Stabilization of available potassium across soil and climatic conditions of the Czech Republic

Abstract

Time-trends of available potassium (K) in an arable land were investigated within long-term field fertilization experiments established in 1979 at nine sites across climatic and soil conditions of the Czech Republic. Annual K application rates necessary for a stabilization of available K at levels of 108–283 mg K kg−1 soil, ranged from 84–506 kg K ha−1. According to the multiple regression analysis, climatic factors were found to be more important than soil properties in explanation of variability among the sites. Higher K application rates were necessary to keep a constant level of available K in wetter and colder climate. The most significant soil parameter was aqua-regia extractable K, being higher at soils with increased content of mica-group minerals. Stabilization of available K was observed after 29 years at non-fertilized plots, where K outputs were probably balanced by K release from weathering and fixed K pool. The role of investigated climatic and soil parameters is discussed. The results confirm that in the Czech Republic, actual agricultural praxis of K-deficient management is highly dependent on soil K reserves. Sustainable K fertilization should respect climatic and soil characteristics of the site.