تأثير روش هاي مختلف خاك ورزي بر خصوصيات فيزيكي خاك و عملكرد كلزا در مناطق مختلف كشور

Effect of Tillage Methods on Soil Physical Properties and Yield of Rapeseed in Different Regions of Iran

In this study, the effect of diferent tillage methods by common implements on soil stability, seed emergence, plant establishment and yield of winter rapeseed were evaluated. The experiments were performed in five provinces of Iran with different climates over three years. Primary tillage methods at different depths included moldboard plowing at depths of 25-30 cm and 15-20 cm, chisel plowing at depths of 20-25 cm and 15-20 cm, shallow tillage with field cultivator at depth of 8-10 cm and shallow tillage with disk at depth of 8-10 cm. Secondary tillage indued use of rotary tiller and disk harrow both at depth of 8-10 cm. The primary tillage methods were the main treatments of the secondary ones, the sub-treatments. Statistical analysis of results indicated that in most experimental regions with loamy soils, plowing depth had no significant effect on root penetration depth, plant establishment and yield of rapeseed. Moldboard plowing at depth of 25-30 cm and harrowing by rotary tiller with 50-75% seed emergence rate and average of 3000 kg/ha yield made the best conditions for seed emerging and crop yield in different climates with irrigated farming but in rainfed conditions, chisel deep plowing and harrowing by rotary tiller with about 40% seed emergence and 2750 kg/ha seed yield obtained better results with respect to other tillage methods.