by
M. Foghi
Ordibehest Avenue, Janb
Omor Senfe, Esfahan - Shilat, Iran
In the first part this paper discusses the impact of drought on water resources and agriculture in Iran. It briefly describes the various types of irrigation systems in use in Iran, and the effort to economise agricultural water use. The second part deals with capture and aquaculture fisheries, including the consequences of the recent prolonged drought on fish farming. The contribution of aquaculture to food security in the country is also discussed.
Iran is one of the countries with the earliest agriculture, with agriculture records going back to 4000 BC. But overuse of the soil has led to soil erosion and desiccation of many water sources. Iran gradually changed into a dry and drought-prone country and today it belongs to the arid/semi-arid zone of Asia.
The average annual rainfall in Iran is 243 mm as compared with the global annual rainfall average of about 835 mm. There are some areas in Iran which have less than 50 mm of rainfall. The rainfall is unevenly distributed throughout the year which prevents optimal exploitation of water resources, with the rain falling largely during the non-vegetative season. While one percent of the world population lives in Iran, Iran has just 0.36 percent of the total renewable freshwater resources of the world. Iran is already using 66 percent of its freshwater resources.
Of the estimated annual 400 billion m3 water received as precipitation 260 billion m3 are lost through evaporation and infiltration. This leaves about 130-140 billion m3 to be used, out of which only 97 billion m3 are exploited: 9 billion m3 for drinking and other human uses, including industries, and the remaining 88 billion m3 for agriculture. In 1961, the per capita water availability in Iran was about 6 500 m3, which has decreased to 2 100 m3 today, and the decline continues. It is estimated that by 2021 only 1 200 m3 per capita will be available.
More than 50 percent of the country’s freshwater resources are in the form of groundwater, which must be conserved for drought years. At present overexploitation of the water resources has resulted in some changes in water quality. The recent two-year drought (1998-2000) has led to overexploitation of the groundwater in all areas, and consequently in some areas salt water has entered the aquifers. There has also been an increase in water pollution. Soil disturbances such as those due to deforestation in the river catchments, water overexploitation and poor water quality are some of the major factors which intensify the scale of the crisis caused by drought.
Irrigated lands cover 8 million hectares (ha) and those under dry farming cover 6.5 million ha, but the latter category has been subject to serious damage imposed by the recent droughts: when comparing dry farming production areas of 1992-1993 with those in 1998-1999 there was a drop from 7.11 million ha to 4.46 million ha. As a result of that, during the same period the total area of farms and orchards declined from 14.36 million ha to 12.32 million ha. At the same time, the total agricultural production increased from 54.22 million tonnes in 1992-1993 to 60.2 million tonnes in 1998-1999.
The area under dry wheat farming was reduced by 45 percent, wheat production by 65 percent, and wheat yields by 37 percent when comparing the year 1993 with 1998-99. This has been the result of the decline in rainfall. To make up for the shortfall, Iran had to import 7 million tonnes of wheat in 1999-2000 which has made it one of the biggest wheat importers in the world.
Water shortage is considered a major factor responsible for the slow growth of agricultural production. Rational and scientific planning in order to secure maximum exploitation of water resources is strongly needed.
The limited water resources and the widespread use of unscientific and traditional irrigation systems which result in up to three times higher water consumption than actually needed for production of crops, are the major constraints facing agriculture in Iran. To overcome this a new irrigation improvement programme is being implemented. Its objectives include increasing production rate in the irrigated farming system through rationalization of water resources. The programme focuses on reduction of the negative impacts of drought, using modern irrigation methods.
There are three common irrigation systems in Iran: surface irrigation, sprinkler irrigation, and gravity drip irrigation.
Surface irrigation system is the oldest and most common system applied. It does not require special equipment and machinery, and if well implemented it is considered to be one of the best systems in Iran. However the water use is wasteful and if poorly used crop yields decline. Surface irrigation is applied as basin irrigation, border irrigation or furrow irrigation.
Soundly managed traditional irrigation system requires 1-1.5 litre of water per second per hectare, while sprinkler systems use only 0.6-0.8 per second. This means that the same amount of water as used in traditional irrigation results in higher production. Sprinkling irrigates the area near the roots meaning that only a small area and only the required soil depth are wetted. This results in lower evaporation rate, as well as reducing the area suitable for weed growth.
Gravity drip irrigation has proved very satisfactory in irrigating plants in the desert, specifically in sandy soils where it is not feasible to apply common surface irrigation or sprinkling. It leads to accumulation of salt in the root area, which can be removed through continuous washing. As the plant receives fertilizers directly, then the efficiency of fertilizer use is increased as well as the efficiency of water use. This system produces good results with crops such as apples, pistachios, peanuts, grapes and watermelons. With sound management this method requires 0.4-0.6 litre/sec/ha. The method is more nature-friendly, but also more costly to apply.
To overcome the crisis resulting from the shortage of water available for irrigated agriculture, the following proposals have been formulated. If implemented, they should result in the urgently needed improvements and in higher crop production.
Provision of training to farmers to raise their awareness of the shortage of water.
Restoration of vegetative cover in catchments.
Upgrading the performance of irrigation water.
Prevention of the input of pollutants into water.
Prevention of fragmentation of agriculture lands and encouraging farmers to integrate farming so as to prevent water wasting.
Construction of dams to create water storage.
Promotion of the use of saline waters in agriculture.
Application of modern irrigation systems.
Recycling sewage.
Estimating exact water requirements of plants.
Introducing plant species requiring less water.
Having the advantage of about 2 700 km of coastline in the Persian Gulf, Oman Sea and the Caspian Sea, Iran has traditionally pursued capture fisheries in those waters. The production achieved from both the southern and northern waters has increased fifteen fold during the period of 1973-1998. Aquaculture started in 1922 with the breeding of sturgeon to produce fry for stocking in the Caspian Sea. This was followed by trout farming in 1959. Today the major aquaculture activities in Iran are well diversified.
Warm water fish farming
The following fish species are farmed: common carp, grass carp, silver carp and bighead carp that are mostly brought from abroad. Production of these species on fish farms has increased by 46 percent since 1989.
Cold water fish farming
Trout farming started in 1959 and the production increased from 599 tonnes in 1978 to 26 700 tonnes in 2000. Rainbow trout (Oncorhynchus mykiss) is the main cold water fish species farmed in Iran.
Fish farming in natural and semi-natural water resources
The total area of inland water bodies including lagoons, lakes, reservoirs, rivers, etc., in Iran is estimated to be about 1.5 million ha. Some of the water bodies are stocked with common, bighead and silver carps. Freshwater and Caspian Sea capture fisheries (including waters enhanced by stocking) have leveled off at around 34 000 tonnes/year, with a steep drop in 2000 probably due to the continuing drought conditions.
Fish stock enhancement
Fish fry and fingerlings are produced under aquaculture conditions for stocking in inland water bodies and the Caspian Sea. This is to compensate for the losses resulting from fishing and to boost the existing fish stocks. The following species are produced and stocked: kutum (Rutilus frisii), sturgeon, bream, trout, perch, colmeh and several species of carp. Over the period 1978-1999 the number of fish fry and fingerlings annually released into the Caspian Sea and inland waters rose approximately 15 fold.
Shrimp culture
Iran enjoys the advantage of a 2 000 km coastline in the south of the country. An area of 16 000 ha has been identified there as suitable for shrimp culture. Shrimp culture operations in Iran started several years ago and production has been increasing, reaching 4 000 tonnes in year 2000. Penaeus indicus, a native species of Iran, is the main cultured species and it yields up to 2 tonnes/ha.
Aquatic invertebrate culture
The focus is on the giant freshwater shrimp (Macrobrachium rosenbergii) and the slender clawed crayfish (Astacus leptodactylus) culture. The crayfish is produced for regular releases into natural water bodies. The giant freshwater shrimp is cultured in monoculture or with common carp.
The low rainfall in recent years has resulted in reduced fish production. When comparing the fish production from natural and semi-natural waters for 2000 with that in 1998, it shows a reduction by 34 percent. Warm water fish farm production was 20 percent lower in 1999 than in 1998, but in 2000 the production was close to the average for years 1995-1998. Cold water fish production has been also affected by the drought through reduced water flow rates in streams and rivers providing water to fish farms. While the total production from cold water fish farms was higher in 1999 than that in 1998, this was the result of opening 82 new fish farms. The average cold water fish production per fish farm during the drought year 1999 was considerably lower than that in 1998.
Drought has also had a negative impact on the shrimp aquaculture industry as a lower freshwater input raises water salinity in ponds and this has a negative effect on shrimp larvae and the final product. The total damage inflicted on prawn production in 2000 is estimated to be 33 000 million rials, of which at least 11 percent is believed to be the result of the drought impact. Lower river discharges into the sea reduce the spawning of shrimps which in turn results in lower shrimp catches. Over the last decade shrimp catches have decreased from 3 759 tonnes to 2 350 tonnes.
Iran like many other countries of the dry zone of Asia faces water shortages. The existing fisheries and its future development faces the problem of how to develop under water use restrictions. Several possibilities are discussed.
Fish farming using micro-water resources
A large volume of fresh water estimated at 53.3 billion m3 is supplied from micro-water resources such as wells, springs and underwater aqueducts (karez). In many of these waters fish are present and fish production could be developed alongside the water used for agriculture and other purposes. Water stored in ponds fed from wells or other sources could support fish stocks. This would also facilitate promotion of aquaculture among the rural population, increase the per capita fish consumption among the farmers, generate income, create job opportunities, and by directing the organically enriched outflows from such fish farms onto fields, increase agricultural production. Production of warm water fish from such ponds reached 2 580 tonnes over the period 1993-1999.
Following the relative success with trout farming on fish farms, a number of coldwater fish production raceway ponds have been constructed near the micro-agricultural water resources. This has provided a good income to private farmers. The outflowing organically enriched water is used for irrigation agriculture. In 1998 coldwater fish farms established on this principle produced 800 tonnes of rainbow trout.
The use of micro-agricultural water resources for fish farming has been most welcome by farmers. The overall warm water fish production plan for 2021 is 454 000 tonnes, and for cold waters 180 000 tonnes. Of these 19 000 and 44 000 tonnes, respectively, should be produced using microwater resources.
Fish pond farms
One of the mechanisms for increasing fisheries production is the establishment of fish pond farms. These may be assisted by the government or be the result of private initiative. On warm water fish farms in Iran fish production is about 3 tonnes/ha, but on some farms it reaches up to 6 tonnes. Cold water fish farms currently in existence in Iran are mostly lacking an electricity supply which does not make possible water recirculation.
Stocking inland waters
There are about 3 500 inland water bodies. Of these about 730, covering a total area of 508 000 ha, are used for fisheries. During 1995-1999 the annual fish production from these water bodies averaged 30 000 tonnes, employing over 130 000 fishermen. It has been recognized that to keep the fisheries sustainable, regular stocking is necessary. Iranian fisheries together with the Ministry of Power is, subject to the Fishery Law, responsible for the coordination of the management of these resources, including stocking. Other enhancement methods have also been applied since 1970, such as cage culture. Fish are raised with some success in canals, with 129 tonnes and 108 tonnes of fish produced in 1998 and 1999, respectively.
Fish farming in rice fields
About 600 000 ha of land in Iran is allocated to rice farming. It is planned to further develop integrated rice-carp farming and trout farming during the post-harvest period. Trout farming would follow when the water temperature does not exceed 20 oC. Farming in rice fields in 1999 resulted in harvest of 126 tonnes of fish. The side benefits of this type of culture are fertilization of fields by fish and control of the rice stem borer by carp feeding on it.
Fish farming in brackish waters
Some areas in the Esfahan, Yazd, Qom, Khorasm, and Kerman provinces have water resources (mainly underground) of a high salinity, with electrical conductivity sometimes exceeding 30 000 micromhos. These waters which are unsuitable for agriculture could be utilised for fish farming. Since 1995 saline water of 10 000-25 000 micromhos has been used for rainbow trout farming in Iran. Trout production in saline water reaches about 3 tonnes/ha but with aeration it could reach 5-6 tonnes/ha.
Macrobrachium rosenbergii has been cultured in water of 20 000 micromhos, resulting in a production of 5-6 tonnes/ha.
This can be summarized as follows:
food production and contribution to national food security
reducing reliance on red meat and pressure on pastures
contribution to sustainable economic development
creation of job opportunities especially in rural areas.
Number of employees in aquaculture sector (inland water farmers and fishermen)
|
Year |
89 |
90 |
91 |
92 |
93 |
94 |
95 |
96 |
97 |
98 |
|
No. of employees |
9 957 |
9 923 |
10 934 |
10 204 |
10 532 |
10 921 |
11 004 |
11 630 |
10 250 |
16 661 |
creation of regional development centers through establishing production farms on land unsuitable for agriculture
development of aquaculture-related industries such as fish feed production, hatchery equipment manufacturing, processing and packaging industries
substitution of farmed fish for captured fish to relieve the pressure on natural fish stocks
increased per capita fish consumption
strengthening the government economy through export of fisheries products.
There is a need to make fish accessible especially to the rural population.
Annual per caput fish consumption (kg/person)
|
Year |
79 |
87 |
89 |
90 |
91 |
92 |
93 |
94 |
95 |
96 |
97 |
98 |
|
Consumption |
1.0 |
2.5 |
4.25 |
4.4 |
4.4 |
4.25 |
4.5 |
4.0 |
4.5 |
4.5 |
4.5 |
4.6 |
Since 1989, the per caput fish consumption in Iran has stagnated at a level of around 4.5 kg/person/year.
