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.
Highlights
The balance of elements has been a main focus of global change ecology and biogeochemical cycling research
Total soil C was significantly (p,0.05) increased by 1.3% to 9.2% for P input compared to P-0, while soil N increased from 3–13% (p,0.05)
The activities of soil eco-enzymes, such as BG, were enhanced from 39% to 75% compared to P-0, with acid phosphate (AP) decreasing by 14–33% (p,0.01) and NAG+leucine aminopeptidase (LAP) showing no significant changes (Table 1)
Summary
The balance of elements has been a main focus of global change ecology and biogeochemical cycling research. Eco-stoichiometry, expressed as C:N:P stoichiometric ratio, can predict nutrient cycling and microbial biomass production in ecosystems [4,5,6] and plays an important role in element regulation during biosphere-scale processes, such as soil C storage and element balance in the soil biomass [7], and governs greenhouse gas (GHG) emissions in terrestrial ecosystems [8]. Microorganisms drive Earth’s biogeochemical cycles [9] by a ‘‘consumer-driven nutrient recycling’’ (CDNR-like) mechanism that determines nutrient cycling, biomass stoichiometry, and community composition [10], and mediates the global C cycle during climatic changes [11] This influences the ecological metabolic rate [4]. We hypothesized that P application could change both soil C-N-P balance and eco-stoichiometric features in paddy soil and stimulate soil C sequestration
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
