Characterization of Piospheres in Northern Liddar Valley of Kashmir Himalaya

摘要

Grazing in pastures results in the formation of degraded patches called piospheres. It alters soil composition and vegetation in the vicinity of the watering points, shade, mineral licks and sheepfolds. A comparative approach was adopted in Liddar valley of Himalaya to study soil and vegetation composition of piosphere patches using various techniques. Pasture soils were investigated for nitrogen (N), organic matter (OM), pH, electrical conductivity (EC), total phosphorus (P_2O_5), total potassium (K_2O), total calcium (CaO), total magnesium (MgO) and total sulfur (S) using energy dispersive X-ray florescence and physical properties like soil texture and bulk density were also studied using respective techniques. Importance value index and plant species compositions were studied using transect method along the weakening effect radiating outward from center of piosphere. The change in their spatial extent was also studied using remote sensing technique. The results indicate that there is an enrichment of nutrients in piospheres such as N (0.02%), P (0.30%), K (0.04%), S (0.04%), and reduction of others like Ca (0.30%) and Mg (0.38%). Soil fractions like clay decreased by (17.62%) coupled with increase of sand and silt portion by 9.83% and 7.78% respectively, which eventually resulted in increase of bulk density by 0.08%. Furthermore, number of species have decreased to half (31) in the piospheres as compared to non piospheres (64). Paired samples t test was performed to determine the differences existed between two grazing intensities. The enrichment of some nutrients especially P results in terrestrial eutrophication which becomes suitable for the encroachment of weedy and unpalatable plant species. Remote sensing data also indicates that the total area under these degraded patches increased from 2.07% in 1992 to 2.69% in 2010. The management perspectives degradation of pasturelands by piosphere formation needs an immediate attention which otherwise shall reduce the