Rock phosphate-potassium and rock-solubilising bacteria as alternative, sustainable fertilisers

Classical, soluble fertilisers create environmental and economic problems. As an alternative, we studied the direct applications of phosphate rock and potassium rock in conjunction with phosphate-solubilising bacteria and potassium-solubilising bacteria for cultivation of hot pepper Capsicum annuum L. Our findings show that integration of P and K rocks with inoculation of P- and K-solubilising bacteria increased P availability from 12 to 21% and K availability from 13 to 15% in the soil as compared with control, and subsequently improved nutrient (N, P and K) uptake to the plant. This integration also increased plant photosynthesis by 16% and leaf area by 35% as compared with control plants. Similarly, biomass harvest and fruit yield of the treated plants were 23% and 30%, respectively, higher as compared with control. Overall, we found that the treatment with P and K rocks and PK-solubilising bacterial strains and the treatment with classical, soluble fertiliser have a similar effectiveness. Therefore, direct application of P and K rocks and solubilising bacteria is a promising, sustainable alternative to the use of classical fertilisers