Pedosphere (2): 484--496, 2026
ISSN 1002-0160/CN 32-1315/P
©2026 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Mineral-associated organic carbon promotes phosphorus accumulation in a long-term fertilized black soil |
Naiyu ZHANG1,2, Xiuzhi ZHANG3, Yanhua CHEN1, Lehlogonolo Abner MATELELE1, Ping ZHU3, Hongfang LIU1, Xianmei ZHANG1, Hongjun GAO3, Gu FENG2, Chang PENG3, Shuxiang ZHANG1 |
1 Key Laboratory of Arable Land Quality Monitoring and Evaluation, Ministry of Agriculture and Rural Affairs/State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences (CAAS), Beijing 100081 (China)
2 College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China)
3 Institute of Agricultural Resources and Environment, Jilin Academy of Agricultural Sciences, Changchun 130033 (China) |
| ABSTRACT |
| Soil phosphorus (P) pools are intimately connected to organic carbon (OC), especially mineral-associated OC (MAOC). However, the relationships between MAOC fractions and P fractions and their responses to fertilization remain unclear. In a long-term field experiment established on a black soil (Mollisol) in Gongzhuling, Jilin Province, Northeast China, in 1989, topsoils with no fertilizer (control, CK), conventional application of chemical fertilizer (CF), and chemical fertilizer combined with straw addition (CFS) were sampled in 2010 (21 years) and 2018 (29 years), and organo-mineral complexes (< 20 μm) were separated and analyzed. Compared to CK, the CF treatment resulted in soil acidification, increasing the content of the MAOC fraction bound to minerals by weak linkages in complexes. The CFS treatment maintained soil pH at 7.84 in 2010 and 7.53 in 2018, with significantly higher contents of four MAOC fractions, remaining water-soluble OC, OC bound by cations, OC encapsulated by resistant carbonate, and insoluble OC (humin), than those in the CF treatment. Fertilization application increased total P content in the organo-mineral complexes, with similar total P content between the CF and CFS treatments. Chemical fertilizer mainly increased highly labile inorganic P (Pi) extracted by resin strips + deionized water, NaHCO3, and NaOH, as well as organic P (Po) extracted by NaHCO3, and straw addition mainly increased moderately labile Pi extracted by dilute HCl. Correlation analysis showed that the dominant MAOC fractions had positive relationships with the increased P fractions. X-ray absorption near-edge structure spectroscopy further identified that the CF treatment increased the proportion of AlPO4, suggesting that MAOC promoted the retention of labile P via association with aluminum (Al) under weakly acidic conditions. The CFS treatment increased the proportion of Ca3(PO4)2 and Ca5(PO4)3OH; moreover, it also increased the maximum P sorption capacity of the organo-mineral complexes, suggesting that MAOC enhanced P sorption via association with calcium (Ca) under weakly alkaline conditions and that adsorbed P would transform into more stable Ca-associated P. Our findings demonstrated that MAOC promoted P accumulation via association with different P fractions, and these processes were mineral- and pH-dependent. |
| Key Words: chemical fertilizer,maximum P sorption capacity,Mollisol,organo-mineral complexes,P fraction,P species,straw addition |
| Citation: Zhang N Y, Zhang X Z, Chen Y H, Matelele L A, Zhu P, Liu H F, Zhang X M, Gao H J, Feng G, Peng C, Zhang S X. 2026. Mineral-associated organic carbon promotes phosphorus accumulation in a long-term fertilized black soil. Pedosphere. 36(2): 484-496. |
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