Agricultural land suitability analysis in Manipur, India using GIS and AHP

This article aims to identify potential sites for agricultural use in the state of Manipur of north east India by employing the analytic hierarchy process in a geographic information system environment in conjunction with the use of remote sensing and soil data. Within the analytic hierarchy process, each terrain variable underwent a pairwise comparison and criteria weights were assigned according to their relative importance. Eight variables were selected and used in land suitability analysis for agriculture. It was found that Manipur had 57% (12,660 km2) of its total geographical area suitable for agriculture. However, 8126 km2 (37%) and 1374 km2 (6%) of the total geographical area was currently and permanently unsuitable land respectively. The distribution of suitable land varied greatly, with highly, moderately and marginally suitable land covering only 8%, 16% and 33% respectively of the total geographical area. The highly suitable agricultural land is predominantly concentrated in the Imphal valley (70%), though 90% of moderately suitable and 96% of marginally suitable land also exist in the hills. The hilly areas constitute 96% and 97% respectively of currently unsuitable and permanently unsuitable land in the state. Suitable land comprises of land with low to medium altitude, gentle to moderate slopes, soil of fine or acceptable quality, and with minimal flood risk. Unsuitable lands tend to be diametrically opposite to these attributes with steep hill slopes. The nature of distribution of land suitability types influences the agricultural pattern in Manipur. Agriculture in the hill areas comprises mainly of shifting cultivation on hill slopes, whereas in the valley region it is irrigated and permanent. This analysis of Manipur has a wider applicability since the shifting cultivation-irrigated agriculture combination is similar to that which exists across much of the highlands of South East Asia.