An Assessment of Topography, Slope and Climate Effects on the Runoff Production within Marly Lands in Zanjan Province by using an Artificial Rain Simulator

The most important factors affecting soil erosion and runoff include climate, soil erodibility, topography, vegetation cover and land management. In this article, an assessment of topography, slope and climate effects on the runoff production within marly lands in Zanjan province by using an artificial rain simulator. In this regard, by overlying slope, climate, and marly units of geological formation maps, by incorporating a rain simulator and an overall of 220 plots were tested. Data, collected from field operations, were analyzed on the basis of Randomized Complete Block Design with Factorial Treatment Structure. The upper red marl units (Mu) has the highest volume of runoff With volume of more than 20 liters per square meter marl and marl units Pliocene (PL) The minimum With volume of 1 liter one liter per square meter respectively. The Pliocene marl units (PL) has the highest infiltration rate of 12.5 cm and lower red marl (OL) had the lowest infiltration rare is about 2 cm. The F-test results of Marnie units on volume and run-off coefficient were statistically significant, while the effect is not significant for the slope and climate on these two features. But in cases of double and triple combinations of these three variables in all cases have a significant effect on runoff generation and runoff coefficient. Statistical data analysis shows the significant effects of the Marl units, Slope and climate on the volume and run-off coefficient (p<0.05). Marly unit can be classified in to four groups, based on the Volume and run-off coefficient, so that Marls of Pliocene (PL), Qom (OM) and lower red (OL) are in a separate class and upper-red (Mu), and Eocen (EM) Marl units are in a unique group. Accordingly, it can be said that the four groups differed in volume and run-off coefficient are significantly different from each other. The results of the slope and climate effects on these two traits showed significant effects on volume and run-off coefficient of the marl units.