Issue link: https://read.dmtmag.com/i/751050
32 DECEMBER 2016 GOOD FRUIT GROWER www.goodfruit.com moisture and temperature at depths of 8 and 16 inches. In the first two years of study, all three colors of netting reduced overall light in the canopy up to 25 percent when compared with a control orchard with no netting. In addition, although overall and direct light were reduced, netting increased the scattered or diffused light, resulting in an increase in canopy volume by 15 percent. That is a significant finding for the project, particularly for varieties like Honeycrisp that can be difficult to grow, Stefano Musacchi, WSU endowed chair and associate professor of tree fruit, said during a field day at the Quincy site in August. "The net can increase the way you can fill up your space in a fast way in the beginning," he said. "Net is really effective in manipulating the capacity of the tree to grow." Lee Kalcsits, WSU assistant professor of tree fruit physiology, said the research- ers thought they would see a reduction in temperature under the netting, in part because it feels cooler than outside the netting. But they discovered that overall air temperature and humidity did not change. What did change was the amount of energy reaching the surface. As a result, they found that trees were more productive for longer during the day under the netting, with photosynthe- sis occurring a little longer into the day past noon. In addition, while leaves can tran- spire to regulate their temperature, fruit doesn't have that ability, resulting in sunburn. The research showed that the fruit surface temperature was only 7 degrees Fahrenheit higher than the air temperature under the netting, com- pared with 20 degrees higher outside. The result: In 2015, between 5 and 8 percent of the fruit underneath the netting experienced sunburn, compared with 25 percent of the fruit outside the netting. No evaporative cooling was applied. In 2016, although the incidence of sunburn was reduced in the control through evaporative cooling, sunburn severity was still reduced in the netting compared to evaporative cooling. The soil also absorbs a lot of energy, and Kalcsits said the researchers were SHANNON DININNY/GOOD FRUIT GROWER A control block without netting, above, shows poor return bloom compared with a block under blue netting, at left.