THE USE OF SHROPSHIRE SHEEP IN TREE PLANTATIONS AND COMMERCIAL FRUIT CULTURES
By Pippa Geddes and Raimund Kohl

One of Britain’s oldest sheep breeds, the Shropshire Down, has recently come to the attention of fruit growers seeking to minimise applications of herbicides in tree plantations and vineyards. The use of Shropshires for controlling weed growth between trees can reduce agrochemical pollution of groundwater and replaces the need for mowing. The sheep can also help to reduce the spread of fungal diseases by consuming the fallen leaves and, as renowned producers of meaty lambs, Shropshires also deliver another valuable income stream for the farmer or grower.

Whereas most other breeds of sheep strip bark and foliage from trees, the Shropshire has a well established reputation for being “tree safe”, particularly in conifer plantations. The compatibility of Shropshires and conifers was first identified more than 20 years ago by Graham Allan, a Scottish shepherd who lives and works in Denmark. He developed and promoted the system of grazing sheep in trees in Denmark and other northern European countries, including Austria, Germany, Switzerland and the UK.  

The breed is now used successfully by hundreds of tree growers and is especially popular with producers of Christmas trees. Provided that Shropshires are managed correctly, they are suitable for use in Spruce (Picea sp.), Pines (Pinus sp.) and Firs (Abies sp.), although the latter can sometimes be vulnerable to nibbling by sheep. Management techniques for ensuring that Shropshires work efficiently in plantations are available in a guide* published by the Shropshire Sheep Breeders’ Association of the UK.

Grazing Shropshires among fruit trees
Practical experience on many farms suggested that Shropshires were also suitable for grazing in deciduous plantations, including orchards of apples (Malus domestica) and pears (Pyrus communis). In addition to keeping weeds at bay, the sheep eat fallen leaves and so can help to prevent the spread of fungal diseases, such as apple scab (Venturia inaequalis). Mechanical removal of fallen scaby leaves is known to reduce the scab infection rate in spring (MacHardy, 1996). Reduction rates of 80% were reported from long-term experimental studies (Sutton and MacHardy, 1993).

Co-author of this article, Raimund Kohl, was instrumental in setting up a trial at the Research Centre for Fruit Growing at Lake Constance, Bavendorf, Germany to establish the suitability of Shropshires for use in commercial orchards. This trial started in 2006 and set out to monitor the performance and behaviour of Shropshire sheep in three different tree plots
(see table 1 below).

Table 1

	Plot 1	Plot 2	Plot 3
Period grazed by Shropshire sheep	During full foliage (May – June)		During leaf fall
Age of trees/ and type of root stock	Older than 20 years, Middle high stem	Planted in 1996, A2 Semi dwarf size	Planted in 1987, M9 Dwarf size
Stem height above the ground (to lowest branches)	Varies	70 to 85cm	60 – 70cm
Management system	Very extensive No grass cut No chemical spraying	Often mulched. Trees pruned in winter. No chemical spraying	Organic apple orchard, sprayed frequently with permitted substances
Vegetation surrounding trees	Old grass	Fresh, young grass	Grass cut very short and mulched

The trial showed that Shropshire sheep are suitable for use in orchards, however some management restrictions must be accepted. The following are the main conclusions of the trial:

• Shropshire sheep were docile and easy to manage amongst the trees. Water and minerals had to be provided for them, but no additional adaptations, such as extra shelter, were required.
• In all plots, sheep kept the ground vegetation tidy and short and routine mowing was not necessary. Nettles were not eaten, but Shropshires will consume them if they are cut and left to dry on the ground.
• Under normal weather conditions, the grass sward remained in good condition whilst sheep were grazing. Shorter grazing periods may be required during exceptionally wet seasons.
• Tree foliage in the growing season was attractive to the sheep. Leaves within reach were eaten, and the height to which tree foliage was consumed corresponded to the height of the sheep. In general, all branches to up to 1m above ground level were defoliated. The animals did not, however, rise on their hind legs to reach higher up. The amount of damage caused to the lower branches and soft shoots depended on the quantity and quality of other herbage on offer, and thus on the pasture management.
• To minimise the tree damage, regulated management of the surrounding pasture is necessary. Sheep should not remain in the same area for longer than three weeks. Large plantations can be divided with electric fencing.
• Thicker bark on older trees remained untouched by the sheep. Some damage was recorded in plots with younger trees. This was observed where herbage supply was short, and occurred only at the location where sheep rested. Compared with an earlier trial using Milk Sheep, the damage caused by Shropshires was insignificant and did not affect the long-term viability of the trees.
• Use of sheep in orchards with strongly growing semi dwarf size root stock (for example: M25, MM106 and MM111) is recommended. With the standard root stock, M9, the leaf loss had too strong an impact on the nutrition of the tree.
• Any spray treatments required by the trees must be carefully coordinated with the sheep grazing management. Disease resistant tree varieties which require a reduced spray programme are best suited to systems where sheep are utilised.
• The very wet weather experienced during autumn 2006 made it impossible to ascertain if Shropshires eat fallen leaves. Leaves on the ground quickly become soggy and smeared with soil, making them unpalatable. Farmers elsewhere, who use Shropshires to graze farm orchards, report that the animals do consume dry, fallen leaves. Further research will be necessary to answer this question conclusively.

 

Environmental benefits
Groundwater monitoring programmes in catchment areas with considerable acreages under fruit and vegetable production show that many agrochemicals used to manage these crops have already reached the groundwater. For example, data is available from the Baden-Württemberg State Agency of Environmental Protection (LUBW) in Germany. Groundwater quality in the Baden-Württemberg state was monitored at 2,500 measuring points. Examination of 10 years’ data showed that 50 of the 86 controlled pesticides and five of the six metabolites were detected. For example, substances such as bentazon; dicamba; dichlorprop (2,4-DP); mecoprop (MCPP); diuron; glyphosate and terbuthylazin were detected. These had been used as herbicides and, in some cases, also for fruit crop production.

LUBW also introduced a special monitoring programme in 2006 to control tolyfluanoid (a fungicide used to control scab) and its metabolite N,N-dimethylsulphide (DMS). Some 56% of 101 measuring points recorded concentrations of DMS above the limit (0.1 µg/L). The highest number of polluted groundwater measuring points could be found in the main fruit and vegetable growing areas, such as the Lake Constance and Upper Rhine area.

Financial benefits
Environmental pollution and the growing market demand for “natural” food are the main reasons for lowering the use of agrochemicals and encouraging farmers to convert to organic farming systems. Shropshire sheep can play a major role in controlling the vegetation in fruit tree plantation and can, therefore, help to replace herbicides. However, farmers’ willingness to use sheep depends to a large extent on the cost-benefit, compared with a conventional system. The table 2 outlines the cost of controlling orchard herbage by mechanical means.

Table 2: Summary of the costs of controlling herbage between trees in one hectare of organic apple orchard

	Working hours (one person for one hour)	Labour cost (12GBP per hour)	Cost of machine – running costs and depreciation  (GBP)
Mowing 6 times per year Tractor, 50kW, 2m mower	12	144	203
Root vole control	14	156	-
Leaf litter mulching with chaff cutter for scab control	4	48	68
Total costs (GBP per hectare)	619

Data are based on work by Stockert (1997) and KTBL Datensammlung ökologischer Obstbau (2005).

When stocked at a rate of between 6 and 10 animals per hectare, Shropshire sheep can replace the need for mowing, root vole control and, to some extent, scab control. The resulting cost savings amount to an estimated £619 per hectare. It is, however, good to mow at least once a year to ensure that any grassy areas not eaten by the sheep are cut short, and any remaining leaf litter will be shredded. The cost for one run with the mower is calculated at £58, and another 4 working man hours (£48) are necessary for some root vole control. So in total, the use of sheep can save around £500 per hectare per year.

To complete the cost-benefit comparison, one must take account the expense of managing the sheep, including labour, additional winter feed and the purchase of routine health-care. Set against these costs is the revenue obtained from lamb sales. In addition, fruit tree growers who market produce direct to the general public may find that Shropshire sheep can be used successfully to promote the “green” credentials of their businesses. Pollution-free production is a very attractive concept to today’s consumer.

Overall, the cost of keeping the sheep is roughly equivalent to the revenue from lamb sales. Thus a saving of £500 per hectare per year is the overall benefit of using sheep, in conjunction with the environmental bonus from having replaced the need for agrochemicals.

The additional workload of keeping sheep keeping is not very heavy and fits in well with the labour requirements of fruit production: The apple harvest in autumn coincides with the time when the sheep can be kept outside with minimal management requirements. On the other hand, the lambing period, which is the busiest time for sheep farmers, occurs in late winter when fruit trees require minimal management.

The future
Most Shropshires are currently used in Christmas tree plantations. But fruit growers are starting to take notice.
The results of the Lake Constance trial were published in 2007, and this has generated considerable new interest in Shropshires. French fruit producers made a joint importation of around 150 British Shropshires in summer 2008, and a repeat order for over 100 sheep was made in 2009. The breed society has received very positive reports of the performance of the sheep when grazed among a number of different fruit tree species, including use to control weeds in vineyards between the grape harvest and bud burst in the spring.
Operating figures show that the use of Shropshire sheep in commercial fruit cultures can be profitable, especially in organic farming systems. The breed society continues to gather technical information about the management of Shropshires in commercial fruit tree cultures, with a view to making this information more widely available to farmers and growers interested in this concept of environmentally friendly weed control.

- ends-

Pippa Geddes, Vice President of the Shropshire Sheep Breeders’ Association (UK), Stable Views, Alderton, Montford Bridge, Shropshire SY4 1AW, United Kingdom,  +44 (0)1743 741689, psellwood@aol.com, www.shropshire-sheep.co.uk.  Pippa is a livestock farmer and has a BSc (Hons) in agriculture. She has worked in agricultural journalism and marketing, and owns the Alderton Flock of Shropshire sheep (established in 1999) based in Shropshire, England.

Raimund Kohl, Secretary of the German Shropshire Sheep Breeders Association, Helferts Farm, Hopfwiesenweg 5, D-69517, Gorxheimertal, Germany, +49 (0)6201 22960, info@helfertshof.de. Raimund is a soil scientist working for Baden-Wuerttemberg State Agency of Environment, he also grows Christmas trees and owns the Helferts Flock of Shropshire sheep (established in 1992), based in south west Germany.

References:
Report on the trial with Shropshire sheep grazing in apple orchards at the Research Centre for Fruit Growing, Lake Constance, Bavendorf, Germany published in the magazine “Obst und Garten”, Issue 05/2007. Authors: Ullrich Mayr, Sybille Spath (both from KOB Bavendorf, Lake Constance Research Centre), Andreas Bruder and Raimund Kohl.

*“Two Crops From One Acre – a comprehensive guide to using Shropshire sheep for grazing tree plantations”, a booklet published by the Shropshire Sheep Breeders’ Association (www.shropshire-sheep.co.uk).

LUBW- Landesanstalt für Umwelt, Messungen und Naturschutz (ed.), 2007: Grundwasser-Überwachungsprogramm – Ergebnisse der Beprobung 2006. Report No.34. ISSN 1437-0131. Available as download: http://www.lubw.baden-wuerttemberg.de

KTBL, 2005: Ökologischer Obstbau 2004/05. Daten für den Ökologischen Obstbau in der Landwirtschaft. ISBN 3-7843-2179-8

MacHardy, W. E., 1996. Apple scab. Biology, epidemiology, and management. APS Press, St. Paul Minnesota.

Stockert, T., 1998: Kostenkalkulation im ökologischen Apfelanbau. LVWO Weinsberg. Available as download: http://www.landwirtschaft-mlr.baden-wuerttemberg.de/servlet/PB//menu/1039812_l1/index.html

Sutton, D. K. und W. E. MacHardy, 1993. The reduction of ascosporic inoculum of Venturia inaequalis by orchard sanitation. (Abstr.) Phytopathology 83, 247