Determination of K quantity- intensity parameters in a toposequence

Spatial variability of soil properties is related to environmental factors such as climate, slope position, topography, slope gradient, elevation, parent material and vegetation. Topography variability and soil formation cause the significant differences in soil characteristics in a hillslope. Topography affects the amount of nutrients, including potassium (K) in the soil. Therefore, knowledge of variability in soil K availability to achieve better production and sustainable management is essential. The relationship of quantity- intensity (Q/I) offers a relatively full of soil K status. The present study was to evaluate the effect of topography on K quantity- intensity parameters using the six horizons in both depths on a sequence in Shahrekord plain.
Soil samples were air dried, to pass a 2 mm sieve and then, selected physical and chemical properties of soil were measured by laboratory standard methods. In these samples Q/I parameters including activity ratio at equilibrium (AR0), labile K (ΔK0), potential buffering capacity (PBCK) and hardly exchangeable K (Kx) also K forms were determined.
The results showed that the effect of topography on K quantity- intensity parameters in both depths was significant (P The results showed that topography caused changes in the soil properties, especially clay, organic carbon and CEC, therefore, can affect the quantity-intensity potassium.