GPS and GIS Based Soil Fertility Mapping for Cuddalore District of Tamil Nadu.

Geo referenced surface soil samples were collected from 79 villages of Cuddalore district, Tamil Nadu and about 474 soil samples were analysed for twelve chemical parameters. The fertility status revealed that the soils were acidic to alkaline in soil reaction, non - saline and low in organic carbon content. The macronutrient availability showed low available N (82.3%), high available P (61.8%), medium to high available K (49.3&31.8%) and sufficient in available S (84.4%). With regard to micronutrients, the soils were predominantly deficient in Zn (76.4%) followed by Cu (38%), B (10.6 %), Fe (1.8 %) and Mn (1.4 %). Using the geocoordinates, thematic maps for all the parameters were prepared,, which also indicated that major area of the district was acidic to alkaline in soil reaction, non-saline, low in OC, low, high and medium in available N, P and K, respectively. Zinc was predominantly deficient among the micronutrients, while all others were in sufficient status. [ABSTRACT FROM AUTHOR]