HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Zhao, Y. Articles by Wang, H. Search for Related Content PubMed Articles by Zhao, Y. Articles by Wang, H. Agricola Articles by Zhao, Y. Articles by Wang, H. Related Collections Carbon Sequestration Hillslope Analysis Pedology

Map Scale Effects on Soil Organic Carbon Stock Estimation in North China

^a State Key Lab. of Soil and Sustainable Agriculture, Inst. of Soil Science, Chinese Academy of Sciences, P.O. Box 821, Nanjing 210008, China
^b Texas Agricultural Experiment Station, 1229 N. US Hwy 281, Stephenville, TX 76401

View larger version (37K): [in a new window]   Fig. 1. Geographical location of the study area—Hebei Province, China.

View larger version (12K): [in a new window]   Fig. 2. Application of sampled data by soil type to all occurrences of delineations of that same soil type in a sample study area using the mean or median methods.

View larger version (21K): [in a new window]   Fig. 3. Application of sampled data by soil type, identity, or similarity in soil parent materials, spatial location, and distribution area to all occurrences of delineations of that same soil type in a sample study area using the pedological professional knowledge based method.

View larger version (16K): [in a new window]   Fig. 4. The effect of soil map scale on the soil organic C stock estimates in the Hebei Province of China, using the mean, median, and PKB (pedological professional knowledge based) methods.

View larger version (25K): [in a new window]   Fig. 5. The SOC (soil organic C) stock estimates for the soil great groups in the study area using the median, mean, and PKB (pedological professional knowledge based) methods and soil maps at five different scales.

View larger version (33K): [in a new window]   Fig. 6. Changes in the estimates of SOC (soil organic C) stocks using the median method for coarse-dispersed brown soils (soil family) as map scale decreases from 1:500 000 to 1:1 000 000. Arrows indicate the map generalization process as map scale decreased, and the two SOC stock values in each shaded box were based on some delineations of a map unit being preserved while others were merged into other map units during the map generalization process. For example, after the overlay analysis of the 1:500 000 and 1:1 000 000 soil maps using GIS (geographic information system) software, 12 337 km2 (293.50 Tg C/23.79 kg C m–2) of coarse-dispersed brown soils on the 1:500 000 scale soil map were preserved at the same locations of the 1:1 000 000 scale soil map; 3585 km2 (85.28 Tg C/23.79 kg C m–2) of coarse-dispersed brown soils on the 1:500 000 scale soil map were merged into delineations of diluvial brown soils, weakly developed brown soils, etc., on the 1:1 000 000 scale soil map; and 2631 km2 (62.59 Tg C/23.79 kg C m–2) of mountain prairie–meadow soils, dark-compacted brown soils, etc., on the 1:500 000 scale soil map were merged into coarse-dispersed brown soils on the 1:1 000 000 soil map during the map generalization process.

View larger version (22K): [in a new window]   Fig. 7. Changes in the estimates of SOC (soil organic C) stocks using the median method for brown soils (subgroup) as map scale decreases from 1:1 000 000 to 1:2 500 000. Arrows indicate the map generalization process as map scale decreased, and the two SOC stock values in each shaded box were based on some delineations of a map unit being preserved while others were merged into other map units during the map generalization process.

View larger version (18K): [in a new window]   Fig. 8. Changes in the estimates of SOC (soil organic C) stocks for leached cinnamon soils using the median method as map scale decreases from 1:2 500 000 to 1:10 000 000. Arrows indicate the map generalization process as map scale decreased, and the two SOC stock values in each shaded box were based on some delineations of a map unit being preserved while others were merged into other map units during the map generalization process; however, all delineations of the leached cinnamon soils map unit were merged into cinnamon soils, aquic cinnamon soils, etc., as map scale decreased from 1:4 000 000 to 1:10 000 000).