With temperatures continuing to climb, how does heat impact crops?

• By Olivia M. Miller/LNP | LancasterOnline

Lancaster County is sweltering this week with the temperature and humidity skyrocketing, but not all crops are suffering under the extreme heat.

Andrea Martin, co-owner of Brecknock Orchards, said Monday afternoon that hot, dry weather is better for fruits if they have an irrigation system.

“The water can go right to the root and keep the fruit dry,” she said. “Dry weather is good at keeping insects and fungus off of the trees and fruit.”

This time of year, the orchard’s irrigation system operates 24/7, constantly moving between plants, Martin said, adding that keeping the fruit hot and dry makes it taste sweeter.

Martin said these produces include peaches, nectarines, blueberries, blackberries, raspberries, zucchinis, onions, cucumbers, eggplants, peppers and flowers.

“Even in flowers, flowers would respond … the same way when there’s wet weather, they’re more susceptible to fungus, don’t hold up as well in a vase,” she said. “Whereas with the dry weather, it’s much better for them resisting fungus.”

Monday marks the county’s fifth day into the second heat wave of the year, with a high of 95 degrees. A heat wave is three or more days in a row of at least 90-degree temperatures.

The National Weather Service extended Monday’s heat advisory until 8 p.m. Tuesday, and a code orange air quality alert was extended to midnight Tuesday.

As of July 2, parts of central Lancaster County are under moderate drought conditions, and the rest of the county is abnormally dry, according to the U.S. Drought Monitor. Abnormally dry conditions are the stage going in or coming out of drought.

According to Millersville University’s Weather Information Center, the year-to-date rainfall through Sunday is 20.16 inches; zero of which fell so far this month. The normal year-to-date precipitation is not much higher at 20.95.

Looking ahead, Tuesday is predicted to have a high of 97 degrees with heat index values as high as 105, the NWS said. Wednesday’s high is only slightly lower at 95 with a similar heat index, and Thursday’s lower still at 91. Each day, there’s a chance of precipitation and thunderstorms.

Despite being on the radar, Kyle Elliott, director of the weather information center, said the county shouldn’t expect to get a lot of rain this week.

“Honestly, we’re probably just going to be left with some isolated showers and thunderstorms here Wednesday afternoon and evening,” he said.

When it comes to field crops, such as corn, soybeans and hay, it’s too soon to say how much this week’s heat will impact the yield, according to Leon Ressler, an agronomy educator with Penn State Extension.

One factor is uneven rainfall across the county in recent weeks, Ressler said.

“Some of the northern part of the county has had less rain than some of us on the southern end,” he said. “So those who miss some of those critical rains are in much more serious trouble than those of us in the southern part of the county where we had a little more rain.”

Ressler said the other factor is the crops’ stage of development, explaining how these crops are planted over months.

“For later planted corn that isn’t pollinating yet, that crop can wither dry weather and temperatures a little better,” he said. “But for the earlier planted corn that’s actually pollinating right now, that could be a serious yield impact.”

“Any drop of rain we get, we’d greatly appreciate it as this point,” Ressler said.