Limits...
Eco-stoichiometric alterations in paddy soil ecosystem driven by phosphorus application.

Li X, Wang H, Gan S, Jiang D, Tian G, Zhang Z - PLoS ONE (2013)

Bottom Line: P input induced C and N limitations as indicated by the decreased ratio of C:P and N:P in the soil and microbial biomass.The lower emissions of N2O and CH4 under the higher P application (P-60 and P-90) in July and the insignificant difference in N2O emission in August compared to P-30; however, continuous P input enhanced CO2 fluxes for both samplings.Thus, it is recommended that the P input in paddy fields not exceed 60 kg ha(-1) may maximize soil C sequestration, minimize P export, and guarantee grain yields.

View Article: PubMed Central - PubMed

Affiliation: College of Environmental and Resource Science, Zhejiang University, Hangzhou, China.

ABSTRACT
Agricultural fertilization may change processes of elemental biogeochemical cycles and alter the ecological function. Ecoenzymatic stoichiometric feature plays a critical role in global soil carbon (C) metabolism, driving element cycles, and mediating atmospheric composition in response to agricultural nutrient management. Despite the importance on crop growth, the role of phosphorous (P) in compliance with eco-stoichiometry on soil C and nitrogen (N) sequestration in the paddy field remains poorly understood in the context of climate change. Here, we collected soil samples from a field experiment after 6 years of chemical P application at a gradient of 0 (P-0), 30 (P-30), 60 (P-60), and 90 (P-90) kg ha(-1) in order to evaluate the role of P on stoichiometric properties in terms of soil chemical, microbial biomass, and eco-enzyme activities as well as greenhouse gas (GHG: CO2, N2O and CH4) emissions. Continuous P input increased soil total organic C and N by 1.3-9.2% and 3%-13%, respectively. P input induced C and N limitations as indicated by the decreased ratio of C:P and N:P in the soil and microbial biomass. A synergistic mechanism among the ecoenzymatic stoichiometry, which regulated the ecological function of microbial C and N acquisition and were stoichiometrically related to P input, stimulated soil C and N sequestration in the paddy field. The lower emissions of N2O and CH4 under the higher P application (P-60 and P-90) in July and the insignificant difference in N2O emission in August compared to P-30; however, continuous P input enhanced CO2 fluxes for both samplings. There is a technical conflict for simultaneously regulating three types of GHGs in terms of the eco-stoichiometry mechanism under P fertilization. Thus, it is recommended that the P input in paddy fields not exceed 60 kg ha(-1) may maximize soil C sequestration, minimize P export, and guarantee grain yields.

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Related in: MedlinePlus

Emission intensities of greenhouse gases responding to phosphorus application for samplings in July and August.The different letters listed above bars represent significant differences at p<0.05 (Duncan LSD test).
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pone-0061141-g002: Emission intensities of greenhouse gases responding to phosphorus application for samplings in July and August.The different letters listed above bars represent significant differences at p<0.05 (Duncan LSD test).

Mentions: Net CO2-C flux ranged from −88.7 to −204 mg·m−2· h−1 and increased significantly (p<0.05) with increasing P application (Fig. 2). The net emission of CO2 increased by 7–45% under P input compared to P-0 in July, with increases of 17% to 40% in August. CH4-C flux, which ranged from 1.7–8.8 mg·m−2 h−1 in July, was significantly (p<0.05) lower by 14%–57% under P input compared to P-0. However, the highest CH4 flux occurred with P-30 in August. The N2O-N flux in our study ranged from −0.02 to 0.05 mg·m−2 h−1. N2O emission in July was significantly (p<0.05) reduced by 34–75% in the tested paddy field with increasing P fertilization compared with P-0; no significant difference was found in August (Fig. 2). Analysis of variance (ANOVA) showed that the soil CO2 flux significantly responded to single factors of P application and sampling time; CH4 flux significantly responded to single factors of P application and interactions of treatment and sampling date, while N2O flux was significantly affected by P application and sampling date as well as interactions (Table 2).


Eco-stoichiometric alterations in paddy soil ecosystem driven by phosphorus application.

Li X, Wang H, Gan S, Jiang D, Tian G, Zhang Z - PLoS ONE (2013)

Emission intensities of greenhouse gases responding to phosphorus application for samplings in July and August.The different letters listed above bars represent significant differences at p<0.05 (Duncan LSD test).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3646879&req=5

pone-0061141-g002: Emission intensities of greenhouse gases responding to phosphorus application for samplings in July and August.The different letters listed above bars represent significant differences at p<0.05 (Duncan LSD test).
Mentions: Net CO2-C flux ranged from −88.7 to −204 mg·m−2· h−1 and increased significantly (p<0.05) with increasing P application (Fig. 2). The net emission of CO2 increased by 7–45% under P input compared to P-0 in July, with increases of 17% to 40% in August. CH4-C flux, which ranged from 1.7–8.8 mg·m−2 h−1 in July, was significantly (p<0.05) lower by 14%–57% under P input compared to P-0. However, the highest CH4 flux occurred with P-30 in August. The N2O-N flux in our study ranged from −0.02 to 0.05 mg·m−2 h−1. N2O emission in July was significantly (p<0.05) reduced by 34–75% in the tested paddy field with increasing P fertilization compared with P-0; no significant difference was found in August (Fig. 2). Analysis of variance (ANOVA) showed that the soil CO2 flux significantly responded to single factors of P application and sampling time; CH4 flux significantly responded to single factors of P application and interactions of treatment and sampling date, while N2O flux was significantly affected by P application and sampling date as well as interactions (Table 2).

Bottom Line: P input induced C and N limitations as indicated by the decreased ratio of C:P and N:P in the soil and microbial biomass.The lower emissions of N2O and CH4 under the higher P application (P-60 and P-90) in July and the insignificant difference in N2O emission in August compared to P-30; however, continuous P input enhanced CO2 fluxes for both samplings.Thus, it is recommended that the P input in paddy fields not exceed 60 kg ha(-1) may maximize soil C sequestration, minimize P export, and guarantee grain yields.

View Article: PubMed Central - PubMed

Affiliation: College of Environmental and Resource Science, Zhejiang University, Hangzhou, China.

ABSTRACT
Agricultural fertilization may change processes of elemental biogeochemical cycles and alter the ecological function. Ecoenzymatic stoichiometric feature plays a critical role in global soil carbon (C) metabolism, driving element cycles, and mediating atmospheric composition in response to agricultural nutrient management. Despite the importance on crop growth, the role of phosphorous (P) in compliance with eco-stoichiometry on soil C and nitrogen (N) sequestration in the paddy field remains poorly understood in the context of climate change. Here, we collected soil samples from a field experiment after 6 years of chemical P application at a gradient of 0 (P-0), 30 (P-30), 60 (P-60), and 90 (P-90) kg ha(-1) in order to evaluate the role of P on stoichiometric properties in terms of soil chemical, microbial biomass, and eco-enzyme activities as well as greenhouse gas (GHG: CO2, N2O and CH4) emissions. Continuous P input increased soil total organic C and N by 1.3-9.2% and 3%-13%, respectively. P input induced C and N limitations as indicated by the decreased ratio of C:P and N:P in the soil and microbial biomass. A synergistic mechanism among the ecoenzymatic stoichiometry, which regulated the ecological function of microbial C and N acquisition and were stoichiometrically related to P input, stimulated soil C and N sequestration in the paddy field. The lower emissions of N2O and CH4 under the higher P application (P-60 and P-90) in July and the insignificant difference in N2O emission in August compared to P-30; however, continuous P input enhanced CO2 fluxes for both samplings. There is a technical conflict for simultaneously regulating three types of GHGs in terms of the eco-stoichiometry mechanism under P fertilization. Thus, it is recommended that the P input in paddy fields not exceed 60 kg ha(-1) may maximize soil C sequestration, minimize P export, and guarantee grain yields.

Show MeSH
Related in: MedlinePlus