Combating desertification in the USSR

A. Babaev and N. Kharin

Agadzhan Babaev of the Turkmen SSR Academy of Sciences, Ashkhabad, USSR.
Nikolai Kharin is head of the Remote sensing Laboratory of the Desert Institute of the Turkmen SSR Academy of Sciences.
Note: This article is adapted from a voluntary contribution to the Tenth World Forestry congress.

Following is a brief description of the work of the Desert Institute of the Turkmen SSR Academy of Sciences, Ashkhabad, USSR on increasing the productivity of arid ecosystems and stabilizing moving sands. A forecast of desertification in the near future is also presented.

Deserts cover more than 210 million ha or about 10 percent of total land area in the USSR. About 94 percent of these desert lands are found in three republics: Kazakhstan, Uzbekistan and Turkmenistan, in a wide belt between the latitudes 36 and 48°N and between the longitudes 48 and 82°E. Deserts are defined as areas with an extremely dry and hot climate, scanty precipitation (less than 300 mm per year) and comparatively sparse vegetation. The deserts of the USSR are mostly situated on plains and residual uplands with elevations of less than 400 m above sea level.

According to their Ethology and landscape features, deserts are classed as sandy, stony, loamy and salty. Sandy deserts occupy about 40 percent of the desert area. They are developed on thick, loose sandy deposits of fluvial and littoral origin. The plant cover of such deserts has the highest productivity. The worldwide species of saxaul (Haloxylon persicum, H. aphyllum) are found there.

The present and potential role of deserts in the national economy of the USSR must not be underestimated. There are about 65 million sheep and goats in the desert pastures of Middle Asia and Kazakhstan, producing 190000 tonnes of wool annually in addition to meat and other by-products (Babaev, Manakov and Nikolaev, 1986). Some 6.6 million ha of fertile soils are improved and used in agriculture in the territory of the three republics; annually about seven million tonnes raw cotton (81 percent of the USSR's gross output of this crop) are produced here. Moreover, the deserts are rich in oil, gas and other mineral resources, and possess vast recreation potential, although they are still virtually unexploited for this purpose.

Desertiffcation of arid lands in the USSR

According to the Map of man-made desertification of the USSR arid lands, scale 1:2500000 (Kharin et al., 1988), compiled by the Desert Institute of the Turkmen SSR Academy of Sciences, 60 percent of the arid land area is in some stage of desertification (Table 1). The map shows changes that have occurred in this desert zone during the last 20 years (1965-1986) and also contains information about various factors provoking desertification, including population density; livestock pressure; the inherent (natural) risks of desertification; the rate of desertification; etc.

The primary causes of desertification in the USSR's arid zones are overgrazing and the felling of desert shrubs (mainly saxaul) for fuel. During the degradation process the composition of plant associations changes, biological productivity decreases and the stability of arid ecosystems is eroded. For example, the average annual production (forage yield) of undisturbed or slightly altered desert pastures is about 0.7 to 1.4 tonnes per hectare. In the case of extreme degradation, this falls to 0.4 tonnes per hectare or less.

TABLE 1. Desertification of arid lands in the USSR, 1965-1985

Territory	Arid surface area	Causes of desertification in affected areas					Unchanged areas
	('000 ha)	Vegetation degradation	Wind erosion	Water erosion	Salinization	Technogenic desertification	(Percentage)
(Percentage)
Kazakhstan	1089.4	45.0	-	-	7.5	5.6	41.9
Uzbekistan	275.6	35.7	4.0	-	4.3	15.2	40.8
Turkmenistan	417.5	43.6	11.5	2.9	5.4	3.1	33.5
Total	1782.5	43.2	3.3	0.7	6.5	6.5	39.8

TABLE 2. Recommended methods of forest plantation establishment depending on moisture content in a 1 m soil layer

Ecological condition	Precipitation		Soil moisture in 1 m layer	Method of establishment
	(Period)	(mm)		Seeding	Planting
Different types of relief with deep ground waters	Oct.-Feb.	70	35
		7-90	35-40		+
		90	40	+	+
	Mar.-May	70	45
		70-90	45-55		+
		90	55	+	+
Sands with thickness of 1.5-2 m over clay deposits	Oct.-Feb.	50	35
		50-70	35-40		+
		70	40	+	+
	Mar.-May	50	45
		50-70	45-55		+
		70	55	+	+
Sands with ground waters et a depth of 3-4 m	Oct.-Feb	50	35		+
		0	40	+	+
	Mar.-May	30-50	30-45	+	+

Technogenic desertification (the result of construction activities or geological exploration) causes considerable damage to arid zones of the USSR, particularly to the sandy deserts whose ecosystems are characterized by a high degree of instability. In cases of severe technogenic desertification, the vegetation cover is destroyed on 50 percent or more of the area.

Another important cause of desertification is soil salinization (Table 1). More than 80 percent of salinization in the arid zones of the USSR is the result of the decrease of the level of the Aral Sea and the damming of the Kara-Bogaz Gol bay on the Caspian Sea. The rest is associated with improper irrigation techniques; in some oases in the arid zone (for example, Tedzhen in Turkmenistan) salinization affects more than 70 percent of the land, and productivity of cotton (the main crop) in such lands may decrease by 30 to 50 percent.

Afforestation of SANDY deserts

Desert reclamation by afforestation in the USSR has a history dating back nearly 100 years. At the end of the nineteenth century, Russian foresters were confronted with the challenge of protecting the Trans - Caspian Railway from sand drifts that buried the settlements and productive lands. By 1925, more than 80 000 ha of irrigated land was buried in the lower flow of the Zeravshan River. Around the Bukhara oasis, the sands were advancing by a wave measuring 150 km in width (Petrov, 1950).

The damage to the national economy associated with the degradation processes in the sandy deserts led to the development of elaborate and extensive reclamation efforts. In the decade 1945-1955, some 640000 ha of moving sands were stabilized and afforested in Turkmenistan and Uzbekistan (Petrov, 1977), totally eliminating damage previously caused by sand drifting into the irrigated lands of the Bukhara oasis, and in the lower Zeravshan and Amu Darya valleys.

Today, a variety of types of shelter-belt are used to protect areas in the sandy deserts of the USSR (Svintsov, 1988). The shelter-belts tend to be widely spread, with widths of 4 to 20 m. The species used include representatives of the genera Haloxylon, Salsola, Aellenia, Calligonum, Ephedra, etc. Within and between these shelter-belts, decreased wind velocity and moderated air temperatures result in evaporation decreases of 20 to 25 percent.

The protective shelter-belts are established by direct seeding or planting of rooted seedlings, depending on ecological conditions (Table 2) (Svintsov, 1988). According to Svintsov, some 90000 ha of forest plantations were established annually in Turkmenistan during the period 1981-1983. The survival rate was 68 to 84 percent with direct seeding and 58 to 94 percent with planting. The experience of the work in Turkmenistan indicates that capital expenditures for the creation of forest belts were recovered in less than eight years. Range productivity increased by an average of 8 to 10 percent; moreover, woody production was in the order of 9 m³ per hectare.

Rangeland improvement in the PIEDMONT deserts

The piedmont deserts contain more than 150 million ha of arid rangelands. In the spring these lands are covered with herbacious vegetation, but with the approach of the summer the yield and the nutritional quality of the forage drop sharply. The herbaceous vegetation dries up and breaks and the chaff is carried away by the strong winds. In winter the grass remnants are buried under snow to a depth that makes them inaccessible to sheep.

The potential importance of these areas has led to experimentation and research into the possibility of rangeland improvement and, particularly, the establishment of cultural phytocoenoses (CPC) - mixed species associations for grazing purposes, in the areas of Badkhyz and Karabil (Turkmen SSR) (Nechaeva and Priod'ko, 1966). Reseeding of mixed species is important because the Karakul sheep grazing in these regions need more diversified forage than other animals.

The territory is characterized by hilly land forms reaching an altitude of 600 to 900 m above sea-level and an annual rainfall of 250 to 270 mm. The most widely distributed plant associations are: Poa bulbosa/Carex pachystylis; Poa bulbosa/Carex pachystylis/Ferula badrakema.

There are about 65 million sheep and goats in the desert pastures of Middle Asia and Kazakhstan

Research carried out by the Desert Institute has shown that the best results are obtained by simultaneous seeding of shrubs, semi-shrubs and herbs. The following groups of plants were found to be promising in CPC creation:

· Shrubs. Haloxylon persicum, Calligonum rubens, C. caput medusae, C. microcarpum, C setosum, Ephedra strobilacea. Salsola paletzkiana, S. richteri, Aellenia subaphylla.

· Semi-shrubs. Kochia prostrata, Salsola orientalis, Artemisia badhysi, A. kemrudica, A turanica, Astragalus unifoliatus, Eurotia ceratoides.

· Perennials. Astragalus agameticus, Dorema aitchisonii, Ferula assafoetida, F. badrakema, Poa bulbosa.

· Annuals. Salsola paulsenii, Eremopirum orientalis, Cutandia memphitica, Eromus tectorum, Agriophyllum latifolium, Malcolmia grandiflora.

TABLE 3. Recommended composition of plant types for the establishment of perennial autumn-winter pastures

Plant type	On ploughed areas	On slightly stabilized sands	On shifting sands
Shrubs	30	40	40
Semi-shrubs	60	30	10
Perennials	10	10	20
Annuals	-	20	30

The recommended combination of plant types is given in Table 3 (Nechaeva and Priod'ko, 1966).

Given the hardy nature of the species used, low to modest technologies (ploughing of soil, coating of seeds) were sufficient to ensure good germination and rapid growth of these plants. The differing above- and below-ground structure of the species used enabled them to utilize different levels of space and soil: up to a height of 5 m above ground level, and to a depth of 20 m below the ground.

Total above- and below-ground biomass of the improved rangeland reached 230 m³ per hectare in comparison to 30 m³ per hectare in natural areas. Summer forage output reached 29 m³ per hectare and, in winter, production of 4 to 8 m³ per hectare was recorded compared with about 1 to 2 m³ per hectare in unimproved areas.

The expenses incurred in the establishment of winter pastures in the piedmont deserts were recovered after two or three years. Afterwards, thanks to their high productivity and ecological stability, improved pastures may be used without additional expenditure for 15 to 20 years.

Forecasting future desertification

When planning measures aimed at the rehabilitation or restoration of arid ecosystems, it is extremely important to forecast desertification development over the next 20 to 30 years. The Desert Institute has identified a number of key factors. Water supply in the pre-Kopet-Dag plain is expected to increase through the use of the Karakum canal; therefore, the area of decertified lands can be expected to decrease in this region. The water content in soils will also be improved and productivity of pastures will rise in the deltas of the Murgab and Tedzhen Rivers as well as in the space between these rivers.

On the other hand, considerable deterioration of the ecological situation is expected in the Aral Sea zone. Irrigation of the Amu Darya and Syr Darya deltas is leading to the progressive depletion of the Aral Sea. In 1971, the size of the Aral Sea was 66085 km². In 1985, it decreased to 28036 km² and by the year 2000, according to forecasts, the water surface will have diminished to 2689 km (Akramov and Rafikov, 1990).

Further intensification of desertification is also expected in some regions of Kazakhstan. In the Mangyshlak and Ustyurt regions a further expansion of technogenic impact on the arid ecosystem is expected. In the lower Urals, salinization and soil degradation are a risk as a result of irrigated farming. In the southern Balkan region, desertification is also expected to progress as a result of increases in cattle populations and intensified technogenic influences.

However, as has been demonstrated by the successful efforts mentioned earlier, if wise human activity is combined with nature conservation measures, it is possible to stop further desertification and to restore degraded lands.

Bibliography

Akramov, Z. & Rafikov, A. 1990. Past, present and future of the Aral Sea. Tashkent. 143 pp.

Babaev, A.G. & Freikin, Z.G. 1977. Deserts yesterday, today, tomorrow. Moscow, Mysl'. 352 pp

Babaev, A.G., Manakov, V.S. & Nikolaev, V.N. 1986. Food potential of deserts. Problems of Desert Develop., No. 4, p 2834.

Kharin, N.G. et al. 1988. Explanatory note. In Map of man-made desertification of the USSR arid lands, scale 1:2500000. Ashkhabad, Ylym. 24 pp.

Nechaeva, N.T. & Priod'ko, S.Ya. 1966. Improved winter rangelands in piedmont deserts of Middle Asia. Ashkhabad, Ylym. 61 pp.

Petrov, M.P. 1950. Combating the shifting sands of the USSR deserts. Moscow, Geografgiz. 350 pp.

Petrov, M.P. 1977. Nature conservation and regeneration of natural resources. Moscow, VINITI 175 pp.

Svintsov, I.P. 1988. Forest reclamation of sandy deserts of Turkmenistan. Ashkhabad, Ylym. 159 pp.