Progress 04/15/18 to 04/14/23
Outputs
Target Audience:Soil scientists, crop physiologists, plant breeders, engineers, and agronomists Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The project contributed to two Ph.D. dissertations in electrical and computer engineering in close collaboration with agronomists. In addition, one post-doctoral researcher was trained through this project. The graduate students and post-doc published work in collaboration with the agronomists. In addition, this project contributed to undergraduate training in both the departments of electrical and computer engineering as well as agronomy. How have the results been disseminated to communities of interest?The results have been communicated through peer-reviewed publications. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
This project led to an improved wearable sensor for real-time on-leaf monitoring of relative humidity, temperature, and vapor-pressure deficit of plants under field conditions. This sensor was flexible and conformable to the leaf surface. By integrating a graphene-based RH sensing element and a gold-based thin-film thermistor on a polyimide sheet, the sensor allowed accurate and continuous determination of vapor pressure deficit at the leaf surface, thereby providing information on plant transpiration. A field experiment was conducted to validate the ability of the sensor to continuously monitor the leaf RH, temperature, and VPD of maize plants. In the summer of 2022, the sensors were installed at maize plants at four sites (Lincoln, Nebraska; Missouri Valley, Iowa; Ames, Iowa; and Crawfordsville, Iowa) using the fields from other projects. The sensor output also demonstrated the influences of light and irrigation on maize transpiration. Further, by attaching multiple sensors to different locations of a plant, we estimated the time required for water to be transported from the roots to each of the measured leaves along the stalk. In addition, several sensors were deployed in maize fields where they demonstrated the ability to detect differences in transpiration between fertilized and unfertilized maize plants. As an example, the result in one experiment showed that at nighttime, both the leaf and air RH rose to almost saturated while both the leaf and air temperature dropped. When the sun rose in the morning, the leaf and air RH decreased with increasing air temperature. With increasing photosynthesis at daytime, the leaves released more water vapor from the stomata, resulting in an increase in leaf RH to a level higher than the air RH. Compared to the unfertilized plants, the fertilized plants released more water vapor due to greater photosynthesis, thus presenting a higher RH and a lower temperature at the leaf; indeed, over the course of the growing season, the fertilized plants fixed approximately, 200% more carbon dioxide than the unfertilized plants which requires greater transpiration. This project also resulted in a multifunctional tattoo array for simultaneous monitoring of relative water content (RWC), biopotential, temperature and at the leaf responding to water stress. The tattoo sensing array could directly be transferred to the leaf surface, requiring no supporting substrate to hold the sensor on the leaf. This method relieved almost all physical constraints of the sensor that other would have impacted gas exchange, photosynthetic activity, and transpiration at the leaf surface. Our multifunctional sensing array consisted of biopotential electrodes, resistive temperature sensors, and impedimetric water content sensors. These substrate-free sensors were formed with filamentary serpentine thin wires for high stretchability and conformity to the growing leaves.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
Yin, S., Ibrahim, H., Schnable, P.S., Castellano, M.J. and Dong, L., 2021. A Field?Deployable, Wearable Leaf Sensor for Continuous Monitoring of Vapor?Pressure Deficit. Advanced Materials Technologies, 6(6), p.2001246.
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Ibrahim, H., Moru, S., Schnable, P. and Dong, L., 2022. Wearable Plant Sensor for In Situ Monitoring of Volatile Organic Compound Emissions from Crops. ACS Sensors, 7(8), pp.2293-2302.
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Ibrahim, H., Yin, S., Moru, S., Zhu, Y., Castellano, M.J. and Dong, L., 2022. In Planta Nitrate Sensor Using a Photosensitive Epoxy Bioresin. ACS Applied Materials & Interfaces, 14(22), pp.25949-25961.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Chen, Y., Tian, Y., Wang, X., Wei, L. and Dong, L., 2020. Miniaturized, Field-Deployable, Continuous Soil Water Potential Sensor. IEEE Sensors Journal, 20(23), pp.14109-14117.
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Progress 04/15/21 to 04/14/22
Outputs
Target Audience:Soil scientists, crop physiologists, plant breeders, and engineers Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The project has provided training opportunities for two Ph.D. students (one engineer and one soil scientist) who are collaborating on the project. The project has also provided training opportunities for several undergraduate assistants and a post-doc. How have the results been disseminated to communities of interest?Results have been communicated through the technical publications previously listed. Also, the sensors are now being deployed on a variety of multi-state projects, which is exposing other scientists and engineers to the sensors. What do you plan to do during the next reporting period to accomplish the goals?We will continue to maintain the sensors deployed in the field. At the end of the crop growing season, we will analyze and interpret data collected from the sensors that are currently deployed across the water availability gradient (Iowa to western Nebraska).
Impacts
What was accomplished under these goals?
Water is generally the greatest limitation on crop production. Our goal is to develop and deploy "wearable" (i.e., nondestructive, leaf-mountable) sensors for the measurement of water transport dynamics in maize. The sensors will be used to enable a high-throughput plant breeding platform that demonstrates the sensors' ability to discriminate among maize genotypes for plant water transport dynamics. The new sensors will advance plant sciences and agricultural research in a manner similar to how wearable human body sensors have advanced human health and biomedical sciences. We have three objectives: 1. Develop, calibrate, and optimize two types of low-cost, leaf-mounted, wearable plant sensors for accurate measurements of plant water dynamics. 2. Use the sensors to develop a water use phenotyping platform that demonstrates the ability of sensors to discriminate among maize genotypes according to plant water dynamics. 3. Test whether differences in plant water dynamics are predictive of yield or stability of yield across environments. Using sensor and grain yield data generated during the project in combination with yield and weather data from the Genomes To Fields project, we will test the association of variation in water transport dynamics with variation of yield and yield stability among hybrids and in relation to environmental parameters. During this reporting period, the sensors were deployed on a range of sites representing a gradient in water availability (Iowa to western Nebraska). The sensors are currently collecting data and this data will be analyzed and interpreted during the next reporting period.
Publications
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Progress 04/15/20 to 04/14/21
Outputs
Target Audience:Scientists and engineers Changes/Problems:Covid resulted in a delay, however, we are otherwise on track. What opportunities for training and professional development has the project provided?The project has provided training opportunities for two PhD students (one engineer and one soil scientist) who are collaborating on the project. The prokect has also provide training opportunities for several undergraduate assistants. How have the results been disseminated to communities of interest?Through the technical publications previously listed. What do you plan to do during the next reporting period to accomplish the goals?We will deploy the sensors and conduct extensive field testing that: 1) validates the sensor function, 2) provides new insights about plant water dynamics that were not possible with current state-of-the-art, and 3) deploy the phenotyping platform.
Impacts
What was accomplished under these goals?
During this reporting period, we optimized the wearable plant sensor for detecting leaf water content levels. The sensor could detect changes in electrical impedance of leaves due to changes in water content. With increasing relative water content, we found that both the permittivity of leaf and the capacitance of the sensor increased. We demonstrated that the ability of the mechanical strain sensing element of on the plant sensor could record subtle changes in thickness leaf over time with a resolution of about 25 micrometers in thickness. We built a readout circuit to record changes in electrical resistance of the strain sensor over time. The experiment showed that the leaf became thicker with increasing water content, leading to an increase in mechanical stress of the strain sensing element; this, in turn, resulted in a decrease in capacitance. We improved accuracy in water content measurement by combining changes in both the permittivity and thickness of the leaf. We measured changes in capacitance of the sensor at 100 kHz under different relative water content determined using a conventional method. There exhibited a 20-25% difference between the sensor output and the conventional method. The sensor attachment to the leaf was found challenging due to the rough leaf surface and the small contact area between the clamping structure and the leaf, which can be improved by optimizing the clamp design. For field applications, we added a Wheatstone bridge-type temperature compensation circuit to the sensor signal readout circuit that consisted of an amplifier, an analog-to-digital converter, and an interface to a microcontroller. In addition, we optimized a soil water potential sensor. The improved sensor overcome three key issues with conventional water potential sensors, including a gradual water loss from a water reservoir to the environment; a limited dynamic range of soil water potentials due to cavitation-induced function failure; and considerable dependence on variations in soil temperature. The optimized water potential sensor used an osmotic solution to replace water in the reservoir. The osmotic solution provided the reservoir with an osmotic potential, thus increasing the total pressure potential inside the reservoir while establishing an equilibrium with surrounding unsaturated soils. This design led to extending the dynamic range of soil water potential down to -1.1 MPa. Also, the sensor exhibited independence on variations in environmental temperature due to the following new design: The sensor consisted of an active element and a reference element. These two elements were identical, except that the reference element was designed with a sealed reservoir. The reference element only responded to temperature variations, thus the temperature influence could be compensated by subtracting the signal from the active element with that from the reference element. This soil sensor was validated in monitoring the dynamic change in soil water potential in real-time. The phenotyping system (at a testing phase only) included both the wearable vapor pressure deficit VPD sensors and soil water potential sensors. Each sensor had a readout circuit, a rechargeable battery and a power bank. Solar panels were used to provide power to the sensors. Eight sensors used a 100W solar panel. A timing control unit was built to program and control measurement time points for the sensors. The control circuit included a card-sized single-board raspberry pi devices, sleepy pi devices with Arduino microcontroller. The sleepy pi allowed the raspberry pi to shut itself down when it was not in use. All the electronics were placed in a tote that was covered by a thermal insulation material to protect the circuits from high temperature. Data was stored in a storage card in the tote.
Publications
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2021
Citation:
Yuncong Chen, In-situ soil water potential sensor and nutrient sensor, Ph.D. dissertation. Iowa State University (2021)
- Type:
Journal Articles
Status:
Submitted
Year Published:
2022
Citation:
A Miniaturized, Double-Chambered, Osmotic Tensiometer with Self-temperature Compensation and Wide Dynamic Range
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Progress 04/15/19 to 04/14/20
Outputs
Target Audience:Scientists and engineers Changes/Problems:We originally intended a much larger field experiment in 2020 with many maize phenotypes. However, due to the COVID pandemic, our ability to develop and deploy sensors was hampered. Hence, we are requesting a no-cost extension to extend this work into 2021. What opportunities for training and professional development has the project provided?The project trained an M.S. student in Electrical Engineering and an undergraduate student in Agronomy. How have the results been disseminated to communities of interest?Yes, we submitted one techncial publication describing the sensors and sensor function in greenhouse and field experiments. What do you plan to do during the next reporting period to accomplish the goals?We will deploy the sensors in a field experiment to phenotype maize for water use efficiency.
Impacts
What was accomplished under these goals?
Impact: We are developing, calibrating and optimizing two types of low-cost, leaf-mounted, wearable plant sensors that can be used to improve water use efficiency and reduce water stress in crop systems. During the project period we developed and deployed sensors in greenhouse and field experiments to validate measurements of relative humidity, temperature, and vapor pressure deficit. We increased our knowledge about how low-cost sensors can function on-plant to measure water dynamics. We project that our work help farmers to improve water use efficiency by reducing wasted water and increasing crop yield. Objective 1. Develop, calibrate, and optimize two types of low-cost, leaf-mounted, wearable plant sensors for accurate measurements of plant water dynamics. During this period, the two sensors described in Objective 1, were developed and deployed in greenhouse and field experiments. The sensors measured relative humidity, temperature, and vapor pressure deficit. The measurements compared well with off-the-shelf devices and accurately captured differences in relative humidity, temperature and vapor pressure deficit between maize crops that received or did not receive nitrogen fertilizer. The relative low-cost of these sensors compared to currently available products promises to improve the productivity, profitability and environmental performance of agriculture by optimizing irrigation inputs and leading to the development of high-throughput phenotyping platforms for water use efficiency. Objective 2. Use the sensors to develop a water use phenotyping platform that demonstrates the ability of sensors to discriminate among maize genotypes according to plant water dynamics. Nothing to report Objective 3.Test whether differences in plant water dynamics are predictive of yield or stability of yield across environments. Nothing to report
Publications
- Type:
Journal Articles
Status:
Submitted
Year Published:
2021
Citation:
Yin S, Imbrahim H, Schnable P, Castellano M, Dong L. XXXX. A Field-deployable, Wearable Leaf Sensor for Continuous Monitoring of Vapor-Pressure Deficit. Advanced Materials Technologies. In review.
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Progress 04/15/18 to 04/14/19
Outputs
Target Audience:Scientists and engineers. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?One M.S. student in Computer and Electrical Engineering. How have the results been disseminated to communities of interest?One conference paper and one conference presentation. One patent application. What do you plan to do during the next reporting period to accomplish the goals?Continue to field test and ruggedize the sensors.
Impacts
What was accomplished under these goals?
We have been developing an integrated 'wearable' plant water sensor for monitoring both relative humidity and temperature at the same measurement point on the leaf. This flexible device allows calculation of vapor pressure deficit. We conducted an initial field experiment of the developed sensors. Twelve sensors, along with their data loggers, were deployed in a maize crop field. These sensors have recorded data for more than three weeks. Batteries are replaced once every eight days. More than half of these devices are still working despite multiple rain events during the experiment. Data analysis will be done after the devices are retrieved from the field. Objective 1... Develop, calibrate, and optimize two types of low-cost, leaf-mounted, wearable plant sensors for accurate measurements of plant water dynamics. With regard to the sensor materials and design, we measured Young's modulus of both Ecoflex silicone (YEcoflex) substrate and leaf (Yleaf). It is found that YEcoflex is less than Yleaf regardless of maize growth stage. This key mechanical measurement result allows the elimination of designing a complex wrinkled substrate for the proposed sensor. Ecoflex could be used as the device substrate for adapting to the plant growth during real-time monitoring of relative humidity and temperature. In addition, we have designed readout circuits for measuring and storing data of the sensor. Objective 2... Nothing to report Objective 3... Nothing to report
Publications
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2019
Citation:
Chen, Y., Tian, Y., Wang, X. and Dong, L., 2019, June. Miniaturized Soil Sensor for Continuous, In-Situ Monitoring of Soil Water Potential. In 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII) (pp. 2025-2028). IEEE. DOI: 10.1109/TRANSDUCERS.2019.8808562
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2019
Citation:
Liang Dong, Smart Sensors for Digital Agriculture, Phenome 2019, Tucson, AZ, February 6-9.
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