Technical Note: Field-Scale Surface Soil Moisture Patterns and Their Relationship to Topographic Indices

Understanding variability patterns in soil moisture is critical for determining an optimal sampling scheme both in space and in time, as well as for determining optimal management zones for agricultural applications that involve moisture status. In this study, distributed near-surface gravimetric soil moisture samples were collected across a 3.3 ha field in central Illinois for ten dates in the summer of 2002, along with dense elevation data. Temporal stability and consistency of the moisture patterns were analyzed in order to determine a suitable grid size for mapping and management, as well as to investigate relationships between moisture patterns and topographic and soil property influences. Variogram analysis of surface moisture data revealed that the geospatial characteristics of the soil moisture patterns are similar from one date to another, which may allow for a single, rather than temporally variable, variogram to describe the spatial structure. For this field, a maximum cell size of 10 m was found to be appropriate for soil moisture studies on most of the sampling occasions. This could indicate an appropriate scale for precision farming operations or for intensive ground sampling. While some areas had consistent behavior with respect to field mean moisture content, no conclusive relationships between the overall patterns in the moisture data and the topographic and soil indices were identified. There were, however, some small but significant correlations between these two sets of data, particularly plan and tangential curvature, and also slopes. In areas of convergent flow, moisture content exhibited a slight tendency to be wetter than average. There also seemed to be a small influence of scale on the relationship between moisture patterns and topographic curvatures.

[1]  D. J. Hunsaker,et al.  Spatial and Temporal Variability of Water Content and Infiltration on a Flood Irrigated Field , 1989 .

[2]  J. Famiglietti,et al.  Variability in surface moisture content along a hillslope transect: Rattlesnake Hill, Texas , 1998 .

[3]  Andrew W. Western,et al.  Towards areal estimation of soil water content from point measurements: time and space stability of mean response , 1998 .

[4]  Todd H. Skaggs,et al.  Spatio-temporal evolution and time-stable characteristics of soil moisture within remote sensing footprints with varying soil, slope, and vegetation , 2001 .

[5]  T. Schmugge,et al.  Passive microwave remote sensing system for soil moisture: some supporting research , 1989 .

[6]  S. Delin,et al.  Management Zones Classified With Respect to Drought and Waterlogging , 2005, Precision Agriculture.

[7]  T. Green,et al.  Measurement, scaling, and topographic analyses of spatial crop yield and soil water content , 2004 .

[8]  Timothy C. Coburn,et al.  Geostatistics for Natural Resources Evaluation , 2000, Technometrics.

[9]  Douglas A. Miller,et al.  SMEX02: Field scale variability, time stability and similarity of soil moisture , 2004 .

[10]  G. Vachaud,et al.  Temporal Stability of Spatially Measured Soil Water Probability Density Function , 1985 .

[11]  P. Wierenga,et al.  Temporal Stability of Spatially Measured Soil Matric Potential Probability Density Function , 2001 .

[12]  B. Fu,et al.  Soil moisture variation in relation to topography and land use in a hillslope catchment of the Loess Plateau, China , 2001 .

[13]  H. R. Mount.  Soil survey of Champaign County, Illinois , 1982 .

[14]  B. Kay,et al.  Factors contributing to temporal stability in spatial patterns of water content in the tillage zone , 2001 .

[15]  J. Stafford,et al.  Hyperspectral image feature extraction and classification for soil nutrient mapping. , 2003 .

[16]  Yiqi Luo,et al.  Mapping soybean sudden death syndrome as related to yield and soil/site properties , 2005 .

[17]  D. Sims,et al.  Optimum pixel size for hyperspectral studies of ecosystem function in southern California chaparral and grassland , 2003 .

[18]  José Martínez-Fernández,et al.  Temporal Stability of Soil Moisture in a Large‐Field Experiment in Spain , 2003 .

[19]  Pierre Goovaerts,et al.  Temporal persistence of spatial patterns for mineralizable nitrogen and selected soil properties , 1993 .

[20]  Walter J. Rawls,et al.  Soil Water Retention as Related to Topographic Variables , 2001 .

[21]  Abdul Mounem Mouazen,et al.  Development of on-line measurement system of bulk density based on on-line measured draught, depth and soil moisture content , 2006 .

[22]  T. Jackson,et al.  PREPLANTING SOIL MOISTURE USING PASSIVE MICROWAVE SENSORS , 1987 .

[23]  G. Starr,et al.  Assessing temporal stability and spatial variability of soil water patterns with implications for precision water management , 2005 .

[24]  A. Kaleita,et al.  Relationship Between Soil Moisture Content and Soil Surface Reflectance , 2005 .

[25]  V. Castillo,et al.  Spatial patterns and temporal stability of soil moisture across a range of scales in a semi‐arid environment , 2000 .

[26]  T. Jackson,et al.  Watershed scale temporal and spatial stability of soil moisture and its role in validating satellite estimates , 2004 .

[27]  Kenneth A. Sudduth,et al.  SIMULTANEOUS SOIL MOISTURE AND CONE INDEX MEASUREMENT , 2004 .

[28]  Dharmendra Saraswat,et al.  THE IMPACT OF TEMPERATURE AND SHALLOW HYDROLOGIC CONDITIONS ON THE MAGNITUDE AND SPATIAL PATTERN CONSISTENCY OF ELECTROMAGNETIC INDUCTION MEASURED SOIL ELECTRICAL CONDUCTIVITY , 2005 .

[29]  C. E. Goering,et al.  Cell Size Selection for Site-specific Crop Management , 1994 .