Abstract
ABSTRACT: The acid release of phosphates from rock phosphates (RP) and the retention of ammonium by inorganic phosphates have been studied separately in composting; however, there is a gap in the knowledge of combined application of RP with organic residues and microorganisms. The objectives were to evaluate the combined application of fresh poultry litter (PL) with RP and P-solubilizing microorganisms (M) on soil organic matter pools, microbial biomass C (MB-C) and on whole-plant silage maize and grain yields. Two field experiments tested the effects of timing of applications of PL (8 Mg ha–1), RP (4 Mg ha–1) and microorganisms on soil organic matter pools, nutritional aspects and productive components of maize crop whole-plant silage. A second experiment evaluated the effects of RP doses (0, 3, 6 and 9 Mg ha–1) with a fixed dose of PL (8 Mg ha–1) on maize grains. Application of PL+RP decreased soil organic C, while RP alone increased the humin fraction C compared to the control. The MB-C in soil with PL and PL+RP+M increased in comparison to the control and the RP. The application of PL, based on an average of fall and spring, increased leaves + stem dry matter, while in the fall on its own, the highest cob yield was observed in the combination of PL+RP, showing synergistic effects. The best ratio of poultry litter to rock phosphate combination is 2:1 in the anticipated fall application on the maize silage crop or immediate application on the maize grain crops.
Highlights
Estimated global P reserves suggest future scarcity of phosphate rocks should not be used as a key motivation for an intensification of research (Baveye, 2015)
The soil organic C levels did not change as a function of poultry litter (PL)+rock phosphates (RP) with P-solubilizing microorganisms (PL+RP+M) application or of PL or RP alone
The C-FA, 36 % of the extracted humic substances did not vary in any of the treatments, while for the C in humic acid (C-HA) that represented 64 % of the humic substances, application of PL+RP+M decreased significant levels compared to the control by 23 % and the PL by 21 % (Figure 2B)
Summary
Estimated global P reserves suggest future scarcity of phosphate rocks should not be used as a key motivation for an intensification of research (Baveye, 2015). Low grade rock phosphates (RP) have been incorporated during the composting process of organic manures, aiming to increase the P supply (Biswas and Narayanasamy, 2006; Ali et al, 2014; Billah and Bano, 2015) mainly through RP dissolution by acid reactions during decomposition and nitrification processes (Mahimairaja et al, 1995; Biswas and Narayanasamy, 2006). Phosphate-solubilizing microorganisms can be added to mixtures with RP and organic fertilizers to increase the P supplies (Khan and Sharif, 2012; Abbasi et al, 2013; Abbasi et al, 2015). Phosphate-solubilizing microorganisms can be added to the composting of RP and manure (Biswas and Narayanasamy, 2006; Khan and Sharif, 2012) to increase the P supplies. Plant growth-promoting rhizobacteria inoculation with poultry litter increased maize growth (Lin et al, 2018)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
