Central Anatolian soils have high risk of erosion, degradation and intensive cultivation. Consequently, they are in danger of exhausting their agricultural use unless conservation agricultural practices are adopted. Conservation agriculture is a key tool in sustainable production systems throughout the world and is developed around soil management technology that minimizes soil disturbance, maximizes the soil cover and promotes crop diversity to offer benefits to farmers and to the environment. It has been particularly effective at sustaining crop production in semi-arid rain-fed regions such as the Central Anatolian soils, where potential evaporation exceeds precipitation during most months of the year, dry farming is extensively practiced, water and wind erosion is common, and proper application of water-and soil-conserving tillage technology is critical. The area under plow expanded its limits as the number of tractors in agriculture dramatically increased in the 1960s. This is the starting point for inappropriate use of the agricultural land. The conservation agricultural technologies, therefore, are of utmost importance for the region. Common farmers' practices of a fallow-wheat system in the central plateau of Turkey are incompatible with the conservation agriculture concept. The objective of this review is to re-evaluate the performances of the partial and full conservation tillage practices previously tried in the region. This review reached the following conclusions: (1) agreeing with the conservation principles, fall tillage as a primary operation in the fallow phase was found to be useless compared with leaving the land without tillage; (2) therefore, much research has focused on spring tillage as a primary operation and employed conventional, semi-conservative and conservative methods. Results showed that the conventional system, in addition to being ecologically unfriendly, is unprofitable as compared with other conservation practices regarding the updated cost analysis; (3) similarly, tillage depth in primary spring tillage was determined to be shallower than the depths currently practiced by farmers, in agreement with the conservation principles; (4) fallow tillage operations in summer to create dust mulch for eliminating soil moisture loss did not increase the crop yields and soil moisture as compared with chemical fallow; (5) no-till fallow was similar to the conventional clean fallow system in terms of moisture and yield levels. However, no-tillage resulted in 50% reduction in the cost of tillage besides its ecologically-friendly effects; (6) the existing dryland agricultural systems in the plateau should be transformed into or changed toward sustainable systems, although further research is required on residue and stubble management, and integrated weed control methods to drill the soil with high amounts of residue on the field.

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-Winter hairy vetch, Vicia villosa Roth, gives high grain and hay yields. Mechanical control of weeds is an ecological alternative to the use of herbicides. Among the various mechanical methods, interrow weeding is cheap and practical. Nonetheless, wider row spacing than common practice is needed to ease the operation. We optimized row spacing and seed rates for high grain yield and to ease interrow cultivation. We used two row spacings of 45 and 60 cm as main plots and five seeding rates of 100, 200, 300, 400 and 500 seed per square meter as subplots. Experiments were conducted in rotation with winter wheat in 2001, 2002 and 2003. The results showed that narrow spacing and high seed rates increased the grain yields of winter hairy vetch. In contrast, wide row spacing reduced the grain yield by 56%. More plants per square meter were obtained with 60-cm row spacing and high seed rates. Row spacing of 60 cm increased the branch number per plant in the dry year and decreased it in the wet year.winter hairy vetch / row spacing / seed rate / grain yield / yield components / path analysis