Abstract only

Central Asia (CA) includes three majór climatic zones: Northern Kazakhstan steppes with sharp continental climate characterized with long and cold winters, short, dry and hot summers; southern part of CA including Uzbekistan, Tajikistan and Turkmenistan, belongs to northern cool and dry sub- tropics; the middle part of the region occupied by Kyrgyzstan and southern Kazakhstan climatically is closer to the south of the region but with lower temperatures throughout the year. Wheat production technologies studies have been studied together with multi-disciplinary teams of NARS during last four years from 1999-2003 as activities of the ADB (Asian Development Bank) supported "On-farm soil and water management" project. Soil tillage and crop rotations are major issues addressed by the project. In northern Kazakhstan at a Shortandy project site located on heavy clay soils deep conservation tillage in the fall after harvest of spring cereals has been a normal practice. However, recent developments in conservation tillage have encouraged to try no-tillage in the fall. Therefore, in four years of the field experiment, no-tillage in the fall provided higher spring wheat grain yields than traditional deep tillage provided adequate nitrogen fertilizer was applied. No-tillage in the fall proved to be advantageous with nitrogen fertilizer application as compared to both shallow and deep tillage, which is evident from the following comparison. The grain yield under no-tillage as compared to deep tillage was 97%, 107% and 113% with no fertilizers, P20 and N40P20, respectively. In rainfed winter wheat based rotations (south Kazakhstan and Kyrgyzstan), moldboard plow still remains major soil tillage equipment in farming practices (Kireyev, 1996).In the recent experiments, conservation tillage gave the same or slightly lower wheat grain yield as that after plowing, but conservation tillage gave opportunity for more sustainable production system. Enough to say that fuel cost for traditional plowing is three times more than for conservation tillage. In countries where inputs are not subsidized this factor would be realized well by farmers. Demonstration of economical efficiency of conservation tillage technology for planting wheat, barley. and safflower .in rainfed farming in south Kazakhstan started showing more interest among farmers. Thus five of them in a project area purchased cultivator-drills in the fall 2003 and planted winter wheat on 50 ha into stubble directly without plowing and harrowing. In irrigated agriculture, sowing winter wheat seeds into standing cotton reduced grain yield by 15-20%, but saved energy and time for seedbed preparation and planting. This technology has been widely adopted in Uzbekistan as it allows to plant wheat in due time for higher yields. In Turkmenistan, four years in a row, soil tillage at various depths (from 10-12 cm to 30-32 cm) before planting of winter wheat did not significantly affect grain yields, whereas reduced conservation tillage contributed to resource saving and allowed timely planting. Effects of timely planting of winter wheat have been reported elsewhere (Harris et al., 1991 ). The reduced tillage technology has been tested in Turkmenistan in on- farm conditions but rate of adoption is slow because all input prices are highly subsidized. The other constraint is lack of efficient chemicals to control weeds, which gradually increase with reduced tillage if not adequately controlled. Studies on crop rotations in different climatic zones have indicated the possibility of better soil fertility management and more economical farming (Harris, 1995; Pala et al., 1999; Rodriguez et al., 1999; Suleimenov et al. 2003). In northern Kazakhstan, where spring wheat normally has been grown in rotation with summer fallow practiced once out of four years, the best results were obtained by replacing summer fallow by oats or field pea. In all three years (2000-2002) the grain yield from the total area including fallow land was the lowest from the rotation of grains with summer fal1ow. The replacement of fallow with oats increased the grain production by 30%. The replacement of fallow with dry pea a1so increased the total production by 10%. Most important is the fact that reduction of summer fallow area will contribute significantly to conser- vation agriculture, because the fallow practice is the most dangerous practice provoking soil erosion. In rainfed winter wheat-based agriculture of southern Kazakhstan and Kyrgyzstan summer fallow plays more important role in grain production because of drier vegetation period. Nevertheless opportunities were found to replace part of summer fallow with food legumes, dry pea and chickpea. These crops provided some wheat grain yield decrease compared to fallow but fallow provides only a single wheat crop in two years and the alternating legume crops themselves produced cash crop with high prices and good demand on market. Besides legume crops con- tributed to better soil fertility management for a more sustainable system. In irrigated farming with winter wheat based rotations, good alternatives to continuous grains are sugar beet, maize, dry pea, soybean and common bean. In cotton-wheat rotations of southern part of CA there is possibility of intensifying farming for better soil fertility management and more profitable and sustainable agriculture through introducing food legumes and oilseeds as double cropping after harvest of winter wheat. The four year experiments and on- farm testing of technologies allowed draw the following conclusions: .Conservation tillage is generally adopted practice in rainfed farming in northern Kazakhstan but can be further improved towards minimum tillage operations including no-till direct planting. .Conservation tillage in rainfed farming in southern Kazakhstan and Kyrgyzstan can be promoted for conservation of natural resources and more economical farming. .There are possibilities of reduced tillage in irrigated agriculture in Central Asia. .In all climatic zones of Central Asia there are good chances to increase role of legume crops in wheat-based rotations for higher fertility, increased total productivity and sustainability of production system.

English

0409|AGRIS 0401|AL-Wheat Program

Juan Carlos Mendieta

CIMMYT Publications Collection