اثر روش هاي خاك ورزي حفاظتي و ماشين هاي كاشت بر خصوصيات فيزيكي خاك و عملكرد گندم ديم

The Effect of Conservation Tillage Method and Seeding Machine on Soil Physical Characteristics and Dryland Wheat Grain Yield

Tillage is used to establish a suitable soil physical condition for seeding and also seedling emergence. Preparation of such a seed bed needs time and high cost. It is necessary to replace conventional tillage with conservation tilling systems to reduce costs, energy and soil erosion under dryland farming systems. This study investigated the combination effects of tillage systems, sowing machines and press wheel weights on dryland wheat (Triticum aestivum L.), seedling emergence, crop establishment and grain yields. Sowing depth uniformity and seedbed physical properties including soil moisture and cone index were also recorded. The experiment was conducted in Izeh, Khouzestan province, Iran. A split plot complete block design was applied with four tillage treatments including no-tillage; conventional tillage" (Moldboard plow + disk) and reduced tillage (twice disk and chisel plow + disk). Three levels of press wheel weight including 4, 5 and 8 kgcmʹ1 of press wheel width were evaluated. Results showed that reduced tillage (twice disk) produced higher and faster rate of emergence (p<0.05) and finally greatest grain yield (1917.7 kghaʹ1). The independent press wheel drill could increase soil moisture and seeding uniformity resulting significant higher seedling emergence as compared to other treatments. This treatment yielded 2202.9 kghaʹ1 grains with greater 1000 grain weight compared to other seeding machines. Five kgcmʹ1 press wheel weight produced the highest (p<0.01) yield. The results suggested that reduced tillage (twice disk) and independent 5 kgcmʹ1 press wheel weight could be more effective than other treatments for wheat production under dryland condition where the experiment was conducted.