Potentiality and irrigability assessment of Shiwalik hill soils of Himachal Pradesh

Abstract

The soils and lands developed under sub-humid sub-tropical climate of Shiwalik foot hills of Himachal Pradesh were evaluated for their productivity and potentiality under different land uses viz. agriculture, pastures and forest/tree crops and suitability for sustained irrigation. The actual productivity of these soils for agriculture was rated extremely poor to nil, poor and average comprising 80.4, 11.3 and 4.4% of total geographical area (TGA) of the watershed, respectively. The corresponding productivity for pastures was 12.0, 51.2 and 33% of TGA. The actual productivity of all these lands for forest/tree land use was found to be extremely poor to nil. The potential productivity for agriculture was in poor, average, good and excellent classes comprising 64.4, 10.5, 12.7 and 8.6% of TGA, respectively. Whereas, it was found to be average, good and excellent for pastures in 39.4, 48.2 and 8.6% of TGA, respectively. For forest/tree land use, the potential productivity was found to be extremely poor to nil for majority of the soils comprising 74% of TGA. Other classesviz. poor and average covered only 14.7 and 7.5% of TGA, respectively. Thus, productivity of most of the soils could be increased to a greatextent by applying improvement measures to overcome the identified constraints as indicated by their potential productivity classes.Based on characteristics pertaining to soil, topography, drainage conditions and cost of land development these lands were classified into four irrigability sub-classes (3s, 4ts, 5ts and 6ts) according to the kind and degree of limitations for sustained use under irrigation. The respective classes covered 115.71, 105.2, 380.45 and 797.29 ha comprising 8.0, 7.2, 26.2 and 54.8% of TGA, there being no class 1 or 2 irrigable land. Topography, shallow soil depth, coarse soil texture, high permeability and low available water capacity are the main limiting factors identified those may be manipulated suitably to increase production potential of these lands.