When it comes to growing summer crops like millet and sorghum for high returns it’s all about preparation. In challenging spring environments the margin for error is high, so it is critical to get maximum production and quality feed from your forage sorghum and millet crops. Here is a list of tips for improving your chance of success.
Sorghum is an excellent yielder and with excellent water use efficiency and can handle much dryer soil conditions than millet. However, when sorghum becomes stressed it can produce prussic acid which can be fatal to livestock if grazed too early with hungry stock. Grazing the stand when it is between 0.8 - 1.5 m tall will give you the safest and highest quality feed. The addition of sulphur lick blocks will assist stock in better utilising this feed source safely.
The most effective way to keep sorghum at its best is to rotationally strip graze and back-fence, to ensure regrowth isn’t grazed too early. As a rule of thumb, remove stock when the stand is at the height of a coke can and don’t graze it again until it reaches your waist/chest. A mechanism to maintain quality in your summer crops is to plant your crops a couple of weeks apart so the area is not ready to graze all at once. If sorghum does get away from the stock, cut it for hay or silage.
Caption: Dairy cows grazing a crop of sorghum in northern Victoria.
Yield potential for sorghum (10-12 tDM/ha) is directly related to moisture and nitrogen. If moisture is adequate then it is important to add 50-75 kg/ha nitrogen after each grazing for quicker regrowth. DON’T FORGET there is a stock grazing withholding period of 3 weeks after nitrogen applications to reduce the risk of nitrate poisoning. Note thatfeeding hay or silage, having fresh water and sulphur lick blocks available are recommended when grazing sorghum.
Millet is at the lower end of the scale nutritionally in the summer crop feed chain, however it is the cheapest to sow and is a safe option in terms of animal health risks. If the season gets challenging then there are no restrictions for cutting or feeding to livestock. Millet suits farmers who want regular grazing about every 2-3 weeks.
To help increase feed value, SPS mixes can be sown such as Mainstar N Millet (Mainstar Brassica 20% Millet 80%) and Millet N Herbs (White Clover 15% Chicory 20% Millet 65%). The addition of brassica, chicory or white clover to millet will increase the protein and digestibility of the feed.