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 (<i>Capsicum annuum</i> L.)

Abstract

Abstract. The ability of soil microorganisms and organic manure to convert insoluble phosphorus (P) to an accessible form offers a biological rescue system for improving P utilization efficiency in soil-plant systems. Our objective was to examine the P mineralization potential of two soluble P fertilizers (SPF), i.e., single superphosphate (SSP) and diammonium phosphate (DAP), and of insoluble rock phosphate (RP) with and without phosphate-solubilizing bacteria (PSB) and poultry manure (PM) and their subsequent effect on the growth, yield and P utilization efficiency (PUE) of chilli (Capsicum annuum L.). An incubation study was carried out on a loam (slightly alkaline) soil with 12 treatments: T 0 -control; T 1 -RP; T 2 -SSP; T 3 -DAP; T 4 -PM; T 5 -1/2 RP+1/2 SSP; T 6 -1/2 RP+1/2 DAP; T 7 -1/2 RP+1/2 PM; T 8 -RP+PSB; T 9 -1/2 RP+1/2 SSP+PSB; T 10 -1/2 RP+1/2 DAP+PSB; and T 11 -1/2 RP+1/2 PM+PSB. Phosphorus mineralization was measured by analyzing extractable P from the amended soil incubated under controlled conditions at 25 • C for periods of 0, 5, 15, 25, 35 and 60 days. A complementary greenhouse experiment was conducted in pots with chilli (Capsicum annuum L.) as a test crop. Growth, yield, P uptake and PUE of the chilli was determined during the study. Results indicated that P mineralization in soil amended with RP was 6.0-11.5 mg kg −1 , while both 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 use of PSB and PM with RP in T 11 stimulated P mineralization by releasing a maximum of 25 mg P kg −1 that was maintained at high levels without any loss. Use of PSB decreased soil pH. In the greenhouse experiment, RP alone or RP+PSB did not have a significant impact on plant growth. However, the combined use of RP, PM and PSB in T 11 resulted in similar growth, yield and P uptake of chilli as DAP. The PUE of applied P varied from 4 to 29 % and was higher in the treatments that included PSB. We conclude that the use of PSB and PM with insoluble RP or with soluble P fertilizers could be a promising approach to enhance P availability from both low-grade RP and SPF for crop production in intensive cropping systems.

Biosolubilization of phosphorus from rock phosphate and other P fertilizers in response to phosphate solubilizing bacteria and poultry manure in a silt loam calcareous soil

“…In a recent study, inoculation of rice with Burkholderia, Enterobacter, Paenibacillus , and Pseudomonas significantly increased the growth characteristics and nutrient contents in rice fertilized with Bayóvar RP compared to Bayóvar RP without inoculation ( da Costa et al, ). Similar stimulating effects of PSBs and organic amendments on plant biomass and P accumulation in different crops treated with RP had also been reported earlier by different workers ( Sharma et al, ; Panhwar et al, ; Saleem et al, ; Abbasi et al, ; Billah and Bano , ).The higher response of plant biomass and P accumulation in plants due to PSBs and PM was attributed to the solubilization and mobilization of native and applied P due to the acidic environment prevailing during the secretion of organic acids from PSBs and PM ( Chen et al, ; Nishanth and Biswas , ).…”

“…The maximum relative increase in P released from RP+PM+PSBs over RP+PM was 52% recorded in RP+PM+PSB 3 treatment at 60 d incubation. Similar effects of bio‐ and organic amendments on P availability and P recovery from RP had also been reported earlier ( Aria et al, ; Alzoubi and Gaibore , ; Abbasi et al, ). The mechanisms involved in the potential of PSBs to solubilize P complexes or insoluble phosphates are well known and have been attributed to the processes of acidification, chelation, exchange reactions, and the production of organic acids as reported by Chen et al ().…”

“…In recent years various techniques for solubilization of insoluble RP and sparingly soluble organic and inorganic P sources have been proposed, with increasing emphasis on application of P‐solubilizing bacteria (PSBs) ( Hameeda et al, ; Panhwar et al, ; Selvakumar et al, ; Abbasi et al, ; Moreno Quevedo et al, ).The P solubilizing potential of these PSBs is due to their ability to produce and release acidic metabolites, such as organic acids, that through their hydroxyl and carboxyl groups chelate the cations bound to phosphate and then convert them into the soluble forms ( Khan et al, 2009). Therefore, the ability of PSBs to solubilize P complexes has been attributed to the process of acidification, chelation, exchange reactions, and production of organic acids ( Goldstein , ; Chen et al, ; Ekin , ).…”

“…Similarly, application of organic manures, compost or plant residues is considered another option to mobilize or solubilize P from insoluble/sparingly soluble P sources (Nishanth and Biswas, 2008;Wickramatilake et al, 2010;Mashori et al, 2013;Abbasi et al, 2015;Agyarko et al, 2016). The P solubilization, due to addition of organic amendments, is mainly due to the production of organic acids, release of CO 2 and release of humate that form a protective surface over colloidal sesquioxides and reduce P fixation (Toor, 2009) Studies related to the efficiency of PSBs alone or in combination with organic manures on different P sources for improving P release capacity or P solubilization to enrich soil are limited.…”

Application of nanoparticle of rock phosphate and biofertilizer in increasing some soil chemical characteristics of variable charge soil

“…This phenomenon was found after one month and four months of incubation, indicated that the increasing of rock phosphate dosage followed by the increasing of potential P in the soil. Meanwhile, reversely biofertilizer decreased potential P. This finding was contradictory to [17] where application of rock phosphate and phosphate solubilizing bacteria increased the potential P. Figures 3 and 4 inform the correlation between Potential P and P-retention and between potential P and available P after one and four months of incubation. Figure 3 informs that potential P increased as the P retention decreased.…”