Parameterization, Calibration and Validation of the DNDC Model for Carbon Dioxide, Nitrous Oxide and Maize Crop Performance Estimation in East Africa
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Date
2021
Authors
Macharia, Joseph M.
Ngetich, Felix K.
Shisanya, Chris A.
Journal Title
Journal ISSN
Volume Title
Publisher
Science Direct
Abstract
Dynamic biogeochemical models are crucial tools for simulating the complex interaction between soils, climate
and plants; thus the need for improving understanding of nutrient cycling and reduction of greenhouse gases
(GHG) from the environment. This study aimed to calibrate and validate the DeNitrification-DeComposition
(DNDC) model for soil moisture, temperature, respiration, nitrous oxide and maize crop growth simulation in
drier sub-humid parts of the central highlands of Kenya. We measured soil GHG fluxes from a maize field under
four different soil fertility management practices for one year using static chambers and gas chromatography.
Using experimental data collected from four management practices during GHG sampling period, we parameterized
the DNDC model. The results indicate that the DNDC model simulates daily and annual soil moisture, soil
temperature, soil respiration (CO2), nitrous oxide (N2O), N2O yield-scaled emissions (YSE), N2O emission factors
(EFs) and maize crop growth with a high degree of fitness. However, the DNDC simulations slightly underestimated
soil temperature (2–6%), crop growth (2–45%) and N2O emissions (5–23%). The simulation overestimated
soil moisture (9–17%) and CO2 emissions (3–10%). It however, perfectly simulated YSE and EFs.
Compared to the observed/measured annual GHG trends, the simulation results were relatively good, with an
almost perfect fitting of emission peaks during soil rewetting at the onset of rains, coinciding with soil fertilisation.
These findings provide reliable information in selecting best farm management practice, which simultaneously
improves agricultural productivity and reduces GHG emissions, thus permitting climate-smart
agriculture. The good DNDC simulated YSE and EFs values (Tier III) provide cheaper and reliable ways of filling
the huge GHG data gap, reducing uncertainties in national GHG inventories and result to efficient targeting of
mitigation measures in sub-Saharan Africa.
Description
Article
Keywords
Animal manure, Climate-smart agriculture, Emission factors, Inorganic fertiliser, Maize, Yield-scaled greenhouse gas emissions
Citation
Macharia, J. M., Ngetich, F. K., & Shisanya, C. A. (2021). Parameterization, calibration and validation of the DNDC model for carbon dioxide, nitrous oxide and maize crop performance estimation in East Africa. Heliyon, 7(5), e06977.