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.
COVER CROPS: ADAPTATION AND USE OF COVER CROPS
Cover crops play an important role in maintaining soil quality and productivity on Ontario farms. Usually we think of cover crops in terms of reducing soil erosion and adding organic matter to the soil – but they can do much more.
Reduce soil erosion
Cover crops can do exactly what their name implies; cover the soil. A cover crop such as rye is commonly used to cover and protect the soil surface from wind and water erosion. The top growth covers the soil surface while the roots bind and stabilize the soil particles.
Cover crops may be planted over a whole field for erosion protection, or they may be selectively planted in the most erosion prone areas such as sandy knolls for wind erosion, water runs or low areas for water erosion.
Add organic matter
Cover crops do add organic matter but the amount really varies depending upon the cover crop species and the conditions under which it is grown. It would take 20 years to build the organic matter 1 per cent (provided that the soil was never worked to speed up decomposition).
Reduce nutrient losses
Some cover crops fix nitrogen but many more require nitrogen to grow. Grass cover crops like rye and Brassicas like oilseed radish are excellent scavengers of nitrogen left behind by the main crop or from manure applications.
This reduces the potential for the contamination of shallow aquifers by nitrates.
Improve soil fertility
Legume cover crops can fix nitrogen for a subsequent crop. Organic growers often include this type of cover crop in order to produce nitrogen for the rest of the crop rotation.
Deep-rooted cover crops can bring nutrients up from deep in the soil profile.
Reduce pest populations
Some cover crop species may be a non-host for a pest or may release materials that are toxic to the targeted pest.
For example many common cover crops have been rated for their ability to support root lesion and other nematode populations.
Reduce compaction and improve soil structure
Cover crops can help to reduce compaction and improve soil structure. The addition of the plant top and, especially root matter, helps to improve water infiltration and holding ability. It can also decrease soil bulk density.
Deep rooted cover crops can help to decrease the impact of soil compaction.
Water management
Cover crops can be grown and the residues used to mulch the crop and help to reduce moisture loss.
In contrast, some growers use cover crops such as rye as a way to reduce soil moisture in early spring. The crop takes up the soil moisture and uses it within the plant. The water is incorporated in the plant tissues or is transpired. Either way the water is removed from the soil.
By Anne Verhallen, soil management specialist, OMAFRA
For entire article, please visit website http://www.omafra.gov.on.ca/english/crops/facts/cover_crops01/cover.htm#reduce nutrient
COMING EVENTS
May 25 – Deadline to apply for Premier’s Award for Agri-Food Innovation Excellence – 2018. For more information, contact the Agricultural Information Contact Centre at 1-877-424-1300 or ag.info.omafra@ontario.ca.
