Site suitability analysis of Gmelina arborea Roxb. using Remote Sensing & Geographic Information System (GIS) in Ranchi district, Jharkhand
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Date
2023
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Birsa Agricultural University, Ranchi
Abstract
The present investigation entitled “Site suitability mapping of Gmelina arborea Roxb. using Remote Sensing and GIS in Ranchi District, Jharkhand” were carried out using ArcGIS and QGIS with the help of JSAC, Ranchi in the study area during the year 2021-22 with the following objectives: i) To prepare land use/land cover map of Ranchi district using high-resolution satellite data. ii) Preparation of thematic geodata base and ancillary database for site suitability iii) Analysis for site suitability in GIS environment for G. arborea.
Multi-criteria approach was used to conduct suitability mapping of G. arborea in Ranchi. Suitability mapping was carried out within the cultivable wasteland sites of Ranchi district, which was masked from the cultivable wasteland map of Ranchi district prepared using two seasons, viz., rabi (Jan–Mar) and kharif (Aug–Nov) Sentinel-II satellite data. Wasteland map of Ranchi was generated at the scale of 1: 50,000 using ArcGIS and QGIS software.
Favorable environment conditions/ limitations i.e., slope, soil characteristics viz soil texture, drainage, depth, pH and climatic conditions viz temperature and rainfall were applied for identification of suitable areas for G. arborea plantation.
Thematic and geodatabase of all the seven parameters were generated using ArcGIS and QGIS. All the layers, viz., soil, slope and ground water were masked using the cultivable wasteland layer as an input. All these layers were overlaid and integrated to derive a suitability map. For G. arborea plantations, Suitability classes were categorized as follows: (i) land units with no or only four slight limitations: highly suitable, (ii) land units with no more than four moderate limitations: moderately suitable, (iii) land units with more than four moderate limitations and/or one or more severe limitations: marginally suitable, (iv) land units with severe limitations: currently not
suitable. Each parameter is assigned with the numbers one to four, highly suitable category of a parameter (e.g., soil texture, slope, groundwater etc.) in a particular area is assigned one followed by a moderately suitable parameter as two, marginally suitable parameter as three and not suitable category of the parameter as four. Area statistics were generated for different suitability classes of wasteland categories developed for Ranchi district.
In Ranchi, wasteland occupied 6.49% (330.97 km2) of total geographical area (5097 km2). Forest scrub showed dominance and occupied 57% (188.05 km2) of total wasteland category followed by open scrub having 24% (78.37 km2), degraded land with 19% (61.77 km2) and brick kiln area occupies 1% (2.78 km2).In block-wise distribution of wasteland, Namkum has highest wasteland area of 39.76 km2 followed by Angara (37.60 km2), Tamar (29.98 km2) and the smallest area in Ratu (2.01 km2).
Approximately 20% (64.31 km2) of the total cultivable wasteland in Ranchi was identified as highly suitable for G. arborea cultivation. Additionally, 16% (53 km2) of the area was categorized as moderately suitable. The largest portion of cultivable wasteland, measuring 128.95 km2, fell under the marginally suitable category, while the not suitable category covered an area of 25% (83.43 km2) of the total area.
Within the notified forest area, a highly suitable area of 46.66 km2 was identified for G. arborea cultivation. Additionally, there was a moderately suitable area of 31.48 km2, a marginally suitable area of 76.79 km2, and a not suitable area of 43.67 km2.In the non-forest area of Ranchi, the suitability assessment identified an area of 17.65 km2 as highly suitable for G. arborea cultivation. Additionally, there was a moderately suitable area of 21.53 km2, a marginally suitable area of 52.16 km2, and a not suitable area of 39.76 km2.