OACC studies aim for sustainability in organic production -
One prevalent question is how to address the issue of phosphorus deficiency in dairy production

By Jeffrey Carter, Special to Ontario Farmer, February 20, 2007

The sustainability of organic agricultural practices is the main thrust of a multi-year research effort coordinated by the Organic Agriculture Centre of Canada (OACC).

Funded with a $640,000 grant through National Sciences and Engineering Research Council of Canada, along with companion funding, the effort began in 2002, the project's principal investigator Dr. Ralph Martin says.

Researchers continue to evaluate findings from the various studies. Dr. Andy Hammermeister, one of the many scientists involved with the work, talked about research at the recent Guelph Organic Conference. He says 60 farms, stretching from Saskatchewan to Nova Scotia, were part of the project along with experimental farm sites.

One of the concerns for organic farmers revolves around the availability of phosphorus and how that relates to the use of forages and manure by organic farmers to maintain their soils, Hammermeister says. "Are we able to sustain phosphorus in our soils with organic practices? It's a big question."

A study of organic dairy farmers - a small part of the overall project - shows the phosphorus-deficiency is a real concern, depending on the specific situation. Farms attempting to be self- sufficient in feed tended to have net loss of soil phosphorus over time, Hammermeister says.

Another study, conducted at the long-term Glenlea Research Farm in Manitoba, linked phosphorus levels to the activities of soil fungi. As phosphorus levels decline, one group of soil fungi became more active, perhaps suggesting that the soil microbial community will attempt to compensate for reduced phosphorus availability.

Another important area of study concerned the comparison of soil erosion susceptibility between organic and conventional systems. While organic systems have been faulted in this area, there's been little research in Canada to back up the assertions.

In order to make a comparison, long-term rotational studies were examined and 225 organic and conventional farmers in seven different provinces were surveyed.

It was found that while organic farm practices tend to have higher levels of tillage, they usually include more perennial crops in their rotations. Perennial crops, whether managed organically or conventionally, promote superior soil aggregate stability. When all factors are taken into account, the study concludes that organic management does not inherently lead to a higher risk of soil erosion.

Another major area of study compared the availability of soil nutrients under a variety of rotations and soil amendment treatments. The rotations included potatoes planted every fourth year in various combinations with wheat, barley and forages. The soil amendments included composted poultry manure, composted beef manure and alfalfa meal.

One finding from the rotational study was that composted beef manure combined with forages in the rotation resulted in the highest tuber yields. Another related to the type of available compost. "You need to be selective. You need to think of which crops you are growing," Hammermeister says.

Among the other studies were: an evaluation of organic techniques, including the use of Bt sprays, to control the Colorado potato beetle; an evaluation of intercropping - the practice of planting a mixture of cereals instead of a single variety; a seeding-rate study; an evaluation of hot steam, open flame and infrared thermal for weed control; and an evaluation of alfalfa mulch on wheat.

Organic farming remains a small part of agriculture in Canada but is one of the fastest growing sectors, with an annual growth rate of about 25 per cent.

Further details of the research are available elsewhere on the OACC website.

 

© Copyright 2007, Ontario Farmer

The Organic Agriculture Centre of Canada (OACC) wishes to thank Ontario Farmer for permission to reproduce this article on our website.

 

Posted March 2007