VAUXHALL, Alta. – Soil conservation farming is dominating dryland agriculture in Alberta and Saskatchewan and Frank Larney feels irrigated agriculture in southern Alberta has some catching up to do.
Irrigation, with its water management capacity, has opened up the crop rotation selection for hundreds of farmers on about 1.5 million acres in district and private projects.
Many of those new crops come with little or no protection for the valuable soil resource, especially in southern Alberta where strong westerly winds and cyclical drought put farmland at risk of severe erosion.
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Larney, who is the assistant section head for land resources at Agriculture Canada’s Lethbridge Research Centre, is getting a grip on rotations that could reduce the erosion risk for irrigation land through a research project near Vauxhall.
“There are a few more barriers to adapting conservation tillage for irrigation,” said Larney.
“For dryland soil conservation, it is mostly a case of keeping the stubble up, keeping trash on the surface of the soil.”
Irrigation promotes production of alfalfa and other forage crops, which are usually maintained on a field for up to seven years, affording ideal soil protection. However, many of the specialty crops allowed by irrigation are row crops that tend to leave the soil’s surface in a cultivated state and bare of plant material in the fall.
Larney said the biggest potential erosion problem comes following production of sugar beets, potatoes and beans because the root crops must be dug out of the earth, disturbing the surface, while beans must be cut loose of the soil, which also disturbs the surface.
“For potatoes, there is a potential the soil will remain unprotected from harvest in September to the following spring,” Larney said.
“For beans, it could be September to the following Victoria Day when the soil is exposed.”
However, science is coming to the rescue.
Henning Mundel, a bean breeder at the research centre in Lethbridge, has developed AC Red Bond, an upright bean variety that works well on narrow spacings, which allows farmers to gain earlier soil protection from the growing plant. As well, because the plants are harvested with a normal combine and aren’t being ripped loose from the soil, a stubble remains.
Chemicals are used to control weeds because the rows are too close together to allow cultivation, another major factor in reducing erosion.
Larney said his crop rotation involved potatoes in the spring of 2004. That fall, he planted fall rye as a cover crop and just before spring seeding this year, applied Roundup to kill the rye plants and leave residue on the surface. He later direct seeded AC Red Bond beans. He left the plant residue this fall rather than seed a cover crop.
The next crop will go on protected soil in the spring.
Manure application is another possibility. It can either be raw manure or composted.
The problem is that most irrigation farmers don’t run cattle, which means finding a source of manure or buying composted manure.
He said the manure doesn’t take the place of other soil-protection techniques such as plant residue, but it does help boost the organic matter of the soil and complements fertilizer applications as a soil amendment, all which helps prevent soil erosion.
