Evaluation of Rock Phosphate and Potassium Feldspar with Biological and Organic Amendments and Its Effect on Soil Phosphorus and Potassium Availability and Uptake, Growth and Yield of Canola

Abstract

This study was conducted to evaluate the efficient use of both rock phosphate (RP) and potassium feldspar (KF) combined with phosphate (PDB) and potassium (KDB) dissolving bacteria inoculation and/or humic material application on soil phosphorus and potassium availability and uptake, growth and yield of canola compared to the use of chemical manufactured fertilizers. Two field experiments using canola as a test crop were performed during the winter seasons of 2014/2015 and 2015/2016 on the experimental farm, Faculty of Agriculture, South Valley University, Qena, Egypt. They had a complete block randomized design with three replications. The experimental treatments included single and dual inoculations of the soil with phosphate and potassium solubilizing bacteria as well as a direct applications of rock phosphate and potassium feldspar with and without humic material additions. The results indicated that the direct addition of P and K mineral materials in a combination with P and K dissolving bacteria as biological amendments as well as humic materials as an organic form to the sandy loam soil improved P and K availability in the soil, their uptake and growth parameters of canola compared to the control. The most effective treatment was (RP+KF) + (PDB+KDB) + humic materials which produced the highest values of growth, seed yield and nutrient uptake by canola plants compared to the control or to their sole application. There were no significant differences in the parameters produced from these treatments and those obtained from using P and K chemical fertilizers. These results reflected the efficient use of natural sources of P and K combined with the biological additions of P and K dissolving bacteria and humic materials as an organic source instead of using P and K chemical fertilizers for growing crops. Therefore, the direct application of rock phosphate and potassium minerals to soils is considered a promising and economic alternative of natural resources.