Effect of K Application with Varying Temperature and Moisture Regimes on Different Forms of Soil K and Other Nutrients in Vertisol.
S. C. Gupta1, K. R. Vegh2, and Josef Koncz2. (1) RAK College of Agriculture, Sehore, India, (2) Research Institute for Soil Science and Agricultural Chemistry, Budapest, Hungary
A laboratory pot culture experiment was conducted at the Research Institute for Soil Science and Agricultural Chemistry, Budapest, Hungary during 2003 to study the effect of various levels of potassium (viz., 0, 25, 50, and 100 kg K2O ha-1) with two moisture regimes (M1:20% and M2: 33%) and two temperature regimes (T1: 260C and T2:360C) on the availability of various forms of potassium and other nutrients in Typic chromusterts. Water soluble K, NH4OAc exchangeable K and Acid ammonium acetate +EDTA extractable K forms (LE - K) of soil K increased with the increasing levels of K application in soil and the increase was more at higher moisture regime (M2)compared to lower moisture regime(M1).Further higher moisture regime also registered an increase in all these forms of soil K even at the K0 level of application compared to initial K at both the stages of incubation while this trend was reverse at low moisture regime where all these forms of soil potassium registered a decrease over initial K at K0 level of application. One normal HNO3 soluble K showed no definite trend with K levels and moisture regimes. However, in general this form of K decreased at higher moisture regime as compared to lower moisture regime. Higher temperature regime showed decrease in WS-K , NH4OAc K and LE K content compared to low temperature in most of the cases. LE extractable forms of other nutrients viz. P, Zn, Fe, and Cu in general showed increase in content with K levels. LE Fe showed increase with moisture regime and incubation time. Increase in temperature decreases LE Fe within same incubation time but, it increases the mean LE Fe with later incubation time (I2). LE, B and Mo content were below the detectable limits of ICP AES and were deficient which is suggestive of their possible response by crops if added from outside sources in these soils.