Limits...
Effects of soil data and simulation unit resolution on quantifying changes of soil organic carbon at regional scale with a biogeochemical process model.

Zhang L, Yu D, Shi X, Xu S, Xing S, Zhao Y - PLoS ONE (2014)

Bottom Line: Results project that from 1982 to 2000, total SOC change in the top layer (0-30 cm) of the 2.3 M ha of paddy soil in the Tai-Lake region was +1.48 Tg C, -3.99 Tg C and -15.38 Tg C based on P5, C5 and C14 databases, respectively.With the total SOC change as modeled with P5 inputs as the baseline, which is the advantages of using detailed, polygon-based soil dataset, the relative deviation of C5 and C14 were 368% and 1126%, respectively.The results also indicate that improving the framework of DNDC is essential in creating accurate models of the soil carbon cycle.

View Article: PubMed Central - PubMed

Affiliation: College of Resource and Environment, Fujian Agriculture and Forestry University, Fuzhou, China ; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.

ABSTRACT
Soil organic carbon (SOC) models were often applied to regions with high heterogeneity, but limited spatially differentiated soil information and simulation unit resolution. This study, carried out in the Tai-Lake region of China, defined the uncertainty derived from application of the DeNitrification-DeComposition (DNDC) biogeochemical model in an area with heterogeneous soil properties and different simulation units. Three different resolution soil attribute databases, a polygonal capture of mapping units at 1:50,000 (P5), a county-based database of 1:50,000 (C5) and county-based database of 1:14,000,000 (C14), were used as inputs for regional DNDC simulation. The P5 and C5 databases were combined with the 1:50,000 digital soil map, which is the most detailed soil database for the Tai-Lake region. The C14 database was combined with 1:14,000,000 digital soil map, which is a coarse database and is often used for modeling at a national or regional scale in China. The soil polygons of P5 database and county boundaries of C5 and C14 databases were used as basic simulation units. Results project that from 1982 to 2000, total SOC change in the top layer (0-30 cm) of the 2.3 M ha of paddy soil in the Tai-Lake region was +1.48 Tg C, -3.99 Tg C and -15.38 Tg C based on P5, C5 and C14 databases, respectively. With the total SOC change as modeled with P5 inputs as the baseline, which is the advantages of using detailed, polygon-based soil dataset, the relative deviation of C5 and C14 were 368% and 1126%, respectively. The comparison illustrates that DNDC simulation is strongly influenced by choice of fundamental geographic resolution as well as input soil attribute detail. The results also indicate that improving the framework of DNDC is essential in creating accurate models of the soil carbon cycle.

Show MeSH

Related in: MedlinePlus

Temporal distribution of average annual SOC change modeled with P5, C5 and C14 from 1982 to 2000 in the Tai-Lake region, China.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3921222&req=5

pone-0088622-g006: Temporal distribution of average annual SOC change modeled with P5, C5 and C14 from 1982 to 2000 in the Tai-Lake region, China.

Mentions: Similar trends can be observed in estimates of average annual-, total SOC change over the 19 year study period for three resolution databases decreased from P5 to C14 (Fig. 6). Simulation results demonstrate that total SOC change of P5 in the top layer (0–30 cm) of the 2.3 M ha of paddy rice fields in the Tai-Lake region was +1.48 Tg C from 1982 to 2000, with the annual SOC change ranging from -45 kg C ha−1 yr−1 to 92 kg C ha−1 yr−1 (Fig. 6). From 1982 to 1988, the SOC change modeled with P5 inputs was almost negative with annual changes ranging from -3.2 kg C ha−1 yr−1 to -45 kg C ha−1 yr−1. According to agricultural statistical data, chemical fertilizer application rate ranged from 180 kg N ha−1 yr−1 to 350 kg N ha−1 yr−1, which is a relatively low value. Low fertilizer application rates often result in reduced SOC sequestration [31], [55]. From 1989 to 2000, rural economic development led to increased fertilizer application from 350 kg N ha−1 yr−1 to 400 kg N ha−1 yr−1. Increasing fertilizer application results in enhanced crop production and residue accumulation, and the latter leads to an increase of SOC. Further, much of the region has been utilizing no-tillage practices in planting wheat since 1991, which contribute to reduced SOC decomposition [35].


Effects of soil data and simulation unit resolution on quantifying changes of soil organic carbon at regional scale with a biogeochemical process model.

Zhang L, Yu D, Shi X, Xu S, Xing S, Zhao Y - PLoS ONE (2014)

Temporal distribution of average annual SOC change modeled with P5, C5 and C14 from 1982 to 2000 in the Tai-Lake region, China.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3921222&req=5

pone-0088622-g006: Temporal distribution of average annual SOC change modeled with P5, C5 and C14 from 1982 to 2000 in the Tai-Lake region, China.
Mentions: Similar trends can be observed in estimates of average annual-, total SOC change over the 19 year study period for three resolution databases decreased from P5 to C14 (Fig. 6). Simulation results demonstrate that total SOC change of P5 in the top layer (0–30 cm) of the 2.3 M ha of paddy rice fields in the Tai-Lake region was +1.48 Tg C from 1982 to 2000, with the annual SOC change ranging from -45 kg C ha−1 yr−1 to 92 kg C ha−1 yr−1 (Fig. 6). From 1982 to 1988, the SOC change modeled with P5 inputs was almost negative with annual changes ranging from -3.2 kg C ha−1 yr−1 to -45 kg C ha−1 yr−1. According to agricultural statistical data, chemical fertilizer application rate ranged from 180 kg N ha−1 yr−1 to 350 kg N ha−1 yr−1, which is a relatively low value. Low fertilizer application rates often result in reduced SOC sequestration [31], [55]. From 1989 to 2000, rural economic development led to increased fertilizer application from 350 kg N ha−1 yr−1 to 400 kg N ha−1 yr−1. Increasing fertilizer application results in enhanced crop production and residue accumulation, and the latter leads to an increase of SOC. Further, much of the region has been utilizing no-tillage practices in planting wheat since 1991, which contribute to reduced SOC decomposition [35].

Bottom Line: Results project that from 1982 to 2000, total SOC change in the top layer (0-30 cm) of the 2.3 M ha of paddy soil in the Tai-Lake region was +1.48 Tg C, -3.99 Tg C and -15.38 Tg C based on P5, C5 and C14 databases, respectively.With the total SOC change as modeled with P5 inputs as the baseline, which is the advantages of using detailed, polygon-based soil dataset, the relative deviation of C5 and C14 were 368% and 1126%, respectively.The results also indicate that improving the framework of DNDC is essential in creating accurate models of the soil carbon cycle.

View Article: PubMed Central - PubMed

Affiliation: College of Resource and Environment, Fujian Agriculture and Forestry University, Fuzhou, China ; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.

ABSTRACT
Soil organic carbon (SOC) models were often applied to regions with high heterogeneity, but limited spatially differentiated soil information and simulation unit resolution. This study, carried out in the Tai-Lake region of China, defined the uncertainty derived from application of the DeNitrification-DeComposition (DNDC) biogeochemical model in an area with heterogeneous soil properties and different simulation units. Three different resolution soil attribute databases, a polygonal capture of mapping units at 1:50,000 (P5), a county-based database of 1:50,000 (C5) and county-based database of 1:14,000,000 (C14), were used as inputs for regional DNDC simulation. The P5 and C5 databases were combined with the 1:50,000 digital soil map, which is the most detailed soil database for the Tai-Lake region. The C14 database was combined with 1:14,000,000 digital soil map, which is a coarse database and is often used for modeling at a national or regional scale in China. The soil polygons of P5 database and county boundaries of C5 and C14 databases were used as basic simulation units. Results project that from 1982 to 2000, total SOC change in the top layer (0-30 cm) of the 2.3 M ha of paddy soil in the Tai-Lake region was +1.48 Tg C, -3.99 Tg C and -15.38 Tg C based on P5, C5 and C14 databases, respectively. With the total SOC change as modeled with P5 inputs as the baseline, which is the advantages of using detailed, polygon-based soil dataset, the relative deviation of C5 and C14 were 368% and 1126%, respectively. The comparison illustrates that DNDC simulation is strongly influenced by choice of fundamental geographic resolution as well as input soil attribute detail. The results also indicate that improving the framework of DNDC is essential in creating accurate models of the soil carbon cycle.

Show MeSH
Related in: MedlinePlus