An evaluation of Soil fertility using soil organic carbon, potassium, phosphorus and salinity factors for rice cultivation by fuzzy logic and AHP techniques

ABSTRACT: Consideringtheimportant role of soil fertility and nutrient management in the modern agriculture, the preparation of high-quality soil fertility map seems to be a crucial step in appropriate site-specific management for crop production especially forrice paddiesinNorthen Iran. This study was conducted to prepare a soil fertility map based on soil available potassium (K), available phosphorus (P), organic carbon (OC)and salinity (EC)parameters in Joybar cityof Mazandaran province, Iran. The fuzzy logic and analytic hierarchy process (AHP) techniqueswere incorporated in this study for mapping soil fertility in Geographic Information System (GIS). One hundred soil samples were collected from 0-30 cm depth and analyzed forsoil OC, K, P andEC. The interpolation of data points was done byordinary krigingmethod. The appropriate fuzzy membership functions were subsequently defined for each four factors. The soil fertility map was prepared by AHP technique with adjustment rate of 0.04.The study area was finally simplified into four soil fertility classes entitled as very weak, weak, moderate and suitablethatare comprised of8, 34, 46 and 12percentageof the studied area, respectively.Thispronouncedsoil fertility map can potentially enable the decision makers to apply the site-specific management on input requirementsof paddy cultivation especially for the soils having very weak and weak soil fertility classes.