TY - JOUR

T1 - Residence time of carbon in paddy soils

AU - Liu, Yalong

AU - Ge, Tida

AU - Wang, Ping

AU - van Groenigen, Kees Jan

AU - Xu, Xuebin

AU - Cheng, Kun

AU - Zhu, Zhenke

AU - Wang, Jingkuan

AU - Guggenberger, Georg

AU - Chen, Ji

AU - Luo, Yiqi

AU - Kuzyakov, Yakov

N1 - Funding Information: Inverse Distance Weighted (IDW) interpolation analyses of NPP and MRT were performed using ArcMap 10.3 (ESRI, Redlands, USA). Statistical analyses were performed using SPSS v20.0 (SPSS, Chicago, USA). After confirming the normal distribution of the data through the Shapiro-Wilk test, one-way ANOVA with Duncan's multiple-range tests were used to compare C residence times between climate zones, geographic sub-regions and main rice-producing countries. Structural Equation Modelling (SEM) was performed to analyse direct and indirect pathways determining C turnover times. In the SEM analysis, the data were fit to the model using the maximum likelihood estimation method. The chi-square (χ2), associated p value, Goodness-of-Fit Index (GFI), and the Root-Mean-Square Error of Approximation (RMSEA) were used to evaluate the fitness of the model (Grace, 2006). The SEM analysis was implemented using Amos 21.0 (Amos Development Corporation, Chicago, USA). Four machine-learning models of partial least squares regression (PLSR), support vector regression (SVR), random forests (RF), and artificial neural networks (ANN) were examined to determine the relative importance of the environmental variables in predicting MRT (Supplementary Materials).This study was supported by the National Natural Science Foundation of China (41977088 and 41807089), National Key Research and Development Program of China (2022YFD1500800). Funding Information: This study was supported by the National Natural Science Foundation of China ( 41977088 and 41807089 ), National Key Research and Development Program of China ( 2022YFD1500800 ).

PY - 2023/5/10

Y1 - 2023/5/10

N2 - Mean residence time (MRT) of carbon (C) in soil is the most important parameter of C sequestration and stability and crucial for CO2 removal from the atmosphere. Climate and soil properties controls of MRT of upland soils are well known, but the drivers of C stability in paddies were never summarized. Here, we estimated MRT of paddies across monsoon Asia using the stock-over-flux method, i.e., soil organic C (SOC) stock over organic matter input considering the net primary production (NPP), and determined the main factors affecting SOC turnover. The average MRT of paddy soils in monsoon Asia ranges between 19 and 50 yr, depending on straw management. These estimates are similar to recent estimates for the global average MRT across all soils, but longer than for upland croplands. Tropical regions have the shortest MRT for rice paddies (16–42 yr), while the MRT of C in soils of temperate and subtropical regions are longer (20–56 yr). Across a wide range of environmental factors, MRT was most strongly affected by temperature. We estimate that 2 °C warming decreases MRT by 7% on average, with the strongest decreases in the western Indonesian islands and north-east China. Because C stocks per area in paddy soils are larger and the MRT is longer than in corresponding upland cropland soils, paddies play a key role in the global C cycle. Our results emphasize the need for management practices that retain stable soil C input rates to reduce possible positive feedbacks for global warming.

AB - Mean residence time (MRT) of carbon (C) in soil is the most important parameter of C sequestration and stability and crucial for CO2 removal from the atmosphere. Climate and soil properties controls of MRT of upland soils are well known, but the drivers of C stability in paddies were never summarized. Here, we estimated MRT of paddies across monsoon Asia using the stock-over-flux method, i.e., soil organic C (SOC) stock over organic matter input considering the net primary production (NPP), and determined the main factors affecting SOC turnover. The average MRT of paddy soils in monsoon Asia ranges between 19 and 50 yr, depending on straw management. These estimates are similar to recent estimates for the global average MRT across all soils, but longer than for upland croplands. Tropical regions have the shortest MRT for rice paddies (16–42 yr), while the MRT of C in soils of temperate and subtropical regions are longer (20–56 yr). Across a wide range of environmental factors, MRT was most strongly affected by temperature. We estimate that 2 °C warming decreases MRT by 7% on average, with the strongest decreases in the western Indonesian islands and north-east China. Because C stocks per area in paddy soils are larger and the MRT is longer than in corresponding upland cropland soils, paddies play a key role in the global C cycle. Our results emphasize the need for management practices that retain stable soil C input rates to reduce possible positive feedbacks for global warming.

KW - Carbon cycle and sequestration

KW - Climate effects

KW - Land use

KW - Organic carbon turnover

KW - Rice fields

KW - Soil carbon stability

UR - http://www.scopus.com/inward/record.url?scp=85150858391&partnerID=8YFLogxK

U2 - 10.1016/j.jclepro.2023.136707

DO - 10.1016/j.jclepro.2023.136707

M3 - Article

AN - SCOPUS:85150858391

VL - 400

JO - Journal of cleaner production

JF - Journal of cleaner production

SN - 0959-6526

M1 - 136707

ER -