Characterization and classification of soils under different land uses in Binwa watershed of Himachal Pradesh

Abstract

The knowledge of soils with respect to their characteristics, properties, classification, distribution and potential uses is always needed for sustainable land use planning. Binwa watershed represents high-, mid- and low hill soil zones and agrosituations of Himachal Pradesh and lies between 76° 34and#8242; 08and#8243; to 76° 45and#8242; 53and#8243; E longitude and 31° 53and#8242; 15and#8243; to 32° 11and#8242; 58and#8243; N latitude. The area under built-up, cropland, tea plantation, forest, scrubland and grasslands, rock outcrops and water bodies is 4.7, 24.9, 1.3, 33.4, 23.4, 8.4 and 3.9 per cent of the total watershed area (340.1 km2), respectively. A reconnaissance soil survey of Binwa watershed was conducted to describe and classify the soils and predict soil potentials for sustainable land uses. Based on 478 augerbore/minipit observations, sixteen pedons were identified to represent soils under different land uses. The soils are characerized by the presence of A-C, A-Bw-C and A-Bt1 . horizon sequences. Soils of high and mid-hill soil zones are loamy skeletal to fine silty, very shallow to very deep and acidic (base saturation lt 60 %), while those of low hill zone are loamy skeletal to coarse loamy, very shallow to deep and non-acidic (base saturation gt60 %). newlineTaxonomically, the soils of Binwa watershed are member of loamy skeletal to fine silty, shallow to very deep, nil to very gravelly, acid to non-acid, mixed, thermic families of Typic/Lithic Udorthents/Dystrudepts/Eutrudepts/Hapludalfs/Paleudalfs and are put into ten tentative soil series, each with unique characteristics, properties and productivity potentials. Use and management of soils had no effect on the natural identity of the soils. Soils were found deficient in available N, P, Mg, S, Cu and Zn. Agricultural lands have more nutrient contents and better nutrient status as compared to non-agricultural lands. Horizon-wise distribution of available nutrients was also studied during the present investigation. newline The agricultural lands belong to land capability class II, III, IV, VI and VII, indicating erosion as a common limitation. Though Class VI and VII agricultural lands are not cultivable, these require intense care against soil erosion to sustain the existing land use. Non-agricultural lands of Binwa watershed are classified as Class VII. Class VII lands can also be effectively used for pasture development and forestry through the adoption of scientific soil and crop management practices. A similar trend of results was obtained with the Storie soil rating index. Actual and potential soil productivity indices revealed that soil productivity of agricultural lands can be enhanced by 1.5 to 8.0 times for crop growing, 1.7 to 3.0 times for pastures and 1.5 to 10.0 times for forest and non-forest tree crops with the adoption of recommended soil, crop and water management practices.