Mineralization of soluble P fertilizers and insoluble rock phosphate in response to phosphate-solubilizing bacteria and poultry manure and their effect on the growth and P utilization efficiency of chilli (Capsicum annuum L.)

[摘要] The ability of soil microorganisms and organic manure to convert insolublephosphorus (P) to an accessible form offers a biological rescue system forimproving P utilization efficiency in soil–plant systems. Our objective wasto examine the P mineralization potential of two soluble P fertilizers (SPF),i.e., single superphosphate (SSP) and diammonium phosphate (DAP), and ofinsoluble rock phosphate (RP) with and without phosphate-solubilizingbacteria (PSB) and poultry manure (PM) and their subsequent effect on thegrowth, yield and P utilization efficiency (PUE) of chilli (Capsicumannuum L.). An incubation study was carried out on a loam (slightlyalkaline) soil with 12 treatments: T₀ – control; T₁ – RP; T₂– SSP; T₃ – DAP; T₄ – PM; T₅ – 1/2 RP+1/2 SSP;T₆ – 1/2 RP+1/2 DAP; T₇ – 1/2 RP+1/2 PM; T₈ –RP+PSB; T₉ – 1/2 RP+1/2 SSP+PSB; T₁₀ – 1/2 RP+1/2DAP+PSB; and T₁₁ – 1/2 RP+1/2 PM+PSB. Phosphorus mineralizationwas measured by analyzing extractable P from the amended soil incubated undercontrolled conditions at 25 °C for periods of 0, 5, 15, 25, 35 and60 days. A complementary greenhouse experiment was conducted in pots withchilli (Capsicum annuum L.) as a test crop. Growth, yield, P uptakeand PUE of the chilli was determined during the study. Results indicated thatP mineralization in soil amended with RP was 6.0–11.5 mg kg⁻¹, whileboth soluble P fertilizers resulted in 68–73 mg P kg⁻¹ at day 0,which decreased by 79–82 % at the end of incubation. The integrated useof PSB and PM with RP in T₁₁stimulated P mineralization by releasinga maximum of 25 mg P kg⁻¹ that was maintained at high levels withoutany loss. Use of PSB decreased soil pH. In the greenhouse experiment, RPalone or RP+PSB did not have a significant impact on plant growth. However,the combined use of RP, PM and PSB in T₁₁ resulted in similar growth,yield and P uptake of chilli as DAP. The PUE of applied P varied from 4 to29 % and was higher in the treatments that included PSB. We conclude thatthe use of PSB and PM with insoluble RP or with soluble P fertilizers couldbe a promising approach to enhance P availability from both low-grade RP andSPF for crop production in intensive cropping systems.

[学科分类] 地球化学与岩石