Salvage Your Drought-Affected Corn
Reading Time: 6 minutes
By Dorothy Rieke – For five long summer days, the relentless sun blazed, penetrating and drying out corn tassels. An unceasing wind drove away what moisture was available in the air. How would this weather affect the corn’s yield? There are few things in farming more terrifying than lack of rain.
Nearly every year, we hear of some farmers discovering that their corn crops have been affected by the lack of rain. In this case, farmers need to determine how drought conditions have affected their crops and how this damage will affect the yields. They must also take steps to obtain major benefits from that damaged crop.
LACK OF MOISTURE AFFECTS CORN
Lack of moisture during any period of growth generally results in a lower corn yield because the nutrient availability, uptake, and transport are affected without the needed water. Also, corn plants, weakened by lack of moisture, are vulnerable to disease and insects.
Unfortunately, a period of four or five days of dry weather and hot sun often reduces yields by five to 10%. Also, the timing of the lack of water has great significance. During pollination or “silking,” a period of that same length can mean reducing yields 40% to 50%.
Moisture stress causes a lack of synchronization between the shedding of pollen and silking during pollination. Because pollen grains are not visible, silking may be delayed.
Also, another problem arises with the lack of moisture. Drought-damaged corn contains nitrates in the bottom six to eight inches of the stalk. Cattle losses may result if this lower part of the stalk is fed to them.
DETERMINING SUCCESSFUL FERTILIZATION
It is possible to determine successful fertilization within one to three days after silk is pollinated. After successful pollination, silk will detach from the kernel. Carefully remove the leaves from the ear shoot, shake the cob, and determine the degree of successful fertilization by noticing how many silks shake loose from the cob.
There are other methods to determine whether stressed corn plants have been pollinated and fertilized. Look for the small white blisters on the ears six to 10 days after the pollen shed. To locate blisters, break several ears in half. Dig out some kernels on each ear. If there are kernels resembling blisters on ears, fertilization has occurred.
If still in doubt as to fertilization, wait five to eight days. At that time, if fertilization has occurred, those blisters should be larger. If the fertilization did not happen, the kernels show no change in size.
Another method to check for fertilization is to slice a few kernels lengthwise to see the young embryos. If the corn has no embryos, the kernels have not been fertilized. If the corn plant has tasseled and shed pollen but has no blisters, chances are, there will be no kernels.
Also, other damage may occur without adequate moisture. In some cases, ears have barren tips, an indication that the tip kernels were not pollinated or were aborted after pollination.
Lack of moisture before the appearance of tassel and silk may mean smaller ears, a reduced number of kernels, aborted kernels, and poor fill resulting in low test weight and reduced yield.
If the corn crop has not been pollinated and kernels are not fertilized (no blisters), farmers have several options. One is to feed the stalks to cattle as silage. Another is to plow up the crop and plant wheat or late grains, sorghum, or soybeans. Another option is leaving the corn in the field and later using that area as pasture.
INSURANCE FOR DROUGHT-AFFECTED CORN
If farmers have federal crop insurance or private insurance companies, the drought-affected corn crop should be examined before harvesting. This inspection determines what needs to be considered to be sure that the crop can be used as forage and still receive the insurance for the difference between the anticipated yield and the amount covered by the policy.
WAYS TO USE DAMAGED CORN
A drought-damaged cornfield can be salvaged in several ways. The silage option is better for stressed corn than grazing because of the potential nitrate problems. Harvesting the drought-damaged cornfield as corn silage reduces nitrates by 30% to 60%. Nitrate poisoning is generally eliminated during fermentation. Allowing the silage to go through the 21-day fermentation process before feeding often reduces the nitrate problem.
The corn can be tested for nitrates after being made into silage. There are certain solutions for this nitrate problem. One is diluting feed with high nitrate content with low nitrate grain or hay. Raising the cutter to leave a foot of the corn stalk may help as nitrate accumulation is generally in the lower portion of the corn stalk. Another solution is feeding the drought-stressed corn slowly so the rumen bacteria will adapt to it.
TESTING FOR MOISTURE
It is difficult to determine when to cut drought-affected corn for silage. Always test the moisture percentage before chopping corn for silage. Just looking at seemingly dry leaves, moisture content can be up to 90% water which is too wet for fermentation. Try this quick method for checking moisture. Select a few stalks and chop them into pieces about the same size as the silage chopper would. If the sample doesn’t drip juice from squeezing and the stalk pieces remain compacted, the moisture is acceptable for corn silage. If your hand is not wet and the material falls apart, the crop is too dry for silage. Delay cutting if moisture is high. Proper time is when some green leaf and stalks remain and the black layer is not on the kernels.
Harvesting the crop for silage at the proper time is important. If the silage is too wet at about 80% moisture, excessive seeping and spoilage will prevent fermentation. If the silage is too dry, it will be difficult to pack in the silo, and dryness interrupts the fermentation process.
Some farmers windrow the crop, letting it wilt in the field until it reaches the desired moisture level.
DANGERS TO FARMERS
There is also the danger of certain nitrogen gases from high-nitrate forage. Do not enter the silo during the first four weeks after loading it. If one needs to enter, run the blower for at least 15 to 20 minutes. Open the hatch door while using the blower. Also, a self-contained breathing apparatus should be worn.
Another option for salvaging a drought-ridden cornfield is to green chop. In this case, daily chop and feed the corn. Again, the cut must be at least eight inches high to avoid the nitrates in the base of the stalk. Another warning is, do not let the chopped corn heat in a wagon. In this case, nitrates will be converted to nitrites which are more toxic than nitrates. Always watch the cattle carefully if feeding green chop.
Damaged corn can also be utilized as hay. Be sure that the bottom eight inches of stalks are eliminated. The corn must be dried down enough to make a good bale. Crimping the stems assists the drying process.
GRAZING THE DAMAGED CORNFIELD
Grazing seasons can be extended with corn that has suffered drought conditions. Always feed hay before letting cattle eat the damaged corn. This helps to alleviate digestive problems. It is good to limit access to the drought-affected field by feeding hay alternately to letting the cattle graze.
Another option is to windrow the damaged corn leaving the windrows in the field for winter grazing. Always be aware of the nitrate problem. It helps to windrow leaving an eight-inch stubble. This allows air to circulate for drying. Also, it is best to feed the cattle hay before letting them graze in the cornfield. Access should be limited depending on the amount of ear development and grain that is being fed.
REDUCING RISKS OF DROUGHT
There are several strategies for avoiding drought-affected corn. One is to plant early so pollination is completed before the hottest and driest part of the summer. Fertilization helps by promoting growth and efficient utilization of moisture. Planting several hybrids with varying maturities may lower the risk of all corn being affected. Controlling weeds that compete with the crop will provide more moisture for the corn plants, and maintaining a cover of residue or no-till, reduces the amount of evaporation leaving more water for the crop.
Today’s farmers live for raising crops to their full potential. In doing this, they meet many challenges. A majority of those challenges are weather-related. The lack of rain is a dark reminder of the exposure farmers have to Mother Nature’s impulses. It is the informed farmer that meets those challenges successfully to gain a profit while working with all kinds of weather-related happenings. The farmers of today take seriously their obligations as Americans — to provide food not just for themselves, but for all.
Originally published in the July/August 2021 issue of Countryside & Small Stock Journal and regularly vetted for accuracy.