Geo informatics-basedland suitability analysis of green gram (Vigna radiata L.) for Kosi region of Bihar

Land suitability analysis is an important aspect of agricultural land use planning. Several approaches viz. remote sensing, geographical information system and multi-criteria decision making were used to analyze the suitable lands for cereals, millets, pulses, oilseeds and other crops. However, digital thematic maps of climatic conditions, topography and soil physic-chemical properties were prepared and overlaid under multi criteria decision-making (MCDM) for land suitability of the assigned crop.With these facts, the present study was carried out to analyze the suitable lands for green gram cultivation in Thakurganj block of Kishanganj district, Bihar.To fulfill the objective, parameters viz. elevation, slope, temperature, rainfall, soil texture, soil pH, EC, OC, and land use pattern were analyzed and mapped under RS-GIS domain. Satellite data of Land sat 8 and the shuttle radar topographic mission (SRTM) were used to map the land use pattern, elevation and slope. However, thematic data of annual rainfall and temperature were also integrated with derived data of analyzed soil pH, EC and organic carbon and their conversion into inverse distance weight (IDW) based mapping process in QGIS software. All these thematic layers (in addition method) overlaid to prepare the potential lad suitability map for green gram, where MCDM based Analytical Hierarchy Process (AHP) technique was used to statistical evaluation for decision making of the derived data, and all the data set were added to prepare the final suitability map of green gram. The pH range of the soils in the study area ranged from 4.42 to 6.67, indicating that they were acidic in nature. However, EC of the soil was found to be non-saline, organic carbon was found to be low to medium and the majority of the area was found to have a loamy soil texture. In terms of elevation and slope, the study area lies between 45–92 m above the mean sea level, and the slope range was observed as 0-3% (gentle or flat). The results revealed that out of the total geographical area only 3537 ha(9.12 %) was found to be highly suitable, followed by 15621 ha (40.28%) moderately suitable, 17584 ha (45.34%) marginally suitable and the remaining 2040 ha(5.26%) was not suitable (NS) for green gram cultivation.