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- Title
Modification of the RothC model for simulating soil organic matter turnover in double rice cropping systems in southern China.
- Authors
Jiang, Guiying; Wang, Jin Zhou; Liu, De Li; Xu, Ming Gang; Huang, Qin Hai; Sun, Nan
- Abstract
We modified the Rothamsted carbon model (RothC) to simulate soil carbon (C) dynamics indouble rice cropping systems in China by adding a parameter to account for the effect ofcarbon input amounts on the decomposition rate of soil organic carbon (SOC). Threelong-term experiments (28-31 years) were conducted under various amounts of C inputs anddifferent fertilizer types in double rice systems in southern China and were used for thecalibration and validation of the modified RothC model. The results showed that the previousRothC model, with a soil moisture modifying factor of 0.2 for the rice phase in summer and0.6 for the upland cropping phase in winter for paddy soils, could not adequately simulate theSOC dynamics of all treatments in double rice soils. In particular, the simulations wereworse with high C inputs, which produced a normalized root mean squared error(NRMSE) and model efficiency (EF) ranging from 18.0 to 53.5% and -95.20 to -1.42,respectively, for the treatments with C inputs ranging from 4.20 to 8.29 t C ha−1. We usedan inverse modelling approach to calibrate one site for an additional factor p andfound this factor was well described as a function of the amount of C input (p =0.146C2 + 0.697C + 0.175, R2=0.997). The modified version with the p functiongreatly improved the simulations, resulting in an NRMSE of 2.6 –15.3% and EF of-1.05 – 0.69 for the three sites. We concluded that this modified RothC model canbe used to estimate soil carbon dynamics in double rice cropping systems with alarge amount of organic carbon inputs, at least in Chinese paddy soils where theapplication of harvested crop residues and animal manure is commonly practiced.
- Subjects
CHINA; HUMUS; DOUBLE cropping; CROPPING systems; STANDARD deviations; CROP residues; MANURES
- Publication
Geophysical Research Abstracts, 2019, Vol 21, p1
- ISSN
1029-7006
- Publication type
Article