Evaluation and simulation of nitrogen mineralization of paddy soils in Mollisols area of Northeast China under waterlogged incubation.
BACKGROUND
Understanding the nitrogen (N) mineralization process and applying appropriate model simulation are key factors in evaluating N mineralization. However, there are few studies of the N mineralization characteristics of paddy soils in Mollisols area of Northeast China.


METHODS
The soils were sampled from the counties of Qingan and Huachuan, which were located in Mollisols area of Northeast China. The sample soil was incubated under waterlogged at 30°C in a controlled temperature cabinet for 161 days (a 2: 1 water: soil ratio was maintained during incubation). Three models, i.e. the single first-order kinetics model, the double first-order kinetics model and the mixed first-order and zero-order kinetics model were used to simulate the cumulative mineralised N (NH4+-N and TSN) in the laboratory and waterlogged incubation.


RESULTS
During 161 days of waterlogged incubation, the average cumulative total soluble N (TSN), ammonium N (NH4+-N), and soluble organic N (SON) was 122.2 mg kg-1, 85.9 mg kg-1, and 36.3 mg kg-1, respectively. Cumulative NH4+-N was significantly (P < 0.05) positively correlated with organic carbon (OC), total N (TN), pH, and exchangeable calcium (Ca), and cumulative TSN was significantly (P < 0.05) positively correlated with OC, TN, and exchangeable Ca, but was not significantly (P > 0.05) correlated with C/N ratio, cation exchange capacity (CEC), extractable iron (Fe), clay, and sand. When the cumulative NH4+-N and TSN were simulated, the single first-order kinetics model provided the least accurate simulation. The parameter of the double first-order kinetics model also did not represent the actual data well, but the mixed first-order and zero-order kinetics model provided the most accurate simulation, as demonstrated by the estimated standard error, F statistic values, parameter accuracy, and fitting effect.


CONCLUSIONS
Overall, the results showed that SON was involved with N mineralization process, and the mixed first-order and zero-order kinetics model accurately simulates the N mineralization process of paddy soil in Mollisols area of Northeast China under waterlogged incubation.
College of Land and Environmental Science, Shenyang Agricultural University, Shenyang, China.|Key Laboratory of Northeast Arable Land Conservation (Northeast China), Shenyang, China.
Yuling
Y
Zhang
College of Land and Environmental Science, Shenyang Agricultural University, Shenyang, China.|Key Laboratory of Northeast Arable Land Conservation (Northeast China), Shenyang, China.
Wenjing
W
Xu
College of Land and Environmental Science, Shenyang Agricultural University, Shenyang, China.|Key Laboratory of Northeast Arable Land Conservation (Northeast China), Shenyang, China.
Pengpeng
P
Duan
College of Land and Environmental Science, Shenyang Agricultural University, Shenyang, China.|Key Laboratory of Northeast Arable Land Conservation (Northeast China), Shenyang, China.
Yaohui
Y
Cong
College of Land and Environmental Science, Shenyang Agricultural University, Shenyang, China.|Key Laboratory of Northeast Arable Land Conservation (Northeast China), Shenyang, China.
Tingting
T
An
College of Land and Environmental Science, Shenyang Agricultural University, Shenyang, China.|Key Laboratory of Northeast Arable Land Conservation (Northeast China), Shenyang, China.
Na
N
Yu
College of Land and Environmental Science, Shenyang Agricultural University, Shenyang, China.|Key Laboratory of Northeast Arable Land Conservation (Northeast China), Shenyang, China.
Hongtao
H
Zou
College of Land and Environmental Science, Shenyang Agricultural University, Shenyang, China.|Key Laboratory of Northeast Arable Land Conservation (Northeast China), Shenyang, China.
Xiuli
X
Dang
College of Land and Environmental Science, Shenyang Agricultural University, Shenyang, China.|Key Laboratory of Northeast Arable Land Conservation (Northeast China), Shenyang, China.
Jing
J
An
College of Land and Environmental Science, Shenyang Agricultural University, Shenyang, China.|Key Laboratory of Northeast Arable Land Conservation (Northeast China), Shenyang, China.
Qingfeng
Q
Fan
College of Land and Environmental Science, Shenyang Agricultural University, Shenyang, China.|Key Laboratory of Northeast Arable Land Conservation (Northeast China), Shenyang, China.
Yulong
Y
Zhang
D064751:Ammonium Compounds / Q000032:analysis; D002681:China; D008962:Models, Theoretical; D009584:Nitrogen / Q000032:analysis*; D012987:Soil / Q000737:chemistry*; D014867:Water
D064751:Ammonium Compounds; D012987:Soil; D014867:Water; D009584:Nitrogen