| heal.abstract |
During incubation of moist soil samples the water-soluble and exchangeable potassium increased with the rate of K-application and varied with moisture content and time of incubation. At moisture equivalent all the applied potassium converted to an exchangeable form, whereas at wilting point a significant part was fixed. The fixed portion increased with increasing rates of application but on a relative basis it was more or less constant. Air-drying, after incubation of seven months, increased the exchangeable K in the samples that had received rates less than 300 kg K2O/ha and decreased it in the samples with higher additions. The water-soluble potassium during incubation remained constant at low rates of application and it increased at higher rates, but it generally decreased upon air-drying. PBC(K) was not affected by K-additions lower than 600 kg K2O/ha and decreased at higher rates. After incubation of one month the PBC(K) was higher for the samples kept at moisture equivalent and lower for those at wilting point, but at the end of seven month incubation both converged to the same value. Air-drying increased the PBC(K) in all cases. The results suggest that soil water management schemes that include a dry period minimize the loss of available potassium. |
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