Sustainability of temperate/alpine pastures vs landform and soil status: A case study of Sikkim using GIS and RS techniques

Temperate/alpine pasture lands and associated landforms and soil status of Sikkim were assessed using IRS-P6 (LISS-III) data. Intensive field survey of 14 sites located at different elevations in mid hills and high hill zones was done for soil status, forage production and landform features. The area under alpine pastures in high hill zone was 7.38% of total geographical area whereas it was 6.76% in mid hills. The various soil characteristics of alpine pastures land in Sikkim were: pH (4.14 to 6.34), organic matter (0.95–2.82%), available N (319.6–1402.7 kg/ha), available P (10.39–29.06 kg/ha), and K (103.65–599.6 kg/ha). These soil characteristics in alpine pasture lands in varying altitudes influence the forage production (0.31 – 3.25 t DM/ha) and CP content (8.5 – 19.5%). About 36.5% of the total pasture lands (14.13% of the total area) were at various stages of degradation. Pasture lands (43.65%) located at different altitudes and slopes in mid hill zones were found to be more susceptible to soil erosion/depletion and landslides. The study reveals that the sustainability of pasture lands and pasture production depends upon the soil health and associated landforms.