Using crabgrass successfully after winter annual pastures

by R.L. Dalrymple

There have been reports of difficulty in making the combination of crabgrass and annual ryegrass as a double crop work consistently. This combination certainly has its own personality, but it does work.

We just must learn to apply the proven experienced principles of production to provide more consistency and better overall production, and at the same time understand the limitations. There has always been some use of crabgrasses in pasture and meadows since it was introduced into the United States in the mid-1800s. Until recent times, this use was almost always accidental or un-preventable as hardly anyone purposely managed for these good grasses. The very successful crabgrasses got a bad rap in the early days of row crop and other crops before herbicides.

My earliest memory of crabgrass management being done on purpose was as a youngster in the 1940s. Even then there was not much use of the crabgrass forages on purpose until the 1970s.

Starting in the 1970s there was a significant resurrection of the use of the native crabgrasses in Oklahoma sandy land forage programs. This was both from the producer, and the crabgrass research and demonstration work started and continued to today by Noble Foundation of Ardmore, Oklahoma.

It was during this time in 1988 that Red River Crabgrass, the worlds first known variety, was released. There was a need and Red River Crabgrass has proven itself well.

The first planned long term usual uses of the crabgrass for forage was as a pure stand for grazing or hay, and as a double crop with cereal rye or wheat. In a pure stand, the crabgrasses have a much longer green season and make much more production.

However research shows that the double crop with rye increased total annual forage by about 40% to 60%. So, there is a distinct advantage to double cropping if it fits the forage flow needs.

With time and many research and demonstration trials and producer experiences, the good forage types of crabgrass have been successfully used in many double crop syndromes other than with rye and wheat.

And these good grasses have also been used successfully as a summer component in many forage mixtures.

A double cropping approach that is used a lot throughout the southeastern USA, from about Oklahoma east and south to Florida, is the Red River Crabgrass and annual ryegrass double crop.

Other good forage types of native crabgrass are also used with many varieties of annual ryegrass. The successes and/or failures of this particular double crop are not dependant on the ryegrass variety as all exude the same general responses. Red River Crabgrass, properly cultured and growing as a single crop on prepared land in central Oklahoma latitude, starts germination in the warm days of early April. In some seasons, grazing can begin as early as the last two weeks in May.

Growth can continue to mid-September and green stockpile can go to first frost, which averages late October. Freeze dried stockpile can be used into some point of winter.

This is the general capability of the variety and of course it all depends on the many facets of man's management and the moisture season.

Annual ryegrass, properly cultured and growing as a single crop on prepared land in central Oklahoma latitude, starts germination in the cooling days of late August and thereafter to the cold of early winter at about early November.

It is green all winter, but makes essentially no practical re-growth from the time soil temperatures gets near 45 degrees F until the warm days of March.

Then, as the days of March get warmer, re-growth starts and growth extends into early summer to about mid-June.

This is the general capability of the ryegrass and of course it all depends on the many facets of man's management and the moisture season.

This is a good spot to mention, too, that Stocker Bromegrass managed for long season winter pasture, can produce considerably more fall forage than annual ryegrass and it can grow into summer four to six weeks longer than ryegrass.

We have had times that Stocker was being grazed the last cycle in the third week of July, which is easily five weeks to six weeks after annual ryegrass died in the same area.

Stocker can be used in a Red River Crabgrass double crop as is ryegrass.

So, when these two forages, Red River Crabgrass and ryegrass, are put into a double crop, it is easy to see the great overlap in the seasons of the forages. Ryegrass competes with crabgrass and crabgrass competes with ryegrass.

This is true with essentially all double crop approaches, but it is drastic in the Red River Crabgrass and annual ryegrass approach.

In the fall time of switching from crabgrass to ryegrass, there can be very little overlap, or up to one to two months or more of overlap, depending on the final graze out or haying management of the Red River Crabgrass.

In the spring season, ryegrass easily grows over into the crabgrass germination and growth season two months, more or less.

This is good and bad at the same time.

If the season of rainfall is good and the management is good for this double crop, the two forages fold together reasonably well. I have properly managed this double crop when the last of the ryegrass grazing was coupled with the first four to eight inches of Red River Crabgrass growth in and among the ryegrass growth.

So, it can be done, but management has to be done correctly and there must be a rain at the needed times.

But, what more usually happens is that we managers have not done some things to make this double crop function at upper level, or a long spell without rain causes slow recovery, and the crabgrass is very slow to make its contribution. So, there is a long season of ryegrass and a short season of crabgrass or maybe none at all.

This is primarily caused by the ryegrass competition with the early Red River Crabgrass as it tries to make early establishment and production.

Extremely dense ryegrass almost totally prevents an early crabgrass start in the syndrome. There are several important management inputs that can greatly influence the outcome of this double crop. We have no control on the weather, unless we use irrigation, but we can do the management correct and have the pastures properly ready for the rains.

Bear with me, this is where we have been heading all along.

Without a doubt, both forage crops respond very well to soil renovation tillage), good fertilization, and rotational grazing. All of those inputs can be lacking, but, the most common thread missing is adequate renovation. Nearly everyone provides some fertilization to cause some good pasture.

Nearly everyone also manages for seed shatter for volunteer management.

And most of the readers of this magazine are surely going to be doing some form of good rotational grazing.

Now, let's examine a couple common ways that this double crop is being managed and outline ways to make the combination more consistent and better.

I am not going to consider any really personal management choices or limitations. You have to sort that out for your own case. I am just going to write about the agronomy of this particular double crop and assume that the land can support the inputs.

The very best means to manage this double crop is to fully use the crabgrass crop at early summer’s end, renovate (do tillage) and plant the ryegrass early in fall, apply ryegrass fertilization at planting time, rotational graze well, graze the annual ryegrass out as early as possible, graze the final forage very short, fertilize for the volunteer crabgrass before it comes up, rotational graze it to early fall, and start over.

Let's examine each input in a little more detail.

Graze or mow the crabgrass to a one to three inch residue (stubble) by ryegrass planting time. Graze this last growth short with non-performing or low performing livestock.

Do the renovation or tillage just vigorously enough to allow a good early ryegrass planting.

Many tools can do the job: mulch treader (usually in the wheat country only), tandem disk, field cultivator, and at bare bones minimum, an aggressive chain harrow, to list a few.

A smoothing tool behind the tillage is essential. The chain harrow may need to be used two or more times over the field when it is moist to do an adequate job.

It is important that the ryegrass have the proper kind and the upper level amount of food (fertilizer) as soon as it is a seedling. Ryegrass requires about 100 pounds of actual nitrogen per acre for the fall phase and another 100 pounds per acre for the spring phase. Early fall nitrogen speeds early growth and provides more early forage whenever that may occur. Apply phosphorus and potassium per soil test results. Good rotational grazing is a given.

As the ryegrass season nears its end, be very certain to use it completely. There is no doubt in my mind that ryegrass and crabgrass are allelopathic (toxic) to each other.

This is no big deal. This characteristic is common with most forages to some degree. The thing is not that it occurs, but the thing is to manage to minimize the influence. Graze ryegrass short (one to three inches) at the end with non-performing or low performing livestock, or mow very short, bale, and haul it off. The less residue left, the lower are the allelopathic agents. It is a volume thing to a large degree.

The same for crabgrass. Let's assume that you have managed well for seed drop for a volunteer stand of crabgrass. We know it is going to come up when the ryegrass is done and the rains come. Most of the time, when there has been fall renovation, crabgrass will be germinating and emerging at the later part of ryegrass grazing.

If you know you are not going to renovate at the end of the ryegrass, then put the first fertilizer on for the crabgrass at the end of the ryegrass use and before the crabgrass initiates germination. This assures the earliest crabgrass production success.

If the pasture is to be renovated at the end of the ryegrass, do the renovation and immediately apply the first fertilizer for the crabgrass. Be aware that this is getting late for the crabgrass and it will not come on until two or more rains.

I believe the better more consistent way is to renovate in the fall and not in the spring for this combination. The fall renovation will help the crabgrass in the spring, just not as much as in the spring.

I just hate to kill an early stand of crabgrass. The next stand may be a long time coming. Some graziers in the humid southeast, however, know the benefits of the renovation and do it at the end of the ryegrass growth and go for more rain.

A good rule is that if the Red River Crabgrass is not up at the ryegrass end, then immediately do the renovation and be ready for the next rain.

Again, use the correct kind and amounts of fertilizer for your case. Do not fertilize baby seedlings of crabgrass as there are times that the salting reaction of the fertilizer kills the tiny one to four leaf seedlings. Fertilize before germination or after seedlings are in the five leaf stage or later.

I truly believe that some discouraging results with this mixture is due to bad timing on the fertilization of the crabgrass component. Ryegrass is not so much bothered.

For Red River Crabgrass to be upper level successful, it must have a good seed shedding for next year’s volunteer stands. Be sure to provide for it in your management.

The last two paragraphs summarize what I consider the best and most predictable and consistent crabgrass and ryegrass double crop approach. I know there are a lot of words in the above paragraph, but it is important. Re-read please.

Many graziers try to manage this double crop without any renovation. They may even try to manage for volunteer stands of both grasses. The allellopathic responses cause big problems here. They are trying to pinch pennies and understandably so.

Consider the case where there is Red River Crabgrass and annual ryegrass double crop started without future planned renovation. Generally what happens, even where there is good seed drop of volunteer, is the forages work well the first one to three years, sometimes longer, and then either one or both begin to fail to some degree. Some times this failure is very drastic.

When most inputs are satisfactory, this failure is generally caused by lack of tillage, even light tillage, and sometimes other factors. Sometimes extra fertilization and really good rotational grazing can make this approach work longer, but it will still have problems doing well in the long term.

We just cannot totally ignore some proper renovation in this double crop if we want it to be upper level in success and production. And extra seed shed for volunteer seems to help.

Pasture diversification is also important. Have some paddocks with other forages to tie the green seasons together. Red River Crabgrass grown as a single crop, compared to this double crop, will be one to two months or more earlier in the early summer and it can be carried into fall as one wants to do.

I have had clients tell me that stockpiled Red River Crabgrass on selected paddocks was more important than early winter pasture on that area. That is a good form of diversification. Some of both may be in order.

Cereal rye and crabgrass double crop is one of the most consistent double crops to manage. Maybe some paddocks in cereal rye and others in ryegrass would be of benefit. Rye quits winter production just as Red River Crabgrass initiates production and the crabgrass after rye is reasonably predictable.

There are many other ways to bridge the gap and still have the super benefits of high quality crabgrass in the forage system.

Remember, for volunteer, there must be a good seed drop. Watch in the growing season and manage for that to happen to be sure of next season’s success. Red River Crabgrass is "green as a gourd" at early seed shedding time. Quality is still good.

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