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Get your farm ready for global warming

Agronomy management: How can you adapt your Prairie farm to changing climate conditions in the years to come?

Many Prairie farmers have gradually come to accept that global warming is real. Over the past 60 years, our Prairie climate has been gradually changing. In most regions of the Prairies the length of the growing season has increased, the amount of heat (growing degree days and crop heat units) has increased and the number of days about 25 C during the growing season has increased.

Prairie farmers must become “climate smart” to gradually adapt and adjust how they farm to continue to be successful.

What is changing?

Crop production has and will continue to be affected as the climate continues to change. The magnitude of climate impact on crop types that can be grown and crop yields will vary depending on your local climatic differences. Climate change will influence many factors that affect crop growth and yield.

Typically, Prairie farmers can expect longer growing seasons and milder and shorter winters. Southern and central Prairies will likely see more warming than other regions. Most regions will have longer frost-free growing seasons, but will also have increased evapotranspiration (crop water use requirement + evaporation). Expected higher temperatures may either enhance or negatively affect crop yield.

The greatest unknown is precipitation. If climate change results in increased growing season precipitation, higher crop yields can be expected. But, if growing season precipitation is lower, crop yields will be negatively affected.

Overall, warmer spring-summer air temperatures and longer growing season conditions will likely benefit crop production across the Prairies. Farmers can adjust by growing crops that require a longer growing season and/or require more crop heat units. This could be very beneficial for irrigation farmers and dryland farmers that continue to have adequate growing season precipitation. But, the combination of higher summer temperatures and longer growing season will negatively affect dryland farmers in drier years — particularly in drought years.

Warmer temperatures can mean increased crop water demands and if growing season precipitation declines, this will cause lower crop yields. This will be a greater concern where water stress is already a problem in the brown and dark brown soil zones of the southern Prairies. Hotter weather at flowering can cause negative effects with crops such as pea or canola, reducing yield potential.

Carbon dioxide (CO2) in the atmosphere has increased from 300 ppm (parts per million) in 1960 to over 400 ppm now. Increased CO2 is expected to increase crop growth but this may not translate into higher crop yields. Warmer temperatures and increased crop water demands may counteract CO2 benefits to depress crop yields.

Adequately fertilized crops are expected to respond more positively to higher CO2 in the atmosphere, than crops with reduced fertilize inputs. Increased CO2 is expected to positively affect C3 crops (e.g. wheat, barley, canola, soybean). But, contrary to popular belief, C4 crops (e.g. corn and sorghum) are expected to be less responsive to increased CO2 to levels in the atmosphere.

Changing climate will impact crop disease and insect pressure. Wetter conditions will likely increase disease pressure, but drier conditions may reduce disease pressure. Milder winter conditions will likely increase populations of some insects such as the cabbage seed pod weevil that affect canola and pea leaf weevil that affects peas and fababean. Drier spring and summer conditions could increase problems with grasshoppers and the wheat stem sawfly. Shifting concerns with diseases and insects will mean farmers must be even more vigilant in scouting for problem insects and diseases and using control when necessary. The pressure will be on our plant breeders to develop more tolerant and competitive crop varieties. Pesticide companies will need to continue to develop new products to control insects and diseases.

Farmers must become “climate smart” about adapting their cropping programs. Agronomy research will be needed as climatic conditions gradually change. Adaptation research must be undertaken to better understand climate change impacts on each crop type grown in each major agro-ecological area of the Prairies.

Researchers, agronomists and farmers will need to understand climate change implications on crop production over the short term and the long term. Each year, short-term adaptation by farmers must consider the local climate trends and look at weather forecasts ranging from daily to the full growing season.

For most farmers, long-term climate projections are still highly uncertain and difficult to plan for. The likelihood of further changes occurring, and the increasing scale of potential climate impacts, means Prairie farmers will need to be proactive, closely watch research results and be prepared to gradually adapt agronomic practices.

Here are a couple of questions to consider: What adaptation options should be considered for moderate climate change for your farm cropping system? What are some of the crops and agronomy planning you can consider in the near future?

Crop planning for climate change

Consider increasing the diversification of crops you grow.

Over the past 40 years, Prairie farms have become more specialized. Making your farm more diverse to perhaps include cattle and grow grass for hay and pasture on a part of your farm might be a consideration. Putting your poorer land back into grass for hay and grazing could result in improving soil quality and increase the diversity of your farming operation.

Consider growing additional crops to account for a more variable climate. Consider growing several cereal crops and pulse crops in your rotation with canola. More diverse crops will help to disrupt insect and disease cycles. Including pulse crops can help to improve soil quality and reduce nitrogen requirements. Consider growing longer-season crops such as corn or soybeans, if your growing season length, amount of crop heat units and growing season precipitation are suitable for these crops. If you’re concerned about drier conditions, consider growing one or more crops that tolerate moisture stress, such as mustard, or grow crops with a lower water use requirement such as pea.

Using soil moisture conservation practices will become increasingly important in the drier regions of the Prairies. No-till, direct seeding and seeding earlier to conserve soil moisture will be essential management practices. Ultimately, farmers will need to produce more food with less water!

Water conservation will become just as important for irrigation farmers. Reduced snow pack is expected in the Rocky Mountains, which will reduce water available for irrigation. It is expected that within the next 30 years most glaciers in the mountains will disappear, reducing water flow in the Bow and South Saskatchewan Rivers. As the urban population on the Prairies continues to grow, there will be increased water demand and conflict, which could further reduce water available for irrigation.

Short-term crop planning

There are several agronomic practices you could use to adapt to our changing climate.

1. Soil moisture conservation. In regions where moisture is limiting, be sure to use no-till, direct seeding to conserve as much moisture as possible for crop growth, to offset warmer, drier conditions.

2. Earlier seeding. With milder winters and slightly longer growing seasons, seeding a bit earlier is an easy adjustment that does not increase your costs. Earlier seeded crops often have a yield advantage over later seeded crops. But, when seeding earlier, plant crops like wheat, barley or peas first than can withstand late spring frosts.

3. Add a winter cereal to your rotation. Milder winters make winter cereal production more viable. When winter wheat is seeded at the optimum time in early fall, it will often out-yield spring wheat by up to 20 per cent or more. This will increase diversity of your crop rotation and will take advantage of early spring moisture.

4. Add a pulse crop to your rotation. Adding a pulse crop will help to improve soil quality, reduce nitrogen fertilizer requirements and add nitrogen to the soil for the next crop. A crop like pea has a lower water use requirement, is shallower rooted and will leave more subsoil moisture for a subsequent crop. Look at all the pulse crops to see which ones would be a good fit for your farm.

For me, the science on climate change is absolutely clear — our climate is changing. “Climate smart” farming is becoming increasing important for Prairie farmers. Adapting our cropping practices with our changing climate is essential to ensure our Prairie agriculture remains economically and environmentally sustainable.

About the author

Columnist

Ross H. McKenzie, PhD, P. Ag., is a former agronomy research scientist. He conducted soil and crop research with Alberta Agriculture for 38 years. He has also been an adjunct professor at the University of Lethbridge since 1993, teaching four-year soil management and irrigation science courses.

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