Abstract

Accurate simulation of ammonia (NH3) volatilization from fertilized croplands is crucial to enhancing fertilizer-use efficiency and alleviating environmental pollution. In this study, a process-oriented model, CNMM-DNDC (Catchment Nutrient Management Model – DeNitrification-DeComposition), was evaluated and modified using NH3 volatilization observations from 44 and 19 fertilizer application events in cultivated upland areas and paddy rice fields in China, respectively. The original CNMM-DNDC model not only performed poorly in simulating NH3 volatilization from upland areas but also failed to simulate NH3 volatilization from paddy rice fields. In the modified CNMM-DNDC model, the major modifications for simulating NH3 volatilization from uplands were primarily derived from a peer-reviewed and published study. NH3 volatilization from uplands was jointly regulated by the factors of wind speed, soil depth, clay fraction, soil temperature, soil moisture, vegetation canopy, and rainfall-induced canopy wetting. Moreover, three principle modifications were made to simulate NH3 volatilization from paddy rice fields. First, the simulation of the floodwater layer and its pH were added. Second, the effect of algal growth on the diurnal fluctuation of floodwater pH was introduced. Finally, the Jayaweera-Mikkelsen model was introduced to simulate NH3 volatilization. The modified model showed remarkable performances in simulating the cumulative NH3 volatilization of the calibrated and validated cases, with drastically significant zero-intercept linear regression of slopes of 0.94 (R2 = 0.76, n = 40) and 0.98 (R2 = 0.71, n = 23), respectively. However, the volatilized NH3 simulated by the modified model still exhibited some deviation from the observations when deep/mixed-placement, irrigation/precipitation, and prosperous/depressed algal biomass accompanied the fertilizer application events. Future studies still need to solve these problems to further improve the performance of the modified model. Nevertheless, the modified model could provide an available method for developing NH3 emission inventories and reducing environmental pollutions.

Highlights

  • This study evaluated and modified the CNMM-DNDC’s scientific processes for simulating NH3 volatilization from cropland soils using 44 and 19 fertilizer application events from cultivated uplands and rice paddy fields in China, respectively

  • The results demonstrated that the simulated NH3 volatilization from uplands following nitrogen fertilizer application accompanied with deep- or mixed-placement or irrigation/precipitation by the modified model still had some deviation from the observations, and more synchronous observations of NH3 volatilization and other auxiliary variables in these situations are urgently needed to further revise the CNMM-DNDC

  • The results of this study suggest that accurate field measurements and a corresponding reliable simulation of floodwater depth are crucial for the simulation of NH3 volatilization by the modified CNMM-DNDC

Read more

Summary

Introduction

DeNitrification-DeComposition), was evaluated and modified using NH3 volatilization observations from 44 and 19 fertilizer application events in cultivated upland areas and paddy rice fields in China, respectively. The original CNMM-DNDC model performed poorly in simulating NH3 volatilization from upland areas and failed to simulate NH3 volatilization from paddy rice fields. In the modified CNMM-DNDC model, the major modifications for simulating NH3 volatilization from uplands were primarily derived from a peer-reviewed and published study. Three principle modifications were made to simulate NH3 volatilization from paddy rice fields. The volatilized NH3 simulated by the modified model still exhibited some deviation prosperous/depressed algal biomass accompanied the fertilizer application events. NH3 in the atmosphere has played a vital role in aerosol formation during several haze periods, which has attracted great attention (e.g., Felix et al., 2013; Kong et al, 2019; Liu et al, 2018; Savard et al, 2017)

Objectives
Methods
Results
Discussion
Conclusion
Full Text
Paper version not known

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

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.