Cereal seed management
Cereal seed management
Time of Sowing
Time of sowing is critical for forage cereals, as it has a major impact on total yield, days to first grazing, and quality at grazing. Cereals can be planted early (late January) in southern regions if there is a need to provide grazing during ewe mating. Oats planted in late February and March will provide high yields for grazing in mid-to-late winter. To reliably achieve two winter grazings from DoubleTake, it must be planted by late-February in both Canterbury and the North Island. Triticale for silage and no grazing can be planted in winter or early-spring (May to September).
Paddock preparation is less critical than for new pastures, as cereal seed is less sensitive to deep sowing, and cereals are more competitive with weeds. Best results will nevertheless be achieved from paddocks that have been sprayed and carefully cultivated, or sprayed and direct-drilled. It is very important to drill nitrogen-based fertiliser (e.g. 150-250 kg/ha DAP) with the seed, especially when direct-drilling. Seed can be drilled at 3-4 cm, depending on soil density. Shallow drilling (<2 cm) on loose soils increases the chances of bird theft.
Seeding rates and treatment
Seeding rates and treatment vary. Oats are sown at about 100 kg/ha. Triticale seed is much larger than oat seed, so the sowing rates must be higher (DoubleTake is planted at 140-180 kg/ha). The seed size and germination percentage varies between lines of seed, so your retailer can advise you on the best sowing rates. If insects such as grass grub are present, treating seed with Gaucho® or Raxil Combi is recommended, especially for autumn-plantings. Raxil® or Raxil Combi are commonly used on cereals planted in winter and spring, to control seed-borne diseases.
Insects may need controlling, especially if seed is not treated. Aphids carry barley yellow dwarf virus (BYDV), and crops planted in late autumn may need spraying (e.g. with Karate Zeon at 20- 40 ml/ha) at GS12 and then 21 days later. Slugs need to be monitored and controlled, especially when direct-drilling.
Weed control is important with cereals, as they can impact on yields and quality at grazing or cutting. Assess the need to spray early, and apply before the cereal seedlings cover the ground. Many different herbicides options are available from seed retailers.
Nitrogen is necessary on most crops to achieve reasonable yields. The establishment fertiliser should be enough until after the first grazing with early autumn-planted trtiticale crops. Nitrogen (40-70 kg N/ha) should be applied after the first grazing. Oat crops will need at least one nitrogen application if grazed in winter, and two if grown for silage in spring. Application rates will depend on paddock history, soil type, and previous leaching. As with most winter-active forages, nitrate toxicity can occur on cereals. Excessive rates of nitrogen fertiliser should be avoided, as should nitrogen fertiliser within four weeks of grazing. Certain crop growth and weather conditions make toxicity more likely to occur, and nitrate levels can be checked by taking fresh samples to your veterinarian.
When triticale is planted in autumn for multi-grazing, the first grazing is important for subsequent production. A common mistake is to let it develop too much herbage before grazing, and this reduces tiller populations. It should be grazed when it reaches 20-30 cm in height (this can be 60-90 days after planting). A first grazing at 20 cm may be needed with early-planted triticale during warm autumns. If a paddock will take more than five days to graze, start at the lower height so that the last breaks are not too rank. Graze animals for a short duration (1 day) then move them to leave a 10 cm (1200- 1500 kg DM/ha) residual. Back-fencing is essential. If you want to restrict animal intake, a run-off paddock may be needed so that the DoubleTake is only grazed for part of the day. Avoid grazing when the soil is wet and soft enough to cause pugging as this will severely reduce recovery. The second grazing should be done in a similar manner. If the crop is to be kept for whole crop cereal silage in spring, grazing should be completed by late August in the South Island, and the end of July in the North Island.
Harvesting Cereal Silage
The correct stage to harvest whole-crop silage is when the grain has reached its full size and weight, but before it becomes hard. The grain needs to get to a greater size than the seed you planted. The grain will have changed from a green colour, to a yellow-golden colour. When you squeeze a grain between your finger nail and finger, it should crease easily, but no liquid or white ‘slop’ should ooze out of the grain. If you pull off the outer coating of the seed, the inside of the grain will be white and have a texture similar to Colby-type cheese. At this stage, the dry matter percentage of the whole crop above harvest height should be 36-40%. If it is drier than 44%, the silage will be difficult to compact and there will not be enough moisture for good ensiling. Also, the grain will be hard, and be more difficult for deer to digest. Where the crop is to be baled, it will be easier to cut slightly earlier (34-37%) to prevent brittle stems poking through the silage wrap.
Once harvested, it pays to protect the silage from rodent attack, as they are strongly attracted to the grain and make holes in covers leading to spoilage of the crop. Options include maintaining a perimeter of baiting, and/or a diesel barrier. Putting a layer of grass silage on a pit of whole crop cereal silage reduces the attraction of rats and mice.
Trials have shown that inoculation of cereal silage with Sill-all® has significant benefits in that pH levels are raised, and lipid and dry matter loss is reduced.
The Value of whole crop cereal silage (WCCS)
WCCS is a breakthrough for New Zealand farming. It creates the opportunity to substantially increase the amount of feed produced from an area of land. For example, on irrigated pastures it is considered that 18 t DM/ha is the limit for annual feedproduction. Large scale trials by AgResearch have shown thatdouble cropping systems with WCCS can produce 28 t DM/ha in a year.
Being able to produce large volumes of quality silage creates many opportunities to increase farm profitability. Sheep farmers use it to boost feeding over winter and produce feed reserves for droughts (including during mating in droughts). Dairy farmers use it in autumn to increase days in milk and cow condition, to fill feed deficits in early spring, and supplement brassica crops during winter. Innovative beef farmers use it to winter l arge numbers of finishing cattle on small are a s,then spread them out to utilise the spring pasture flush.
WCCS has a very useful nutritional balance. It has a high concentration of carbohydrates, including starch which is important for putting condition and weight on cattle. It has a good level of effective fibre, and is used to balance other low fibre feeds (e.g. winter brassicas, Italian ryegrass). Trials have proven WCCS produces good milk responses in dairy cows, and liveweight gain in cattle and sheep.