TY - JOUR

T1 - Microbial iron reduction compensates for phosphorus limitation in paddy soils

AU - Wang, Chaoqun

AU - Thielemann, Lukas

AU - Dippold, Michaela A

AU - Guggenberger, Georg

AU - Kuzyakov, Yakov

AU - Banfield, Callum C

AU - Ge, Tida

AU - Guenther, Stephanie

AU - Bork, Patrick

AU - Horn, Marcus A

AU - Dorodnikov, Maxim

N1 - Funding Information: The authors gratefully acknowledge the China Scholarship Council (CSC) for financial support for Chaoqun Wang. This work was supported by the research grant from German Research Foundation (DFG Do 1533/3-1; GU 406/33-1; HO4020/8-1). Michaela Dippold was funded by the Robert Bosch Junior Professorship. The authors would like to thank Bernd Kopka and Marvin Blaue of the Laboratory for Radioisotopes (LARI) of the University of Goettingen for their advice, support, and measurements. We also thank Jake Beyer and Dr. Florian Carstens for constructive advising as well as a technical staff of the Department of Agricultural Soil Science, University of Goettingen, Karin Schmidt, for microbial biomass carbon measurement. Funding Information: The authors gratefully acknowledge the China Scholarship Council (CSC) for financial support for Chaoqun Wang. This work was supported by the research grant from German Research Foundation ( DFG Do 1533/3-1 ; GU 406/33-1 ; HO4020/8-1 ). Michaela Dippold was funded by the Robert Bosch Junior Professorship. The authors would like to thank Bernd Kopka and Marvin Blaue of the Laboratory for Radioisotopes (LARI) of the University of Goettingen for their advice, support, and measurements. We also thank Jake Beyer and Dr. Florian Carstens for constructive advising as well as a technical staff of the Department of Agricultural Soil Science, University of Goettingen, Karin Schmidt, for microbial biomass carbon measurement.

PY - 2022/9/1

Y1 - 2022/9/1

N2 - Limitation of rice growth by low phosphorus (P) availability is a widespread problem in tropical and subtropical soils because of the high content of iron (Fe) (oxyhydr)oxides. Ferric iron-bound P (Fe(III)-P) can serve as a P source in paddies after Fe(III) reduction to Fe(II) and corresponding H2PO4- release. However, the relevance of reductive dissolution of Fe(III)-P for plant and microbial P uptake is still an open question. To quantify this, 32P-labeled ferrihydrite (30.8 mg P kg-1) was added to paddy soil mesocosms with rice to trace the P uptake by microorganisms and plants after Fe(III) reduction. Nearly 2% of 32P was recovered in rice plants, contributing 12% of the total P content in rice shoots and roots after 33 days. In contrast, 32P recovery in microbial biomass decreased from 0.5% to 0.08% of 32P between 10 and 33 days after rice transplantation. Microbial biomass carbon (MBC) and dissolved organic C content decreased from day 10 to 33 by 8-54% and 68-77%, respectively, suggesting that the microbial-mediated Fe(III) reduction was C-limited. The much faster decrease of MBC in rooted (by 54%) vs. bulk soil (8-36%) reflects very fast microbial turnover in the rice rhizosphere (high C and oxygen inputs) resulting in the mineralization of the microbial necromass. In conclusion, Fe(III)-P can serve as small but a relevant P source for rice production and could partly compensate plant P demand. Therefore, the P fertilization strategies should consider the P mobilization from Fe (oxyhydr)oxides in flooded paddy soils during rice growth. An increase in C availability for microorganisms in the rhizosphere intensifies P mobilization, which is especially critical at early stages of rice growth.

AB - Limitation of rice growth by low phosphorus (P) availability is a widespread problem in tropical and subtropical soils because of the high content of iron (Fe) (oxyhydr)oxides. Ferric iron-bound P (Fe(III)-P) can serve as a P source in paddies after Fe(III) reduction to Fe(II) and corresponding H2PO4- release. However, the relevance of reductive dissolution of Fe(III)-P for plant and microbial P uptake is still an open question. To quantify this, 32P-labeled ferrihydrite (30.8 mg P kg-1) was added to paddy soil mesocosms with rice to trace the P uptake by microorganisms and plants after Fe(III) reduction. Nearly 2% of 32P was recovered in rice plants, contributing 12% of the total P content in rice shoots and roots after 33 days. In contrast, 32P recovery in microbial biomass decreased from 0.5% to 0.08% of 32P between 10 and 33 days after rice transplantation. Microbial biomass carbon (MBC) and dissolved organic C content decreased from day 10 to 33 by 8-54% and 68-77%, respectively, suggesting that the microbial-mediated Fe(III) reduction was C-limited. The much faster decrease of MBC in rooted (by 54%) vs. bulk soil (8-36%) reflects very fast microbial turnover in the rice rhizosphere (high C and oxygen inputs) resulting in the mineralization of the microbial necromass. In conclusion, Fe(III)-P can serve as small but a relevant P source for rice production and could partly compensate plant P demand. Therefore, the P fertilization strategies should consider the P mobilization from Fe (oxyhydr)oxides in flooded paddy soils during rice growth. An increase in C availability for microorganisms in the rhizosphere intensifies P mobilization, which is especially critical at early stages of rice growth.

KW - Ferric iron reduction

KW - Land use in subtropics

KW - Phosphorus isotopes

KW - Phosphorus pools and availability

KW - Plant-microbial competition

KW - Redox potential

UR - http://www.scopus.com/inward/record.url?scp=85130189538&partnerID=8YFLogxK

U2 - 10.1016/j.scitotenv.2022.155810

DO - 10.1016/j.scitotenv.2022.155810

M3 - Article

C2 - 35561910

VL - 837

JO - Science of the Total Environment

JF - Science of the Total Environment

SN - 0048-9697

M1 - 155810

ER -