Erosion is a selective process. And some of the clay particles that are important in fertility transmitted into small aggregates. Gradual transfer of these particles, it results in larger particles with less fertility. Therefore, it is necessary to carry out research on fertility and granolometry. This research was done to objective determine soil fertility losses due to dry-farming erosion and sediment granolometry. At first, provinces were studied for dry-farming areas and production and were selected four areas. Required soil transferred to rain and erosion simulator laboratory. Characteristics such as Particle size distribution (PSD), Nitrogen, Available Potassium and absorbable Phosphorus was measured and were determined the amount of fertility losses due to erosion and sediment granolometry. Results showed that in pishkamar and kouhin the particle size distribution of sediment was smaller than the main soil, in Sararood closer to the main soil and in Gachsaran more than the main soil. Total nitrogen of the main soil of pishkamar, Sararood, Kuhin and Gachsaran was obtained 0.08, 0.1, 0.06 and 0.09%, respectively. absorbable Phosphorus and Available Potassium in the selected areas, were calculated 4.76, 104.5 and 4.47, 359.5 and 2.02, 222.4 and 9.62, 360 mg / kg, respectively.