Determination of Crop Management Factor at Different Growth Stages of Rainfed Chickpea in Semiarid Region for Using in USLE Model: A Case Study in Tikmeh Dash of East Azerbaijan

In developed countries the values of crop management factor (C) for different crops is provided in tables, but due to climatic, pedologic and crop management differences of these countries with our country, using of these information could be associated with a large uncertainty. For this reason, this study was conducted in order to determination of C factor and its variations in different growth stages of rainfed chickpea. So there conventional sowing rate (30, 35 and 40 kg/ha) of rainfed chickpea (Cicer arietinum) were planted in erosional plots. In order to calculation of C factor, some plots were plowed along the slope and were left without cropping, as control plots. After each rainfall event, the generated runoff and sediment, were measured. Results were analyzed as a split plot in time design. The mean values of C factor for 30, 35 and 40 kg/ ha seeding densities were 0.66, 0.44 and 0.33 respectively, and the average for all treatments was 0.48. At the whole, the lowest values of C factor were related to canopy development stage, and the highest values were related to canopy establishment stage of chickpea. The variation of C factor in three different seeding density were greater than the variation of this factor in three different growth stages. So that, with increasing seeding density from 30 to 40 kg/ha, the C factor values increased on average by 50%, while, the values of C factor at maturing stage were on average 30% lower than canopy establishment stage.