Effects of terracing on soil quality attributes in Chehelchay watershed, Golestan province

Whereas biological and engineering methods of soil conservation are complementary but pedoturbation by machinery in engineering practices are considered as one of the disadvantages of this method. To investigate the effect of terracing as engineering practices on soil quality attributes, four terracing sites with different aspects, slope, direction, elevation and ages were selected. Soil samples were taken from 0-30 cm depth. The results showed that terracing operation influenced soil physical, chemical and biologic quality indices and have to be considered in land use operation and management. Managers should analyze the effect of this operation on ecosystem health and find the relationships between social and economic aspects. The results of physical soil quality attributes showed that terracing reduced soil aggregate stability from 0.61 to 0.24 mm. Also this operation increased the soil pH from 7.32 to 7.64, EC from 0.347 to 0.808 ds/m, CaCo3 content from 8.96 to 38.69 percent, SP content from 45 to 49 percent, Total N content from 0.124 to 0.176, absorbable P from 1/64 to 5.38 and absorbable K from 71.45 to 159.29 mg/Kg and also reduced OM content from 2.73 to 1.27 percent and CEC from 85.6 to 66.7 cmol+/Kg. Soil respiration as a biological index were measured and based on results of this study, terracing reduced this biologic index. Physical, chemical and biologic soil quality indices were statistically different in four sites.