Livestock — Agriculture

Photo: fallow field

Winter annual weeds in winter wheat

The presence of weeds in wheat will reduce yields. There are two major classes of weeds in wheat: winter annuals and summer annuals. Winter annuals emerge in fall, winter, or early spring and compete with wheat for moisture, light, and nutrients. Given the current drought conditions we’re dealing with, any competition for moisture is going to hurt yields. Summer annuals emerge in the spring when soils reach a certain temperature. They can compete with wheat for moisture, light, and nutrients but also interfere with wheat harvest and the next crop planted after wheat. Even so, it is the winter annuals that have the greatest effect on wheat yields.

It is estimated that winter annual weeds reduce wheat yields by an estimated 10% each year. When wheat prices are low it can be difficult to justify the cost of spraying. As of late wheat prices have been above average and, given the slow start many wheat fields have had due to a lack of moisture, it certainly makes sense to spray. Weeds that germinate in the fall have the greatest impact on yield. Many are aware of this and sprayed their wheat fields in the fall. I’ve recently scouted many fields that were sprayed in the field and found them to be almost completely weed-free. This allows greater tillering of the wheat and this is important because good tillering generally equals good yields.

Most fields, however, were not sprayed in the fall. Recent scouting of these fields has generally found them to be full of both henbit and chickweed. In many of these fields, you can’t even see bare ground. Where there’s not wheat, there are weeds. We often say that most weeds should be sprayed when they are small and actively growing. Henbit and chickweed are small and actively growing right now. They are two of the earliest growing weeds that we have. Many don’t even notice them until they begin to bloom a couple of months from now. By then, they’re more difficult to kill and have already done most of the damage they’re going to do. Right now is the time to start looking at wheat fields and thinking about spraying.

By far the most common product used to control broadleaves in winter wheat is Harmony Extra. Harmony has proven to be an effective product and, when used properly, doesn’t cause problems for double-crop soybeans. It is important, however, to not rely on just one product every year. Producers should rotate to herbicides with different modes of action whenever possible. Other herbicides that are effective on henbit and chickweed that can be applied in the spring include Finesse, Osprey, Banvel, and Buctril. These will have different timing and plant-back restrictions so be sure to read the label before use. The 2013 Missouri Pest Management Guide has more information and can be obtained from your county extension office.

2, 4-D is a popular herbicide used for broadleaf control in wheat primarily because it is generally effective and it is cheap compared to many other herbicides. 2, 4-D is typically only effective on chickweed and henbit when these weeds are very small. This presents a problem because 2, 4-D can only be applied to wheat after it has fully tillered but before jointing. Spraying 2, 4-D outside of this “safe window” will cause damage and yield loss to wheat. So by the time you can safely spray 2, 4-D, it probably won’t provide complete control of chickweed and henbit.

There are a couple more things to keep in mind when considering spraying for weeds in wheat. Many wheat producers like to seed red clover into wheat so they can cut it for hay after wheat harvest. There may be even more of this happening this year due to the difficult hay season we had last year. Nearly all herbicides that control chickweed and henbit will also severely damage emerged red cover. In addition, the residual activity of many herbicides may prevent clover seed from ever germinating. The other thing to consider is applying the herbicide as a tank mix partner with liquid nitrogen. This is possible with many herbicides and can be very effective. The main issue is that this practice will often yellow and stunt the wheat, sometimes resulting in yield loss. The other issue is that herbicides are often needed before it is the ideal time to apply nitrogen to wheat. For more information on winter annual weed control in wheat, contact your county extension office.

Crop Insurance 101: What is APH?

One acronym used frequently in the realm of crop insurance is APH. APH stands for actual production history, and it is the basis for establishing a yield guarantee for all Federal Crop Insurance Corporation-backed insurance plans except for the Group Risk Plan (GRP) and Group Risk Income Protection (GRIP), which rely on historical county yield data instead of an individual farm’s performance history. Establishing an APH yield requires a minimum of four years (and a maximum of ten years) actual production records. Sale receipts, farm or commercial storage records, and/or feed consumption records are all valid forms of information to establish actual production history. The records used to establish an APH yield must be for continuous years, starting with the most recent year and continuing back in time. Once a missing year is reached, no history prior to that date can be used. For example, if a farmer has nine years of production spanning a ten-year period, only the years after the missing year are counted. Federal crop insurance plans do not permit farmers to drop yields from poor production years in establishing their APH. The only exception to this rule is if the crop being insured was not planted in a certain year. In that case, a zero acreage report is submitted and continuous records are maintained even without data for that year. This exception is important for farmers who practice crop rotation or summer fallow.

For farmers who cannot establish at least four successive years of yield records, a transition or T yield for each missing year is used in calculating their APH. T yields are based on a 10-year historical county average yield. Farmers who are short one year of yield records out of the four required to establish an APH are assigned a yield equal to 100% of the T yield to substitute for the missing year’s yield.  If records for two years are missing, yields equal to 90% of the T yield are substituted for the missing records.  If three years are missing, the yield values used are 80% of the T yield.  If a farmer has no yield records, the four yield values used are 65% of the T yield.

Once four years or more of yield values are available, the APH is the simple average of all the yearly yield values. The four years of history will eventually build to ten years.  After ten years of history is established, the APH becomes a rolling ten-year average yield.

While the process of determining an APH yield is somewhat complicated, the process is important to understand as it has a significant bearing on the amount of risk protection offered by federal crop insurance plans. To learn more about APH and crop insurance options that may be available to you, contact a crop insurance agent or an MU Extension Agricultural Business Specialist.

By: Whitney Wiegel, Agricultural Business Specialist, University of Missouri Extension

Making silage from drought-damaged corn

Dry conditions around the state have many corn producers wondering about making silage from drought-damaged corn. Although silage made from drought-damaged corn is usually not as good as that made from unstressed corn, drought-damaged corn can make good livestock feed.

As a rule, drought-damaged corn will have 85 to 95 percent of the feeding value of normal corn silage. Ideally, corn silage would be 60 to 70 percentage moisture at harvest. If drought-damaged corn contains less than 60 percent moisture, producers could add some water at the silo.

However, when drought slows plant growth and delays maturity, the moisture content is often higher than is suggested by the appearance of the crop. Taking the time to check the moisture content before harvesting could save a lot of trouble later. MU publication G3151 ( contains detailed information on how to measure the moisture content of silage using a microwave oven.

Drought-damaged corn should be chopped to 3/8 to 1/2 inch in length. This length of chop should help in packing the silage to exclude as much oxygen as possible. Producers should also sharpen the knives on their equipment before making silage.

Other tips include filling the silo quickly and packing the silage as tightly as possible. Remember, to make good silage, oxygen should be excluded at all points. One concern with drought-damaged corn is high nitrate levels in the silage. High nitrate levels are frequently found where high levels of nitrogen fertilizer were applied and where drought-damaged corn is chopped a few days after a rain.

Other factors that contribute to high nitrate levels in corn silage are cloudy weather, extremely high plant populations and shortages of soil phosphorus and potassium.

Ensiling drought-damaged corn is preferred to greenchop because during the fermentation process, the nitrate content can be reduced by 20 to 50 percent. If a producer suspects that the crop may have high nitrate levels, they should have it analyzed before harvest, if possible.

One word of caution: corn with high nitrate levels produces more silo gas (mainly nitrogen dioxide and nitrogen tetroxide) than normal corn silage. During the fermentation process, a portion of the nitrate in corn silage is converted to nitrogen dioxide or nitrogen tetroxide; the higher the nitrate levels in the plant, the more silo gas that is produced. The reddish-yellow fumes of silo gas often smell like chlorine bleach, and silo gas is toxic to humans. Remember that silo gas is heavier than air and thus tends to accumulate in low areas.

Most often, this is a problem for producers with upright silos, as the silo gas tends to accumulate in feed rooms at the bottom of silo chutes. Silo gas can be a problem for other silage storage systems as well and one should exercise caution around silos during the filling and fermentation process.

If producers have corn with high nitrate levels, there are a few things they can do.

First, they might delay harvesting until the plant begins to "outgrow" the nitrate accumulation. Usually, drought-damaged corn will have normal levels of nitrates after 10 days to two weeks of normal growth (once the drought ends!).

Second, producers might increase the cutting height to 8 or 10 inches. Nitrate levels are usually highest in the lower part of the stem, so increasing the cutting height can help lower nitrate levels in silage.

Finally, if they have high nitrate corn silage in the silo, they could dilute the silage in the ration with other low-nitrate feedstuffs.

Several producers have asked about making "big round bale silage" or baleage from drought-stressed corn. For those not familiar with the practice, this is simply baling high moisture forage and then wrapping the bales with plastic film to exclude oxygen. This could be a way to store the crop if typical silage-making equipment is not available, though corn is difficult to run through a standard round baler. Balers that have recutters to reduce particle length will make better silage out of corn than will balers without this equipment. Even for balers with recutters, corn stalks are prone to poking holes in the plastic film and thus spoiling silage. While 4 mil plastic thickness is recommended for normal grass silage, drought damaged corn made should be wrapped to a 6 mil thickness.

Harvesting drought-damaged corn for silage can be a way to salvage an otherwise useless crop. Paying close attention to moisture content, length of cut, packing and nitrate levels in drought-stressed corn cut for silage will help make the most of a bad situation.

By: Rob Kallenbach

Opportunities for cattle producer exist during drought

When drought hits an area, cattle producers can sometimes struggle with what possibilities exist that may help in handling the situation.  Drought has long lasting impact on the producer and their livestock.  With our abnormally dry conditions, livestock producers are looking at all of their options and making plans accordingly.

The greatest impact of drought for a cattle producer is the reduction of forage resources for your operation.  The reduction in forage production is less severe on pastures that were in good to excellent health prior to the drought. However, the extended dry conditions and limited feed resources forced producers to graze their pastures harder the previous fall and winter.

There is little that a producer can do to change this today except to remember that the producer who makes the decision to "hammer" a pasture in order to get more pounds of cattle on a given area will likely suffer the following year more than the current year. To say it differently, the ability of perennials to recover post-drought is directly related to their health before and during the drought. It is smarter long-term management to be more concerned about future plant health than this year's weaning weights. Remember that a producer of beef must first be a grower of grass.

Consider splitting your pastures and rotationally grazing the paddocks. This allows a rest period for the grass and if rain does come it is likely to respond quicker. Also, rotational grazing reduces selectivity in a cow’s grazing habit, enhances forage utilization rate and can improve pasture carrying capacity by 10% to 30%.  This strategy can have a long term benefit to forage production and utilization for the cattle operation.

The drought presents an opportunity for the cattle producer to re-evaluate their stocking rates and matching their cattle more closely to their forage resources.  Early weaning calves can reduce grazing pressure by 25-35%.  Instead of weaning calves at 7-9 months of age, consider weaning at 5-6 months of age.  This would provide the producer the options to market early and capture a premium with the current high cattle prices or to drylot and background the calves.  Additionally, early weaning reduces the cow’s nutritional requirements by 30-40%.

Now is the time to identify the late calving, unsound and poor producing cows and cull them from the herd.   The current cattle market prices are favorable for culling.  This sound business principle would provide you the ability to focus resources that will give you the greatest returns on your investment and not those with lower marginal returns.

Livestock must have adequate water.  During dry conditions when their feed has lower water content they need even more. A drought year could be a good year for developing additional sources of water for future use.  More water sources are always a valuable management tool.

Drought conditions can cause significant hardship and stress for livestock producers.  However, use this as an opportunity to improve your management of your forages and cow herd.  Once the growing conditions improve, you will be better positioned the capture a greater value of return.  The current dry conditions can have long lasting impacts, but let’s make those impacts a benefit instead of a detriment.

By:  David Hoffman, Livestock Specialist, University of Missouri Extension