Source: HOLLAND SCIENTIFIC submitted to NRP
SUNLIGHT INDEPENDENT CROP CANOPY REFLECTANCE SENSOR
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
SMALL BUSINESS GRANT
Reporting Frequency
Annual
Accession No.
0196935
Grant No.
2003-33610-13873
Cumulative Award Amt.
(N/A)
Proposal No.
2003-04051
Multistate No.
(N/A)
Project Start Date
Sep 1, 2003
Project End Date
Aug 31, 2005
Grant Year
2003
Program Code
[8.13]- (N/A)
Recipient Organization
HOLLAND SCIENTIFIC
5011 SOUTH 73RD STREET
LINCOLN,NE 68516
Performing Department
(N/A)
Non Technical Summary
Over application of nitrogen fertilizer on agricultural and commecial landscapes has resulted in contamination of ground and surface waters. This project proposes to develop a new sensor technolgy that will help reduce the amount of N applied to crops and turf by determining the amount of N needed by the plant via the plants reflectance characteristics.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
4047210201035%
4047210202065%
Knowledge Area
404 - Instrumentation and Control Systems;

Subject Of Investigation
7210 - Remote sensing equipment and technology;

Field Of Science
2010 - Physics; 2020 - Engineering;
Goals / Objectives
The Phase II research goals are aimed at continued research and development of a multispectral, pulsed LED, light sensor that synchronously amplifies and demodulates reflected light in order to obtain spectral information pertaining to the plant and soil being measured. The primary technical questions and developmental issues that will be investigated and evaluated are: 1. Test performance of amber, green, orange and red LEDs for use in biomass and chlorophyll assessment. Performance data will be compared against Minolta SPAD and Holland Scientific Crop Circle sensor data. Also to be investigated, will be alternate ways in which the fluorescence information obtained by the sensor can be used as a covariant in making chlorophyll/biomass determinations. 2. Refinement and alternative embodiments of the sensor technology. To be investigated will be low cost embodiments of the sensor electronics and packaging. Also to be investigated, will be other sensor embodiments to address other measurement needs. For example, handheld devices vs. on-the-go sensors for example. 3. Development of appropriate methods for plant nutrient recommendations and plant status determinations. Primary emphasis will be for nutrient need determination in corn production and stress/biomass/disease determination for turf. 4. Determine sensor system performance on various crop and turf landscapes. Application of a variable rate system with algorithm developed by the USDA-ARS will be performed. Use of system on turf for the purpose of nutrient, stress and disease assessment will be conducted.
Project Methods
1. LED performance verification: The objective of this task will be to determine the LED wavebands required to obtain useful spectral information with regard to the target being measured, whether it be plant material or soil. Of consideration for choosing a particular LED wavelength and material chemistry will be one of off-band IR light generation. New high intensity LED technologies emit a good deal of off-band IR light that interferes with the visible band reflectance measurement. IR light generation by the LED will cause the visible band reflectance signal to appear greater in magnitude than it really is; causing a skew in the biomass determination. 2. Refinement and alternative embodiments of the sensor technology: The prototype sensor developed during phase I produced very good data from test crops and turf; however, the sensor requires refinement for commercialization. The areas of refinement deal primarily with the data communication methodology, the optical system and the device packaging. Also, to be investigated will be alternative embodiments of the sensor with respect to packaging and electronic implementation. With regard to packaging, there are two embodiments that will be developed. The packaging embodiments will include both vehicle mounted packages and a handheld instrument packages. 3. Development of appropriate methods for plant nutrient recommendations and plant status determinations: The primary research emphasis for this section will be on N management for corn production and disease/stress/biomass determination for turf. Close collaboration with the USDA, Jim Schepers with the Lincoln, NE ARS and Jack Meisinger with the Beltsville, MD ARS, and the PI's of the IFAFS grant (John Shannahan USDA-ARS Lincoln, NE et al.) will help assist in the development of the N sufficiency model and recommendation for corn production. As for turf research, collaboration with the University of Nebraska-Lincoln (UN-L) turf grass research group will assist in the development of detection algorithms and methodologies for using sensor data to determine disease and stress in turf grass. 4. Evaluation of sensor system performance on various crop and turf landscapes: For the corn production component of the research, on-farm trials will be conducted that involve field-length replicated strips of three different N application strategies on three different farmer fields in the central Platte Valley, near Shelton, NE in years one and two of this study. For the turf component of the research, the study will be broken up into two components. One pertaining to turf nutrient monitoring and the other to early stress detection. N treatment research will be conducted using N treated turf plots at the UN-L turfgrass research facility located at Mead, NE.

Progress 09/01/03 to 08/31/05

Outputs
Research conducted and successfully completed during Phase II include the development and refinement of the sensor technology into a commercial product and the evaluation of the sensor in crop/turf mapping and variable rate nutrient applications. The sensor has demonstrated itself to be a reliable and effective tool for crop/turf status assessment. The sensor has significantly reduced size and weight over early prototype devices and competing, commercially available sensors. Additionally, the optical platform developed has resulted in a sensor that has exceptional range and sensitivity. The new device now has the capability of measuring plant canopy characteristics over 8 feet from the sensor while offering exceptional signal-to-noise performance. This technology is innovative because it utilizes a pulsed LED light source that simultaneously emits visible and near infrared light (NIR) of equal spatial distribution. As a result, it successfully mimics the spatial composition of natural light. This provides better sensing capabilities and the ability to operate at all times of the day regardless of ambient illumination. Additionally, since the light is pulsed rapidly, the sensor is capable of distinguishing between its own light source reflected by the plant canopy and ambient light. Because of this feature, the sensor may be used for collecting data regardless of ambient lighting conditions. The new active sensor is a robust remote-sensing device that may be used in vehicle-mounted and handheld applications for measuring crop/plant canopy biomass or soil color. This sensor may be used to collect and store data for later analysis or it may be used for on-the-go applications, such as variable rate application of fertilizer, herbicide, seeds, etc. The technology may be used for a variety of different precision agriculture applications. Specifically, the data collected by the sensor may be utilized with a GPS for crop mapping, soil mapping, turf mapping, etc.; or it may be used for varying the rate of fertilizer based on crop canopy reflectance characteristics, or seed application based on the characteristics of the soil. These precision agriculture methods may be used on a variety of different crops, ranging from corn, wheat, and cotton, to foragable biomass and turfgrass. Furthermore, the sensor may be used independently or as a network of sensors. This technology is a tool for collecting valuable information on crop biomass and soil characteristics that can be integrated into existing precision agriculture practices of crop mapping and site-specific management.

Impacts
The new active sensor will provide improved performance over existing crop canopy sensor technology by eliminating the reliance on fair weather sunlight conditions. Since the sensor is not limited by the amount of ambient light, the sensor can be operated outside of daylight hours even in complete darkness. The unique measurement capability of the sensor enables early detection of nutrient stress and disease in crops and turf. Using this sensor with on-the-go variable rate applicators will help reduce over-application of fertilizer that has resulted in elevated levels of nitrate in ground and surface waters. For recreational/sports turf managers, the new sensor will aid in the early detection and treatment of diseased and stressed turf.

Publications

  • Holland, K.H., J.S. Schepers, J.F. Shanahan and G.L. Horst. 2004. Plant canopy sensor with modulated polychromatic light source. Proceedings 7th International Conference on Precision Agriculture.


Progress 01/01/04 to 12/31/04

Outputs
Development of the sensor technology continued into the first half of 2004 producing prototype sensors tested by USDA collaborators. The resulting sensor was significantly reduced in size and weight over earlier prototypes. Additionally, the optical platform under went a complete redesign to improve the sensor's range and sensitivity. The new sensor now has the capability of measuring plant canopies up to 8 feet from the sensor while offering exceptional signal-to-noise performance. The sensor technology is now commercially available. Work continues on expanding the sensor technology's capabilites. Modifications of the sensor for measuring chlorophyll content via plant fluoresence are under way. Additionally, work on sensor fusion into variable rate application systems continues. Variable rate application tests from the 2004 field season look exceptionally promising. Development of a PC based variable rate application controller has commenced. The new control software will provide researchers and produces a quick and low-cost solution for performing and experimenting with variable rate application technology.

Impacts
New, on-the-go, canopy sensing technology will enable producers to reduce the amount of applied fertilzer (N). The sensing technology inconjuction with variable rate fertilzer applicators will allow precise control of N as dictated by crop requirements. Lowering N rates will help improve surface and ground water quality by reducing runoff and leaching of due to excess application.

Publications

  • Holland, K.H., J.S. Schepers, J.F. Shanahan and G.L. Horst. 2004. Plant canopy sensor with modulated polychromatic light source. Proceedings 7th International Conference on Precision Agriculture. Minneapolis, MN (In Press).