Climate Effects on Crops
Modeling done by the Scripps Institution at the University of California, San Diego indicates that temperatures in Yolo County are likely to be 1.3°C-2°C (2.3°F-3.6°F) hotter in 2050 regardless of the extent of greenhouse gas mitigation efforts, and between 2.3°C-5.8°C (4.1°F-10.4°F) hotter in 2100 depending on the success of emissions reduction efforts. Precipitation is likely to remain the same through 2050 and to decline slightly toward the end of the century. This highlights the need for information on how specific crops may be affected and for adaptation strategies which are crop and location specific. Interestingly, the changes in climate mentioned above suggest that by the latter half of this century Yolo's climate will likely resemble Merced County, CA. This rough comparison means that local producers may be able to look south for ideas on what strategies and crops might be suitable for Yolo in the decades ahead. Below we give a few specific examples.
Installing buried drip irrigation. Photo courtesy of Gene Miyao.
By the end of the century, yields from some orchard crops are expected to decline due to insufficient chilling hours in the winter. Higher summer temperatures are also likely to decrease yields of walnuts and table grapes. Almonds may benefit from a decline in winter freezes, as will citrus and olive production. Warm-season horticultural crops (tomatoes, cucumbers, sweet corn, and peppers) are likely to be less viable in Yolo County by 2050, prompting a shift to hot-season crops such as melon and sweet potato. A switch to higher cash value crops with greater income per amount of applied water is expected. Grain growth will benefit only very slightly from elevated carbon dioxide concentrations, and wheat, barley, corn, and rice will be vulnerable to heat waves during their reproductive phase, lowering yields.
Climate change may also lead to a northern migration of weeds, diseases, and pests due to warmer winter temperatures. One example of how this may already be occurring in Yolo County is the recent outbreak of alfalfa stem nematode. Investment in technology, plant breeding, and cropping system research will result in less yield loss, higher yield reliability, and greater agricultural sustainability. In addition, research is needed on responses to simultaneous increases in temperature and carbon dioxide levels and on the implications for stomatal closure, growth declines, and effects on water use efficiency so that crop breeding stays one step ahead in coping accurately with environmental change.
Higher temperatures during the summer is likely to reduce livestock productivity and the supply of irrigated forage crops.
Mariani Nut processing plant. Photo credit Susan Ellsworth.
Several potential adaptation and mitigation strategies for climate change by growers are being researched. These strategies include:
- Changes in crop mix
- Irrigation strategies
- Fertilizer use
- Cover cropping
- Conservation tillage
- Manure management
- Carbon sequestration in tree crops and vines
- Organic production