Plant nutrition and soil fertility require an adequate management of essential macro- nutrients such as potassium (K) and phosphorus (P) and Nitrogen (N), which are mandatory for plant development. Modern intensive agricultural practices face numerous challenges that pose major threats to global food security. In order to address the nutritional requirements of the ever-increasing world population, instead of chemical fertilizers and pesticides the biofertilizers are increases the crop production. In this study, in vitro and greenhouse experiments were carried out to investigate K solubilization traits of two Actinomycetes (KSA 09 and KSA 16) under fertilization with feldspar. The pot experiments revealed that both strains (Streptomyces fenghuangensis, Streptomyces atacamensis compared to the uninoculated control. These findings showed that strains are promising candidates for the implementation of efficient biofertilization strategies to improve soil fertility and plant yield under K fertilization.