期刊
BIOLOGY AND FERTILITY OF SOILS
卷 53, 期 7, 页码 767-776出版社
SPRINGER
DOI: 10.1007/s00374-017-1221-1
关键词
Phosphorus; N cycling; Ammonia oxidation; Denitrification; Functional genes; Nutrient balance
类别
资金
- National Natural Science Foundation of China [41522107, 41430860]
- Strategic Priority Research Program of the Chinese Academy of Sciences [XDB15020401]
- National key research and development program [2016YFE0101100]
- Australia-China Joint Research Centre Healthy Soils for Sustainable Food Production and Environmental Quality [ACSRF48165]
- Youth Innovation Team Project of ISA, CAS [2017QNCXTD_GTD]
Previous studies have shown that phosphorus addition to P-limited soils increases gaseous N loss. A possible explanation for this phenomenon is element stoichiometry (specifically of C:N:P) modifying linked nutrient cycling, leading to enhanced nitrification and denitrification. In this study, we investigated how P stoichiometry influenced the dynamics of soil N-cycle functional genes. Rice seedlings were planted in P-poor soils and incubated with or without P application. Quantitative PCR was then applied to analyze the abundance of ammonia-oxidizing (amoA) and denitrifying (narG nirK, nirS, nosZ) genes in soil. P addition reduced bacterial amoA abundance but increased denitrifying gene abundance. We suggest this outcome is due to P-induced shifts in soil C:P and N:P ratios that limited ammonia oxidization while enhancing P availability for denitrification. Under P application, the rhizosphere effect raised ammonia-oxidizing bacterial abundance (amoA gene) and reduced nirK, nirS, and nosZ in rhizosphere soils. The change likely occurred through greater C input and O-2 release from roots, thus altering C availability and redox conditions for microbes. Our results show that P application enhances gaseous N loss potential in paddy fields mainly through stimulating denitrifier growth. We conclude that nutrient availability and elemental stoichiometry are important in regulating microbial gene responses, thereby influencing key ecosystem processes such as denitrification.
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