ICARDA Annual Report 2001

Researchers involved in integrated natural resource management need to take action on a wide range of factors in pursuit of sustainable agricultural production. The first step in most projects is to compile a detailed description of the study region. A collaborative project involving ICARDA, the University of Bonn, and the Atomic Energy Commission of Syria has undertaken a comprehensive description of the land resources, land capability, and land degradation issues in the Khanasser area of northwestern Syria (Fig. 15).

The project undertook a land and soil classification study at three levels of detail:

• Reconnaissance survey, covering the area southeast of Aleppo, particularly the Khanasser Valley, the Jebel El-Hoss and Jebel Shbeith
• Semi-detailed survey of the Khanasser Valley
• Detailed participatory survey in Khanasser village.

The first stage provided an agroecological characterization of the whole Khanasser area, at a scale of 1:200,000 (red frame in Fig. 15). The objective of this ‘level 1’ assessment was to obtain an overview of the major soil types, including their location and management properties, and to identify areas for more intensive survey work. The inventory included soil resources, land use, and land cover. Soil resources were assessed by interpreting Landsat imagery from 1998 and 1999, and the data were supplemented by terrain observations and soil sampling. The land use/land cover map was developed using the same Landsat imagery.

The Khanasser area represents a transition zone between rainfed and irrigated crop production and livestock systems. Land degradation issues include salinization in irrigated fields, water and wind erosion, groundwater depletion and contamination, and a decline in the cover and quality of the natural vegetation. In dry areas it is often difficult to distinguish human-induced land degradation from natural processes of deterioration, such as gully formation, wind erosion and deposition of soil, and salinization of depressions. Changes in the landscape, vegetation, or land use can provide evidence for land degradation, but what time scale should be considered? Land can degrade rapidly or slowly, depending on its resilience and the pressure exerted on it. There are usually no datasets available that go back far enough to monitor slow degradation processes. In addition, some forms of degradation may have occurred in the distant past, with the area having since found a new equilibrium.Land degradation in the Khanasser Valley was studied by comparing aerial photographs taken in 1958 (Fig.18) with Landsat satellite imagery dating from 2000 (Fig.19). Changes in settlement patterns, land cover and use, gully distribution, and the wind deposition of soil were noted and the data supplemented with field observations and interviews with farmers who could remember back to 1958. The most significant change in land use was marked by an expansion of rainfed agriculture from about 30% of the valley in 1958 to nearly 100% in 2000. This expansion occurred at the expense of rangelands, which were the predominant land cover in 1958. There has been little change in the area under irrigation (compare Figs. 18 and 19).

Interviews with older farmers indicated that barley has been the dominant crop and farm sizes have changed little in the 40-year period. Although land ownership is passed down from father to son, families continue to farm the land in common operations. Fertilizer use has been non-existent and soil fertility has been maintained by observing a fallow

The second stage provided a meso-scale inventory of the land resources of the Khanasser Valley, at a scale of 1:50,000 (blue frame in Fig. 15). This ‘level 2’ assessment was carried out to define landscape units with different management requirements and land use options. The inventory was, therefore, more intensive, relying heavily on fieldwork, with further soil sampling and analysis. Land suitability maps were prepared for several important crops and land use categories. The soil map and land suitability map for rainfed barley are shown in Figs. 16 and 17, respectively.

The ‘level 3’ assessment focused on Khanasser village. Its aim was to understand farming systems and farmers’ perceptions of resource-related problems. Farmers, particularly those who had been farming in the area for over 40 years, were asked to provide information about land quality, productivity, production risks, resource degradation, and land use in the area surrounding the village.

The study generated some important lessons, which can be put to good use in other sites where similar research is needed. Firstly, a multi-scale approach offers a very efficient and cost-effective framework for conducting land resource studies and up-scaling research results. It also offers an efficient methodology for integrating farmers’ knowledge with scientific mapping procedures. Secondly, researchers should adapt their land evaluation methods to local conditions, taking account of different scales and study objectives. Different crop or system requirements should be linked to land characteristics and qualities that can be mapped with confidence, thereby avoiding the danger of reaching unrealistic conclusions.

period. However, fallow frequency has reduced from 1 year in every 2 in 1958 to 1 in 4 in 2000, and the farmers felt that fertility had declined. They also observed that both the area and diversity of natural vegetation had reduced, due to the encroachment of farmland and the destructive effects of tractor cultivation. Farmers who did not own livestock believed that sheep had a negative effect on soil quality. They also claimed that they have no control over the numbers of sheep and the grazing intensity. Farmers who did own livestock, unsurprisingly considered the economic benefits to outweigh the negative effects on the land.

Farmers’ management practices to combat the decline in fertility have been ineffective. Fertilizer use is widely considered uneconomic in a dry environment with a high risk of crop failure. Deep plowing every four years was mentioned as a ‘nutrient pumping’ practice to replace nutrient-depleted topsoil with less depleted subsoil. The effect of this practice on longer-term nutrient availability requires further study. Other forms of land degradation appear less important. Gullies are very common on hill slopes in the area. However, the interviews with farmers indicated that the gullies probably existed before 1958 and had extended only slightly in the past 40 years. A comparison of current measurements with the 1958 aerial photographs will indicate whether any significant elongation has in fact occurred.

The combination of information sources used in this study (remote sensing, field surveys, and farmer interviews) was able to provide indirect evidence of a decline in soil fertility and production capacity, a major form of land degradation. The study’s results can now be used to develop suitable strategies for reversing the decline.