Farmland under summerfallow continues to decline—to fewer than six million acres last year compared to nearly 20 million in 1991. And this trend is expected to continue.
Frank Larney, a research scientist with Agriculture and Agri-food Canada, lists many reasons for the decline. The past few decades have seen increasing awareness of environmental concerns and the need for soil conservation measures, he explains.
Summerfallow and its associated tillage practices have long been known to cause loss of soil organic matter, nitrogen and soil moisture, and in some cases, increases in soil salinity. Summerfallow also makes soil more susceptible to wind and water erosion, adds Larney. Blowing soil can carry nutrients and herbicides into waterways leading to water quality problems. Larney’s research has found that wind erosion can result in herbicide losses up to 30 times greater than losses due to water erosion. Wind erosion also negatively affects air quality.
The realization that traditional cultivation and summerfallowing makes inefficient use of rainfall and leaves soil susceptible to erosion spurred research into conservation management practices as well as engineering advances by agricultural machinery companies. As a result, soil and crop management has been revolutionized over the past few decades.
Across Canada, more producers are adopting low-disturbance and zero-till cropping practices that protect the soil and improve soil quality. Eliminating or reducing tillage raises yields and lowers production costs. Additionally, reducing summerfallow and tillage cuts greenhouse gas emissions by sequestering carbon in the soil.
“We have moved away from cropping systems that involve monoculture cereal production, frequent summerfallowing and the extensive use of mechanical tillage for weed control and seedbed preparation,” says Stewart Brandt, a soil and crop management specialist with Agriculture and Agri-Food Canada. Today, he adds, the focus is on conservation farming practices — minimum till, zero till and direct seeding. Improved synthetic fertilizers and herbicides have also reduced the need to summerfallow for nitrogen release and weed control, especially in the black, grey and wetter parts of the dark brown soil zones.
“Coincident with the adoption of direct seeding and reduced tillage practices, we have diversified what we grow by moving from a monoculture cereal, primarily wheat, cropping system to more diverse and extended crop rotations,” says Brandt. Crop diversification allows growers to increase cropping frequency and reduce summerfallow.
Research indicates that on most soil types diversified crop rotations provide higher and more stable net farm income than monoculture rotations. Additionally, soil quality can be significantly improved with the adoption of direct seeding and more continuous cropping using diverse crops in the rotation.
Expanding markets and commodity prices are also providing incentives for producers to reduce summerfallow and put more land into production. In Saskatchewan, for example, there has been a rapid and vast increase in land sown to specialty crops over the past few decades, largely because of market developments both within Canada and abroad.
New crop types and varieties, which allow for no-till direct seeding, provide opportunities for new and expanded markets as well. Some use moisture and nutrients more efficiently, have increased yields, and better disease and insect resistance, explains Brandt. For example, the recently developed Brassica juncea is better adapted to the semi-arid brown and dark brown soil zones, providing producers in these areas with another crop option and the possibility of new markets.
Additionally, the economics for conventional summerfallow, just aren’t there, says Larney. Fuel costs with summerfallow are higher by as much as 40 to 60 per cent than with direct seeding. Direct seeding and less tillage also have reduced costs associated with equipment repairs and maintenance, as well as reductions in time and labour requirements.
The loss of crop income in the fallow year is another reason for the reduction in summerfallow acres, especially in the moister soil zones and during wetter years.
All said, it’s a combination of many factors and developments over several decades that has lead to the decline of the once widely promoted agricultural practice of summerfallowing. The result has been more profitable and sustainable farms. FF