Seeding a cover crop can be useful, but make sure it fits your rotation
The use of cover crops is nothing new. Thomas Jefferson and George Washington talked about cover crops in the late 1790s. And you’ve probably heard people talking about “green manure” crops that used to be more common where you farm. There are various reasons that cover crops slipped from popularity, and some good reasons that they are on the comeback in some situations.
In general terms, cover crops are non-crop plant species selected to seed into crop production fields. They can be seeded during the crop season, but often times are seeded as a “follow-up” to the growing season. The main goal of a cover crop is to conserve resources and boost the ecosystem.
Cover crops contribute to those goals by potentially increasing soil infiltration to reduce runoff and soil erosion. And, the right kinds of cover crops provide improved wildlife habitat.
That’s aboveground. In the soil, properly managed cover crops can increase soil porosity and organic matter, which tends to increase water-holding capacity, again, reducing runoff and erosion.
If you plant legumes, like the green manure crops on granddad’s place, you can fix nitrogen to credit into your fertility plan. Cover crops can also be a part of weed and disease management.
Yes, cover crops have benefits that we know about and some that we haven’t discovered yet. On the other hand, cover crops also have a few management issues that you need to consider.
When you are making a plan for cover crops, you must have a goal. If you are doing it because your neighbors are doing it you might want to rethink why you are doing it. There are a lot of different crops that are utilized in a cover crop situation: • Wheat • Tillage Radish • Turnips • Oats • Rye • Clover • Cowpeas • Hairy Vetch • Italian Ryegrass, Marshal Ryegrass, Lolium multiflorum
One cover crop in particular has been a hot topic lately: ryegrass Lolium multiflorum. For the record, I categorically advise against ryegrass. It has the potential of turning into a problematic weed on cropland. In other parts of the world, ryegrass is resistant to several different herbicide modes of action that would make it very difficult to control in our fields (ALS, ACCASE, Glycines, Chloroacetamides and Glutamine synthase inhibitors).
Some other cover crops have weedy characteristics too. As you consider cover crops, you need to have a plan to kill it or be willing to interplant. We have solid herbicide options to kill most of the cover crops at certain timings. However, if the spring is delayed or we have a very wet spring and can’t get across the field to spray, those options will need to be altered on a field-by-field basis. Managing the cover crop becomes an integral part of spring planting. This can cause problems when its time to plant our normal cash crop. The delayed planting of some fields this spring could be the difference of making a great crop or a bad crop.
In June and July, I receive several calls on rotation restrictions following our soybean and corn herbicides. Most herbicide labels don’t have any information on what the cropping rotation or grazing restrictions are when the following crop is a cover crop.
Cover crops depend on good fall growth to serve their purpose of reducing soil erosion, increasing nutrient retention or breaking the hard pan.
Failure in fall can severely reduce tonnage and your conservation goals.
Choose the cover crop that best fits your reasoning. I don’t believe that one blend of species will be the right blend for every producer.
Dr. Kelly Nelson at the University of Missouri research station in Novelty, Mo., is demonstrating seeding times and rates of different cover crops in corn and soybeans. Dr. Kevin Bradley at the University of Missouri is researching the use of cover crops to suppress weeds into corn or soybean crops. Bradley’s work was presented at the recent Pest Management Field Day. This was the first year of data from those plots.
There is a lot of research/information needed to fully integrate cover crop systems for our trade territory. I do believe they have benefits, but with the benefits come hurdles. Through sound research and your on-farm experience you can use cover crops to your benefit. Find a wide range of information on cover crops at the Midwest Cover Crops Council: http://www.mccc.msu.edu. Contact your local store for more information and recommendations.
Dr. Weirich is director of agronomy for MFA Incorporated.
In 2012, MFA Incorporated started a training program to educate our staff on new and upcoming agronomic products and practices that can help our farmer/owners be more profitable. The camp is beneficial in that it allows MFA staff to experience these products with a hands-on approach. 2012 turned out to be an abnormally dry year and our corn site was below average. Just as for our customers, corn yield was disappointing on those plots. However, our soybeans continued to thrive.
Regardless of end-of-year yield, our training proceeded. Some 338 MFA employees received training in various agronomic sessions. We had six different stops including a focus on varieties, fertility, soybean agronomics, insect scouting, fungicide options and herbicide resistance programs. The 2012 field program was very successful even with the drought.
In 2013 we plan on even a better turnout for our training. With the upcoming release of Extend (from Monsanto) and Enlist (from DOW Agrosciences), we will have several stops educating our staff on the proper use of these technologies. We’ll focus on the importance of managing these traits and challenges associated with these herbicide traits. This theme of herbicide trait management will only grow in the future, as more and more herbicide resistance traits are incorporated in corn and soybean varieties. Training MFA employees in these matters will provide you with quicker answers and more in-depth expertise at the local level.
Meanwhile, the training site serves as two purposes—training and product evaluation. We will evaluate experimental varieties, herbicides, adjuvants and agronomic practices. We also have several MorCorn and MorSoy experimental varieties to evaluate at 10 different locations across our trade territory. The replicated variety trials were established to evaluate performance of the experimental varieties and assist in the proper placement of the varieties. We will look at about 84 corn and soybean varieties at the training campsite, including MorCorn, MorSoy, Dekalb, Asgrow, Mycogen and NK. The replicated variety trials were established to evaluate performance of the experimental varieties and assist in the proper placement of the varieties.
Evaluation of new crop-protection products is key. We are evaluating foliar fertilizers, fertilizer additives, seed treatments, etc. to make sure that the products we sell perform for our producers. Agriculture is changing and so are the products that we apply to our crops to maximize profit. Through our product testing and staff training we hope to deliver proven products and top expertise. We’ll let you know how the tests go. Please feel free to contact one of our locations for the results after harvest.
Dr. Jason Weirich is director of agronomy for MFA Incorporated.
Developing a fertility program for your forage crops may not be as simple as determining nutrient needs for row crops. In row crop production you apply nutrients with the simple goal of maximizing yield. While you would like to grow as much forage as possible, your real goal should be maximizing the utilization of the forage grown. Before developing a fertility program for your cool season grass pasture and hay fields, it is a good idea to evaluate your current forage species and stand health. Evaluating your current forage inventory will help determine seasonal production and times of excess or shortages in forage production. The goal should be to increase forage production or availability when forage is typically short and to increase utilization of forages when excess growth occurs.
You can use fertilizer, specifically nitrogen, to promote growth to meet seasonal needs. Grasses respond well to nitrogen fertilizer. Each ton of fescue produced requires 40 pounds of nitrogen. The soil will supply some nitrogen to the plant. The goal becomes to provide additional nitrogen to promote growth when needed. You can use nitrogen to promote growth of fescue in the spring and late summer. Determining when and how much nitrogen to apply will depend on your specific goals and should be evaluated on a field-by-field basis.
In order to get maximum benefit from nitrogen applications, soil-test levels for pH, phosphorus and potassium should be within recommended ranges. Apply lime, phosphorus and potassium according to soil test results.
Stockpiling tall fescue for fall and winter grazing Stockpiling is the practice of accumulating growth in the late summer and fall with the purpose of grazing the forage produced through the winter months. Nitrogen applications in early to mid-August will promote growth of tall fescue and increase total forage production. Target thick and healthy stands for nitrogen applications. It is best to graze or mow summer growth down to three inches before fertilizer applications.
Response to nitrogen fertilizer will depend on available moisture. Apply 40 to 60 pounds of nitrogen in early to mid-August for fall growth. Apply higher rates when excess forage is needed if moisture is adequate and yield potential is high. In order to maximize forage utilization and return on fertilizer investment for stockpiled forage, cattle should be managed with controlled grazing. Strip grazing will reduce waste and maximize forage intake. Research conducted at the University of Missouri has demonstrated that stockpiled tall fescue maintains quality throughout the winter months.
Spring applications of nitrogen to promote growth of tall fescue Spring nitrogen applications should be made to promote growth at the time of greatest forage need. If managing for hay or maximum tonnage, the nitrogen should be applied before grass greens up in early spring. Figure about 40 pounds of nitrogen per ton of growth desired.
If you have adequate forage early in the spring or can’t keep up with the early flush of growth, you can apply nitrogen after the first grazing cycle. Applying later in the spring will reduce overall tonnage but should extend the grazing season longer into the summer months.
Using fertilizer to promote forage growth to meet production goals and seasonal needs reduces waste and maximizes forage utilization. Steve Cromley is senior staff agronomist for MFA Incorporated.
Getting legumes into grass pasture is a time-honored way to make better grazing and hay. If you plan to interseed new legumes into an existing grass stand, consider following ideas to improve the success rate of your seeding.
Grass stands are commonly lower in nutrients than what will be needed by the legume. Soil fertility should be brought up to a level adequate for the interseeded legume. Phosphorus is commonly low in grass pastures unless animal manure has been applied regularly. Phosphorus encourages root growth and development as well as nodule production.
Soil pH generally needs to be higher for legumes than grasses. Apply lime several months prior to seeding the legume to adjust for proper soil acidity levels at the time of seeding.
Well-established grasses may make it difficult to get a legume going. There are several methods that can be used to weaken the existing sod, allowing the legume to become established. Grazing, mowing, light tillage, burning, chemical control, frost seeding and no-till drilling are all potential ways to aid in legume establishment in a heavily sod-dominated pasture. The thickness of the grass canopy and roots both need to be considered. If the existing sod has a thick vigorous root system, then a management practice such as light tillage will help weaken the stand to allow for legume establishment. A no-till drill used in combination with a sod-suppression management practice will help ensure good seed to soil contact and even emergence.
It is important to inoculate legume seed before planting. Even if the pasture has previously grown legumes inoculant should be used because Rhizobium bacteria populations necessary for good nodulation can vary across pastures. It is a relatively cheap practice to help ensure good legume establishment.
The benefits Successfully interseeding legumes can also reduce the need for nitrogen fertilizer. Legumes have a symbiotic relationship with nitrogen-fixing bacteria. As older legume roots die, grasses can take up nitrogen from their decaying roots, increasing protein content and yield. A good legume stand can fix between 50 to 300 pounds of nitrogen per acre and should comprise about 30 to 50 percent of the pasture. One way to look at the value of legumes is to consider that adding nitrogen fertilizer will increase total dry matter yield for the year it is applied, but a legume will improve the seasonal distribution of forage dry matter across multiple grazing cycles. Nitrogen fertilizer will also increase the competitive advantage of the grass over the legume.
Protein is in high demand for growing and developing livestock. Legumes have higher protein content than grasses and can be a great benefit to help meet livestock’s protein intake need. They can also improve the palatability and digestibility of the forage system. Improving the quality of feed has shown to directly benefit animal performance through increased gains, higher conception rates, increased milk production and higher weaning weight. Legumes also help decrease fescue toxicosis in fescue infected with endophyte.
Adding legumes to an established grass pasture provides many benefits. A substantial and healthy legume component in your pasture delivers increased nutritional quality, reduced need for nitrogen fertilizer and a longer grazing season. These benefits all mean lower input costs per pasture acre and increased animal performance through grazing better quality forages.
Adam Noellsch is a staff agronomist for MFA Incorporated.
There is a trend across MFA’s trade territory—a shift of acres away from CRP ground back into crop production. When brought back into production, most CRP acres will go to soybeans the first year. In some cases growers prefer corn the first year. Most of the CRP acres that are coming back into production haven’t seen a crop in 10 to 15 years, some fields have been out of production even longer. I have had the opportunity to visit with several producers about their plans to establish soybeans across these acres. Most of the conversations have revolved around weed control and the planning to fight weeds present in the CRP and ones that might emerge with the crop. But one thing producers sometimes overlook is the importance of inoculating soybean seed. I’ve visited with some producers who plan on planting soybeans into CRP land who were not concerned or didn’t plan on inoculating. That’s a recipe for less than optimal yield.
Inoculants are very important to soybean production. Soybeans are a member of the Leguminosae family and this family has the ability to live in a symbiotic (beneficial to both) relationship with Bradyrhizobium japonicum. This bacterium is specific to soybean and cannot inoculant any other legume.
For the relationship to exist and be beneficial to both, B. japonicum must be present in the soil in relatively high numbers at planting time. In fields where soybeans haven’t been planted for three to five years, it is essential to inoculate your soybeans. Studies from some of the Midwest universities show a benefit from inoculating your soybeans every year while others say you only need to inoculate when soybeans have been absent for several years. I suggest that you do a study on your own farm to determine what best fits your operation. A simple side-by-side evaluation of both practices can help you determine what system to use.
When B. japonicum is present in the soil, it attaches and colonizes on the soybean root hairs immediately behind the growing root tip. Sometimes people confuse the nodules produced by B. japonicum with soybean cyst nematode. SCN are white to yellow in color and the B. japonicum is a wart-like structure. B. Japonicum will grow rapidly and start producing nitrogen around the V2 to V3 stage. If you are curious if your nodules are producing nitrogen you can cut one of the nodules in half. The inside of the nodule will have a pink or red interior. This color doesn’t define the nitrogen efficiency of the nodule or plant. Nodules will fix nitrogen for six to seven weeks.
Soil moisture, soil temperature, soil pH, diseases and micronutrient availability are some of the factors that influence the ability of B. japonicum to fix nitrogen.
Soybeans get about 35 percent of the nitrogen they consume from the soil. The rest of the nitrogen that the soybean plant needs comes from the symbiotic relationship of soybean and B. japonicum. Most of the 35 percent comes from organic matter or fertilizer that has been used in previous crops. If the soil nitrogen level is very high it will inhibit nodules and the B. japonicum will shut down until the soybean utilizes the soil nitrogen. Soybeans can require more than 300 pounds of nitrogen per acre, and most of it is needed during the initial flowering through seed set stages. During pod fill it is not uncommon for the soybean to produce three pounds of nitrogen per acre per day.
Several companies are selling inoculants with growth promoters. One of the common growth promoters on the market is LCO. These promoters are nutrients or chemical enhancers that stimulate root growth or enhance the communication between bacteria and roots to make the nodules form quicker than normal. We are evaluating these growth promoters and other products at the MFA Training Camp site, and will provide the results of these studies when they are available.
I hope that if you are putting a soybean crop on first-year removed CRP ground that you will inoculate your soybeans. Contact your local MFA agronomist to develop a plan for your inoculant needs.
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