Dynamics of potassium by the combined use of organic manures and inorganic potassium fertilizers on available nutrients of groundnut crop (Arachis hypogea) in Madukkur soil series

A pot culture experiment was conducted to study the effect of combined use of organic manures with inorganic Potassium (K) fertilizers on available nutrients of groundnut crop under Madukkur soil series at Tamil Nadu Agricultural College and Research Institute, Madurai during kharif season of 2008-2009. The experiment was laid out in completely randomized design (factorial) with two replications. Main pot treatments comprised of three types of manures viz., control (M0), pressmud @ 5 t ha-1 (M1), vermicompost @ 2 t ha-1 (M2), farmyard manure @12.5 t ha-1 ( M3 ) and sub pot treatment comprised of 4 levels of K viz., 0 (K0), 100 (K1), 75 (K2) and 50 kg of K2O ha-1 (K3) with a recommended dose of fertilizer respectively. The results revealed that the among the various levels of treatments, Among the nutrient level 100 kg K2O ha-1(K1) with pressmud @ 5 t ha-1 (M1) (K1M1) levels have recorded the highest values of available nitrogen, phosphorus and potassium (211.77, 12.76, and 256.87 kg ha-1) while the untreated control registered the lowest values. The available calcium and magnesium content was found highest (228.83 and 123.55 ppm) when applied with 100 kg K2O ha-1 with pressmud @ 5 t ha-1( K1M1 ) respectively and the lowest value recorded in the control pot