The meltdown in the cattle industry coupled with high grain prices have many producers wanting to switch hay and pasture land into annual crop production this spring. While some producers have done this successfully, it appears to be a very high-risk gamble at best.

Nick Underwood, an agronomist with Reduced Tillage Linkages in Alberta, has been asked this question many times this spring. His answer: "Don’t do it! Everything is going against you and you are setting yourself up for a failure."

Key to any successful cropping system is controlling the growth of non-crop species. When seeding into sod, growers must somehow control very hardy perennial species. Underwood says spring is the worst time of the year to control perennials. "First, you need a minimum of four to five inches of new growth for a glyphosate product to work, which likely going to delay seeding. Second, in the spring the movement of nutrients within a perennial plant is upwards, feeding the above ground growth. As a result, you get poor translocation of glyphosate and you may not get a good kill of the root, so regrowth becomes a problem."

Underwood says you also need to consider the power required to physically seed into sod. "The draft requirement is huge. Power requirements goes up two or three times when trying to seed into growing or recently sprayed sod. Many growers have found they simply do not have the power to pull an air drill through sod that has not decomposed."

Finally, Underwood says sod that has not decomposed generally makes a poor seed bed. Seed to soil contact is often poor because the soil does not flow back into the seed trench. Penetration is often uneven so seed depth varies. Sod often has higher disease pressure and lower fertility, so seed treatment costs and fertilizer costs are higher. To Underwood, these higher costs coupled with the very real risk of poor yields makes trying to seed into sod that has not been sprayed out the year prior a very big gamble.

On the other hand, Ken Stewart of High Prairie, Alta., has taken grassland out of production in the spring each of the last four years. This spring he intends to direct seed into 1,200 acres of grassland. Stewart admits seeding into spring-killed sod is a high risk cropping option but it has worked for him.

Stewart agrees grass control is very important. He applies at least the equivalent of 1.5 litres per acre of Roundup Original (434 grams of active ingredient per acre). If there is alfalfa in the stand, he will use Eclipse or another product or tank mix to get better control of the alfalfa.

"You need good growth of the grass to achieve control so timing of spraying and seeding can be a big issue in the spring," Stewart admits. Since Stewart’s land is typically very wet in the spring, seeding tends to be later anyway. As a result, the grass is often at the spraying stage by the time Stewart is able to get onto the land. In fact, sometimes the sod is the first thing he seeds into in the spring as his stubble is too wet. If the grass was not ready for spraying when he needed to seed, Stewart has even occasionally direct seeded into the sod and then sprayed out the grass before the crop emerged.

Stewart seeds with a John Deere 1895 coulter drill. The coulter and disk openers penetrate well and give consistent depth and good seed to soil contact.

Stewart prefers to seed a Roundup Ready canola variety so he can apply a couple of passes of glyphosate in crop. The in-crop application of glyphosate assists in controlling any grass regrowth. Because his land tends to stay wet in the spring, Stewart always plants a hybrid RR canola variety. He feels the fast growing hybrids will use the excess moisture better than OP varieties. He also selects the earliest hybrid to compensate for the later seeding date.

"If you are going to try to spray out sod and seed immediately, don’t skimp on spray or fertilizer,” he says. “You have to get good control of the grass and you have to give the growing crop all the nutrients it needs. Sod fertility is likely going to be low so your fertilizer rates are going to be high." Stewart soils tests grassland before seeding and applies all the fertilizer that is called for. Even though sod seeding is very high risk, Stewart does not try to cut inputs in case the crop does not establish.

 

The forage specialist 

Calvin Yoder, forage specialist with Alberta Agriculture, does not endorse trying to spray out sod in the spring and immediately seed, but he recognizes that the respective grain and cattle prices will push some growers into attempting to do so this spring. "Whereas spraying out the sod in the fall and seeding the next spring will always work, trying to spray out and immediately seed in the spring is a lot more risky and there will be failures."

Yoder says the chance of successfully converting grassland to a cash crop in the spring depends on a number of factors. "The type of sod you are seeding into is the first consideration. Timothy is much easier to kill than other grasses or legumes so your chance of success is higher. Older stands will be much more root bound, more difficult to kill, and tougher to seed into than newer stands. And grassland from seed production will be easier to seed into than hay or pasture land."

Yoder says, “You must delay the spray operation until the grasses are actively growing and you must apply enough glyphosate so the grasses will be killed."

Disk type seeding implements penetrate sod better than hoe openers and you get better soil to seed contact, he adds.

And the crop you seed is important. “When seeding into timothy sod, Roundup Ready canola is the choice of most growers. The in-crop glyphosate application will suppress timothy regrowth. As well, timothy sod is not as root bound and hard, so the seed bed is a little more forgiving and the small canola seeds have a better chance than in a more dense sod," Yoder says.

"If you are seeding into a mixed grass or grass-legume stand, cereals are probably a better choice. Oats is likely the most forgiving crop and will increase your chances of success. Still, there are no guarantees when trying to direct seed into recently killed grassland.

 

5 tips for better success 

You are best to spray out a forage stand in the fall, but many of you will endeavor to take advantage of high grain prices and take out a forage stand this spring. The odds are stacked against you, but these steps will help:

 

1.                Spray after the perennial grass is actively growing, otherwise you won’t get any uptake or translocation.

2.                You will have more success seeding into a grass crop such as timothy, and the younger the stand, the better.

3.                Short-season Roundup Ready canola gives you a chance to apply glyphosate in-crop to keep the grasses
                   back. The short-season crop gives you time to spray the grass ahead of seeding. If you are seeding into a
                   mixed hay stand, Calvin Yoder says oats are a better choice.

4.                Use a low disturbance opener so you can penetrate the living root masses. Even then, this will be a much
                   harder pull for your tractor. Ken Stewart uses a coulter disc drill.

5.                Ken Stewart says don't skimp on fertilizer.

 
Source: April 7, 2008 issue of Grainews - reprinted with permission