|
|
||||||||
a Dep. of Agronomy, Univ. of Kentucky N-122 Ag. Science North, Lexington, KY 40546-0091
b Center for Precision Agricultural Systems, Washington State Univ., Irrigated Agricultural Research and Extension Center, 24106 N. Bunn Road, Prosser, WA 99350-8694
* Corresponding author (mueller{at}uky.edu)
The quality of soil property maps may be improved and spatial sampling intensities reduced by incorporating secondary data to enhance spatial estimates. The purpose of this study was to evaluate how scale of sampling and secondary spatial information (terrain attributes) affected the quality of spatial estimates of soil C. A field in Central Michigan was sampled using 30.5- and 100-m regular grids and the samples were analyzed for total C. Extracting a 61-m grid from the 30.5-m regular grid (G30) data set created an additional data set. Total C maps were created at each scale using ordinary kriging, kriging with a trend model, cokriging, kriging with an external drift, and multiple regression. Each resulting map was compared with an independent validation data set (n = 24) to evaluate map quality. At the 30-m grid scale, there were modest differences between maps created with ordinary kriging (root mean squared error [RMSE] = 2.9 g kg-1, isotropic model; RMSE = 3.0 g kg-1, anisotropic model), kriging with a trend model (RMSE= 2.8 g kg-1), cokriging (RMSE = 2.9 g kg-1), kriging with an external drift (RMSE = 2.6 g kg-1), and multivariate stepwise regression (RMSE = 3.2 g kg-1). Prediction errors were generally larger at the 61-m grid scale and procedures that utilized secondary the terrain data (cokriging, RMSE = 3.8 g kg-1; kriging with an external drift, RMSE = 3.8 g kg-1; stepwise multiple regression, RMSE = 3.0 g kg-1) outperformed procedures that did not (isotropic ordinary kriging, RMSE = 4.3 g kg-1; kriging with a trend model, RMSE = 4.3 g kg-1). At the 100-m grid (G100) scale, geostatistical procedures were not appropriate because of the small sample size (n = 12) yet multiple regression performed well (RMSE = 3.8 g kg-1). Maps of soil C created with regression most resembled the soil color patterns evident in an aerial photograph of the field.
Abbreviations: ATV, all terrain vehicle DEM, digital elevation model G30, 30.5-m regular grid G100, 100-m regular grid, GVAL, validation data set G1000, 1000 randomly selected points GPS, global positioning system IAVIF, intercept adjusted variance inflation factors MSE, mean squared error RMSE, root mean square error RSV, relative structural variability
This article has been cited by other articles:
![]() |
F. Chen, D. E. Kissel, L. T. West, W. Adkins, D. Rickman, and J. C. Luvall Mapping Soil Organic Carbon Concentration for Multiple Fields with Image Similarity Analysis Soil Sci. Soc. Am. J., January 11, 2008; 72(1): 186 - 193. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. P. D'Acqui, C. A. Santi, and F. Maselli Use of Ecosystem Information to Improve Soil Organic Carbon Mapping of a Mediterranean Island J. Environ. Qual., January 9, 2007; 36(1): 262 - 271. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. N. Kravchenko and G. P. Robertson Can Topographical and Yield Data Substantially Improve Total Soil Carbon Mapping by Regression Kriging? Agron. J., January 1, 2007; 99(1): 12 - 17. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. N. Kravchenko, G. P. Robertson, X. Hao, and D. G. Bullock Management Practice Effects on Surface Total Carbon: Differences in Spatial Variability Patterns Agron. J., October 3, 2006; 98(6): 1559 - 1568. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. C. Kaspar, T. B. Parkin, D. B. Jaynes, C. A. Cambardella, D. W. Meek, and Y. S. Jung Examining Changes in Soil Organic Carbon with Oat and Rye Cover Crops Using Terrain Covariates Soil Sci. Soc. Am. J., May 23, 2006; 70(4): 1168 - 1177. [Abstract] [Full Text] [PDF] |
||||
![]() |
T.-L. Liu, K.-W. Juang, and D.-Y. Lee Interpolating Soil Properties Using Kriging Combined with Categorical Information of Soil Maps Soil Sci. Soc. Am. J., May 23, 2006; 70(4): 1200 - 1209. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. N. Kravchenko, G. P. Robertson, S. S. Snap, and A. J. M. Smucker Using Information about Spatial Variability to Improve Estimates of Total Soil Carbon Agron. J., May 3, 2006; 98(3): 823 - 829. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. G. Mueller, N. B. Pusuluri, K. K. Mathias, P. L. Cornelius, and R. I. Barnhisel Site-Specific Soil Fertility Management: A Model for Map Quality Soil Sci. Soc. Am. J., November 1, 2004; 68(6): 2031 - 2041. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. G. Mueller, N. J. Hartsock, T. S. Stombaugh, S. A. Shearer, P. L. Cornelius, and R. I. Barnhisel Soil Electrical Conductivity Map Variability in Limestone Soils Overlain by Loess Agron. J., May 1, 2003; 95(3): 496 - 507. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| The SCI Journals | Agronomy Journal | Crop Science | |||
| Journal of Natural Resources and Life Sciences Education |
Vadose Zone Journal | ||||
| Journal of Plant Registrations | Journal of Environmental Quality |
The Plant Genome | |||