A weekly report prepared by the staff of the Ministry of Agriculture, Food and Rural Affairs (OMAFRA). If you require further information, regarding this report, call the Elora Resource Centre at 519-846-0941. Office hours: 8:30am to 4:30pm.
For technical information, call the Agricultural Information Contact Centre at 1-877-424-1300 or visit the OMAFRA website: www.ontario.ca/omafra.
Soil management: plant cover crops following cereals to improve soil
If you have not planted cover crops before, planting them following wheat or other crops harvested in late summer is a good place to start. Cover crops can help improve soil structure, cycle nutrients, provide feed for livestock and much more. Cover crops are a key part of maintaining 30 per cent soil cover 100 per cent of the time. One key thing they do is extend the amount of time there are living roots in the soil. That, along with the other plant material, provides food to maintain or bolster soil life. Cover crops are not a magic solution for your soil problems, but when combined with other good soil management practices will help improve soil health.
Red clover is still the best cover crop option in winter wheat, as it provides a nitrogen credit to the following crop and produces significant top and root growth. Planting a cover crop after cereal harvest is the next best option. Many think that volunteer cereal growth is good, but a planted cover crop can provide up to five times the above ground biomass and root growth into the fall. It is also better than volunteer cereal growth at suppressing weed growth.
Cover crop selection
The cover crop chosen for a field will depend on why you want to grow the cover crop. You will also need to consider how it will fit into your cropping and tillage system and how much time there will be for the cover crop to grow. The OMAFRA website (in the soil management section) provides comprehensive information on cover crop species selection and management. The Agronomy Guide for Field Crops, OMAFRA Publication 811 also has cover crop information.
The Midwest Cover Crop website, http://www.mccc.msu.edu/selectorINTRO.html, provides an Ontario cover crop selection tool.
When to plant
Following cereals or any other crop, plant the cover crop as soon as possible to achieve the most growth.
Another great opportunity to plant cover crops is following corn silage harvest, as there is little cover left to protect the soil.
Annual cover crops can be planted up until six weeks before the expected killing frost. After that point planting a winter cereal as a cover crop is the best option.
How to plant
If volunteer cereal growth or weeds are present, consider spraying to prevent the spread of weeds and competition with the cover crop. Ensuring that the straw was evenly spread at harvest will improve cover crop establishment. A drill, planter or air-seeder can be used. Cover crops can be no-tilled or planted in tilled ground. Less tillage may be needed for residue management, as the cover crop can help the process of residue breakdown. Placing the seed in the ground will provide the best opportunity for quick establishment. Seed can also be flown on, broadcasted or broadcasted and worked in, or applied with a liquid manure application.
Options
A simple way to start is with one or two species. A spring cereal alone or with radish or a clover is a good way to start. The radish and spring cereals will be killed by frost. As experience grows consider more complex mixes that include grasses, legumes and brassicas. Other options include oats or barley with peas, which can be used for forage or winter cereals for over winter growth.
Nitrogen and Cover Crop Growth
Spring cereals and the brassicas require nitrogen to grow as do corn and cereals we grow for grain. If manure has been applied, then there will likely be enough nitrogen for good cover crop growth. If the cover crop follows a winter wheat crop, then there may be very little growth without adding 30 to 50 lbs/acre of nitrogen. Legume cover crops should be inoculated if they haven’t been grown in the field before.
Termination
Before planting a cover crop it is important to think about what management it may require. Many cover crops, such as spring cereals and radish are killed by frost and as such don’t require a herbicide treatment. Others such as the winter cereals and clovers will survive the winter and will need to be killed in the fall or following spring. Some will go to seed, so they will need to be mowed or managed before viable seed is produced. Other methods that can be used to manage or terminate the cover crop are tillage, using a roller crimper or grazing.
Beware! Giant Hogweed
Be on the watch for Giant Hogweed. If you are aware of locations where it was present last year it is more than likely it will be there again this year. The white disk-like flowers of Giant Hogweed are now evident and reminiscent of Wild Carrot or Queen Anne’s Lace but on a much larger scale. These plants are usually five feet or more tall and the flower is 10 – 24 inches across. Be sure to avoid getting the sap from this plant on your skin or in your eyes as it can cause severe skin blisters and even blindness if it gets into your eye. The sap contains a chemical that destroys the skin’s ability to block the ultra-violet rays of the sun, resulting in deep burns.
The main stem may reach 4 inches across and is hollow between the nodes. It will be spotted with reddish purple sharp irregular bumps. Giant Hogweed has very large leaves, up to three plus feet with sharp pointed lobes. The flower head could be compared to Wild Carrot in that the umbel divides into 30 to 50 branches which in turn consist of another umbel of 30 to 40 flowers and later seeds. The whole head is flat on the bottom with slightly rounded top and white flowers and seeds.
Angelica is a plant with a round, greenish-white flower head and is occasionally confused with Giant Hogweed but is not dangerous. Angelica is not quite as tall and its leaves are divided into many leaflets. If you locate a plant with large leaves with the potential to grow to 10 or 12 feet and don’t know what it is, I suggest you call me at 519-846-3394. Giant Hogweed is a noxious weed and must be destroyed. Know it and beware of it.
