Soil Nutrient Dynamics in 28- years old Restored Rock Phosphate Mined Site in Doon Valley
Shikha Uniyal Gairola and Prafulla Soni**
(** Scientist G & Head Forest Research Institute Dehradun)
Present investigation was conducted to know the soil nutrient dynamics (NPK) in 28-years old restored rock phosphate mine site in Doon Valley. The study was carried out for a period of 2 years in five plantations sites viz. shisham dominated restored site (site 1), khair dominated restored site (site 2), mixed tree cover site (site 3), natural forest site (site 4) and pine dominated restored site (site 5). The results reveal that available nitrogen was 0.0882±0.003 in first year while it was calculated to be 0.0936 ±0.003 in second year. Available Phosphorous and exchangeable potassium in the same site for the first year were calculated to be 0.00238±0.0004 and 0.0071±0.0008 while in the second year both the nutrients were calculated to be 0.00286±0.0004 and 0.0078±0.0008. Likewise in site 2 NPK for the first year was calculated to be 0.091±0.01, 0.00546±0.002 and 0.00898±0.002 and for the second year it was calculated to be 0.0942±0.004, 0.00592±0.002 and 0.00962±0.002. In site 3 NPK was evaluated 0.0772±0.003, 0.00176±0.0003 and 0.00712±0.001 for the first year while in the second year it increased to 0.0772±0.003, 0.0024±0.0003 and 0.00778±0.001. In pine dominated restored site NPK was calculated as 0.0924±0.001, 0.00138±0.0002 and 0.00696±0.002 in the first year and similarly in the second year it was calculated as 0.0966±0.001, 0.00196±0.0003 and 0.00764±0.002. These four sites were compared with the adjoining natural forest site. In natural forest site NPK was calculated as 0.087±0.001, 0.0007±0.0002 and 0.0127±0.001 in the first year and in the second year it was calculated as 0.0922±0.001, 0.00136±0.0002 and 0.0135±0.001.