effect of tillage erosion on soil displacement and productivity (case study: tutkabon, guilan)

this research was conducted in a part of the dry farming lands of the southern guilan province, aimed at examining the impact of tillage erosion on the soil displacement and consequently its productivity. in order to achieve the research aims, 18 sampling points were spotted in some different locations of the landscape in seven adjacent fields, based on the adjacency to the field ridges (borders). soil fertility characteristics at 0-30 cm depth as well as components related to wheat yield were determined at each sampling point. cluster analysis by the ward method grouped the soils in three as based on their fertility as well as productivity. the criteria considered in grouping soils' fertility consisted of nitrogen, phosphorous, potassium and organic carbon contents. the productivity of the soil was classified as based on ear number, one thousand grain weight, number of grains in ear as well as grain yield. there was no significant relationship found between the grouped points, in terms of fertility and productivity, probably due to differences in crop management in the adjacent fields. the terrace elevation formed between two fields was observed to be 1 to 3.2 meters in the slope direction, and 1 to 1.3 meters in the lateral direction. in addition, the soil volume displaced in the two directions was estimated to be 8 to 36 and 5 to 22 tons per hectare per year, respectively.