|
|
Article: SOIL CONSERVATION
|
|
SOIL CONSERVATION - Jon Radojkovic
Looking at the soil as a dead inert mass is a misconception that was initally written about by soil guru Sir Albert Howard.
"The soil is full of live organisms and is pulsating with life," wrote Sir Howard. Yet in the intervening 60 years since he wrote his book, The Soil and Health, farming practices, led by advocates of chemical farming as the answer to feeding the world, are slowly coming around full circle to some of Sir Howard's principles. He promoted, among other things, crop rotation, planting cover crops and the significance of humus, which is plant deposit that slowly decomposes and enriches the earth. "Humus is the most significant of all of nature's reserves," he wrote.
Today, with Green House Gases and other detrimental environmental consequences as a result of poor farming practices, Conservation Canada is a leader in the fight through experimentation, of how to keep our soils healthy, and at the same time our farms economically viable.
"The whole economics have changed," says Glen Hass, a retired Saskatchewan agrologist, extension specialist and former executive director of the Soil Conservation Council of Canada (SCCC).
"Larger farms, higher fuel costs, higher crop input costs, means farmers need to be more efficient. So bad management or poor practices, which people think may save money, just don't cut it anymore. Farmers are interested in the best management practices which benefit the soil, water and improve crop yields, but at the same time they need to make economic sense," said Hass
As an example SCCC began experiments on a typical fall wheat crop. After a wheat crop is harvested, there is at least two months of growing weather still to come. This is where some of Sir Howard's experiments in the 1940's are coming to mean something today as well. Leaving the soil as bare earth after a wheat harvest for up to two months before winter sets in leaves a space for farmers to use that sunshine to improve their soils and their bottom line. One solution is planting cover crops.
The SCCC did eighteen research/demonstration cover crop plots following a winter wheat harvest over a 3-year period. Cover crop species included annual ryegrass, buckwheat, oats, oilseed radish, peas and red clover. Different types of manure were also evaluated (swine, liquid dairy, or solid cattle manure) as well as and non-manure plots were evaluated at each site.
The results after three years of trials (2003-2005) in south western Ontario have shown that cover crops after wheat can produce significant plant biomass. These plots showed various cover crops captured significant nitrogen in their plant material, and greatly reduced late fall soil nitrogen levels. All the soil health measures improved such as increasing organic matter, water infiltration and water holding capacity, and reducing soil erosion.
In dollar terms cover crops can reduce synthetic nitrogen inputs for the next crop, while adding nature's most significant reserve: humus, as Sir Howard had said.
"Climate change is clearly associated with Green House Gas emissions, and farmers and ranchers understand the relationship it has to the sustainability of their farms and ranches. To them, climate change means the higher probability of drought, excess precipitation and a number of other extreme weather scenarios that could mean the loss of crops and livelihood. In short, it hits them where they live," explained senior scientist Dr. Ray Desjardins, from Agriculture and Agri-Food Canada.
To reverse climate change, zero tillage, cover crops and summerfallow are being recommended. "Canadian soil has lost about 1,100 million tonnes of carbon since the beginning of cultivation. Thanks to practices such as reduced tillage, we're starting to reverse that process." says Desjardins, who has worked as a leading scientist on the Greenhouse Gas Mitigation Program (GHGMP), a national program dedicated to reducing greenhouse gases on farms and ranches.
Although scientists and farmers have often been at odds with each other, one scientist, is recommending the best ways to find out more is to have farmer to farmer discussions. "Farmers can talk to each other and show each other what they are doing - those are the actions that plant the seeds of ideas. One farmer can say, 'that idea is working here, maybe that will work on my farm too'. says Odette Ménard, a soil and water conservation specialist with the Québec Ministry of Agriculture.
Fact sheets have been produced for farmers such as the Greenhouse Gas Mitigation Program for Canadian Agriculture. The ministry found that farmers liked to receive a two-page fact sheet on improved management practices once a month rather then 20-page report once a year. See www.soilcc.ca.
"No matter where you farm in Canada, the challenge ahead for producers is to balance the requirements of best management practices with economics," says Hass.
And as for Sir Howard, after so many years, he is slowly being proven right.
|