Is Wheat the Best Crop to Grow in a Dry Year?

Significant areas of Alberta and Saskatchewan have had below average snowfall following an unusually dry 2001. Deciding which crops to grow on which fields, is based on production costs, crop price, rotational considerations, erosion protection and production risk. Production risk is higher in a dry spring, so some producers who have diversified into oilseeds and pulses may be considering a move back into a cereal summerfallow rotation. Researchers at the Semi-arid Prairie Agricultural Research Centre (SPARC) in Swift Current have taken a new look at some long-term data to help assess producers' options.

The relationship of crop yield to water use has been studied for many years. When SPARC's yield data was combined with Saskatchewan Agriculture and Food's estimates of crop production costs and price outlooks, the result was an interesting perspective on production risk by looking at net return. Production costs considered included seed, fertilizer, pesticides, machinery operating and machinery overhead. Land, financial, management and labor costs were not included.

Water use at the break-even point can be used as an indication of production risk, with lower water-use values indicating lower risk. It ranged from 105 mm for field pea to 165 mm for Kabuli chickpea (See graph). Durum wheat required an extra 30 mm of water to reach break-even yields when compared to spring wheat. However, durum's net revenue curve rises more steeply, indicating more profit potential than spring wheat for each increment of additional moisture. Similarly, oriental mustard required an extra 30 mm of water to break even compared to canola, but also has a steeply rising profit curve under better moisture conditions.

These curves represent the average production at each moisture level. However, there can be a considerable range of actual production, depending on temperature and rainfall distribution in the growing season. In addition, because research was conducted in the Swift Current area, it does not represent conditions in the Black Soil Zone.

Despite these limitations, this analysis suggests that switching to cereals does not reduce production risk. Field pea, lentil, canola and desi chickpea offer similar net return curves, although all are more costly to grow than wheat.

There is risk in either choice. If drought hits and crops fail, the lowest cost one B wheat B loses the least money. If the weather changes, wheat has the lowest potential to turn the rainfall into revenue. Producers who have been successfully diversifying their cropping and extending their rotations over the past several years may not get the risk reduction they are looking for with a major shift back towards cereal crops and summerfallow. Summerfallowing in a dry year does not store much moisture.

Whatever crop is chosen, establishing a good, well-nourished stand as quickly as possible is as important in a dry year as in normal conditions. It is important to use what little moisture is present to grow the crop. Early seeding will take advantage of any moisture accumulated over the winter, and avoiding tillage reduces evaporation losses. Under-fertilized crops grow slowly, allowing valuable moisture to be lost through evaporation. They also compete poorly with weeds.

There is still time for significant precipitation to improve crop prospects, and producers are unlikely to make major changes in response to a one or two-year drought. However, if they believe the climate has become drier, then crop practices and choices will adapt.