Source: SOIL INFORMATION SYSTEMS, INC. submitted to NRP
INDIRECT ESTIMATION OF SOIL WATER RETENTION CURVE USING SOIL IMAGING PENETROMETER (SIP)
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
Reporting Frequency
Annual
Accession No.
0210049
Grant No.
2007-33610-17927
Cumulative Award Amt.
(N/A)
Proposal No.
2007-00377
Multistate No.
(N/A)
Project Start Date
Jun 1, 2007
Project End Date
Jul 31, 2008
Grant Year
2007
Program Code
[8.4]- (N/A)
Recipient Organization
SOIL INFORMATION SYSTEMS, INC.
2453 ATWOOD AVE.
MADISON,WI 53704
Performing Department
(N/A)
Non Technical Summary
The soil water retention curve (WRC) plays a critical role for the solution of various agricultural, hydrological and environmental problems such as the prediction of infiltration rate, surface runoff for irrigation design, modeling of contaminant transport in the unsaturated zone, estimation of soil water holding capacity for crop growth simulations, and the evaluation of soil strength and compressibility for trafficability assessment. These models require high vertical and horizontal spatially resolute data in order to perform well. However, the laboratory, labor, and time costs required to achieve good performance are cost prohibitive using currently available methods. Therefore, new methods are needed for accurately estimating the soil WRC in a cost effective manner. The purpose of the proposed study is to utilize a miniature digital camera, embedded in a soil probe, in combination with other soil sensors to enable the rapid, digital, objective assessment of the soil WRC at horizontal and vertical spatial resolutions not feasible using currently available methods.
Animal Health Component
10%
Research Effort Categories
Basic
20%
Applied
10%
Developmental
70%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1010110206140%
1010110208030%
1017210208030%
Goals / Objectives
The primary objective of the Phase I study is to demonstrate the feasibility of using soil image analysis in conjunction with measurements from other in situ soil sensors for the estimation of the soil water retention curve. The relative performance of three estimation methods will be compared. The most promising method will be developed during Phase II. Several questions will be asked, including: How can pore structure information, such as pore size distribution and porosity, be estimated with reasonable accuracy from soil images? How can pore structure information derived from soil images be incorporated into different indirect estimation methods? How would each method perform if input variables obtained from soil images are used?
Project Methods
Our research will build upon the considerable body of research in the literature on the indirect estimation of soil water retention curves and upon our previous work on the extraction of quantitative soil metrics from in situ soil imagery and other in situ soil sensors. However, the research is unique in that we will use data extracted from the in situ soil images, and other sensors, as the input parameters for three indirect estimation methods identified from the literature. Our previous work with the Soil Imaging Penetrometer (SIP) did not address the estimation of the soil water retention curve. First, soil images and other penetrometer-based sensor data will be collected by taking multiple measurements at 30 locations from a 2000 acre research facility in De Forest, WI. At the same locations, duplicate soil samples will be taken at two discrete depths. The water retention curve of soil samples will be determined in a laboratory by standard methods. Second, several image processing techniques will be used to extract quantitative measures related to soil pore structure and fractal dimensions from the soil images collected in the first step. Third, the water retention curve will be estimated using three approaches: 1) pedotransfer function using artificial neural networks, 2) pore size distribution and capillarity, and 3) fractal concepts and percolation theory. Fourth, van Genuchten model parameters will be estimated using a non-linear optimization approach. The agreement between the models and laboratory measurements will be evaluated in terms of bias, mean difference, root of the mean squared difference, and the Pearson correlation coefficient, or similar metrics. Fifth, the feasibility of the overall approach will be discussed in relationship to currently available techniques for obtaining the same information, and the most promising estimation method will be recommended for Phase II.

Progress 06/01/07 to 07/31/08

Outputs
OUTPUTS: In Phase I, we collected a diverse training set of 60 soil samples. Field data collection was performed at four locations throughout the state of Wisconsin. These include the University of Wisconsin Research Stations in Arlington, Marshfield, and Platteville and one private landowner, Opitz Farms near West Bend. At these four locations, five fields were used at the UW - Arlington Station, and one field was used at each of the other locations. Field sites were chosen based on several factors including being able to utilize relationships established during prior research and development projects, soil and crop types and their accessibility during the summer months of a Midwest growing season. Data collection began on June 28th, 2007 and was completed on September 6th, 2007. Field work included the collection of soil images with the SIP (Soil Imaging Penetrometer) along with other in situ probe based soil sensor data and physical soil samples collected adjacent to probe measurements. The soil samples were sent to a laboratory and images from the SIP were analyzed using a number of image processing and computer vision techniques. The laboratory and penetrometer data was used to train and validate an artificial neural network (ANN). Two other methods (physical approach, fractal approach) were also tested. The results of our findings have been disclosed within a Phase I final report submitted to the USDA as well as in a Phase II proposal. SIS, Inc has met with cooperators at the USGS Wisconsin Water Science Center in Middleton, WI and presented our results of Phase I research within a PowerPoint presentation. We then proposed a cooperative effort in the near term for testing our SIP derived SWRC using their CPT platform at a test site of their choice in northern Wisconsin. PARTICIPANTS: Daniel Rooney (Soil Physicist, Principle Investigator) was responsible for overall project direction and coordination and provided scientific input for soil property measurements with geophysical sensors; Woody Wallace (Geomorphologist) contributed to project management, soil imaging system design, integration, and evaluation; Nick Guries (Geomaticist, Programmer) contributed to image processing, and statistical analysis. Nick also worked to set up the Artificial Neural Network; John Samuelson (Soil Scientist, Field Applications Specialist) contributed to project management included budget tracking and assisted in laboratory management. Mark Kuehn (Soil Information Specialist, Geographer) contributed to project management including coordination of field work activities and sample management. Partner organizations that helped contribute their facilities to the use of this project include three University of Wisconsin Research Stations, located in Arlington, Marshfield, and Platteville. One private cooperator, Jeff Opitz allowed us to perform data collection on his farm near West Bend, WI. TARGET AUDIENCES: Our initial target audience is focused on the grape industry of California. We believe that managers and consultants who are currently using WRC data for working with water management issues in vineyards will see this technology as most valuable. Vineyards are chosen because they are a high value specialty crop and a first adopter of new technologies, including the SIS. As the business grows we will be able to expand the use of the technology to other agricultural markets (practically any irrigated or drained crop) and non-agricultural markets, such as construction, storm water infiltration system design, and environmental remediation. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Of the three methods tested, training the artificial neural network (ANN) by using laboratory, Soil Image Penetrometer (SIP) data, and Soil Information System (SIS) penetrometer sensor data showed the most promising results with the lowest RSME (e.g. 1.18 % v/v at 0.33 bar) values and the highest coefficient determinations (e.g. r2 = 0.83 @ 0.33 bar). Two other methods for utilizing information from SIP imagery alone did not produce results due to limitations of the resolution of the camera. Therefore, using the SIS penetrometer sensor data+SIP ANN method holds the most promise for rapidly and accurately estimating the soil WRC and has the potential to significantly outperform laboratory-based pedo transfer functions (PTFs), while being much cheaper and less time consuming to collect and process. The combination of SIS+SIP slightly outperformed the SIS penetrometer alone and significantly out performed the use of the SIP alone. This result is not surprising given the range of pore size that is visible by the current sensor (pores corresponding to pressures less than 0.1 bar). Based on the information learned from this research, in the future we will use ANN to derive soil WRC measurements using only SIP and SIS data as inputs. Although we recognize that more testing over a wider geographic area would be required in order to demonstrate full commercial application, we feel that the Phase I results indicate a high degree of technical feasibility. That combined with the cost effectiveness of our approach compared to conventional methods puts us well positioned for successful commercialization. Our ability to integrate the new technology with the SIS technology that is already commercialized provides a clear path to commercialization of the new penetrometer and data that it produces.

Publications

  • No publications reported this period