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Composting and agriculture a match made in soil

Ontario greenbin compost agricultural trials confirm benefits of compost for the agricultural industry – but there is still a long way to go

Susan Antler - Executive Director at Compost Council of Canada.
Susan Antler - Executive Director at Compost Council of Canada.

At a time when “doom and gloom” is frequently associated with the state of our environment, a compelling opportunity is being presented to two largely unconnected forces – agriculture and waste management. The opportunity: return compost made from the organic residuals being recycled by residents through local municipal greenbin programs to build the health and vitality of agricultural soils, strengthen soils’ resilience against potential drought conditions and use soil as a “carbon bank” for climate change mitigation.

Compost’s multiple benefits are well-suited to benefit agricultural soils. But, while there has been some market inroads made by specific compost producers (largely focused within the organic agricultural community and for high value crops) the overall agricultural market for compost, and more specifically greenbin compost, remains largely untapped.

To move from “textbook” to in-field reality, the Greenbin Compost Agricultural Trials were developed by the Region of Peel, Ontario, with support from The Compost Council of Canada and the Green Municipal Fund. At each of the 15 participating farms, greenbin compost was incorporated into specific field plots. Side-by-side comparisons were set up, with municipal compost compared to commercial fertilizer and/or other organic amendments (biosolids). Depending on the source of the compost, municipal compost included combinations of leaf and yard waste and food waste materials.

The results of the three-year applied research trials in Ontario are showing that compost is helping to re-build soil structure, creating healthier soils. One farmer involved observed that “Worm activity is extreme now. There are literally thousands of worms. Water retention and soil tilth are better, and the soil smells better.” Combined with improved yield, these increases are encouraging.

However, the reality is that it takes time to build healthy soil. Right now, there is a disconnect between expenditure and results. Farmers must pay the cost of acquiring, transporting and applying compost up front, just as they do with commercial fertilizers. But unlike commercial fertilizers, compost doesn’t always result in immediate, quantifiable increases in crop yields.

Compost’s benefits accrue over several years. Depending on a variety of weather, soil and other factors, yields might rise, remain constant or even decline in the first year or two of compost application, requiring considerable investment. Financial returns may only be realized after multiple years of effort and commitment by farmers to their soil.

The Region of Peel studies are also reinforcing the need for the compost industry to increase its diligence on producing quality product – both in terms of agronomics and aesthetics.

Currently, the “foreign matter” (primarily small pieces of plastic debris in the form of film and hard ‘chips’) which can be found in compost produced from greenbin sources can be a deterrent to having it applied to agricultural soils. Aesthetically, this material detracts from the perceived quality of compost.

Of course, beyond the efforts of individual farmers and compost producers, the commitment to “feed the soil… compost!” must also be the responsibility of society at large.

Compost’s return to the soil serves as a “carbon bank”, helping to store carbon and remove it from the atmosphere. The recent United Nations Climate Change Conference, COP21, held in Paris in December, 2015, saw the launch of the “4/1000 Initiative: Soils for Food Security and Climate”. The intent of the initiative being to achieve a 4/1,000 annual growth rate of the soil carbon stock, considered crucial to improve soil fertility and agricultural production, and helping to achieving the long-term objective of limiting global temperature increases to +1.5/2 degrees C.

Soil carbon sequestration also strengthens the soil’s ability to retain moisture, “buying time” during drought conditions. As identified by the Food and Agricultural Organization of the United Nations, “… Compost is important because it enhances overall soil health and its resilience to shocks such as drought, including climate change adaptation.”

Overall, compost is an expenditure that offers an excellent return on investment. Its application in the agricultural sector provides improvement of soil health, supports local food production and mitigates climate change.

Proven research, in-field observations and yield results all show that applying compost to agricultural lands is the right thing to do. Still, there are currently considerable obstacles in the way. Most of these obstacles can be overcome with a concerted focus by government through policies and programs to have compost viewed not as a cost but as an investment.

This article is reprinted here from its original, as featured in Recycling Product News, July/August 2016 edition.