Soil fertility assessment for ensuring food security in lower Himalayan range using GIS techniques

Abstract

Mountainous regions are highly vulnerable to food security as compared to plains because of lack of farmland and higher probability of disasters. Soil fertility plays a crucial role in agricultural production. In the present investigation, soil fertility of Nainital district, a hilly region in Himalayan range, was analyzed to map its spatial distribution. A soil database was created by taking 180 surface soil samples using stratified multistage random sampling method from fields of median sized farmers alongwith geographical location, from each block covering whole Nainital district of Uttarakhand, and were assessed for combined soil fertility with a soil fertility index (SFI). Spatial variability of soil chemical properties was computed and the respective surface maps were prepared using inverse distance weightage (IDW) algorithm embedded in Quantum GIS (QGIS). The layers of three important soil nutrients i.e. available nitrogen, available phosphorous and exchangeable potassium were coalesced to evaluate overall soil fertility. The soils of Nainital district were observed to be mostly under medium to highly fertile category, except in specific cases where available phosphorus was quite low. The results indicated 6.89%, 80.44%, and 12.67% of total geographical area (TGA) under less fertile, moderately fertile and highly fertile category, respectively.