Soil site suitability analysis using geo-statistical and visualization techniques for selected winter crops in Sagar Island, India

The present study comprehensively assessed soil site suitability for selected winter crops in the coastal saline agro-ecological environment of Sagar Island, India by integrating land limitation and crop suitability evaluation framework of FAO. Soil properties (e.g. texture, pH, organic carbon; SOC, electrical conductivity; EC and available macronutrients- NPK) were obtained through extensive grid based (size: 1 km by 1 km) soil sampling and estimation in the laboratory following standard procedures. Geo-statistical and visualization methods were applied to match the suitability for selected crops based on their essential soil quality requirements. The weights of the soil parameters have been assigned through PCA analysis, based on the relative importance of soil properties sensitive to crop specific growth and development. The inverse distance weighting (IDW) interpolation and reclassification methods were adopted for generation of spatial layers of those soil properties. Results revealed that, nearly 61% of the geographical area (14618 ha GA) of the Island is under agricultural landuse (AL), mostly dominated by lowland rice-fallow based mono-cropping system (76% of AL) followed by rice-rice double cropping (in 14.8% AL). Soil suitability analysis for growing winter crops within agricultural area revealed that 38.4% (5607 ha) of AL is highly suitable (S1) for sunflower, 11.9% of AL (1739 ha) for chilli, 6.8% (987 ha) of AL for potato and only 1% (150 ha) of AL is considered to be highly suitable for mustard crop cultivation. However, the predominant fine textured soils of the Island falls under moderately suitable (S2) category for growing chilli (85.1% of AL), mustard (64.6% of AL), sunflower (55.7% of AL) and potato (53.0% of AL) crops. More than one third of the soils within the agricultural landuse were found not optimum for growing potato, sunflower and mustard. Findings from the study can be harnessed in increasing crop area diversification and intensification with appropriate irrigation and crop management practices in Sagar Island and similar such coastal Islands.