Supplementary memorandum submitted by
Natural England (SFS 63a)
1. CONTEXT
1.1 This further evidence is presented within
the context of food and environmental security given in our original
submission to the Committee. In the submission we stated that,
in our view, the current problems of food insecurity in the UK
are concentrated at the household level and relate to dietary
patterns and nutritional security, rather than an absolute shortage
of food or chronic problems with supply.
1.2 In the long term, however, we cannot guarantee
such a secure food supply given a number of underlying factors
such as climate change, population growth, and the depletion of
oil. We therefore need to develop strategies to ensure the UK's
food security whilst protecting and enhancing our natural environment.
1.3 As well as more sustainable food production,
we believe nations should seek to avoid and lessen the projected
increase in demand for food as far as possible, through encouraging
more sustainable consumption and diets and less waste in supply
chains and by households.
2. INTERRELATIONSHIP
BETWEEN FOOD
PRODUCTION AND
THE NATURAL
ENVIRONMENT
2.1 The natural environment provides a diverse
range of edible plants and animal species that have been and continue
to be used as food. About 7,000 species of plants and several
hundred species of animals have been eaten by humans at one time
or another. Today, however, only 15 plant species and eight animal
species are relied upon for 90% of all human food.[47]
2.2 Many key ecosystem services provided by the
natural environment are necessary to sustain agricultural productivity,
such as the "regulating" services of water purification
and nutrient cycling. Agriculture is also reliant on the services
provided by biodiversity: a familiar example being the pollination
services provided by bees, valued at an estimated £200 million
to UK agriculture.[48]
2.3 Biodiversity can also provide a pest
regulatory function in agricultural systems by supporting predator
species which suppress populations of pest species, for example,
hoverflies and ladybirds regulating aphid numbers in a crop. In
less intensive systems, it is possible therefore for these species
to have an agronomic value by being part of an ecosystem that
suppresses pests and diseases.
2.4 In more intensive agricultural systems,
the use of agro-chemicals to perform this function has an impact
on both the target species and the natural predator species, either
directly or through reduced food availability. Biodiversity can
also be in direct competition with production, through competition
for resources such as sunlight, nutrients, and space. It will
therefore be affected by more intensive production, even if the
production is much "cleaner" in terms of less pollutants.
2.5 Although we currently have no models
for predicting the likely impacts on biodiversity of further intensification
in food production, over the last fifty years the increases in
agricultural yields have been accompanied by a reduction in farmland
biodiversity.
2.6 We note the Government Office for Science's
recent report which concludes the UK production of wheat and oilseed
rape could potentially be increased by 41% and 55% respectively
over the next five or so years, but that this would cause adverse
environmental effects, particularly increasing greenhouse gas
emissions and decreasing biodiversity.[49]
2.7 Hence while some aspects of increased
food production are compatible with a healthy natural environment
(e.g. the reduced diffuse pollution benefits provided by precision
farming), some practices for controlling pests and the competition
for sunlight, nutrients, and land can create trade-offs between
maximising production and maintaining biodiversity.
3. PRIORITIES
FOR RESEARCH
AND DEVELOPMENT
3.1 In our original written submission we
stated that we need to facilitate research, development and extension
of new farming practices, designs and technologies that can produce
food with a lower impact on the environment, such as improved
husbandry techniques, better timing and accuracy of input applications,
and development of crop varieties and management systems.
3.2 In developing countries, failed crops at
a local level can be a cause of hunger and malnutrition. In situations
where crop yields are extremely low and contributing to hunger,
there is an obvious need to increase yields. In countries where
yields are currently high, the research and development priority
should be to find ways to lower environmental impacts while maintaining
productivity.
3.3 It has been estimated that over the
next 25 years average global wheat yields will need to increase
from 2.6 to 3.5 tonnes per hectare to feed a growing
population.[50]
In 2007, average wheat yields in the UK were 7.2 tonnes per
ha.[51]
Although further yield increases might be possible in the UK,
(the Government's chief scientist, John Beddington, has indicated
wheat yields of 13 t/ha may be achievable by 2050),[52]
there are likely to be more opportunities for increasing production
sustainably in countries where agricultural yields are currently
lower, many of which are expected to experience the projected
increases in populations.
3.4 As we note above, it will be difficult
to increase yields significantly in intensive farming systems
without creating adverse impacts on the natural environment. A
key challenge will therefore be to maintain or increase food production
while at the same time maintaining or increasing the resources
available to non-crop biodiversity in and around fields. A certain
degree of "inefficiency" in agricultural systems is
in fact desirable to support this biodiversity. In addition, our
ability to protect the natural environment outside of agricultural
fields may improve, such as with improvement in the management
of field margins and reductions in diffuse pollution benefiting
aquatic species in rivers.
3.5 To maintain or increase food production
and lower environmental impacts, the development and use of different
crop varieties will be important. The full breadth of technological
approaches needs to be explored, with a full appreciation of the
likely benefits, costs and risks of different technologies taken
into account. The maintenance of plant genetic diversity is essential
in terms of allowing the flexibility to adapt to changing conditions
and providing resilience to environmental challenges. Likewise,
it is important for technological approaches to be innately flexible
and adaptable to a variety of situations, users and environmental
conditions.
3.6 As well as improvement in plant varieties,
we also need research and development of practices and techniques
in the way crops and livestock are managed—including cultivations,
rotations, animal husbandry, soil conservation, nutrient management,
pest control and energy use. Furthermore, we need to increase
our knowledge of smaller scale, highly productive polycultural
systems designed around ecological principles. Although these
systems are not always commercially viable at present, they may
become so in the future if and when circumstances change.
3.7 Below we describe some of the practices,
systems, designs and technologies which we believe have the potential
for increasing or maintaining production whilst lowering environmental
impacts, and which should therefore be considered as priorities
for agricultural research, development and extension.
3.8 Agro-ecological systems
— Active design of integrated systems following
ecological principles. Various methods of design such as zoning,
mapping resource flows, etc. Aims to replicate forms and functions
of local ecosystems.
— Use and encouragement of plant-animal
relationships, with symbiotic relationships (e.g. plant foliage
as feed for animals which supply manure as fertilizers to plants).
— Use of many of the below practices and
techniques in systems (e.g. integrated pest management, organic
practices and techniques, etc).
— Small "plot" sizes and spatially
complex interrelationships between multiple crops making it difficult
for crop specific pests and diseases to establish high population
levels.
— Identification of most suitable crops
according to natural characteristics of area, chosen for good
disease resistance, and which exhibit similar characteristics
to wild cousins (and are therefore better able to exist without
interventions).
— Active creation of "edge effects"
and micro-climates to enable better growth and yields, through
various approaches, e.g. wind breaks to slow wind and reduce evaporation.
— Continuous cover cropping and perennial
plants favoured to reduce need for disturbance of soils, effort
in cultivation, and to utilise vertical space and available solar
energy.
— Spatial and temporal annidation (i.e.
production of more than one crop in the same space, e.g. intercropping/stacking,
and production of more than one crop at different times of year,
e.g. crop rotations).
3.9 Aquaculture
— Choice of appropriate aquatic and/or
marine species, e.g. indigenous to area, requiring no/fewer external
inputs (e.g. fish meal for predatory species).
— Production with a high degree of integration
with local ecosystems and low stocking densities to avoid disease.
— Use of other plants or animals to utilise
and assimilate "wastes" from system.
3.10 Organic agriculture
— Ecological approach encouraged. Employs
many of the practices and techniques described above and below,
such as crop rotations, green manures, and biological pest management.
— Use of clovers and other legumes to fix
nitrogen, mulches used to control weeds, selection of plant breeds
for disease resistance, etc.
— Generally lower stocking densities of
animals and high welfare standards.
3.11 Hydrology and Integrated Water Management
— Mapping of water courses and flows within
a farm, good ditch management, and control of livestock to watercourses.
— Assessing and planning for water needs,
identifying best times for application, monitoring and repairing
leaks.
— Investment in water storage capabilities,
such as ponds, and rain harvesting systems, utilising large roof
areas on farm buildings.
— Use of "terra forming" to retain
water in system, e.g. swales, and cultivations along the contours
of fields.
— Extraction for irrigation below the replenishment
rate of aquifers and water efficient irrigation systems.
3.12 Integrated Pest Management
— Selection of crop varieties for pest
resistance, crop rotations, and timing of cultivations, identification
and monitoring.
— Control of pests through the use of natural
predators and parasites, reducing or avoiding the need for pesticides.
— Control of weeds using mulches, membranes,
rotations, etc.
— Responsible, safe, and minimal use of
pesticides, correct selection, application and timing, etc.
— Development of "biopesticides"
and other biological controls.
3.13 Crop management and cultivations
— Crop rotations to improve fertility and
nutrient replenishment (e.g. beans before wheat) or improve soil
structure, control perennial weeds, etc.
— Intercropping where two or more varieties
of crops are grown alongside each other, potentially with synergies
(e.g. alliums deterring pests from carrots).
— Undersowing of crops with other plants
to suppress weeds, protect soils, and used as green manures.
— Minimum tillage to protect soils from
erosion, and benefit soil organisms.
— Cultivating along the contours of fields,
to slow water runoff and allow better infiltration.
3.14 Integrated Soil Management
— Good knowledge of soils, crop management,
cultivations, and nutrient management.
— Improving organic matter content to improve
soil structure, enable better moisture retention (will improve
resilience to drought), and sequester carbon.
— Improving soil structure to allow beneficial
soil organisms to function (through sub-soiling, soil lifting,
soil conditioners, biological activity (worms), etc).
— Structures and management to avoid soil
erosion, such as perennial plantings (grasses, hedges, trees)
around cultivated areas or along contours to stabilise soils,
use of cover crops, etc.
3.15 Integrated Nutrient Management
— Assessing and calculating nutrient needs
and availability from manures, etc.
— Utilisation of available organic fertilizers,
such as composts, manures, and nitrogen fixing plants.
— Soil testing and mapping to identify
areas requiring more/less fertilizers and precision techniques
to allow more accurate delivery of nutrients.
— Application of fertilizers timed to coincide
with plant need, correct calibration of equipment, etc.
— Encouragement of mychorrizal associations,
so that plants can thrive at lower soil nutrient and soil water
availability.
3.16 Integrated Livestock Management
— Stocking densities and timings which
avoid over and under-grazing.
— Good grassland management to encourage
dense swards to avoid poaching, sequester carbon, etc.
— Use of agricultural wastes, byproducts
and other resources as feed.
— Timely stock movements, good access,
tracks and pathways, shelter, location or use of feeders and watering
points, etc.
— Use of manures as part of Integrated
Nutrient Management.
3.17 Animal breeding and management
— Breeding and alteration of environmental
factors to improve conversion ratios, including gene mapping,
parentage testing, etc.
— Choice of breed appropriate for production
system and climatic conditions, e.g. hardier breeds for out wintering,
uplands, etc.
— Good husbandry and welfare to reduce
mortality rates of animals.
3.18 Plant breeding and genetic modification
— Breeding and engineering of gene-products,
bioactive molecules, crop germplasm, etc. to develop plants with
desirable characteristics, such as:
— over-expressing certain genes that allow
roots to absorb more nitrogen, thus allowing crops to produce
the same yield with less nitrogen fertilizer;
— perennial versions of commonly cultivated
annuals, and development of drought and salt tolerant crops; and
— improved resistance of crops to biotic
stresses, such as weeds and pests, through building internal defences.
3.19 Other technology and machinery
— Appropriate choice of machinery and equipment
(e.g. implements for cultivation,) to undertake tasks effectively
and reduce environmental risks.
— Computer modelling and satellite navigation
to allow accurate sowing and harvesting of crops.
4. YIELDS OF
DIFFERENT AGRICULTURAL
SYSTEMS AND
PRACTICES
4.1 Research centres and institutions throughout
the world have undertaken or have ongoing crop trials, comparing
yields of different varieties, under different environmental conditions,
with different amounts of inputs, or managed with different production
techniques. There is also a significant amount of privately funded
research into animal genetics, genetic modification and conventional
plant breeding.
4.2 A number of trails have sought to make comparisons
between systems, either between organic and conventional systems
or comparing conventional, integrated, and organic systems. Some
studies have measured yields from particular agricultural practices
such as intercropping, urban and peri-urban horticultural production,
and agro-forestry experiments.
4.3 The comparison of farming systems, including
yields, can however be highly problematic, even in situations
where the results are unlikely to be controversial. Problems arise
due to definitions (particularly of the different agricultural
systems), the objectives and design of studies, time periods,
methods and standards used for comparison, and the need to isolate
factors which affect performance but are not related to the system.
4.4 Despite these problems, a number of
studies do provide indicators as to the effects of different systems
on yield.
4.5 A long term comparative study of organic
and conventional crop yields on nutrient depleted soils in Sweden
showed conventional crop yields were significantly in excess of
organic yields, although the difference was much less for grass/clover
than for all crops in the rotation. Comparison of Long-Term
Organic and Conventional Crop-Livestock Systems on a Previously
Nutrient Depleted Soil in Sweden Holger Kirchmanna,*, Lars Bergströma,
Thomas Kätterera, Lennart Mattssona and Sven Gessleinb a
Dep. of Soil Science, Swedish Univ of Agricultural Sciences, 2006.
AVERAGE CROP YIELDS (±SE) DURING THE
PERIOD 1981-98
|
| Mean dry matter yield
|
|
| Type of system | All crops in the 6-yr rotation cycle†
| Barley | Winter wheat
| Grass/clover‡
|
| kg ha-1
| | | |
| Conventional | 6380 ± 755a §
| 3745 ±
650a
| 6075 ±
524a
| 7480 ± 755a |
| Organic | 3170 ± 436b
| 2105 ±
176b
| 4200 ±
544b
| 6140 ± 146a |
| Control | 2080 ± 336c
| 1119 ± 75c |
3680 ±
644c |
not grown |
|
| † Column refers to all six crops in rotation incl. winter oil seed rape, sugarbeet and oats in the conventional and beans, peas and potatoes in the organic system.
|
| ‡ Grass/clover includes weeds.
|
| § Within columns, mean values followed by different letters are significantly different at P < 0.05.
|
4.6 A different result was identified by another long-term
study, comparing four farming systems that differ in crop rotation
design and material input use: a 2-year and a 4-year rotation
conventional system, an organic and a low-input system. Results
from the first eight years of the project show that the organic
and low-input systems had yields comparable to the conventional
systems in all crops which were tested—tomato, safflower,
corn and bean. Clark S, et al 1999a. Crop-yield and
economic comparisons of organic, low-input, and conventional farming
systems in California's Sacramento Valley. American Journal of
Alternative Agriculture v 14 (3 Sustainable Agriculture
Farming Systems project (SFAS) at UC, Davis.
4.7 One of the longest running agricultural trials on
record (more than 150 years) is the Broadbalk experiment
at the Rothamsted. The trials compare a manure based fertilizer
farming system ( not certified organic) to a synthetic chemical
fertilizer farming system. Wheat yields are shown to be on average
slightly higher in the organically fertilized plots (3.45 tonnes/hectare)
than the plots receiving chemical fertilizers (3.40 tonnes/hectare).
Soil fertility, measured as soil organic matter and nitrogen levels,
increased by 120% over 150 years in the organic plots, compared
with 20% increase in chemically fertilized plots. Jenkinson,
D. S. et al, 1994. In Long-term experiments in Agricultural
and Ecological Sciences (eds Leigh, R A & johnston, A E) p
117-138 (CAB Int. wallingford, U.K. 1994).
4.8 A review of European data on organic yields concluded:
— Organic cereal yields are typically 60-70% of those
under conventional management.
— For most countries, studies show a high variation
in both the absolute and relative yields of potatoes.
— Organic vegetable yields are often as high as under
conventional management, but it is difficult to draw general conclusions
due to the high diversity of different vegetables.
— Little data is available on pasture and grassland
yields in organic farming reported values lie in the range of
70-100% of conventional yields, depending on the intensity of
use.
— In livestock production, performances per head are
quite similar to those in conventional farming. But due to lower
stocking rates on organic farms, yields per hectare are lower.
Economic Performance of Organic Farms in Europe. Offermann
and Nieberg. 2000.
4.9 The effect on yields of intercropping at various
densities has been studied. In field trials in 1987-88, wheat
and field beans were grown as sole crops and additive intercrops.
The intercrops consisted of all density combinations of wheat
and beans from 25 to 100%. Crops of 50:50 winter wheat
and field beans were shown to require 30-50% less land to obtain
the same yield to when the crops are grown separately. Effects
of plant density on intercropped wheat and field beans in an organic
farming system H. A. J. Bulson, R. W. Snaydon and C. E. Stopes
Agricultural Botany Department, University of Reading.
4.10 A study of urban and peri urban agriculture calculated
that horticultural species, as opposed to other food crops, can
provide up to 50 kg of fresh produce per m² per year
depending upon the system employed. The report also states that
urban producers achieve efficiencies in production by making use
of under-utilized resources, such as vacant land, treated wastewater
and recycled waste and unemployed labour. It estimates that productivity
can be as much as 15 times the output per hectare of rural
agriculture. Urban and Peri-urban Agriculture: report presented
to the FAO Committee on Agriculture (COAG) meeting in Rome 25/26 January
1999.
April 2009
47
United Nations Convention on Biological Diversity. Agricultural
Biodiversity: Introduction. UN, 2005. Back
48
NAO, The Health of Livestock and Honeybees in England,
National Audit Office, 2009. Back
49
The potential to increase productivity of wheat and oilseed
rape in the UK, GOS, March 2009. Back
50
Ortiz et al. Climate Change: Can wheat beat the heat?
Agriculture, Ecosystems & Environment 126 (2008) 45-58. Back
51
Defra (2008) Agriculture in the United Kingdom 2007. Back
52
Evidence submitted to the EFRA enquiry on food supplies. Back
|
