Intl. J. Agric. Env. Biotech. 5(4): 441-444, December, 2012 Potassium dynamics in representative soils of low, mid and high altitude zones of North Kashmir S.A. Bangroo*, Mushtaq A. Wani and Tahir Ali Sher-e-Kashmir University of Agricultural Sciences & Technology of Kashmir, Shalimar Campus, Jammu & Kashmir,India * E.mail: shalzsab@gmail.com Paper no: 65 Received: 23 rd July 2012 Received in revised form: 19 th October 2012 Accepted: 29 th December 2012 Abstract Three altitude- low (Silty clay loam), mid (Clay loam) and high (Silty loam) zone soils of District Ganderbal, Kashmir (India) were studied for quantity/intensity (Q/I) relationship to evaluate the K dynamics. K L, ∆K°, K X and PBC K were found to be higher in mid altitude soils. The values of K L, ∆K° and K X ranged from 0.50 to 0.60, 0.12 to 0.15 and 0.38 to 0.44 cmol Kg -1 in mid, low and high altitude soils respectively. The equilibrium activity ratio (AR e K ) of K varied from 0.34 to 0.82 × 10 -3 (mole/l) 0.5 , potassium buffering capacity (PBC K ) from and free energy (-∆G) of K – (Ca+Mg) exchange ranged between 22.7 to 34.7 (cmol Kg -1 )/ (mole/l) 0.5 and - 4.2 to - 4.7 K cal mole -1 respectively. The soils showed high capacities to maintain the potential of K against depletion, as they represented very high linear PBC K . Significant correlations were found between Q/I parameters and soil properties. Among the studied soil attributes, most of the variation was accounted for i) by organic carbon, clay, cation exchange capacity (CEC) and exchangeable K (Ex-K) on K L, “K° and K X ; ii) by pH, electrical conductivity (EC) and CaCO 3 on AR e K and ∆ G. @2012 New Delhi Publishers. All rights reserved Keywords : Potassium dynamics, Activity ratio, Quantity intensity labile potassium The Karewa soils of Kashmir are characterized by low clay, silt and high organic matter, dominated by weathered potassium (K) bearing minerals and have high K saturation percentage. In spite of the fact that the total K of these soils is high but a small portion of this element is accessible for plants (Wani 2011). Availability of K to plants depends on its intensity, capacity and removal rate of soils (Abaslou and Abatahi 2008) The commonly observed form of quantity/intensity relationship generally consists of two parts, the linear upper part and a curved lower part (Beckett 1964). The linear part confirms to Gapon type exchange equations (Bolt 1955) and describes the rapid non-specific exchange on planer surface of clay minerals (Dhillon et al., 1990). The curved part confirms to exchange at sites on the freyed edges or in the interlayer space of clay minerals. Influence of different soil parameters on the K dynamics in maize growing Karewa soils of North Kashmir (India) has been investigated by Nakashgir et al., (1997). In this paper the Q/I parameters of K using thermodynamic approach has been reported. Influence of soil parameters on the dynamic relationship between Q/I and buffering capacity of K was also studied. Material and methods Two surface samples from each location representing low, mid and high altitude zones of maize growing Karewa soils of North Kashmir were collected, air dried and ground to pass through 2mm sieve. The mean values of physico-chemical characteristics of soil samples are given in Table 1. Soil Science