Scientific research

Agroforestry amelioration for rehabilitationof degraded irrigated land

Author: Knowledge Management in CACILM Phase II, ICARDA.

Definition of technology:

Plantation of salt-tolerant tree species, mainly with nitrogenfixationand high bio-drainage capacities is established on arableareas unused due to a strong salinization and waterlogging.

Brief summary of technology:

There are many sites of the degraded arable land in Uzbekistan,the use of which is unprofitable for production of the main crops.Planting of multi-purpose tree species on such land promotes restoration of soil fertility and their use for agricultural production.Abandoned land starts to bring benefits, providing the populationwith fuel and construction wood, cattle with a deciduous forage, etc. The well-considered selection of tree species providesecological services, such as decrease of waterloggingthrough a biodrainage and control of soil salinization; nitrogenfixationcapacity of certain species enriches the soil with nitrogen,and litter from leaves with humus. These sites can again beturned to a category of an arable land or to continue to use themfor wood production in a long-term perspective.

The selection of multi-purpose tree species for set of criteria,main of which are salt and drought resistance, biodrainage andnitrogen-fixation capacity is the main considerations to establish forest plantations on marginal land. For conditions of theKhorezm province, nitrogen-fixation species such as Russian olive(Elaeagnus angustifolia), fast-growing species Asiatic poplar(Populus euphratica) and long life species Siberian elm (Ulmuspumila) are recommended.The land preparation is traditional (planning, plowing, leaching).Saplings of various species are planted in clean rows by a 1х1.75m scheme, with alternation of species in each 5-7 rows. Densetree stand allows to collect a biomass for fuel and a forage by athinning. When the width of inter-row increases to 3-5 m, thebiomass is received by rational by dehorning. Irrigations are carriedout within the first 2 years with reduced rates (by 10-30%), alater the trees get nutrition at the expense of groundwater.

Location: Yangibazar district, Khorezmprovince; Beruniy district, Karakalpakstan.

Area of technology application: 4 ha.

Stage of intervention: rehabilitation / restorationof the degraded land.

Main land use issues and the main causes of landdegradation:

Natural preconditions and land and water mismanagementcaused waterlogging and a secondary soil salinization and land abandonment from agriculturalproduction. Restoration of the saline marginal landwith traditional methods of leaching is difficult and expensive.

Main technical features of technology:

Improvement of an soil cover, increase of organic matter,nutritious elements, restoration of soil fertility; asequestration of carbon dioxide in a biomass and thesoil.

Type of land use Conservation measures

Arable land.

Cultivation of annual agricultural crops- Во(Ca).

Vegetation measures:

В1: Coverage with trees and bushes.

Management measures:

У1: Change of land use type.

Environment

Habitat Anthropogenic environment

Average annual rainfall: <250 mm.

Altitude (meter above sea level): 100-500 m.

Landscape: plain.

Slope (%): 0-2% (flat, smooth).

Soil fertility: low.

Humus content in arable horizon: low (<1%).

Natural soil drainage/infiltration: moderate.

Size of land area (ha): 15-50 ha.

Landholder: farmers.

Land ownership: state, lease.

Water use rights: through Water Consumers Associationsand management of irrigational systems.

Market orientation: Mixed farming (subsistence andcommercial).

Assessment

Impact of technology

Main advantages:

- restoration of the abandoned land by a simplemethod;

- the technology is based on traditional methods ofcultivation of tree crops (local tree species are used);

- tree plantations are established with little irrigationrates;

- provides cheap and ecologically clean means of copingwith waterlogging through biodrainage;

- multi-purpose orientation: ecological benefits are: acarbon sequestration, improvement of soil quality,economic: source of fuel and construction wood,additional source of fodder to cattle.

Main disadvantages:

- long duration of the expectation period of benefits;

- insufficiency of interests/motives at farmers;

- there are no free finance sources for an investmentin long-term prospect.

Acceptance/adoption of technology: The technology is implemented within ZEF/UNESCO/UrSU Project. Finantialsupport is required for the wide dissemination. Probably, land leasing does not stimulate farmers to invest inlong-term prospect. Farmers do not have sufficient understanding that abandoned land can bring benefits in anear future, already during the first 3-5 years. Promotion of this method is necessary.

Reference(s): WOCAT Database . Technology code: T_UZB004ru.

Compiled by: Ibragimov R., CACILM MSEC. Date: 29.09.2011.

Contact person: Asya Hamzina, ZEF/UNESCO/UrSU Project.

Address: 3, Valter Flex-strasse, V-53113 Bonn, Germany.

Tel.: +49-(0)228-73-1795; Факс. +49-(0)228-73-1889

Е-mail:  asia_khamzina@uni-bonn.de

Name of person (s) collected this description: Tatyana Hamzina, Chief specialist on soil reclamation studies and irrigationregime. UZGIP LTD.

Address: 44, Navoi str., Tashkent, Uzbekistan.

Tel.: +998 90 9945654

Email:  tatyana_khamzina@mail.ru

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