PROPERTIES OF PHOSPHORUS-MOBILIZING BACTERIA AND THEIR EFFECT ON CEREAL CROP YIELDS ON LUVISOL LOAMY SAND SOILS

Abstract

Some properties of P-mobilizing bacteria were investigated. P-mobilizing bacteria capabilities of transfer the insoluble Са₃(РО₄)₂ into accessible form and stimulation of root development determine their positive effect on nutrition regime and crop yields. The efficiency of P-mobilizing bacteria introduction was found to depend on the content of mobile of phosphorus in soil. Under Luvisol loamy sand (coarse) soil supply by Р О 207 mg/kg^-1 most effective was 2 5 introduction of P-mobilizing bacteria at the backgrounds of N₁₂₀K₉₀ and N₁₂₀K₉₀Р₁₀ that provided winter triticale yields 46.5-48.0 c/ha^-1 and reliable responses to inoculation 3.0- 3.3 c/ha^-1; under soil supply by Р О 244 mg/kg^-1 grain response 2.3 c/ha^-1 was obtained 2 5 only at background of N K ; in a range of soil supply by Р О 286-394 mg kg^-1 grain 120 90 2 5 responses was not statistically sound. Application of P-mobilizing bacteria on Luvisol loamy sand (bind) soil was most effective if mobile phosphates contents were in diapason of 200-400 mg kg^-1 at the backgrounds of N 60^K90 that resulted in spring wheat responses 4.3-4.7 c/ha^-1; at the backgrounds of N P K grain response 3.6 c/ha^-1 was obtained only if P O content 60 30 90 2 5 in soil not exceed 200 mg/kg^-1. Under high soil supply by mobile phosphates the introduction of P-mobilizing bacteria is not profitable.