Further supplementary memorandum submitted
by the ACP London Sugar Group (O 78B)
WATER USAGE ISSUES IN ACP CANE SUGAR PRODUCING
COUNTRIES
During the Evidence Session on 4 May Mr Tyack
and I undertook to write to the Committee on the question of water
usage issues in ACP cane sugar producing countries.
On the general question of the environmental
benefits of sugar cane growing, we believe we have covered these
adequately in sections 2.5 and 2.6 of our first submission, to
which we would respectfully refer the Committee.
We are of course aware that there are concerns
in some cane-growing countries as to the impact of this crop on
local water supplies. To quote a typical comment from a well-known
researcher:
"In India, for example, there are concerns
about water being diverted from domestic food production by small
farmers to irrigate larger-scale sugar cane production for export."
(Guardian, letters 24 February 2004, from Colin Hines)
We do not know whether this is true of India,
but can state with considerable certainty that it is not true
for any of the sugar industries in the ACP States Signatory to
the Sugar Protocol with whom we have to do.
The issue of water use in sugar cane cultivation
is complex and highly dependent on environmental factors. Sugar
cane is a large fast-growing plant and has a relatively high water
demand. However with a deep rooted growth habit sugar-cane is
also capable of making very effective use of subsoil water and
can be less dependent on frequent irrigation than other field
crops.
In this letter we cover the following issues
which we hope will provide a detailed answer to the Committee's
question:
— whether cane is irrigated or rain
fed;
— where water used for irrigation comes
from (eg wells, rivers, dams);
— irrigated cane water needs compared
with other viable crops;
— whether cane growing could divert
water away from local populations or pollute water supplies; and
— the impact of cane growing on water
management and water supply.
We have taken comments from all the major ACP
sugar producing countries and a number of smaller ones. It will
be apparent that there is a major distinction to be drawn between
the traditional island producers and the continental African producers,
while in many ways Mauritius and Guyana present features not found
elsewhere.
1. IS CANE
IRRIGATED OR
RAIN FED?
In the Caribbean islands of Trinidad, Jamaica,
Barbados and St Kitts cane is 100% rain fed. The same is true
of Fiji. Consequently the question of competing with water requirements
for the population does not arise.
As far as Guyana and Belize are concerned they
are both rain fed industries and the only irrigation is occasional
and on young plants. The question of competition with other crops
and drinking water does not therefore arise. In Guyana there is
an occasional need for supplemental rainfall when the dry season
is extended. Irrigation by flood is also used to control soil
dwelling insect pests, as the industry as a rule does not use
insecticides. Cane is also transported by water-way.
Mauritius is divided into three climatic zones,
namely a sub-humid zone receiving less than 1,500 mm rainfall
annually, a humid zone with 1,500 to 2,500 mm and a super-humid
one with more than 2,500 mm per year. Only cane in the sub-humid
region is irrigated because irrigation of sugar cane fields located
below 1,500 mm isohyet[1]gives
40 to 80 tonnes/ha more cane than under rain fed conditions. The
irrigated area under sugar cane amounts to 21,000 hectares out
of a total of 72,000 ha.
All cane in Swaziland is irrigated, with about
one-third of the cane's water requirement being met from rainfall.
The same is true in Zimbabwe, and we understand that the estates
in Malawi, Tanzania, Zambia, the Congo, Co®te d'Ivoire and
Mozambique are in a similar position.
2. WHERE WATER
USED FOR
IRRIGATION COMES
FROM?
In Mauritius irrigation is derived from groundwater
from boreholes and surface water from dams, reservoirs and rivers.
Water for transport and irrigation in Guyana
east of the Berbice River comes from conservancies, shallow reservoirs
created by damming small rivers with seasonal flow which retain
rainfall and upland flow during the wet seasons. In the East Berbice
region, agriculture water is obtained from the Canje River.
In African countries such as Swaziland water
is provided from river flow and from dams.
3. IRRIGATED
CANE WATER
NEEDS COMPARED
WITH OTHER
VIABLE CROPS?
Sugar cane produces a biomass as high as 150
tonnes/ha. It obviously has higher water needs than other crops
such as potato and onion. Thus while sugar cane may need 1,500
mm water to reach its full potential, root crops such as onion
requires only 400 mm. However, the actual irrigation water requirement
is much lower than the calculated 1,500 mm because of the contribution
of rainfall, which varies from country to country.
4. DOES CANE
GROWING DIVERT
WATER AWAY
FROM LOCAL
POPULATIONS OR
POLLUTE WATER
SUPPLIES?
Mauritius is a well-watered island receiving
annually on average more than 2,000 mm of rainfall. There is more
than enough water to satisfy demands from agriculture and other
sectors of the national economy as well as for domestic purposes.
The problem lies in water storage particularly when rainfall distribution
is uneven (more than 70% of the rainfall is received between December
and April). There are not enough reservoirs or dams built to store
the water and therefore most of the rainfall received goes to
the sea. If there is indeed water shortage, the policy in terms
of water use is that irrigation water supply to cane is interrupted
and priority is given to domestic uses. Some sugar estates have
their own water storage facilities for irrigation. In cases of
emergency, eg drought, this water is also diverted to domestic
uses.
Cane cultivation does not pollute water supply.
Sugar cane is an environment friendly crop as was demonstrated
by a large scale collaborative study between MSIRI and the Queensland
Department of Natural Resources supported by the Australian Centre
for International Agricultural Research on agrochemical movement
in sugar cane fields. The amount of soil and agrochemicals moved
from sugar cane fields was agronomically unimportant and environmentally
insignificant. Thus less than 2 tonnes sediment/ha/yr (the acceptable
threshold is 10 tonnes/ha/yr), 1 kg phosphorus/ha/yr and 0.25%
of herbicides applied to sugar cane were moved to contaminate
fresh water sources in Mauritius.
The Guyana sugar estates share water from the
conservancy sources with other agriculture (predominantly rice)
on the coast. These water sources do not conflict with domestic
water use, which in coastal Guyana is derived principally from
artesian wells.
In Swaziland and other African countries cane
has helped to enhance water management, and it is on the back
of the large scale mill, dam and water resource developments that
the industries there have grown and increased their efficiency.
In Swaziland the sugar industry helps promote
better water use by the local population, and the establishment
of Farmers' Associations regulates the use of the water. Cane
rather than being looked upon as diverting water away from local
populations instead allows local populations use of water by providing
a viable crop suited to smallholder production. Access to water
for sugarcane improves the lot of local communities by allowing
them to irrigate vegetables and have clean household water. Sugar
cane growing does not pollute water supplies and the millers are
embracing the ISO environmental standards.
5. WHAT ARE
THE POSITIVE
EFFECTS OF
CANE GROWING
ON WATER
MANAGEMENT AND
WATER SUPPLY?
(a) Creation of dams and reservoirs
Most African ACP sugar producers have developed
sophisticated systems of dams and aquifers to stabilise water
supplies, particularly in Swaziland and Zimbabwe.
In Mauritius, too, several reservoirs and dams
have been created to cater for the irrigation needs of sugar cane.
This available water storage capacity is also used for other purposes
(eg Midlands Dam).
(b) Protection against erosion and pollution
Sugar cane grows rapidly and with its extensive
root system occupies the land for the better part of its eight
years crop cycle. Thus, as opposed to land cultivated with short-cycled
crops, land under sugar cane is well protected against erosion
by rainfall. There is also less direct runoff from cane land than
from bare land, as shown in MSIRI's study on agrochemical movement
in sugar cane fields mentioned above, thus ensuring that water
supply is not polluted.
(c) Flood protection
In the traditional sugar cane producing islands
of the Caribbean and Fiji, because sugar requires less fertiliser
than other comparable crops, any impact of fertiliser run-off
following heavy rain is minimised. Moreover, sugar stabilises
the fields, thus cutting down on total run-off and helping to
prevent soil erosion. Were it not for cane all of the eroded material
would end up in the water courses resulting in blockage and contribute
to flooding. Flooding would present a problem to animals and housing.
A positive benefit of the sugar industry in
Barbados is the system of recharge and drainage wells which are
maintained by sugarcane growers and which help recharge the underground
aquifers in addition to mitigating the effects of flooding during
the rainy season.
The Guyana coastal area is low-lying and rainfall
is high. Hence the major water management concern is drainage.
A complex network of drainage canals linked to discharge sluices
connecting with the sea or river estuaries has been developed.
The integration of drainage and water transport/irrigation networks
makes it possible to recirculate water in dry weather and to prevent
ingress of salt water from the sea. The Guyana sugar industry
is closely integrated with its surrounding environment and undertakes
considerable maintenance on the drainage infrastructure and sea
and river defences of the Guyana coastland which is essential
to the well-being of the surrounding villages which are below
sea level and would otherwise be at risk of flooding from the
combination of the Atlantic at the front and the Rivers of the
Interior behind them. Without the presence of the sugar estates,
it is probable that the coastal defences would be more at risk
and flooding would occur with greater frequency.
(d) Promotion of awareness of value of water
resources
Cane growing in Mauritius has increased the
awareness that water is a valuable resource which must be conserved
and used efficiently and which needs to be free from contaminants
to protect aquatic life and biodiversity.
In Swaziland sugarcane has often replaced other
crops that have failed as smallholder crops for various reasons—for
example, cotton growers have been able to switch to sugar cane
once water has become available. The new Water Act will lead to
the establishment of River Basin Authorities to help administer
water use. The Act promotes a drive to water use efficiency (WUE).
WUE is high in Swaziland and the smallholder sector is very productive
and efficient when compared with others in the world. It is also
important to appreciate that cane is grown in the arid lowveld
and it is this crop that has opened up the lowveld in particular
to development and social structures (eg schools and clinics)
as well as new business development. The provision of water, leading
to the planting of sugar cane, has also led to the development
of utility services provided by government such as roads and electricity.
Sugar cane has been a catalyst for development, including smallholder
production. Water has also played a role in improving food security
by enabling other crops to be grown.
18 May 2004
1 Isohyet: A line drawn through geographical points
recording equal amounts of precipitation during a specific period. Back
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