Soil potassium release characteristics in terms of constant rate k and step k in vegetable growing soils of Ranga Reddy and Mahaboobnagar districts of Telangana

Abstract

In the present investigation potassium release characteristics of the soils in terms of constant rate k and step k were studied in vegetable growing soils of Ranga reddy and Mahaboobnagar districts of Telangana. Rangareddy and Mahaboobnagar soils were slightly acidic to moderately alkaline in reaction, non saline in nature, organic carbon was low to high, low CEC. The texture of the soils of Ranga Reddy were loamy sand, loam and sandy loam and Mahaboobnagar were sandy loam, loam, loamy sand and sandy clay loam. The soils of Ranga Reddy and Mahaboobnagar districts were light textured with sand as dominant fraction. The step K, which is supposed to be plant utilizable non- exchangeable K varied from 1.5 to 5.43 me 100g-1 with an average of 3.09 me 100g-1 in soils of Ranga Reddy and it varied from 1.62 to 4.48 me 100g-1 with an average of 2.84 me 100g-1 in soils of Mahaboobnagar. The constant rate K varied from 0.6 to 0.83 me 100g-1 with an average of 0.68 me 100g-1 in soils of Ranga Reddy. It varied from 0.88 to 1.02 me 100g-1 with an average of 0.92 me 100g-1 in soils of Mahaboobnagar. A significant and positive correlation of step K with different forms of K indicates that these are dynamic and reflect the dependence on each other. The step K and constant rate K were positively correlated with CEC, clay and silt, which might be due to clay content containing non-exchangeable K in the fixed form.