1. Microbial response on changing C:P stoichiometry in steppe soils of Northern Kazakhstan.
- Author
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Liu, Yuhuai, Shibistova, Olga, Cai, Guan, Sauheitl, Leopold, Xiao, Mouliang, Ge, Tida, and Guggenberger, Georg
- Subjects
PHOSPHATE fertilizers ,STEPPES ,PLANT residues ,MICROBIAL metabolism ,ORCHARD grass ,SOIL mineralogy - Abstract
Background and aims: The stoichiometric ratio of carbon (C): phosphorus (P) acquisition is strongly correlated with soil available C:P ratio. However how the stoichiometric relationship between acquiring C and P through microbial metabolism affects bioavailable P is poorly understood in semi-arid agricultural ecosystems. Methods: Our objective was to investigate the underlying mechanisms of the P availability in typical P-limited steppe soil from Kazakhstan in response to mineral nutrient (Na
2 HPO4 ) with and without Dactylis glomerata L. leaves addition in a 38-day incubation experiment. Results: Four bioavailable P fractions content (CaCl2 -P, Citrate-P, Enzyme-P, and HCl-P) were improved. Sole application of P fertilizer decreased the maximal velocity (Vmax ) of P acquisition enzyme (phosphomonoesterase) but increased microbial C limitation, resulting in increasing the ratio of C to P acquisition but decreasing the ratio of available dissolved organic C: Olsen-P. In contrast, plant residues returning (the application of sole D. glomerata leaves and the combined application of D.glomerata and mineral P) increased Vmax of C (β-1, 4-glucosidase, β-D-cellobiosidase, β-1, 4-xylosidase) and P acquisition enzymes, however decreasing microbial C and P limitation through improving microbial metabolism. Furthermore, the spearman correlation and piecewiseSEM analysis suggested that microbial C limitation and EEAC:P had a negative effect on P availability, illustrating that the decreasing of microbial C limitation can improve soil bioavailable P. Conclusion: The decomposition of organic residues eliminated microbial P limitation and increased P availability by allocating C and P acquisition enzymes to balance the stoichiometric ratio of microbial C and P demand. [ABSTRACT FROM AUTHOR]- Published
- 2023
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