Harvesting drought-stressed soybeans for forage

Feeding drought-stressed soybeans to livestock is an option, but make the decision carefully.

Some soybean producers may be considering harvesting severely drought-stressed soybean fields for forage this summer. This is not an easy decision and producers should consider the value of the soybean grain compared to the value of the soybean forage. Other considerations include impacts on crop insurance payments, federal disaster aid and feeding restrictions for all pesticides applied to the soybeans.

Value of soybean grain versus value of soybean forage

Estimating the potential grain yield of drought-stressed soybeans is very difficult. This is because plants that have retained more than 50 percent of their leaves have the potential to produce a good grain yield as long as significant rain occurs before they stop producing flowers (early August). Be patient and assess the grain yield potential in mid-August. At this time, if more than 50 percent of the leaves have been lost, the plants have stopped producing flowers and few pods are present, grain yield will be very low.

A reasonable estimate of the dry matter yield for drought-stressed soybean forage would be 1.5 tons per acre. According to the feed tables in the Nutrient Requirements of Dairy Cattle, soybean silage harvested at early maturity contains 17.4 percent crude protein (equivalent to mature alfalfa hay), 1.29 NEL 3X Mcal/Kg (equivalent to mid-maturity alfalfa hay), 46.6 percent NDF (equivalent to mature alfalfa hay) and 5.7 percent ether extract or oil content (about 2.5 times the amount in alfalfa hay). These values will change with the development stage of the crop. This is especially true for the ether extract or oil content. Because the oil is in the seeds, larger, more mature seeds will increase the oil content.

Impacts on crop insurance

The key message here is communicate closely with your crop insurance agent before taking any actions such as harvesting the crop for forage (including grazing) or destroying the crop and planting an alternative forage crop. Failure to communicate with your agent prior to these actions will result in a loss of indemnity payments.

USDA program eligibility

Contact your localUSDA Farm Service Agency office to determine how harvesting the field for forage or replanting to an alterative forage crop will affect USDA program eligibility.

Pesticide feeding restrictions

Soybeans treated with the following herbicides can be harvested as feed and fed to livestock:

Always read and follow information listed on these product labels regarding feeding treated crops. The Poast/Poast Plus labels are a good example of why this is important because they state that treated soybeans can be harvested for hay, but not for silage. Soybeans treated with herbicides other than those listed above cannot be harvested as feed and fed to livestock.

Soybeans treated with the insecticides listed in Table 1 can be harvested as feed and fed to livestock. Soybeans treated with insecticides other than those listed in Table 1 cannot be harvested as feed and fed to livestock. As always, carefully check and follow the product label.

Table 1. Insecticides having specific statements on their labels that allow harvesting treated soybeans for livestock feed.

Product

Active ingredient

Forage and hay pre-harvest interval (PHI)

Baythroid XL

cyfluthrin

15 days for dry vines (hay) and green forage

Bifenture EC

bifenthrin

No specific statement on label

Brigade 2EC

bifenthrin

No specific statement on label

Dimethoate

dimethoate

Some formulations - do not graze within five days of last   application. Other formulations list no specific statement on label.

Intrepid

methoxyfenozide

7 days for hay or forage

Lannate LV   & SP

methomyl

3 days for forage, 12 days for dry hay

Leverage 2.7

imidacloprid/ cyfluthrin

45 days for dry vines (hay), 15 days for green forage

Leverage 360

imidacloprid/ cyfluthrin

15 days for dry vines (hay) and green forage

Radiant SC

spintoram

No specific statement on label

Sevin

carbaryl

14 days for grazing or harvest for forage

Source: Christina DiFonzo, MSU Extension field crop entomologist

Soybeans treated with the fungicides listed in Table 2 can be harvested as feed and fed to livestock. Soybeans treated with fungicides other than those listed in Table 2 may not be harvested as feed and fed to livestock. As always, carefully check and follow the product label.

Table 2. Fungicides having specific statements on their labels that allow harvesting treated soybeans for livestock feed.

Product

Active ingredient

Forage and hay pre-harvet interval (PHI)

Alto 100 SL

cyproconazole

14 days for grazing forage (no information on hay)

Headline

pyraclostrobin

21 days for hay and 14 days for forage

Headline SC

pyraclostrobin

21 days for hay and 14 days for forage

Priaxor

fluxapyroxad + pyraclostrobin

21 days for hay and 14 days for forage

Quadris

azoxystrobin

0 days for hay and forage

Quadris Xtra

azoxystrobin + cyproconazole

14 days for hay and 14 days for forage (when 6.8 fl. oz. per acre or less has been applied)

Quilt

azoxystrobin

0 days for hay and forage

Source: Martin Chilvers, MSU Extension field crop pathologist

Harvesting for hay

Harvesting soybean forage for silage is preferred over baling it as dry hay because ensiling retains more dry matter during harvest and storage. However, it is possible to make high quality hay from soybeans in the R3 to R5 growth stages. There are lots of leaves at these stages and the pods are less likely to shatter during mowing and raking operations. Use a roller-type mower conditioner set to lay the hay in a wide swath and leave about 4 inches of stubble. When dry, slowly and gently rake the swath into a windrow in the morning when humidity levels are higher to avoid leaf loss. Invert the windrows after several hours of good drying conditions and bale in the early evening to avoid further leaf loss.

Harvesting for silage

The crop can be harvested from R3 to R6. Soybeans harvested at R3 to R5 will produce high quality forage and have lower oil content than those harvested at R6. The higher oil content may cause fermentation problems. However, soybeans harvested at R6 will produce more dry matter. Mow the crop with a mower conditioner equipped with roller crimpers. Experience from Wisconsin indicated that flail conditioners cause more damage and dry matter loss than roller conditioners. As with alfalfa, soybeans should be allowed to wilt in the field to 65 percent moisture before chopping.

Determining the whole plant moisture content is critical to achieving proper fermentation. Collect representative samples from the chopper and use the microwave method to determine whole plant moisture levels before chopping each field. Adjust the chopper to produce a 3/8-inch cut to improve packing.

Feeding soybean hay

Soybean hay has a tendency to cause bloat in cattle, so it should be fed carefully. Mix the soybean hay with grass hay or fill the cattle up on grass hay prior to feeding soybean hay. Horses can safely consume soybean hay if it is baled and stored properly.

Feeding soybean silage

Feed quality of soybean silage is equivalent to alfalfa haylage. Soybean silage is less palatable than haylage or corn silage. However, it can make up 15 to 20 percent of a dairy ration without impeding animal intake or milk production. The exception is when the soybeans are harvested after the R6 stage is reached as more seed (higher oil content) is present, which can affect fermentation and palatability.

Harvesting soybeans for forage is an individual decision and should be given careful consideration. Be patient and wait until early to mid-August to make the final decision as soybeans can recover from drought stress if significant rainfall occurs before August.

References:

This article was produced by the SMaRT project (Soybean Management and Research Technology). The SMaRT project was developed to help Michigan producers increase soybean yields and farm profitability. SMaRT is a partnership between MSU Extension and the Michigan Soybean Checkoff program.

Additional information: