Memorandum submitted by Broom's Barn Research
Station (O50)
EXECUTIVE SUMMARY
This submission is from Broom's Barn, the national
centre for sugar beet R&D, whose role is to improve the productivity,
profitability and environmental impact of sugar beet production
in England. The submission concentrates on the environmental impact
of beet, and how this will change if beet becomes unprofitable.
— Beet is always grown as a spring-sown
"break" crop in rotation with other crops, most of which
are winter cereals.
— The beet crop therefore provides
diversity in the arable landscape, contributing support to many
bird species, some of which are already in decline.
— Because beet is a break crop, it
helps to maintain yield and reduces the need for fertilizer and
pesticide in other crops in the rotation.
— Pesticide use in beet is relatively
benign and no beet pesticide has caused a breach of the Environment
Quality Standards for surface or ground water.
— Significant nitrate leaching into
surface or ground water from beet is rare, unlike leaching from
cereals and potatoes.
— If beet ceases to be profitable,
we believe it will be replaced by combinable winter crops, leading
to a major loss of habitat diversity and increases in problems
associated with pesticide use.
— Soil erosion from beet fields is
not a serious problem and would probably not improve if other
crops replaced beet.
— The energy efficiency of sugar beet
production is such that it is an attractive candidate for a bio
ethanol feedstock; its production would provide the same environmental
benefits as beet produced for sugar, over an additional area.
— The alternative to sugar from beet
is sugar from cane, whose environmental profile, even in the most
sophisticated cane producing areas, is not blameless. Many old,
persistent, toxic agrochemicals are used.
— There is scope to improve the environmental
profile of beet still further and we have an active R&D programme
to achieve this.
In conclusion, as a break crop beet improves
the environmental impact of the whole rotation and it adds diversity
to the landscape that helps to support a range of wildlife, much
of which is already in decline. To provide these benefits via
an agro-environment scheme instead of the beet crop would be very
expensive for the taxpayer.
INTRODUCTION
Broom's Barn Research Station is the UK's national
centre for sugar beet agriculture and is an integral part of Rothamsted
Research, the world's oldest agricultural research institute.
Rothamsted Research is sponsored by the Biotechnology and Biological
Sciences Research Council, but most of the work at Broom's Barn
is funded by the UK sugar industry (growers and the processor).
Our research portfolio covers aspects of crop production and profitability,
reducing costs and pesticide inputs and minimising the environmental
impact of crop production through developing sustainable systems.
Broom's Barn is the largest sugar beet research station in Europe,
employing 13 postdoctoral research scientists, 12 graduate scientists
and appropriate support staff.
This submission concentrates on the impact of
sugar beet crop production on the environment of beet producing
farms in England, and on how this could change if the crop ceases
to be profitable. There is a brief statement about the environmental
impact of sugar cane production. The submission is divided into
the following topics:
1. Indirect effects of including beet in
the mix of crops on farms, providing diverse habitats for fauna
and flora.
2. Direct effects of beet in a crop rotation.
3. The direct effects of growing beet as
opposed to other crops.
4. Potential of beet crops for bioenergy
production.
5. The environmental impact of sugar from
cane.
6. Research to improve the environmental
profile of beet still further.
1. Indirect effects of beet crops in the
arable landscape
1.1 Beet, by regulation and for the reasons
of sustainable pest and disease control, cannot be grown on the
same piece of land any more frequently than every third year:
the average frequency is between four and five years. Therefore
the area of the crop (170,000 ha per year) has an influence on
the environment of about 760,000 ha and on 7,700 holdings[38]
Thus, beet must be grown in rotation with other crops, and this
ensures a diverse range of habitats.
1.2 The most common crops grown on beet
producing farms are winter cereals (wheat and barley). In local
authority wards with more than two beet growers, 66% of the arable
area is winter crops[39]
These are sown in September and October for harvest during the
next July and August. This land is being prepared for sowing or
is cropped for 11 months of the year. These crops have a dense
canopy structure for much of the spring and early summer and are
unsuitable habitats for many farmland bird species.
1.3 More than 90% of beet is preceded by
a winter cereal, so the land is not cropped from cereal harvest
(August) through until the following March/April, when beet is
sown. For much of this time (three to six months) the fields are
undisturbed cereal stubbles, which are excellent winter feeding
habitats for seed eating birds such as finches and buntings[40]
1.4 Beet crops retain an open vegetation
structure and areas of bare soil until early summer, providing
nest sites for many ground-nesting birds such as stone-curlew,
lapwing and skylark[41]
The stone-curlew is a UK Biodiversity Action Plan priority species
whose numbers are threatened in W Europe. Beet is 63% of the area
of open-canopy cropping in regions where it is grown[42]
1.5 About half of the beet crop is harvested
after mid November and the next crop is therefore not sown until
spring. During this period the aftermath of the beet provides
valuable food sources for geese, swans, skylarks, golden plover,
lapwing, pied wagtail and meadow pipit[43]
More than a quarter of the world's population of pink-footed geese
feed on beet fields in Norfolk during winter[44]
2. Environmental benefits of beet as a part
of arable rotations
2.1 Continuously growing closely related
crops leads to a build up of pests and diseases which, if not
controlled by other means, cause yields to decline. Arable farmers
try to use "break" crops to prevent this. In wards where
there are more than two beet growers, 10% of the area is beet
and 63% is cereals[45]
so wheat followed by another cereal is common. There is little
chance to expand the area of other break crops, they are not sufficiently
profitable or their market is satisfied[46]
Therefore any reduction in the beet area will tend to increase
the area of winter cereals. Each hectare of beet removed will
tend to add 2ha to the area of second or third successive winter
cereal. Second wheat crops yield about 1 t/ha less than the first
and cost about £20/ha more to grow, mostly because they need
more nitrogen fertilizer. First wheat yields about 20% more than
continuous wheat[47]
3. Direct environmental impacts of beet cropping
3.1 Recent studies, funded by the beet sugar
industry, examined a range of production scenarios representing
more than 90% of the UK beet crop. The study concentrated on the
ecotoxicity of pesticide use, pesticide and nitrate leaching,
energy consumption and global warming potential.
3.2 Ecotoxicity scores assess the risk that
pesticide use will damage non-target fauna. Beet and wheat score
similarly well, much better than other break crops[48]
Beet's position will improve still further when aldicarb (a granular
insecticide) is withdrawn from use in beet in 2005. There were
no significant instances of pesticides leaching from beet fields
when the production scenarios were modelled: pesticides used on
beet crops have not caused failures of Environmental Quality Standards
for surface or ground water[49]
unlike pesticides used on winter cereals.
3.3 Modelled nitrate leaching losses from
beet were trivial, averaging 3.3kg N/ha, compared with losses
from other crops which ranged from 19 to 65kg N/ha.
3.4 Energy consumption studies took account
of input manufacture (seeds, fertilizers, pesticides etc), agricultural
operations, transport and machinery manufacture. Inputs ranged
from 15-25GJ/ha with a mean of 20.4GJ/ha by the time the beet
arrives at the sugar factory gate. This is slightly less than
the average for wheat at the farm gate, and is much less than
potatoes. Energy output in delivered beet ranged from 150-220GJ/ha,
giving output/input ratios ranging from 6-13.
3.5 Global warming potential considers the
probable output of all greenhouse gases, expressed as tonnes of
CO2 equivalent/hectare of crop. Sugar beet output is about 1.4
t CO2 eq/ha, similar to winter wheat and much less than potatoes.
However, to balance this, sugar beet crops fix about 35 t CO2/ha.
3.6 In relation to soil conservation/degradation,
sugar beet used to be subject to serious wind erosion. Research
has been taken up to protect the surface soil in exposed sandy
and peaty soils so that, in any year since 1990, no more than
500 ha of crop were resown due to wind damage.
3.7 Sloping fields with unstable sandy soils
are prone to water erosion during storms. Water erosion does occur
when beet is grown on these fields, but only small quantities
of soil (0.3mm/ha) are moved and almost none of this leaves the
field[50]
Winter cereal crops grown on the same fields are at a similar
risk of erosion[51]
3.8 Soil adheres to sugar beet when they
are harvested, but this represents only a small percentage of
the weight taken to the sugar factory (4.6% in 2003). This soil
is not lost, but is recycled for soil improvement, landscaping
and reclamation projects.
3.9 Water is scarce in eastern England,
and water for irrigation should be reserved for the most valuable
crops. Only about 5% of beet is irrigated.
3.10 Weeds are more difficult to control
in beet than in cereals and this has the advantage that some broadleaf
species, like fat hen, produce many seeds in beet fields. These
plants support populations of invertebrates and seeds to support
populations of birds during late autumn and winter, when food
is scarce[52]
3.11 Harvest of any crop removes plant nutrients
from the field, and beet is no exception. However, when beet is
processed, large amounts of potassium can be extracted from molasses
and recycled in a material called "raffinate". This
potassium-rich fertilizer, now being marketed to beet growers[53]
is a clear demonstration of a sustainable approach to use of resources.
3.12 The sugar extraction process use lime.
Once this has been used in the sugar factory it is recycled to
neutralize and condition agricultural soils.
4. BEET AS
A BIOENERGY
CROP
4.1 The EU biofuels directive calls for
2% biofuels use across the EU road transport system by 2005 in
order to cut CO2 emissions in the UK by about 2Mt/a. Candidate
fuels are biodiesel and bioethanol. Candidate feedstocks for bioethanol
are beet and wheat. Beet has a large positive energy output/input
ratio and, unlike wheat, produces sugar, the most efficient feedstock
for ethanol production. Beet used for bioethanol production will
have the same environmental benefits in arable landscapes and
cropping systems as beet produced for sugar extraction. There
are significant opportunities to optimise the energy efficiency
of using beet if sugar and bioethanol are produced side by side
in the same factory. Concentration on wheat as a starch-based
feedstock will intensify the deleterious effects of winter-cropped
landscapes.
5. THE ENVIRONMENTAL
IMPACT OF
SUGAR CANE
PRODUCTION
5.1 Sugar cane is the alternative to sugar
beet as the natural source of sucrose sweetener. It is grown in
semi-arid tropical and subtropical environments, where its environmental
profile is not blameless.
5.2 Cane is a tall (>3m) perennial crop,
in the ground for four to seven years before the next cane crop
is planted. It is grown as a monoculture: in cane environments
it is usually the only crop species. This has serious adverse
effects on biodiversity and on the farmers' ability to control
pests and diseases[54]
In consequence, even with sophisticated agriculture and with sensitive
environments (coastal Queensland, Everglades in Florida) pesticides
have to be either persistent or applied repeatedly, sometimes
from the air (eg thallium sulphate rodenticide).
5.3 There are serious issues about pesticide
pollution of ground water, rivers and coastal areas (eg diuron
herbicide in Queensland). A toxic group of chemicals, organophosphates
(OP's), are heavily and repeatedly used to control various boring
insects. In some areas with sophisticated agriculture there are
analytical services to assess whether the OP content of soil is
large enough so that farmers do not reapply the materials unnecessarily.
OP's are hardly used in UK beet.
5.4 Persistent herbicides have to be used
in cane to control rhizomatous grasses that spread rapidly in
perennial crops: thus atrazine and asulam use is common.
5.5 Cane grown in many semi-arid areas has
to be irrigated during the dry season. In Queensland, 40% of the
crop is irrigated: in Mauritius 20%. Cane is an inefficient converter
of water to sugar, and in many regions this water consumption
is not sustainable and is now in conflict with the water demands
of the population eg for tourism.
6. IMPROVING
THE ENVIRONMENTAL
PROFILE OF
BEET IN
ENGLAND
6.1 Current research and technology transfer
efforts at Broom's Barn hold the promise of improving the environmental
profile of beet crops still further.
6.2 Research is aimed at improving the natural
resistance of the beet plants to pests and diseases, using genes
from beet's wild relatives. For example, research is being done
to improve resistance to yellowing viruses (to reduce use of insecticides)
and to foliar fungal diseases.
6.3 A technology transfer initiative is
demonstrating the wildlife, soil protection and economic benefits
of leaving uncropped margins within beet fields.
6.4 Crop management systems are being investigated
to produce more weed seeds in beet crops (as food for small birds)
while minimising the impact on the profitability of the whole
farm rotation.
7. CONCLUSION
7.1 Sugar beet is a spring break crop in
rotations that are dominated by winter-sown crops. The latter
do not support many of the farmland bird species that are in decline.
By contrast, beet adds diversity to the arable landscape and supports
wildlife because it allows stubbles to remain over winter and
provides an open canopy structure in summer (favoured by stone-curlew,
skylark and lapwing). Weeds in beet are difficult to control and
these too provide food for wildlife. In addition, the aftermath
of beet crops provide valuable feeding sites for geese, plover
etc during winter.
7.2 If beet ceases to be grown, the benefits
of a diverse landscape will not be provided by other crops. Instead
winter crops will cover almost all the land.
7.3 Pesticide use in beet has a similar
ecotoxicity profile to wheat and is more benign than many other
crops. Beet pesticides do not feature in breaches of water quality
standards. Thus, the deleterious aspects of pesticide use would,
if anything, worsen if beet is replaced by other crops.
7.4 Energy consumption by beet is similar
to wheat and beet is a serious candidate as a biofuel feedstock.
The crop sequesters large amounts of CO2 and has a benign global
warming profile.
7.5 Sugar from cane is the alternative natural
sweetener, but the environmental profile of cane is not blameless.
7.6 There is research to improve the environmental
profile of beet still further. However, if beet ceases to be attractive,
farmers will probably turn to wheat or rape, neither of which
provide the diversity benefits of beet. To provide these benefits
by direct payments to farmers, perhaps via an agro-environment
scheme, will be very expensive.
31 March 2004
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