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

Land suitability analysis is an important aspect of the agricultural land use planning, and the 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 using over layed digital thematic maps of the climatic condition, topography and soil physic-chemical properties and land use pattern for particular area of interest.
Hence, 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, and 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. However, satellite data of Land sat 8 and the shuttle radar topographic mission (SRTM) were used to map the land use pattern, elevation, and slope. Apart from these data sets, thematic data of annual rainfall and temperature were also analysed and integrated with derived data of analyzed soil pH, EC, organic carbon, and soil texture for their conversion into inverse distance weight (IDW) based mapping process in open source QGIS software. Finally, all these thematic layers were overlaid considering the statistical evaluation of multi-criteria discision making approach to prepare the potential land suitability map for green gram. The results revealed that 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.