Increasing grain prices may once again make cropping of marginal lands economic. Unfortunately many hayfields that were sown back to grass are susceptible to erosion. Marginal lands are due to such factors as salinity, topography, fertility, and stoniness to name a few. Each of these factors pose unique problems in cropping. However, from a conservationist point of view it is important to keep cover on these lands at all times. The purpose of this article is to outline ways in which to keep erosion to a minimum on these soils.
In the past forage lands were worked several times in the year to kill the existing vegetative stand. This practice took the field out of production for one year. The field also required 7 to 8 tillage passes to kill the forage and prepare a decent seedbed. However, there are more options available today. The use of Roundup to kill the stand followed by direct seeding is a cheaper and more cost effective way to bring a forage stand back into annual cropping. Similar to direct seeding, there are a number of management steps that will allow the success of this transition.
Firstly consider the type of forage present, smooth bromegrass and alfalfa are difficult to kill completely with one pass of glyphosate especially if reduced rates are used. Timing is also critical to achieving good control. One cannot expect to spray in the spring, seed the following week and grow a profitable annual crop. The best time to spray with glyphosate is before the first cut of hay with the recommended rate and if there is a lot of second growth is to do a follow-up spray in mid-August. This will allow some of the sod to break down and the soil should store moisture for the next growing season.
Understand that when the sod is breaking down, it ties up nitrogen that will not be available to crop. To remedy this increase fertilizer rates by 10 to 20 lbs of N per acre in the first cereal crop following the year of herbicide application.
One should also choose a competitive cereal crop like wheat or barley for the first crop to further weaken any remaining forage plants. Choosing a cereal will also permit the use of a broadleaf herbicide to control any alfalfa regrowth. With smooth bromegrass, a preharvest application of Roundup will be required to further control this grass.
Any direct seeding machine will do an adequate job of seed placement into forage stands killed by herbicides. However, hoe or shank openers may pop more rocks onto the soil surface, requiring a rolling or stone picking operation. If herbicides are to be used to control forage stand always consult the 1995 Crop Protection Guide for products and registered uses. This Guide is Available at Rural Service Centers throughout the province.
Marginal lands can be brought back into annual crop production safely and without fear of soil erosion by employing the use of herbicides and direct seeding management. For more information on how to apply this to your farming situation contact your Regional Soil Conservationist.