Called poor man’s corn for good reason, sorghum sudangrass is a warm season forage crop that looks like corn, grows like corn, but sure doesn’t cost what corn does.
On trials on our farm, we’ve seen both extremes in production. In good years it was taller than our 4255 tractor, and in poor years it was struggling to reach waist height. The reason, I found out, is that sorghum sudangrass requires both heat and moisture. With heat, it is fairly forgiving. Cool years still result in acceptable production. Moisture, on the other hand is more crucial. Under drought stress, the plant will stop growing and wait for the moisture to come. When it does, it takes off very quickly. Without adequate soil moisture, however, production drops off significantly.
Normally sorghum sudangrass is seeded in June into warm soils. Seed is about 20,000 to 24,000 seeds per pound (44,000 to 53,000 seeds per kg), so most varieties are seeded around 20 pounds per acre. Quick fertilizer recommendations are to treat this crop similar to barley. Do not place much or any fertilizer with the seed. There is a threat of applying too much nitrogen to cause nitrate build up in the plant, so a split application of nitrogen would be advantageous.
Weed control options are limited due to this crop’s lack of acres in Western Canada. Due to its aggressive growth rate under moist conditions, however, weeds may not be much of an issue.
There are a couple uses for-this crop. It can be grazed, cut for silage under a multiple cut scenario or stockpiled for either grazing or silaging. It is a very sweet tasting plant and very palatable for livestock.
There are some rules for grazing and silaging. When cutting, try to leave four to seven inches (10 to 18 cm) of stubble. This will allow the plant to regrow faster. Never graze it down to less than 18 inches (45 cm) in height. It does regrow very quickly, so rotational grazing should be implemented. Haying under multiple cuts is not recommended due to the crop’s relatively slow dry down.
Prussic acid poisoning is a risk with fresh new growth of small plants, after a frost or harvesting during stress, such as drought. Do not graze or cut plants before they are 18 inches (45 cm) in height. After a frost, wait four to six days before harvesting by either grazing or cutting to allow the prussic acid to break down. Silaging will also help reduce the prussic acid levels because the chopping process will allow it to gas off. Nitrates are not a big concern unless the crop is poor or there are high levels on nitrogen in the soil. Nitrates tend to accumulate on the lower part of the plant and will leach out in time. If you are concerned about either level, get a feed test done.
Sorghum sudangrass can be a hit or miss on the Prairies. Its main driver for yield is moisture, and this spring, we are not short of soil-stored moisture. It is lower cost than corn with similar yields. Cows love the feed it produces and it can have exceptional feed test results. Sorghum sudangrass is something to consider for 2011.
KevinElmyoperatesFriendlyAcresSeed Farm,alongwithhiswife,Christina,and parents,RobertandVerene,nearSaltcoats, Sask.Contacthimat306-744-2779