This Washington State University weather station in Tonasket is part of the AgWeatherNet service, providing growers  with detailed environmental data.

This Washington State University weather station in Tonasket is part of the AgWeatherNet service, providing growers with detailed environmental data.

courtesy washington state university

More precise integrated pest management practices go hand in hand with accurate weather and environmental data. You can’t have better targeted insect sprays or use predictive disease models without information like rainfall, temperature, degree-days, and such.

More than 135 public weather stations are linked in Washington State to create AgWeatherNet, a network that’s managed by Washington State University. Michigan has a similar network called Enviro-Weather that links about 65 weather stations in the state and 6 stations in Wisconsin. Such programs provide users with detailed environmental data that, when combined with tools like disease and insect models and evapotranspiration rates, can guide irrigation and pest management decisions.

“Precision agriculture needs good weather data to make good decisions,” said Dr. Gerrit Hoogenboom, AgWeatherNet director. “But data is only as good as the location.”

In Washington, most of the automated stations are located in the irrigated regions of eastern Washington. Weather variables collected by the stations include air temperature, relative humidity, dew point temperature, soil temperature at eight inches, rainfall, wind speed, wind direction, solar radiation, and leaf wetness. Some stations also measure atmospheric pressure. These variables are recorded every 5 seconds and summarized every 15 minutes by a data logger.

Although major agricultural production regions in the state are well blanketed with stations, not every grower has a weather station on his or her corner. Growers must often use the nearest station as a reference point.

Growers need to know the high and low spots in their particular orchards and vineyards—their vulnerabilities—and be able to correlate data from the nearest weather station, Hoogenboom said.

“The local AgWeatherNet station should serve as a reference point, like the canary in the orchard instead of canary in the mine,” he said.

Washington’s premium wine grape growing region of Red Mountain, near Benton City, is an exception to using the nearest station as a reference point. Hoogenboom notes that Red Mountain temperatures are quite different than the nearest station at the bottom of the hill.

For areas like Red Mountain that may not correlate well with the nearest station, Hoogenboom said that WSU can accept donations to fund establishment of new ­stations.

“We [WSU] don’t encourage growers to put up their own station because the private stations can’t be managed and maintained as part of the AgWeatherNet grid,” he said. “We have no control over quality of the data or if the sensors are working properly. If an AgWeatherNet station data logger goes down, WSU can fix or replace it immediately, but that’s not the case with private stations.”

Forecasting

Through a research project funded by the Washington Tree Fruit Research Commission, WSU is working to improve the weather prediction capabilities of AgWeatherNet. Currently, AgWeatherNet stations record events that just happened. Weather forecasting would be based on a prediction model that could be linked to frost and cold hardiness models and could help growers better ­prepare for cold events or disease risk.

Hoogenboom said WSU is working with the state’s grape industry to see if it’s feasible to collect inversion layer data during cold spells. Inversion layers can influence a grower’s ability to warm up air with wind towers or other devices when cold temperatures threaten grapevines and buds. Collecting data on inversion layers involves monitoring wind speeds at different heights with towers, so it can be very costly.

In the near future, WSU hopes to have “push” technology available for AgWeatherNet that could alert users through their smartphone or e-mail of frost warnings or potential disease outbreaks and not be dependent on users visiting the AgWeatherNet Web site.

AgWeatherNet is free to users, but requires online ­registration. The service had nearly 5,900 registered members as of October.