Even though farmers in the Pacific Northwest won’t feel the effects of climate change as much as their counterparts in southern regions, they will need to adjust their cropping strategies.

The University of Idaho is in year four of a five-year project to study how changes in temperature and precipitation projected to happen in the next 30 to 50 to 100 years will impact cropping practices in the Pacific Northwest, particularly dry land wheat production areas.

“We’re starting to get robust results,” said Kristy Borrelli, University of Idaho extension specialist in charge of the Regional Approaches to Climate Change (REACCH) project. One of those findings is that management decisions may be able to override some of the impacts from climate change.

“Farmers are used to adapting to changes season-to-season or even within a season,” she said. “They are used to handling risk factors, they make different decisions based on what they know or see.”

They’ll need every bit of that adaptability to adjust to a climate that is projected to be warmer and also wetter than what is considered normal today.

During a presentation during the Far West Agribusiness annual meeting in Twin Falls, Borrelli talked about trends rather than specific increases in temperature or precipitation. Numbers can vary between models used by scientists based on assumptions, but all of the models used by scientists from the three universities and one federal research agency involved in the project agree that temperature is likely to increase in the next century.

Precipitation is a harder to predict, but is likely to increase slightly. What producers will definitely notice is when that precipitation falls. Precipitation amounts in late winter to early spring are likely to increase by 17 percent while late spring and early summer rains will decrease by 14 percent. That is likely to reduce the amount of irrigation water available at the same time irrigation demand is expected to increase by 4 percent.

Water users are already starting to see that shift occur. According to data collected by the Agriculture Research Service in Boise, 54 percent of the precipitation that fell in the Reynolds Creek basin fell as snow in 1984, compared to just 4 percent in 2009.

Farmers are already placing a greater emphasis on building soil organic matter to reduce wind erosion and improve soil quality, but the practice that can help crops weather dry conditions better. Borrelli said research in the PNW has shown that farmers who managed for increased organic matter did not suffer as large of yield losses during drought as those who didn’t.

Once consequence of warmer temperatures is that region is likely to be frost-free for 40 to 60 days longer each year. Under that scenario, planting a few weeks earlier may allow a crop like wheat to mature before temperatures get hot and fields dry out.

Agriculture is the second largest contributor to the greenhouse gases that are largely blamed for climate change. Dave Huggins, a soil scientist with the Agricultural Research Service in Pullman, Wash., said plowing up prairies in North America, Australia and the Soviet Union between 1850 and 1950 released carbon dioxide that had been trapped in organic matter. Organic matter is 58 percent carbon dioxide.

But higher carbon dioxide levels can also benefit crops because plants will use it as a fertilizer. That fertilization helps boost yields and can offset some of the negative factors from climate change, Borrelli said.

Under scenarios studied by researchers that included three sites with different soils and climatic conditions, winter wheat yields increased by 25 percent when producers selected different varieties and planted earlier compared to a 10 percent increase with climate change alone. But potato yields decreased 10 to 36 percent even when management decisions and carbon dioxide fertilization are accounted for.

She cautioned growers to be careful when looking at results from climate change studies, reiterating that trends — not absolute numbers — are more reliable. A one-stop website highlighting the REACCH project results will be up later this spring.

Even so, members of the audience took umbrage with some of the assumptions made by project cooperators. Adrain Arp, Jerome, pointed out that blaming carbon dioxide for climate change is driving up energy costs for agriculture, an industry that is highly energy dependent.

Borrelli said the purpose of the study is not to convince every one that climate change is real but to help educate producers about what might happen so they can better handle production risk in the future.

“Can we find better ways to grow crops more efficiently using less water,” Borrelli said. She said she believes the answer is yes.

Scientists from Washington State University, Oregon State University and the Agriculture Research Service are cooperating in the $20 million project that was funded by the National Institute for Food and Agriculture.

Source - http://magicvalley.com/