costs were not applied to the break cropenterprises, typically oilseed rape and winter beans, given the dif-ferent approaches associated with the operations of these crops andstraw residue management not being relevant to these crops.

Unlike tramline disruption and residue incorporation, theimpact of the adoption of minimum tillage was not separately iden-tified but incorporated directly as changes within the machineryoperating costs for each individual crop enterprise margin. Theimpact on operations of adopting minimum tillage was applied toall the major crops within the farm rotation as it was assumed thatif the equipment was available and in use for the establishment ofwinter cereals it would also be used for the establishment of breakcrops, particularly oilseed rape which is often established usingminimum tillage. The investment cost for purchasing additionalequipment for minimum tillage was not considered, the empha-sis of the analysis being only on a comparison of the operationalcosts. The costs associated with contour cultivation would also beincorporated directly as changes within the machinery operatingcosts for each individual crop enterprise margin. The additionalcosts associated with the beetle bank would also apply to all crops.Once a beetle bank is established within a field it would haveimplications for all crops grown in that field throughout a rotation,reducing the area of crops grown and thus output and potentiallyaffecting the operational work rate given rise to increasing costs.A separate initial cost for the establishment of the beetle bankwas also identified given that this requires an additional in-fieldoperation to take place. Within the spreadsheets, impacts on yield,fertiliser or agrochemical requirements as a result of mitigationcould also be incorporated directly as changes to revenue and costs.Changes to the individual crop enterprise margins then have impli-cations for the resultant overall crop rotation margin per hectare. Itwas assumed that crops grown and the areas they covered wouldremain unchanged as none of the mitigation options would requirechanges to the crop rotations. It was also assumed that mitigationtakes place across the farm as a whole irrespective of need. Thiswould not necessarily be the case in practice, particularly wherethere are additional costs. A more accurate picture would be todetermine what percentage of the land and hence crop area wouldrequire implementation of the mitigation option. Realistically, mit-igation would be most effectively targeted at specific fields proneto problems with soil erosion, and fields which are high in P andclose to water courses. Adopting mitigation across a smaller areawould reduce the extent of the impact on the overall crop rotationmargin per hectare.

The final stage of the analysis was to extrapolate the resultsbeyond the three case study farm models to generic farm typolo-gies at a regional level to set the case study farms in the context ofwider farming practice. Two regional models were developed, onefor the West Midlands and one for the East Midlands. It was withinthese regions that the three case study farms were located. Theregional models were constructed around three key cereal crops,wheat, barley and oats, and two break crops, oilseed rape and beans.Defra (2006) June Agricultural Survey and Farm Business Survey

(2007a,b; pers. comm.) data were used to define typical farms andcropping patterns. Financial crop enterprise data for the regionswere taken from the relevant Farm Business Survey for the 2006harvest year and used as the baseline level for the analyses. To move

A. Bailey et al. / Land Use Policy 30 (2013) 234– 242 237

Table 2Mean overwinter surface runoff, sediment and phosphorus loss for the three case study sites.

Site Long-term annual rainfall (mm) Runoff (mm) Suspended sediment (kg ha−1) Total phosphorus (kg ha−1)

Rosemand (silt) 660 17.5 1070 0.70Old Hattons (sand) 700 5.7 201 0.60

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rom the individual crop enterprise margins to the overall crop rota-ion margin per hectare, the percentage area of crops grown within

region was taken from the Defra June Agricultural Survey. Thedoption of the mitigation options was then incorporated withinhe two models along similar lines to that used for the farm level

odels, either as additional costs linked to individual crop enter-rise margins or as a direct change to the operational costs. As withhe farm level models, this then had implications for the overallrop rotation margin per hectare.

esults

urface runoff, sediment and phosphorus loss

Mean annual rainfall over the three years of the study rangedrom 650 mm to 700 mm across the three sites. Details of meanurface runoff, sediment and P loss, the key indicators used in thistudy, are given in Table 2 to illustrate the differences between thehree sites and soil types. Mean overwinter runoff encompassingll treatments ranged from 5.7 mm on the sandy soil at Old Hattonsp to 25.2 mm on the heavy clay at Loddington; suspended sedi-ent loss was from 201 kg ha−1 on the sand up to 1070 kg ha−1 on

he silt; and total P loss was from 0.36 kg ha−1 on the clay up to.70 kg ha−1 on the silt. The high P loss of 0.60 kg ha−1 on the sandyoil at Old Hattons in relation to sediment loss is likely to reflecthe long-term application of high P content sewage sludge by theandowner at this site. A detailed description and discussion of theunoff, sediment and phosphorus data can be found in Deasy et al.2009), see also Stevens et al. (2009) and Silgram et al. (2010).

Results demonstrated that compacted, unvegetated tractorheelings (tramlines) were important sources and pathways forollutant transport at all sites and in all years. Compared to lossesrom vegetated areas between tramline wheelings, losses of sus-ended sediment were between four and 230 times greater fromramline areas compared to the vegetated areas between tramlines,nd P losses were between three and 293 times greater. The pri-ary reason for variation was due to soil type, with the clay soil

t Loddington more cohesive than the sand and silt at Old Hattonsnd Rosemaund respectively. However, there was also variationetween years. Nevertheless tramlines consistently representedhe dominant surface pathway for fine sediment and P loss on allhree soil types.

Results demonstrating the effectiveness of the different mitiga-ion options are presented in Tables 3a–3c for each site and soilype. Effectiveness is defined as the mm reduction in runoff andhe kg ha−1 reduction in sediment and phosphorus loss from the

itigation treatments when compared to the control treatmentcross all of the years that the options were trialled. Effectiveness islso given as a percentage reduction. Thus, figures are calculated byomparing mean values for mitigation treatments against controlreatments by year and by site.

Disrupting tramlines using a simple tine once in the autumnignificantly reduced runoff, losses of suspended sediment, and

osses of total P (P < 0.01), compared to losses from conventionally

heeled tramline areas, although it was only effective in four outf five site-years at Rosemaund on silt and Old Hattons on sand (seeilgram et al., 2007, 2010). The importance of tramlines means that

313 0.36

focusing on tramline losses of suspended sediment and P using aform of the tramline disruption treatment trialled in this project,or another tramline management option, appeared to be a veryeffective way to reduce sediment and P losses from arable land onmoderate slopes and a range of soil types.

Making use of crop residues through chopping and incorpo-rating straw, rather than baling and removing it, protects the soilsurface from the erosive energy in incident rainfall. At Old Hattonson sandy soils, where this option was trialled in year 1, the resultsindicated that the treatments receiving 2.5 t ha−1 straw choppedand incorporated reduced runoff, sediment and P losses, althoughthese results were not found to be statistically significant (P = 0.08).

Minimum tillage was generally an effective means of controllingsediment and nutrient loss, although this effect differed betweensites and between years. It was effective on the clay soils at Lod-dington in years 2 and 3 (P < 0.05) and on the sandy soils at OldHattons where it was trialled in year 3. Conversely, in year 1 onthe clay soils at Loddington runoff, suspended sediment and total Plosses increased by two to three times under minimum tillage, andin year 3 on silt soils at Rosemaund, suspended sediment and totalP losses also increased very slightly under minimum tillage. TheRosemaund results should be considered in the context of a rela-tively dry winter monitoring period when losses of runoff, sedimentand P were low.

Cultivation on the contour was an effective mitigation treatmenton the clay soils at Loddington in one of the two years that it wastrialled, however, it affected ponding and routing of runoff on thehillslope which meant it was not always effective. Including a 2 mwide beetle bank on the contour significantly reduced runoff, sed-iment and P loss in year 1 (P < 0.01), and was also effective in year2 on traditionally ploughed soils.

Financial impact

The results presented here cover both the farm and regionallevels. Table 4 illustrates the 2006–2008 cropping areas and, basedupon this, an overall crop rotation margin per hectare for each casestudy farm and region, the latter for 2006 only due to unavailabilityof data at the time of the analysis. The difference between yearsat the individual farm level is primarily due to fluctuating cropprices with low commodity prices in 2006 and much higher pricesin 2007, although these are set against increases in variable andfuel costs. These fluctuations allow the impact of the mitigationoptions to be viewed at a time of both relatively high and low prof-itability in the farming community. Returns at the regional levelare much lower than the returns estimated for the individual casestudy farm’s. This reflects a poorer performance at regional levelwith lower commodity prices and higher production costs, partic-ularly for labour and machinery, when compared to those derivedfor the individual case study farms. It should be noted that the datafor the regional analysis reflects crop prices received over a periodof time. The prices would also include both forward contracts andspot prices rather than just the spot prices used for the individ-

ual farm analysis. Additionally, the higher production costs at theregional level may reflect the ongoing increase in input costs thatoccurred at this time whereas input prices for the case study farmswere taken at a point in time each year.

238 A. Bailey et al. / Land Use Policy 30 (2013) 234– 242

Table 3aEffectiveness of mitigation options on silt.

Treatment Trial years Reduction, compared to control treatment, in

Runoff (mm) Suspended sediment (kg ha−1) Total phosphorus (kg ha−1)

Tramline disruptiona 1, 2, 3 5.3–75.4 (95–97%) 373–4780 (98–99%) 0.72–2.89 (97–99%)Minimum tillage 3 a a a

Data is excluded from the table where treatments were not effective in reducing runoff, sediment and/or phosphorus loss compared to the control treatments. This is forease of illustration, but the following should be noted in any interpretation.

a Not effective when trialled in year 3, with increased runoff and sediment loss from both the disrupted tramlines and minimum tillage treatments. However, this effectshould be considered in relation to the low runoff and sediment losses measured for all treatments at this site in that year.

Table 3bEffectiveness of mitigation options on sand.

Treatment Trial years Reduction, compared to control treatment

Runoff (mm) Suspended sediment (kg ha−1) Total phosphorus (kg ha−1)

Crop residue incorporation 1 0.2–2.0 (24–50%) 9–200 (40–43%) 0.03–0.52 (34–50%)Tramline disruption 2, 3 3.5–11.0 (69–88%) 49–783 (75–96%) 0.19–2.14 (72–95%)Minimum tillage 3 2.2–7.8 (66–81%) 107–847 (94–98%) 0.33–2.28 (92–97%)

Table 3cEffectiveness of mitigation options on clay.

Treatment Trial years Reduction, compared to control treatment

Runoff (mm) Suspended sediment (kg ha−1) Total phosphorus (kg ha−1)

Minimum tillagea 1, 2, 3 13.6–31.6 (36–62%) 54–1133 (47–62%) 0.04–0.86 (34–52%)Contour cultivation (plough) 1, 2, 3 16.5–56.0 (64–76%) 90–1223 (67–79%) 0.09–1.00 (60–79%)Contour cultivationb (minimum tillage) 1, 2, 3 40.9 (73%) 319 (45%) 0.39 (48%)Beetle bank (plough) 1, 2 14.0–17.6 (45–91%) 41–228 (37–94%) 0.214–0.45 (32–97%)Beetle bankc (minimum tillage) 1, 2 11.9 (64%) 63–124 (16–81%) 0.04–0.24 (9–74%)

Data is excluded from the table where treatments were not effective in reducing runoff, sediment and/or phosphorus loss compared to the control treatments. This is forease of illustration, but the following should be noted in any interpretation.

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Table 5 shows the cost (and savings) associated with the miti-ation options for the individual crop enterprise and overall cropotation margins across the three case study farms, the latter partic-larly relevant where options are not applied across all crops within

farms’ rotation. It also shows the cost (and savings) at the regionalevel. Table 6 shows the percentage effectiveness of each mitigation

ption (from Tables 3a–3c) alongside the financial impact on theverall crop rotation margin at the regional level (from Table 5),efore showing the cost effectiveness of these options (percentage

able 4ropping area and overall crop rotation margin per hectare, 2006–2008.a

Site Year Cropping area (%)

Wheat Barley Oats

West Midlands 2006 53 16 6

Rosemaundb2006 38 16 21

2007 40 15 13

2008 39 16 17

Old Hattons2006 41 33 0

2007 32 33 6

2008 63 12 0

East Midlands 2006 56 11 2

Loddington2006 51 0 7

2007 45 0 12

2008 47 0 9

a Yields and prices for the 2008 harvest were not available at the time of the analysis.ields and prices were the average of the previous two years’ results.b In 2007, ADAS Rosemaund was sold and the majority of fields not under trials were p

he mid-point of the previous two years’ cropping.

nt loss.r 3 with increased surface runoff and sediment loss., but did achieve some reduction in sediment and phosphorus loss.

reduction against pounds saved or spent) and the resultant overallcrop rotation margin for 2006 in both the West and East Midlandsregions.

The tramline disruption option took place as an additional passin cereal crops following autumn spraying, and was identifiedas a separate cost which was deducted from the relevant crop

enterprise margin in both the farm and regional models. Labourand machinery costs for this operation are comparable to that ofspring tine harrowing given the similar equipment used. In the

Overall crop rotation margin (£ ha−1)

Oilseed Rape Beans

12 5 £58

17 0 £18323 0 £50220 0 £291

26 0 £20230 0 £60425 0 £423

18 6 £68

20 14 £20123 11 £48422 15 £304

The calculation of the net return for each case study farm therefore assumes that

ut down to potatoes. For the purposes of the project cropping areas were taken as

A. Bailey et al. / Land Use Policy 30 (2013) 234– 242 239

Table 5Impact of mitigation options for individual crop enterprise and overall crop rotation margins per hectare at the farm and regional level, 2006–2008.a

Mitigation optionb Impact on margin (£ ha−1)

Case study farms Regional farm overall crop rotation margin

Individual crop enterprise margin Overall crop rotation margin

Minimum tillage +£50 +£45 to £50 +£68 to £70Contour cultivate £0 £0 £0Tramline disruption −£3 to −£5 −£2 to −£4 −£2 to −£4Beetle bank −£2 to −£5 −£2 to −£5 −£2Crop residue incorporation −£25 −£19 −£17 to −£19

−, reduces crop margin; +, increase crop margin.a The data presented reflects the range of impacts found across all three farms in all years and for both regions for the 2006 harvest. At the time of the analysis farm business

survey data, used for the regional analysis, was not available in 2007 and 2008.ps onl

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b Tramline disruption and straw residue options are applied to winter cereal crore assumed to apply to all crops within a rotation.

xperimental set-up a much slower work rate than that possibleith normal cultivation practice was evident, equating to a cost

f £38 ha−1 on silt at Rosemaund (heavy soil) and £18 ha−1 onand at Old Hattons (light soil). This reflected the small nature ofhe experimental hillslope lengths, the time taken for setting uphe machinery and the 12 m spacing between each tramline usedor experimental purposes. In commercial practice, the per hectareork rate would increase as 24 m tramline spacing is far more com-on on many farms in England. Therefore, and more realistically,

n light soils, up to 12 ha/h could be achieved at a cost of £2 ha−1.ssuming a conservative work rate of 10 hectares per hour on lightoils the cost would equate to £3 ha−1 per crop. A slower work ratef five hectares per hour per crop on heavier soils would equateo a cost of £5 ha−1. Within the overall crop rotation margin perectare, at both the farm and regional levels, this would equate to

cost of between £2 and £4 dependent on crop margins that yearnd the soil type. No additional equipment costs were calculated

s it can be safely assumed that on the majority of farms the typef equipment required would already be available and in use foronventional operations. Furthermore, there was no impact on thegronomy of the adjacent crop.

able 6ost-effectiveness of the mitigation options and impact on the overall crop rotation marg

Mitigation option Effectiveness (%) Impact on m(£ ha−1)

West MidlandsPlough (control)

Options that save moneyContour minimum tillage 45–73 +£70

Contour min. tillage with beetle bank 9–97 +£68

Minimum tillage 4–98 +£70

Contour plough c 60–79 £0

Options that cost moneyTramline disruption 69–99 −£2 to £4

Contour plough with beetle bank 32–97 −£2

Crop residue incorporation 24–50 −£19

East MidlandsPlough (control)

Options that save moneyContour minimum tillage 45–73 +£68

Contour min. tillage with beetle bank 9–97 +£66

Minimum tillage 4–98 +£68

Contour plough c 60–79 £0

Options that cost moneyTramline disruption 69–99 −£2 to £3

Contour plough with beetle bank 32–97 −£2

Crop residue incorporation 24–50 −£17

t zero cost, cost-effectiveness for contour cultivation cannot be calculated. If a £5 ha−1 cosnd crop residue incorporation in terms of cost-effectiveness. Other options involving co

a Regional farm business survey data for 2007 and 2008 was not available at the time ob Cost-effectiveness calculation based upon lowest potential effectiveness against cost.

y with regard to determining the impact at farm/regional level. The other options

To set the context for the cost of straw residue incorporation, thecost associated with straw baling and removal was considered asan additional deduction from the relevant cereal enterprise oper-ating margins, as with tramline disruption, in both the farm andregional models. The costs were based upon contractor costs asthis was the approach used at the site in question. This amountedto approximately £1 ha−1 for each cereal crop reducing the overallcrop rotation margin per hectare by less than £1 ha−1. This allowsdirect financial comparison with straw cutting and incorporation.Straw cutting was undertaken at harvest and incorporation tookplace during subsequent crop establishment. Straw cutting can addan additional £5 ha−1 to harvesting costs due to a slower work rate(Nix, 2005). If using a contractor to undertake straw cutting as a sep-arate operation costs can be as high as £25 ha−1 (Nix, 2005) which,within the overall crop rotation margin per hectare, would equateto a cost of £19 ha−1 at the individual farm level and between£17 and £19 ha−1 at the regional level. The variation in cost

reflects the difference in the original margins achieved between thetwo regions. Other impacts associated with straw incorporation,such as improved organic matter content giving rise to improvedyields and, conversely, increased weed and disease problems, were

in per hectare at the regional level, 2006.a

argin Cost-effectiveness (% reductionper £ saved/spent) b

Resultant overall croprotation margin (£ ha−1)

£58

0.64 £1280.13 £1260.06 £1280.00 £58

23.00 £54 to £5616.00 £56

1.26 £39

£68

0.66 £1360.14 £1340.06 £1360.00 £68

27.60 £65 to £6616.00 £66

1.41 £51

t is assumed then the contour plough option would fall between tramline disruptionntour cultivation would remain as they are currently ranked.f analysis.

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40 A. Bailey et al. / Land U

ot evident primarily as a result of the short trialling of thisption.

The switch to minimum tillage is implicitly included in theodel within the relevant crop enterprise margins. In the farmodel impacts on the crop enterprise margin were incorporated

s direct costs/benefits. In the regional model impacts were incor-orated as percentage changes for each crop enterprise margin. As

s to be expected, the switch to minimum tillage system reducedstablishment costs and thereby increased the crop rotation marginy £45–50 ha−1 at the farm level and £68–70 ha−1 at the regional

evel, the relative impact being greater with the lower returns foundt the regional level. Field records across all three years suggestedhat at all sites there were no impact of treatments on fertiliser orgro-chemical applications, or crop yield. Similarly, at Loddington,here minimum tillage was trialled for all three years, there waso additional cultivation to counteract problems with compaction,

requently undertaken one year in four or five under such systemsn the UK. Additional costs associated, for example, with reducedields as a result of compaction, operations to counteract thisnd/or increased agro-chemical costs as a result of increased weedurdens would reduce the calculated margin. Guidance providedy the Environment Agency (2003) suggests savings from reducedillage can be as little as £10–£25 ha−1, however, the cost estimatesiven here are similar to those reported in the Diffuse Water Pollu-ion from Agriculture (DWPA) User Manual at £30–50 ha−1 (Cuttlet al., 2007).

The change to operating across the contour was not explicitlyosted as there was little evidence of either increased or reducedosts. In reality, there is the possibility of additional time spent inhe field as a result of a reduced work rate which would increase theperational costs per hectare associated with crop establishment,nd also potentially affect fertiliser applications and the sprayingf agrochemicals. Many farmers are reluctant to adopt contour cul-ivation because of the difficulties associated with cultivation andpraying operations across the contour. D’Arcy and Frost (2001)uggest extra costs associated with contour ploughing of £5 ha−1,hile the DWPA manual reports costs of £23 ha−1 (Cuttle et al.,

007). Conversely, contour ploughing can reduce costs, for examplehrough improved fuel use efficiency. The opportunities to adoptontour ploughing, and whether it can improve or reduce workates and associated costs, is heavily dependent on slope.

The establishment of a beetle bank across the contour of a fieldas to include a number of costs. First there is the cost associatedith the loss of productive land. To some extent this is dependent

n the size of the field and the proportion of land that is taken outf production as well as the opportunity cost of the crop enter-rises within the farm rotation that it replaces. Second there aredditional costs associated with the reduced field size leading to alower work rate and, as a result, increased crop enterprise opera-ional costs. At the site where the beetle bank was established lesshan 1% of the field area was taken and it was estimated that, forhe two years it was present, it reduced the overall crop rotation

argin per hectare by between £2 and £5 ha−1, the greater costeing associated with the opportunity cost of better returns fromrop commodity production. In addition to impacts on the cropargins, there are costs in the first year for establishment and in

ubsequent years for maintenance. The initial cost for the estab-ishment of a beetle bank covers land preparation, sowing of grasseed and cutting in the first year. A fully mechanised operationith plough, seedbed cultivation, drill and roller was assumed. The

ost for establishment, which is not included in the margin figure,as estimated at £163 ha−1. This is comparable with costs given

y Nix (2005) for establishing 2 m grass margins and beetle banksuoted as £3–5 per 100 m and equating to £150–250 ha−1. In prac-ice, areas taken for the beetle bank would probably be less thanne hectare, allowing for some reduction in cost if the area was

cy 30 (2013) 234– 242

small enough to be seeded by hand. In subsequent years regularmaintenance of the vegetation may be required. This did not takeplace during the time that the beetle bank was in place at the casestudy site. Nix (2005) suggests a cost of approximately £21 ha−1 forgrass mowing/topping or 50–60 pence per 100 m (£25–30 ha−1) forthe maintenance of 2 m conservation margins. The DWPA manual(Cuttle et al., 2007) calculates overall costs at £32 ha−1, althoughit is assumed that a greater proportion of land area is taken out ofproduction.

Discussion and conclusion

The control of diffuse pollution is receiving considerableresearch and policy interest across Europe, driven partly by theintroduction of the EU Water Framework Directive. The UK gov-ernment is currently approaching the challenges of the Directivein a number of ways: through Cross Compliance measures underthe Single Payment Scheme of the Common Agricultural Pol-icy, including soil management and the control of nitrates underNitrate Vulnerable Zones (Rural Payments Agency and Defra, 2007);through incentive based policy under Environmental Stewardshipwith vegetative buffer strips (Natural England, 2009); and throughthe targeted England Catchment Sensitive Farming Delivery Initia-tive (Defra, 2009).

The MOPS project reviewed in this paper highlights the cost of anumber of existing and additional within-field mitigation optionsfor reducing P loss, only some of which are incorporated withinCross Compliance and Environmental Stewardship. It is in this con-text that each of the options trialled in the MOPS project should beevaluated. Under Cross Compliance, focused on reducing erosionand runoff through soil management, relevant measures referredto include adoption of minimum tillage and direct drilling, culti-vations across the slope, and retaining crop residues. Farmers arerequired to undertake a soil protection review and consider soilmanagement, but not necessarily adopt the suggested measures. InEnvironmental Stewardship, under the Entry Level Scheme com-ponent, there are incentives for ‘buffer strips’ and ‘beetle banks’,although not necessarily within-field, but there is also an optionfor ‘in-field grass areas to prevent erosion and runoff’. As an incen-tive based voluntary initiative it is up to individual farmers to optinto Stewardship and sign up to the different options if they feelthe incentives are worthwhile.

Minimum tillage is suggested as one option for soil manage-ment under Cross Compliance due to the potential for increasingsurface roughness and thus reducing erosion. In the MOPS projectminimum tillage was the only option to reduce costs and improvecrop margins. It was associated with high ongoing annual cost sav-ings of £45–50 ha−1 at the farm level and £68–70 ha−1 at the widerregional level. This ignored the initial high capital investment topurchase the required equipment, although some benefit could beachieved through the sale or exchange of existing equipment. Ris-ing fuel costs may also encourage more farmers to consider thisoption on suitable soils. In terms of mitigation effectiveness, theproject found that minimum tillage reduces runoff, sediment andP losses from arable land under combinable crops if establishmentconditions are favourable, which was not always the case. Therewas also a wide variation in the amount of runoff, sediment and Ploss reduction achievable, from 34 to 98%.

Cultivations across the slope (contour cultivation) are alsosuggested under Cross Compliance. Contour cultivation has thepotential to control diffuse pollution losses but would only be prac-

ticable on a limited range of slope angles and forms. In the MOPSproject it was effective in two years of monitoring in reducingsediment and P losses by 45–79% and did not obviously affect oper-ations or costs. However, in other situations the work rate across

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he contour could be slower leading to an increase in costs. Con-ersely, there are potential cost savings through reduced fuel use.he greatest reductions, 60–79% for P loss, were achieved on tradi-ionally ploughed soils whereas contour cultivation in combinationith minimum tillage showed less reduction for P loss. The addi-

ion of a beetle bank on the contour raises costs, but can lead tourther reductions in sediment and P loss of 9–97%, with the great-st reductions, 32–97%, also occurring on traditionally ploughedoils. However, the usefulness and cost of this option is heavilyependent on field size, with smaller field sizes increasing both theosts associated with the ability to undertake operations and theoss of land to a level which would not be economic. There are alsodditional costs for the initial establishment and ongoing main-enance of the barrier. The incentives for beetle banks and in-fieldrass areas under Environmental Stewardship may overcome somef these issues, but with limited applicability and the resistancef farmers to both contour cultivation and within-field measureshese are not options that many farmers are likely to adopt.

Retaining crop residues is the final mitigation option men-ioned in policy, under Cross Compliance. In the MOPS project, cropesidue incorporation, with reductions for runoff, sediment and Poss between 24 and 50% and costs as high as £19 ha−1 across aotation, would appear not to be as effective or as affordable as thether options identified. However, the cost given here assumes aeparate operation. Costs will be lower where the cutting of straws undertaken by the combine at the time of and as part of the har-est, although there may be a small additional cost as a result of alower harvesting rate and also subsequent cultivation work rate.ther factors linked to the farming system will also be influential.here are benefits and costs in terms of future crop productivitys a result of straw residue incorporation not considered in thisesearch. Further, the market for the straw and its potential valueould also determine whether it is beneficial to remove and sell thetraw or leave it in the field for incorporation during cultivation forhe following crop.

The one mitigation option not addressed under Cross Com-liance nor Environmental Stewardship is tramline management.ramlines are an important component for the management ofombinable crops, but lead to sediment and P losses. Tramlineanagement treatments such as tramline disruption trialled in

he MOPS project have the potential to be a cost-effective miti-ation option, reducing runoff, sediment and P losses by 69–99%.ssuming tramline spacing of 24 m and a 3–5 year rotation, tram-

ine disruption could be achieved for a low cost of £2–4 ha−1. Peround (£) spent, this leads to 23–28% effectiveness in reducing sed-

ment and P loss per pound, much higher than the other optionsxamined. The costs identified here assume a separate field visitfter cultivation and the final autumn spray applications. Costsould be reduced further if the tramline disruption could be com-ined in some way with the last autumn spraying, although thisould negatively affect the work rate for spraying. A more detailedve year study of a wide range of alternative options for managingramlines in cereal crops (including seeding tramlines, use of lowround pressure tyres, and roller/tine configurations for differentoil and site conditions) is now underway with funding from theefra Sustainable Arable LINK programme (see Farmers Guardian,1 December 2009, p16).

In conclusion, the field trials demonstrated that each of theitigation options had some potential for reducing sediment and

losses from arable land under cereal crops, with options thatllowed cost savings and options that were associated with somedditional costs. The nature of costs reported here and their relative

mpact is dependent on other factors including the market forces

hich influence input costs and crop prices, illustrated by the fluc-uations that occurred over the period of this study. Within theroject, the success of all of the mitigation options depended to a

cy 30 (2013) 234– 242 241

large extent on farmer attitude and willingness to implement eachoption. The uptake and success of each of the options commerciallywill depend on farmer perceptions of the benefits derived formthe mitigation options, adoption costs (e.g. equipment, training),potential real and perceived agronomic risks (e.g. on disease, pests,yield, compaction), and how mitigation management practices canbe practically and most cost-effectively integrated into conven-tional farming operations, which may include revisiting the roleof Cross Compliance or incentive schemes such as EnvironmentalStewardship.

Acknowledgements

This work was funded by the UK Department of Environment,Food and Rural Affairs (Defra) under the Mitigation of Phosphorusand Sediment (MOPS) project contract (PE0206). The authors wouldlike to thank ADAS UK Ltd., Severn Trent Water plc, and the Gameand Wildlife Conservation Trust and the Allerton Project for accessto field sites and logistical support; Paddy Keenan at the LancasterEnvironment Centre for undertaking the laboratory analyses; staffat ADAS including John Lapworth, Tony Wade, Phil Bounds and RobHowells, and Gareth Morris, Angela Wakefield, Brenda Cookson;and students at Lancaster University for their input to the experi-mental fieldwork campaigns. Data provision by the Farm BusinessSurvey teams at the Universities of Reading and Nottingham is alsoappreciated. The authors would also like to thank the journal edi-tor and the two anonymous reviewers who provided commentson an earlier draft. Nevertheless, the opinions expressed here andconclusions reached are solely the responsibility of the authors.

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