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ISU field day featured cereal rye cultivars

By Staff | Jun 9, 2017

A roller crimper is a no-herbicide mode of terminating rye in a cover crop program.



AMES More growers are showing interest in utilizing cover crops in their production systems. many times seeded to cereal rye.

To assist producers in making their seed choices for cereal rye, Iowa State University Extension researchers have developed a study on different cereal rye cultivars.

At a field day hosted by ISU recently, Ajay Nair, assistant professor in the Department of Horticulture at ISU and Kristine Neu, a PhD student at ISU showed the different cereal rye cultivars planted at the horticulture research farm which includes Aroostook, Elbon, Wheeler and Wrens Abruzzi as well as a demonstration on terminating the cereal rye with the use of a roller crimper.

A cereal rye cultivar field day was held June 1, at the ISU Horticulture Research Station, near Ames.

Neu said the research project is in its second year.

“The whole purpose of this study is to trial cultivars of cereal rye and see if it actually makes a difference on what cultivar of rye you are planting,” said Neu.

Nair said the majority of growers may not know what it is they are growing for their cover crops.

“Most of the time the local suppliers it’s a lot of variety not stated, so you’re not sure what you are getting,” he said.

One of the main focuses of the field day was educating the crowd on when to terminate the rye using a roller crimper based on the productive phase of the cereal rye.

“We focus on anthesis, because when you are killing rye with a roller crimper you have to make sure the rye hits anthesis, otherwise it won’t die,” said Nair. “It will keep coming back, you have to wait until the rye comes to the productive phase then you roll it down.”

Nair said anthesis, which is the productive phase in winter grasses such as cereal rye is triggered by two things: winterization and day length. Nair added that if the cereal rye is not put in to winterization, it will not flower and hit anthesis.

“If you plant in the spring, it won’t flower,” he said. “It will remain in a vegetative stage.”

The second part of the growing stage of cereal rye to get it to anthesis is day length.

“Cereal rye is a long day plant,” said Nair. “As soon as the long day requirements have been met, it will go in to anthesis. Trigger of day length, not temperature. Time of plant to get to its productive phase is dependent on day length, so rye is a long day plant.”

Typically for this region, Nair said seeded rye will come to anthesis in around the 15 to 18th of May, regardless of the planting date in the fall. The cultivars were planted last fall with some in September and some in October and they all hit anthesis at about the same time.

“We are growing rye to produce as much biomass as we can and we mainly wanted to focus on cultivars that have adapted to our region, anthesis wise, that although they were planted a month a part, anthesis time only varies five days, not much difference even though they were planted one month a part,” said Nair.

“Not everything will hit anthesis at the same time, but eventually, in a matter of two to three days, everything will be hitting anthesis and that is the time to roller crimp,” said Nair. “From the time it hits anthesis, I would not wait more than two weeks, because the last thing you want is the rye to go to see. We try to do it within a one week period. It hits anthesis and in one week we will crimp.”

Nair said when there are dust of pollen and anthers sticking out and the pollen is starting to fly, that is how to tell when the rye has entered anthesis.

Neu warned of roller crimping rye too soon.

“We had a producer tell us he crimped the rye too soon and a storm came through and picked it back up again, putting that producer right back to where he started,” said Neu.


Neu said they will measure biomass at anthesis and at the field day, she explained they had collected biomass samples and will come back later in the summer and collect more samples for tests to try to gauge any differences on how these different cereal rye cultivar’s mulches are suppressing the weeds.

“It’s better to go to a known cultivar which have a proven track record of the amount of biomass they can produce and the time frame of when they hit anthesis,” Nair said. “We want more biomass and earlier anthesis. We want growers to move away from using cultivars where they do not know the variety.”

Seeding cereal rye

At the research station, Nair said they prefer to drill the seeds over the method of broadcasting seed, but stated broadcasting does work well for when it is time to get the cereal rye seeded in the fall in to standing crops.

“With a drill, we ensure things are nicely seeded, seed to soil contact is good and they germinate very evenly and uniformly,” he said.

Neu said seeds of the different cultivars vary in size and with help from the seed science lab at ISU, she was able to establish a seed count per pound.

“We planted by seed count this year with a goal of getting a planting population of 29 plants per square foot,” said Neu.

In order to achieve that kind of stand, Neu said they seeded Aroostook at 80 pounds per acre; Elbon at 60 pounds per acre; Wheeler at 99 pounds per acre and Wrens Abruzzi at 61 pounds per acre.

“Last year was planted all by the pound, not by the population,” said Neu. “So, to compare the two years against each other for biomass will be impossible.”

Although biomass comparisons will not work from the past two years of research on the cereal rye, Nair said they have discovered that seeding rate will affect the growth and competition of the cereal rye, but not the date of anthesis.

“Too much seed doesn’t guarantee a lot of biomass,” said Nair. “Yes, there will be a lot of plants, but they will be smaller because they are competing with themselves.”

Research has shown, Nair said that the 80 to 100 pounds of seed per acre will produce enough biomass to keep the weeds down in the season.

“Some growers we have worked with in the past have used rye at high rates; we have growers that use 200 pounds per acre, even 400 pounds per acre. We think that is excessive, especially when the cost of cereal rye is going up,” said Nair. “120 to 180 pounds is a cutoff point. No point putting in more rye past 120 pounds per acre. There is no benefit, just spending more money for seed.”

Current research is showing at the farm some cultivars are yielding better than others.

“Elbon seems to be more vigorous and taller over the Aroostook,” said Nair. “Elbon seems a little bit more adapted to our region, so it is doing better than Aroostook.”

Roller crimper

Brandon Carpenter, agriculture specialist at the ISU Horticulture Research Farm described to the crowd about the roller crimper process used to terminate rye.

The particular machine used at the research farm, Carpenter said is an IMJ brand machine that features a chevron pattern of blades on the roller.

The chevron pattern helps with the shaking, and so I always have blades touch the ground, so it rolls smooth,” he said.

This particular model, he added is filled with water and used on the front of the tractor, mounted to the loader.

“They can be put on the back of the tractor, but we had trouble running it behind there because the tires were forming an impression in the ground and they aren’t enough to kill crimp or kill the rye, so we were finding everywhere the wheels had gone, the rye was standing back up,” he said. “So we found it best for us to have it on the front of the machine, or possibly a lighter machine won’t make the deep tire prints.”

The farm’s particular roller will weigh 4,000 pounds and is 10 1/2 feet wide. Carpenter said he runs at about 5 mph, finding that if you go any slower, you don’t get a very good crimp of the cereal rye.

Nair said some producers are now starting to own their own roller crimpers.

“Growers are slowly investing in a roller crimper, and majority are organic growers. This is a great way to terminate rye organically without using herbicides,” he said.

Nair also advises to roll crimp the rye against the grain so the gaps are closed to keep weeds from growing.

“So you have weed control, crimp in the opposite direction the rye was drilled, but then come back with your corn or soybeans and plant in the same directions of the roller crimper,” said Nair.

Studies are being conducted on what other varieties of crops can be planted along with cereal rye to help establish a diversified cover cropping system. Hairy vetch is being researched as a potential legume to be used in such cover crop practices, but currently, research is showing rye is an ideal cover crop.

“Rye is a versatile crop for our region, it is one of the best cover crops we can grow here,” said Nair. “Because number one, it can be seeded very late, all it needs is about 38 degree soil temperature for the seed to germinate, and it takes a long time for soil to get to that 38 degrees so we can plant it later in the fall, and it does good when it is mixed with hairy vetch as a companion crop, it takes winters very well and it can be flown in while corn is standing, it is a pretty good cover crop for our region.”

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