«ZEF Work Papers for Sustainable Development in Central Asia No. 1 Economic Restructuring of Land and ...»
Shelterbelts will normally be established on fertile, productive land rather than on marginal soils. Thus, other species than those used for afforestation may be used in shelterbelts. The production reduction due to land set aside for the shelterbelts (trees and bushes, planted in strips of up to 5 m wide and which will take some time to become effective) is likely to be compensated for by the crop yield increase attributed to shelterbelts (Onyewotu et al. 1998, PFRA Shelterbelt Centre 1999), but again, this has to be demonstrated for Khorezm.
We expect to be able to demonstrate that the efficiency of the remaining land, water and other inputs can be improved substantially. The land can be used more intensively by inserting a catch crop (a nutrient-conserving crop) between the traditional cotton-wheat rotations. The introduction of minimum tillage and mulching techniques will help to conserve nutrients in the soil and preserve/re-introduce soil life, and prevent soil loss to wind erosion.
Further, with a water use efficiency in Khorezm that is somewhere around half the efficiency reached in other countries in comparable climatic regions, considerable savings are to be realized by a more rational use of irrigation water. This, and the water eventually saved by not cultivating the marginal areas can be used for flushing salts from some of the most salt affected soils (and, eventually, to feed the Aral sea). The overall reduction in water use would also reduce the high water table. More intensive land use and more efficient use of inputs should also lead to higher productivity, making farming more profitable and afforestation affordable.
Agroforestry and arid zone forestry have been widely promoted in the last decade. Agroforestry landscapes represent complex systems that alter the ecological conditions of a whole region, improving microclimate and hydrological regulation and increasing soil formation processes (Pawlowskij 1988). The manifold benefits of trees in landscape ecology include ecological functions related to their effects on wind, water, and soils. Forest systems contribute to landscape biodiversity. They have effects on adjacent land, e.g. field surrounded by forest patches or strips, where they improve microclimate, provide an input of plant residues (organic matter), and increase crop yield (Manyong et al. 2000). Large-scale changes in vegetation cover can have considerable effects on regional climate. Not least, forest products can yield an important additional income to rural population (Arnold & Townson 1998). They provide shade to humans and to cattle, and improve livelihood and the quality of life. All these effects are well documented (Huxley 1999, Young 1997, Baumer 1990, Raussen 1990, FAO 1989, Keswani & Ndunguru 1982). Structured landscapes with varied land uses that provide sustained economic productivity, ecological stability, optimal use of resources, and an overall quality of life should form the core of any strategy to combat desertification (Katyal & Vlek 2000).
In semi-arid and arid regions, forests occur only under two circumstances: (1), naturally, in floodplains along riverbeds, and (2), in irrigated landscapes. Natural floodplain forests in the lower Amu Darya River are the Tugai forests (Treshkin et al. 1998) that, in different formations, cover 120.000 ha in all Central Asia (a similar areas to the floodplain forests of Amazonia). They consist of tree species tolerant of high soil moisture and salinity and able to live under the low air humidity conditions of the desert (Treshkin et al. 1998). Typical plants include floodplain tree ZEF Bonn: Land- and Water Use in Khorezm 16 species such as Populus and Salix, but also salt-tolerant grasses (that have the potential to be used for phytomeliorative purposes (Bachiev, Treshkin & Kuzmina 1994). Tugai forests cannot survive without being flooded once every one or two years. With the absence of such natural floods due to the reduced water flow in the Amu Darya, the area of these forests has drastically diminished from over 350.000 ha in the beginning of the century to 22.000 ha in the 1990s, and all the remaining forest patches apparently have been degraded, as the tree productivity decreased by about 25% from 1960 to 1995 (Treshkin et al. 1998).
All forest stands in the irrigated areas are planted; they are thought to occupy not more than 3% of the landscape in Khorezm. Poplar (Populus ariana) and, occasionally, Pine (Pinus sp). are planted for the production of wood for construction and handicraft purposes. Khorezm is additionally characterized by many hedgerows that have only recently been planted among the fields, mainly as windbreaks, but also for other purposes (e.g. mulberry trees for silk production). However, these plantings are not based on a scientifically sound planning (Botman pers. comm.).
Although some tree species such as poplar have been grown for centuries in Khorezm, the establishment of forests is a relatively new experience in Khorezm. The region lacks a forestry research program. For species to be established, growth, survival and production conditions must be first determined, i.e. a thorough screening of suitable local and imported species must be undertaken, in order to be able to recommend species adapted to every site (soil, water conditions) and predominant purpose e.g. (bio-drainage, windbreak, forest products or other) and adapted to the harsh environment. The benefits of different approaches must also be comparatively assessed.
One particular constraint to the evaluation of different options is uncertainty as to the legal situation. Some information from Uzbekistan suggests that no more than 3% of all irrigated, agricultural land can be planted to forest by law. However, it will be essential to analyze the relevant provisions, in order to discover where regulatory, administrative and judicial competence is situated. This includes clarification whether the pertinent norms are national legislation or administrative decrees, whether they apply regionally or nationally, and what sanctions the law stipulates in case of infringement. The intended increase of forests on up to 20% of the land, based on the apparently weak productivity of these marginal soils, will conflict with this and a legal solution must be sought (link to Module H).
A third aspect to be covered is the question of the utilization rights of forests and their products. The land is actually common good but is becoming increasingly privately owned. The trees and forests on it can belong to either the owner of the land or the person that planted the trees (for a similar problem in China in the fifties cf. Wu & Shepherd 2000).
The ameliorative effects of forest shelterbelts have been extensively studied (Kayimov 1993). The average increases in crop yield on the adjacent agricultural land of 10% given by Dolgilevitch (1983) and Moshaev (1988) can reach 20% under optimal structure and after the shelterbelt trees have reached their final height (Vinogradov 1988). A woody biomass of 20-60t ha-1 was determined by Kayimov (1993), but annual tree production varies widely. In the Fergana valley, 25-26 year old poplar trees reach a total biomass of 1.0-1.3 t per tree ; elm 0.5-0.8 t per tree ; and for ash and maple 0.2 t per tree, values that can be used to calculate annual stand production (Kayimov 1993). Grasses and understorey wood annually produce 0.15-2.5 t ha-1 in such shelterbelts (Chawronin et al. 1986). Architecture, structure and species composition of the forest shelterbelts in the region are extensively discussed in Kayimov (1986, 1987), Kayimov et al. (1990), Moltshanova (1982), and Moltshanova & Kayimov (1985).
For different areas of the USSR, so-called “effective norms” for an optimal share of forest shelterbelts as windbreaks have been established (Table 3). For Uzbekistan, based on wind speed and frequency, an effective percentage of forests in the range of 0.5-3.0% was established by Moltshanova & Bojko (1968). It is likely, however, that optimizing the ecological functions mentioned under “Afforestation” will require higher proportions of forest in the landscape. We assume that the forest landscape in Khorezm can be increased to 8-10% without a loss in agricultural production, because the reduced cropping area will be balanced by a higher production on the remaining area (due to side effects of shelterbelts, but also due to an intensification of the agricultural production; cf. Module A).
ZEF Bonn: Land- and Water Use in Khorezm 17 A reforestation program is already being run in the neighboring province, Karakalpakstan, by the State Forestry Committee of the Republic of Karakalpakstan, Nukus, in three circumstances: In the dried Aral Sea bottom (North of Muynak), in the desert, and in irrigated areas. However, the plantation on the dried Aral Sea bottom has only been successful on former “beach” areas near the shoreline where salinity is low (Wucherer pers. comm. 2000). One successful example of reforestation is the establishment of a shelterbelt of 100 ha of forest (UNDP project) to protect the city of Nukus from desert sands coming with the wind. During a visit in 2000, the three-year-old trees were about 4 m high (Ganiev, Martius, pers. comm.). Experience may also be drawn from large afforestation programs that have been undertaken in China since the Fifties, considering mainly the functions of sand-/windbreaks, intercropping, farmland shelterbelts, and diversification (Wu & Shepherd 2000).
To resume, almost nothing is known about the present situation and the potential for forestry in Khorezm. However, initial efforts to reforestation are being observed in the region. Therefore, scientific research programs accompanying these attempts are urgently needed, in order to assess the constraints and improve the overall system performance with special regard to water saving.
220.127.116.11 Agricultural Production Systems18.104.22.168.1 Crop Production Efficiency
Food security is mainly a concern in Sub-Saharan Africa and South East Asia, but other developing countries will also face a decrease in per capita food availability (Pinstrup-Andersen et al. 1999). The transformation economies of the Central Asian countries will likewise be affected by the global trends of growing food insecurity, further aggravated by the threat of extreme climatic changes, and the present scenario of extremely low resource use efficiencies in currently used crop production systems (UNESCO 2000 a). In Uzbekistan, agriculture is a major part of the economy, accounting for 30% of gross domestic product, 44% of employment, and 60% of export earnings (ADB 1999). By far the most important crop is cotton, and basic food requirements still depend largely on grain imports, although increasing areas, withdrawn from cotton production, are planted to grain crops (ADB 1996, 1998, 1999).
To achieve a sustainable intensification of agriculture, Reeves (2000) outlined a “new” research paradigm based on an integration of the four scientific realms: environment, crop genotype, management, and human sciences. Crop breeding and/or the testing of new varieties will not be part of the present project, as this area is well covered by scientific institutes in Uzbekistan and a GTZ project. A surge in cereal yields was experienced worldwide over the past 30 years, particularly on irrigated land as a unique conjunction of agronomic and plant breeding advances (Evans 1998). In contrast, the addition of new farmland has played a secondary role in keeping up with population increases. In Khorezm, however, production increases still are mainly achieved by adding new desert land to the system under irrigation, at a current rate of annually 5000 ha (Chapter Irrigation).
22.214.171.124.2 Agriculture in Uzbekistan
Uzbekistan covers an area of 447.4 thousand km3, of which 4.2 million ha are irrigated arable land. With a population of 23.7 million in 1997 only 0.17 ha arable land are available per capita (the same as in China). The growing population rate in the Aral Basin during the last century was strongly correlated with the enormous increase of the irrigated area in this region (Figure 3).