Appraisal of Soil Fertility Status in Salt-affected Soils of Ongole Division, Prakasam District, Andhra Pradesh

Abstract

An investigation was carried out to study the nutrient status and dehydrogenase activity (DHA) in salt-affected soils of Ongole division, Prakasam district, Andhra Pradesh. The soils were neutral to strongly alkaline (pH 6.5 to 9.1) in reaction having electrical conductivity (EC) value higher in surface soils (17.0 dS m-1) than sub-surface soils (15.3 dS m-1). The data on nutrient status showed that the soils are low in organic carbon (OC) and available nitrogen (N), medium to high in available phosphorus (P) and high in available potassium (K). Soil available N had a significant and positive correlation with OC (r = 0.71**). Among the DTPA extractable micronutrient cations, manganese (Mn) and copper (Cu) were found to be above critical limit, whereas the soils were deficient in iron (Fe) and zinc (Zn) supply. The soil pH had a significant and negative correlations with available Fe (r = -0.234*), Mn (r = -0.247*) and Cu (r = -0.219*). The DHA of these soils ranged from 4.50 to 31.90 µg TPF g-1 soil d-1. The decrease in DHA with a rise in salinity as well as alkalinity in salt-affected coastal soils indicate negative correlation with soil pH(r = -0.665**), whereas it had significant positive correlation with OC (r = 0.236*) and available N(r = 0.205*).