By Lorne Klein
Regional forage specialist, Weyburn office
Saskatchewan Ministry of Agriculture
In some areas of the province there has been a noticeable increase in soil salinity over the last five years. The increase is partially due to the above average growing season rainfall. In some cases the salinity has been compounded when fields were not cropped due to excessive moisture.
Salinity is easily noticed in early spring when conditions are dry. On severely affected sites there will be a white layer of salt on the soil surface. Severe salinity commonly develops along road allowances and along the margins of wetlands and water courses.
Fall harvest is a good time to evaluate the extent and severity of salinity. The salinity rating is severe on areas dominated by foxtail barley, kochia or bare soil. Continued attempts at annual cropping these areas have little chance of success and will likely allow the situation to worsen and expand. Consider the good producing acres you have to harvest just to break even for the costs of cropping the saline areas with no crop. Land managers commonly mow and cultivate or disc these areas, adding more costs with little chance of returns.
Where severe salinity occurs on the margins of fields, sloughs and water courses with permanent vegetation, the best option is to seed the areas to saline tolerant perennial forages and swing wide with your annual cropping equipment. You will be annually cropping fewer acres and be more pro? table!
The more difficult decision is when small saline pockets occur, scattered throughout annual cropland. With today’s large scale equipment, driving circles around small pockets of saline soils is not feasible.
Saline tolerant perennial forages include slender wheatgrass, smooth brome, tall wheatgrass, tall fescue, western wheatgrass and AC Saltlander. Mixtures that include AC Saltlander will have a small amount of downey brome. Monitor the site for downey brome and pick plants to avoid spreading seeds to other areas. Include alfalfa and sweet clover as legumes in the mix.
Be patient after seeding severely affected sites. It can take a decade and more for preferred plant species to establish and dominate. There are examples where native plant species with extreme saline tolerance get started, spread and now dominate the site after decades. Mowing or cutting the stand each year tends to slow the establishment of the beneficial species which have the ability to dominate the weeds.
Some land managers have spread excessive amounts of manure on saline areas. Saline soils are often already rich in nutrients due partially to the lack of previous crop production. Relatively small amounts of manure (one inch thick) applied prior to seeding may help with perennial forage establishment.
Fall is a good time to map out severely saline areas and commit to seeding them to perennial forage. You will be cropping fewer acres and minimizing the spread of the salinity.
By Lorne Klein