Scientific research

Increasing fertility and preventing secondary salinization on slightly saline irrigated soils

Author: Knowledge Management in CACILM Phase II, ICARDA.

Definition of technology:

The complex of agro-technical measures, including excessive application norms of organic fertilizers, diversification of crops in cotton-wheat system and the use of crop residues as organic fertilizers prevents secondary salinization processes and provides increase of soil fertility.

Brief summary of technology:

An increase of land degradation in Uzbekistan in recent years is mainly due to increased rates of the secondary salinization and decrease of soil organic matter contents. For several years, the cropping pattern in the farmland consisted of cotton – cotton or wheat – wheat rotation, or wheat is cultivated following cotton. Consequently, from June – the time of wheat harvest, field is left uncultivated. Bare soil is left unprotected from summer heat, and as a result it severely dries, looses structure and thus, tolerance to erosion. In soils that are prone to salinization the salts reach and accumulate in the root zone of plants. Salts have toxic effect on plants and destroy soil structure, deteriorate agronomic and water-physical soil properties. When dried, structureless soils harden and become denser, and when wetted they quickly become saturated and poorly hold moisture, which is negatively reflected in the productivity potential.

The system of measures suggested in this technology in the first place includes leaching, which should be conducted in autumn under adequately functioning drainage network, then application of increased rates of organic fertilizers (manure or manuremineral composts of 30-40 t/ha or bio-humus of 5 t/ha). Cotton is planted in spring. Crop diversification in the cropping pattern “cotton-wheat” suggests cultivation of other crops in the following sequence: “cotton-wheat-leguminous (mung bean)-green manure crops-cotton”. Reaching final cotton cultivation, this cycle is repeated. The topsoil is covered with vegetation all year round, which prevents capillary uplifting of salts with groundwater to the upper soil profiles. Plant residues, left in fields serve as a source of humus. For the next three years the soil leaching is not required and thus, water saving takes place. Accumulation of organic matter leads to the development of highly productive soils with good structure, which creates favorable conditions for formation of high yields.

Location: “Garasha” farm, U.Yusupov area, Bayavut district, Sirdarya Province.

Area of technology application: 30 ha.

Location: “Bahtiyor Narzulla” farm, Angor district, Surkhandarya Province.

Area of technology application: 5 hа.

Stage of intervention: alleviation/reduction of land degradation.

Main land use issues and the main causes of land degradation:

Low soil fertility, inadequate supply of nutrients and organic matter (humus). Transition from automorphic to hydromorphic regime due to rising groundwater closer to the land surface, salinization.

Main reasons – soils are prone to salinization due to unfavorable natural conditions and inappropriate irrigation management practices, low application rates of organic fertilizers, removal of crop residues from fields and poor crop rotation.

Main technical features of technology:

Improving ground cover with biomass, increasing organic matter contents and nutrients, prevention of secondary soil salinization.

Type of land use Conservation measures

Arable land.

Production of annual crops Во(Са).

Agronomic measures:

А2: Organic matter / soil fertility.

Environment

Habitat Anthropogenic environment

Average annual rainfall: 250-500 mm.

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

Landscape: plains.

Slope (%): flat, gentle slope, 1-3%.

Soil fertility: low, average.

Humus content in arable horizon: 0.5-1%.

Natural soil drainage/infiltration: average.

Size of land area (ha): 35 ha.

Landholder: farmer, households.

Land ownership: long term lease.

Water use rights: through WUAs and organizations responsible for management of irrigation systems.

Market orientation: State Order, mixed farming (subsistence and commercial).

Assessment

Impact of technology

Main advantages:

- prevention of secondary salinization processes;

- increasing crop yields;

- saving irrigation water;

- lower application rates of mineral fertilizers;

- additional farm income by selling repeated crop yields.

Main disadvantages:

- difficulties in consequent crop production related to additional costs of labour and water application.

Acceptance/adoption of technology: Due to the difficulties in subsequent crop production and inssuficient amounts of applied organic fertilizers (manure, dung, etc) this technology is used by farmers only from place to place, not everywhere.

 Reference(s):

1. Scientific report of the applied project: «Мирзачўлвоҳасуғориладигантупроқларинингунумдорлигиниошириш, мелиоративҳолатинияхшилашгайўналтирилгансамарадорагротехнологикечимларниишлабчиқиш». Project leader: Professor Tashkuziev M.M.;

2. M.M. Tashkuziev, A.A. Sherbekov, J.M. Reymbaev, T.T. Berdiev. Techniques of improving the amelioration status and fertility of soils subjected to salinity on light gray soils / / Agricultural science to agriculture, VIII International scientificpractical conference dedicated to the 70th Anniversary of the Altai State Agrarian University. Book 2, Barnaul, 2013;

3. Summary Report on mega project K-7-012: “Узбекистонреспубликасисуғориладиганерларинингтупроққопламиникомплексўрганиш, тупроқэкологик-мелиоративҳолатинияхшилашҳамдаунумдорлигинитиклаш, баҳолашвабошқаришнингсамарадортехнологиялариниишлабчиқишProject leader, Professor R.K.Kuziev.

4. Tashkuziev M.M., Berdiev T.T. Application of agricultural technologies to improve soil fertility conditions in the desert zone of Uzbekistan // “Agricultural science to Agriculture” VII International Scientific Conference, Barnaul 2012.

Name of person(s) collected this description: Prof. Ma`ruf Tashkuziev, National Research Institute of Soil Science & Agrochemistry.

Address: 3, Kamarniso str.,Tashkent, Uzbekistan. Tel.: +99871 2271399; Mob.: +99890 9975784.

E-mail: maruf41@rambler.ru

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