Progress 09/01/03 to 08/31/06
Outputs
Technological advancements are needed to cost-effectively improve the precision of soil nutrient information. On-the-go soil sampling has the potential of improving the density of soil chemical property information at an affordable cost. In a Phase I project, Veris Technologies demonstrated the feasibility of pH mapping, with a sampling device that collected soil cores, measured pH directly on the cores utilizing ion-selective electrodes (ISE's), and discharged the cores on-the-go. The purpose of the Phase II project was threefold: 1) to develop the Phase I sensing device into a complete pH sensing system, 2) to further develop the system to include other ion-selective electrodes, and 3) to develop the capability of deriving prescriptive information, such as lime requirement, in conjunction with other sensor data. In order to develop a pH sensing system capable of operating in a wide variety of soil and field conditions, the mechanical, hydraulic, and electronic
components of the system were configured, designed, tested, and refined. For commercial viability, the system needed to be relatively simple and easy to operate, and capable of collecting high-quality pH data with a volume of 200 acres/day. Phase II research has resulted in such a pH sensing system, termed the Veris Mobile Sensor Platform (MSP), with initial commercialization underway. Research conducted on this system has shown it to be proficient in collecting field-sensed pH measurements that are well-correlated to lab-analyzed validation samples. Prescriptive information using sensed pH, along with a small number of calibration samples and other sensor information such as soil electrical conductivity (EC), has been shown to be effective for generating precise lime recommendations. A limitation of the current MSP is reduced pH electrode life in sandy soils, resulting in high per-acre operating costs when used in those soils. Direct soil measurement using ISE's for measuring
potassium (K) and nitrate (N) were deemed not commercially viable, due to the fragility and operating expense of those electrodes. To address this challenge, a significant innovation for the MSP was designed and tested: a module which creates a soil-water solution measurement. Not only does this innovation allow the use of expensive, fragile electrodes such as those for N and K, it offers much longer wear life and reduced operating costs for pH as well. Commercialization of the MSP with direct-soil pH measurement has resulted in systems operating in ten states and three foreign countries. Response to the system has generally been positive, and it is expected that the introduction of the soil-solution module will lead to increased consumer acceptance and higher sales volumes. A patent on the standard MSP is pending, and it is anticipated that patent coverage on the soil-solution module will be sought as well.
Impacts
In the United States, there are approximately 135,000,000 acres of low pH soils. Worldwide, 45% of all arable land suffers from low pH. All current methods of soil sampling estimate the soil pH at un-sampled locations, either by averaging the composited values or by interpolating the values of individual samples. The density of the data collected by the Veris Mobile Sensor Platform reduces the error associated with these sampling methods. In field tests conducted under Phase 2, the spatial variability of soil pH on many fields has been demonstrated, and the improvements in pH accuracy made by the Veris Mobile Sensor Platform are significant. As the first commercial system capable of mapping a soil chemical property on-the-go, the Veris pH Manager has generated widespread interest in improved mapping. Units have been sold in 10 states and three foreign countries. The detailed lime prescriptions offer a significant improvement in lime accuracy, which should ultimately
improve yields, nutrient utilization, and growers' profits. Also, an on-the-go soil-solution creating system has been developed and tested, which represents a major advancement in on-the-go nutrient mapping capability. This device has been shown to provide accurate potassium mapping, however nitrate tests weren't as promising. Once successfully commercialized, this module has the potential to significantly improve usage of potash, and possibly nitrogen.
Publications
- Lund, E.D., and V.I. Adamchuk, 2006. On-the-go Mapping of Soil pH and Other Soil Properties Using Ion-Selective Electrodes in a Soil-Water Solution. Proceedings of 8th International conference on Precision Agriculture, Minneapolis MN
- Lund, E.D., V.I. Adamchuk, K.L. Collings, P.E. Drummond and C.D. Christy. 2005. Development of soil pH and lime requirement maps using on-the-go soil sensors. Proceedings of 5th European Conference on Precision Agriculture Malmo Sweden
- Adamchuk, V.I., E.D. Lund, B. Sethuramasamyraja, M.T. Morgan, A. Dobermann, D.B. Marx. 2005. Direct measurement of soil chemical properties on-the-go using ion selective electrodes. Computers and Electronics in Agriculture 48(3):272-294.
- Lund, E.D., V.I. Adamchuk, K. L. Collings, P. E. Drummond, and C. D. Christy. 2004. Managing pH Variability With On-The-Go pH Mapping. Proceedings of 7th International conference on Precision Agriculture, Minneapolis MN
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Progress 01/01/05 to 12/31/05
Outputs
This project has resulted in a commercially available pH mapping system, the Veris Mobile Sensor Platform featuring the pH Manager. These machines have been purchased by ag input suppliers, crop consultants, and researchers in 12 states and 3 foreign countries. During the early part of the Phase II project, efforts focused on developing the control and measurement functions required to measure pH on the go. Fine-tuning these functions continues today. At all phases of the project, sensor-derived pH and lime maps were validated with lab-analyzed soil samples. The validation process has evolved into a field-calibration and lime requirement modeling software routine. This method involves collecting 5-10 lab-analyzed soil samples, and performing a multiple regression routine that uses the lime recommendations from the lab, soil electrical conductivity (as a surrogate measure of soil buffering) and the on-the-go pH sensor data to generate a lime rec for each pH sensor data
point. After meeting these objectives relating to pH measurements, recent efforts have centered around developing a system for measuring soluble potassium and nitrate nitrogen using ion-selective electrodes. Due to the abrasive nature of soils and the fragility of the PVC membranes on these electrodes, direct-soil measurement is not feasible. A system which creates a soil-water mixture has been developed and is being field-tested. The balance of the Phase II project will focus on additional development and field-validation of this system.
Impacts
As the first commercial system capable of mapping a soil chemical property on-the-go, the Veris pH Manager has generated widespread interest in improved mapping. The detailed lime prescriptions offer a significant improvement in lime accuracy, which should ultimately improve yields, nutrient utilization, and grower profits. The nitrate and potassium mapping option, if successfully commercialized, has the potential to significantly improve usage of these fertilizers.
Publications
- Lund, E.D., V.I. Adamchuk, K.L. Collings, P.E. Drummond and C.D. Christy. 2005. Development of soil pH and lime requirement maps using on-the-go soil sensors. Proceedings of 5th European Conference on Precision Agriculture Malmo Sweden
- Adamchuk, V.I., E.D. Lund, B. Sethuramasamyraja, M.T. Morgan, A. Dobermann, D.B. Marx. 2005. Direct measurement of soil chemical properties on-the-go using ion selective electrodes. Computers and Electronics in Agriculture 48(3):272-294.
- Lund, E.D., V.I. Adamchuk, K. L. Collings, P. E. Drummond, and C. D. Christy. 2004. Managing pH Variability With On-The-Go pH Mapping. Proceedings of 7th International conference on Precision Agriculture, Minneapolis MN
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Progress 10/01/03 to 09/30/04
Outputs
This project was divided into three parts: 1) Creation of a pH sensing system, 2) Further develop the system to include other ion-selective electrodes (K, N, Na), and 3) Develop prescriptive information from this system in conjunction with other sensor data. Most of the technical objectives for first part of the project have been achieved. A pH sensing system has been developed and initial commercialization is underway; termed the Veris Mobile Sensor Platform (MSP). The Veris Mobile Sensor Platform is tractor or pickup powered. It is designed to operate in a variety of field conditions, including no-till and conventional tillage, on bedded fields, and in vineyards. Advancements made in the area of improved data accuracy fall into two categories: 1) improved soil-electrode junction, and 2) improved data processing. Improved soil-electrode junction: Field trials and subsequent discussions with electrode vendors have led to the adoption of a double-junction reference
electrode. Extensive testing in low CEC soils established the need for purified water. Improvements in soil-to-electrode contact have been made with the addition of two new components to the system. Improved data processing is provided by variable log times, which is part of new firmware that allows the unit to automatically cycle to collect another sample as soon as 4 successive readings have settled to within .02 pH of each other. Extraction routine reviews the logged pH data and selects data that meet certain quality criteria. A major objective of the project is to reduce the per-acre operating cost. Since the single largest operating expense are the pH electrodes, most of the efforts have concentrated on this component. A portion of the travel budget has been spent visiting current and prospective electrode vendors. This has resulted in a securing a new vendor who produces a lower cost pH electrode, which appears to have improved measurement life as well. With the addition of a
sand guard, operating life in abrasive soils have been increased significantly. A significant obstacle has been encountered with the second set of objectives, namely the fragility of K and N ion-selective electrodes. While the pH electrode is glass and can withstand a certain amount of abrasive soils, the K and N electrodes are constructed of PVC membranes. As a result, their wear characteristics for direct soil measurements are unacceptable in a commercial application. An alternative sampler system design, which puts soil into a slurry condition, has been prototyped. This appears promising and will be a focus of the balance of the Phase II project. The third set of objectives deals with using additional sensors and geo-statistical techniques to derive prescriptive information from the ion-selective electrodes. The main focus of this effort has centered around using soil EC and near-infrared spectroscopy (NIRS) data to improve prediction of lime rec. To date, five fields have been
mapped with pH electrodes along with EC and NIRS sensors, and various data analysis techniques are being used to fuse the data.
Impacts
In the United States, there are approximately 135,000,000 acres of low pH soils. These soils are primarily located in the eastern half of the United States. Worldwide, 45% of all arable land suffers from low pH. While there are a significant number of low pH fields that need pH measurements, only a percentage of these fields are actually tested. All current methods of soil sampling estimate the soil pH at un-sampled locations, either by averaging the composited values or by interpolating the values of individual samples. The density of the data collected by the Soil Sampling System reduces the error associated with these sampling methods. In field tests conducted under Phase 2, the spatial variability of soil pH and other properties has been evident. Improvements in lime application accuracy have averaged 700 lbs/acre by using the automated sampling device, versus currently available sampling practices. This improved accuracy will allow growers to improve lime
applications on fields currently sampled, and encourage additional sampling on fields currently not sampled.
Publications
- MANAGING pH VARIABILITY WITH ON-THE-GO pH MAPPING E. D. Lund, K. L. Collings, P. E. Drummond,C. D. Christy, and V. I. Adamchuk Proceedings of 7th International Conference on Precision Agriculture, Minneapolis MN (2004)
- (IN REVIEW) Computers in Agriculture 2005 Direct measurement of soil chemical properties on-the-go using ion selective electrodes V.I. Adamchuk, E. Lund, B. Sethuramasamyraja, M.T. Morgan, A. Dobermann
- Proceedings of the 5th European Conference on Precision Agriculture 2005 Development of soil pH and lime requirement maps using on-the-go soil sensors E.D. Lund, V.I. Adamchuk, K.L. Collings, P.E. Drummond and C.D. Christy
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