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Soil and microbial biomass stoichiometry regulate soil organic carbon and nitrogen mineralization in rice-wheat rotation subjected to long-term fertilization.
- Source :
- Journal of Soils & Sediments: Protection, Risk Assessment, & Remediation; Aug2020, Vol. 20 Issue 8, p3103-3113, 11p
- Publication Year :
- 2020
-
Abstract
- Purpose: Soil microbial biomass (SMB), as the source and sink of soil nutrients, and its stoichiometry play a key role in soil organic carbon (SOC) and nitrogen (N) mineralization. The objective of this study was to investigate the responses of SOC and N mineralization to changes in microbial biomass and SOC, N, and phosphorus (P) stoichiometry resulted from long-term fertilization regimes. Materials and methods: Soil was sampled from a rice-wheat rotation system subjected to 37 years of nine fertilization treatments with different nutrient input amounts: control (CK), N alone, N combined with mineral phosphorus (NP), NP plus potassium (NPK), manure alone (M), and M combined with N (MN), NP (MNP), NPK (MNPK), and a higher rate of M with NPK (hMNPK). The sampled soil was incubated for the determination of SOC and N mineralization, C, N, and P stoichiometry of soil and SMB, and associated soil enzymes related to C and N cycling. Results and discussion: Relative to the CK and treatments with mineral fertilizers, treatments with manure (M, MN, MNP, MNPK, and hMNPK) significantly increased SOC and N mineralization by 48–78% and 54–97%, respectively. Microbial metabolic quotient (qCO<subscript>2</subscript>) decreased by 32–55% in treatments with manure compared to the N and NP treatments, but showed no effect on the qCO<subscript>2</subscript> when compared to the NPK treatment. The leucine amino peptidase (LAP) enzyme showed significant positive correlation with SOC and N mineralization, and negatively related to the qCO<subscript>2</subscript>. Significantly negative correlations were also observed between SOC and N mineralization and soil C:P and N:P ratio, as well as microbial biomass SMBC:SMBP and SMBN:SMBP stoichiometry, respectively. However, the availability of N and P had limited effects on the qCO<subscript>2</subscript> after reaching a certain value (0.69–0.72 mg CO<subscript>2</subscript>-C g<superscript>−1</superscript> MBC h<superscript>−1</superscript>). Conclusions: Lower soil elemental (C:P and N:P) and microbial biomass stoichiometry (SMBC:SMBP and SMBN:SMBP) and increase of LAP resulted from combined application of manure and mineral fertilizers, accelerated SOC, and N mineralization. Mineral nutrient input with manure amendments could be an optimal strategy to meet the microbial stoichiometric demands and enhance nutrient availability for crops in agricultural ecosystems. [ABSTRACT FROM AUTHOR]
- Subjects :
- HISTOSOLS
NITROGEN fertilizers
MINERALIZATION
STOICHIOMETRY
SOILS
FERTILIZERS
Subjects
Details
- Language :
- English
- ISSN :
- 14390108
- Volume :
- 20
- Issue :
- 8
- Database :
- Complementary Index
- Journal :
- Journal of Soils & Sediments: Protection, Risk Assessment, & Remediation
- Publication Type :
- Academic Journal
- Accession number :
- 144656002
- Full Text :
- https://doi.org/10.1007/s11368-020-02642-y