Heat and drought stress are having several significant impacts on hazelnut growers in during the dry summer in western Oregon. Increasingly hot and dry conditions are making water management more challenging. Hazelnut trees are highly sensitive to water stress. Even slight water stress during critical growth periods can significantly reduce vegetative growth, fruit development, and final yield.
Integrating advanced technologies into hazelnut farming offers a promising way to improve water management, enhance crop quality and tackle challenges posed by drought.
Researchers have developed various sensors to measure how much water crops need. One standout method is infrared thermometry, which uses infrared technology to measure plant temperature and monitor water loss without damaging the plants. This method can be used with drones or satellites for large-scale monitoring.
To help hazelnut growers manage water more efficiently, a research team at Oregon State University used infrared thermometry to develop the first Crop Water Stress Index (CWSI) model specifically for hazelnuts. The researchers used affordable, open-source infrared thermometers and data loggers to help hazelnut farmers manage irrigation better and increase their yields.
The resulting study, published in the journal Sensors, took place in a Jefferson hazelnut tree orchard at OSU’s North Willamette Research and Extension Center in Aurora, where trees were watered using a drip irrigation system. A weather station measured important weather conditions to calculate how much water the plants needed each day. The experiment included three different irrigation treatments: well-watered, moderate and dryland.
Researchers used a homemade device called Low-Cost Open-Source Sensor (LOCOS) to record weather and temperature data near the trees. The infrared thermometer was placed on the north side of the tree to get more stable and accurate readings.
The CWSI model was tested and compared with other plant water status measurements. The results showed that when the plant's water potential — a measure of water stress — was below a certain level, the plants were not stressed. However, unirrigated hazelnuts showed signs of stress during the hot season, while irrigated plants did not.
The project was led by Lloyd Nackley, associate professor in the Department of Horticulture in the College of Agricultural Sciences and Extension specialist in nursery production and greenhouse management; and Nik Wiman, Extension orchard crops specialist. Dalyn McCauley, a senior faculty research assistant and engineer with expertise in irrigation and plant sensing, built the sensors and conducted the experiment.
The study, funded by an Oregon Department of Agriculture Specialty Crop Block Grant, proved that low-cost technology works well and created the first stress index for Jefferson hazelnut trees. Using sensors to manage irrigation is crucial for hazelnut farmers, especially as the frequency and severity of droughts continue. This new model and the use of low-cost technology can help farmers monitor their crops more effectively and make better irrigation decisions.
The study highlights the potential to use low-cost technology to monitor and manage water stress in hazelnut trees. Integrating advanced technologies into hazelnut farming offers a promising way to improve water management, enhance crop quality and tackle challenges posed by drought.