Supplemental Irrigation Potential For Wheat In The Central Anatolian Plateau Of Turkey PDF Download

Wheat (Triticum aestivum) is the major food crop produced on the Anatolian Plateau of Turkey where due to limited rainfall the farmers follow the traditional system of fallow farming. They are presently producing an average of 1.15 tons of grain per hectare during the crop year. This rate of production does not meet the needs of the country and during the last 15-20 years Turkey has frequently had to import wheat. The present fallow system permits extensive livestock grazing during the late fall and winter months in the noncrop year. Spring tillage practices are delayed to permit weed growth for additional foraging by livestock during the early and late spring period. This delayed spring tillage, using wooden or steel plows, leaves the soil loose and subject to rapid drying. Little plant residue is left on the surface to protect the soil and maintain water infiltration rates. The farmer also must cultivate several times before planting in order to prepare a satisfactory seedbed. Under these conditions Turkish farmers have learned that seed planted early in the fall in dry, warm soil may be germinated by light rain, subsequently dry out and then die. Thus, they have over time adopted the practice of delaying planting until late fall when temperatures are cooler and frequent rains more certain. Under these conditions the crop is largely dependent upon late spring and early summer rains for satisfactory grain production. Climate in dryland regions of Oregon and Washington are similar to those in the Anatolian Plateau. Previous research conducted on the Anatolian Plateau indicated that modified technology from Oregon and Washington could be adopted to Turkish conditions resulting in substantial increases in grain yield. The objective of this study was to compare three fallow-tillage systems for moisture conservation and early vs. late seeding dates on subsequent grain yield of wheat. The tillage treatments were (1) a fall chisel operation followed by a spring chisel tillage, (2) chiselling twice in the spring in perpendicular directions, and (3) moldboard plowing in the spring. All three systems received subsequent tillages with a sweep-harrow combination as required to maintain a weedfree fallow and uniform seedbed. The amount of moisture conserved was not affected by the three tillage systems employed and grain yield was not different due to tillage method. All of the systems conserved sufficient water to allow early seeding into residual moisture with a deep furrow drill. A 94 per cent stand emerged within 15 days. At a later sowing date wheat was seeded into dry soil using a double disc drill. Emergence was delayed due to late rains. After 56 days an 89 per cent stand had emerged. In this experiment a 36 per cent grain yield increase resulted from early seeding; 3.79 tons per hectare compared to 2.79 tons per hectare from the late seeded plots, a highly significant difference. The 3.79 tons per hectare is 2.64 tons per hectare more than the average yield from local farms, where a traditional fallow system is followed. The major components contributing to the yield increases from early seeding were (1) more plants and heads per unit area, (2) more kernels per head and to a lesser degree (3) kernel weight. This study suggests that if Turkish farmers adopt improved summer fallow systems, wheat yields can be increased significantly; thus, reducing or perhaps eliminating the need for importing wheat. However, the loss of grazing land under a clean fallow system for livestock will need to be evaluated in terms of the total economic and social conditions to determine if the increased wheat yields warrant the change in farming practices. It is anticipated that the loss of forage during the fallow period would be offset by the increase of stubble and cereal aftermath as a result of grain yield increase during the cropping sequence.