Investigation of Temporal and Spatial Changes of Nitrogen pollution in Drainage of lands with Different land-uses in Shirood Watershed Located in Mazandaran Province

Sediment of eroded soils have different effect on environment based on amount of materials and elements. Nitrogen is an important nutrient that use a lot in agriculture and excessive use of this cause reduce the waters quality.

This project aim is measurement and comparison of soil nitrogen pollution in different land use and relation between each land use drainage pollution when weather is rainy in area of Bostankar river that is located in Shirod city one of the functions of Tonekabon of Mazandaran province. Because of this, soil was sampled from six land use; forest, Orange garden, Kiwi garden, Flower garden, Rice and Tea farms at winter and spring. Then, a water sample was taken from these lands' drainages. Eventually, for checking of Bostankar river situation, water samples wat also taken at 15 points along the river. Amount of total nitrogen, soluble and clinging were measured at water and soil samples.

Results showed that nitrogen amount in drainages at spring were increased than winter, that reason of this matter can be agriculture activities like fertilization and tillage in this period of time. Maximum and minimum nitrogen amount in spring relate to Flower garden and forest, equal 6.60 and 0.30 mg/lit, respectively.

For controlling the nitrogen output and nitrogen pollution at area of study soil, amount of nitrogen fertilizer use should be based on plant need and soil test result.