AGRICULTURE COMPOSTING

Basic Principles of Zeolite in Composting Operations

Composting is a process that converts organically bound nitrogen to ammonium nitrate and ammonia, both of which are plant-accessible nutrients. It also kills pathogens, dries manure, and kills weed seeds. Ultimately, the goal is to produce high-quality compost that can be used as a bio-based soil amendment (Olds College, 2004).

Methane and nitrous oxide are two greenhouse gases produced during the composting process (Olds College, 2004). Scientists have concluded that both gases are more potent than carbon dioxide. Aluminum silicates (such as zeolite) can sequester nitrates, sulphates, and hydrogen ions, which can prevent methane and nitrous oxide production during the composting process; studies have demonstrated that aluminum silicates can reduce emissions by 20 percent (Olds College, 2004).

Natural zeolite provides value to the composting processes because of its ability to absorb water and adsorb plant- available nitrogen through cation exchange. Also, zeolite prevents soil compaction and works to increase infiltration, both of which promote soil aeration. This benefit is made possible by the mineral’s high surface area and porosity.

A study by Zhang and Sun (2015) examined the effects of an earthworm cast and zeolite mixture on the composting of green waste. The results indicated that the mix improved the quality of the compost products in regards to nitrification, enzyme activities, and microbial numbers. Also, the compost matured in only 21 days as opposed to the common 90 – 270 day time period required of traditional composting (Zhang & Sun, 2015).

Zeolite has two methods of holding cations such as ammonium and plant nutrients. The first method is by absorption in its porous matrix. The second method is by cation exchange (CEC) – zeolite holds ammonium and other plant nutrients in the Crystal structure where they are not water-soluble but are plant-accessible on an as-needed time-release basis.

How does Using zeolites Benefit my soil?

Using zeolite will cut fertilizer and water costs by holding the nutrients and water in the root zone until the plant is ready to utilize them. Thereby requiring less fertilizer and water to be applied. This promotes good stewardship of the land by reducing pollution brought on by fertilizers leaching to the groundwater or running off into surface water sources. Zeolites, when used properly, can yield some impressive results in regards to faster germination times, faster growth rates, larger plants, crop yields and reduced fertilizer and water applications.

Reduces water requirements during irrigation as zeolite holds moisture in the growth zone.

Zeolite has a high CEC that enables a greater loading of plant nutrients such as nitrogen & micronutrients. The nutrients are held in the growth zone and are plant accessible but not Water-soluble.

Reduces nitrogen fertilizer requirements as a large portion of nitrogen fertilizers leach through the growth Zone and into the aquifer. Zeolite will hold nitrogen and prevent the pollution of the water table by nitrates and nitrites.

Zeolite prevents compaction, increases infiltration, and helps the aeration of deep

Zeolite is 100% natural for organic operations and when composted with manure, it becomes a natural fertilizing system.

Zeolite Use in Compost or Dry Stacked Manure

The compost or dry stacked manure should be top-dressed with a thin layer of zeolite after it is turned or after the addition of a new layer of manure. Alternatively, a layer of Zeolite should be placed in the area of the barn receiving the fresh manure. Composting is an important process that

(1) converts organically bound nitrogen that is not plant accessible to ammonium hydroxide, ammonium nitrate, and ammonia that are all plant accessible

(2) kills the pathogens, (3) reduces or eliminates the odor

(4) dries the manure

(5) reduces the flies, and

(6) kills weed seeds. Composting should be conducted in-vessel to prevent groundwater and air pollution. Wash down operations are no longer environmentally acceptable due to groundwater pollution of nitrates, nitrites, and hydrogen sulfide.

Incorporating Zeolite in Manure Compost Retains Nutrients & Reduces Greenhouse Gas Emissions

Project Applicant – Dr. Abimbola Abiola, Olds College School of Innovation:

The Challenge – To show through an on-farm demonstration project that the incorporation of zeolite into livestock manure during composting reduces the production of nitrous oxide and methane, while retaining valuable nutrients.

Funding Allocation – The Greenhouse Gas Mitigation Program (GHGMP) for Canadian Agriculture has allocated $2.1 million for beef sector projects over three years ending March 31, 2006. The GHGMP has contributed $87,500 toward this project. With manure composting growing into an economical and practical method for managing cattle manure, improving the process by retaining more of the valuable nutrients, and reducing odour and greenhouse gas emissions are also becoming important considerations for cattle producers. The Olds College School of Innovation will demonstrate how to achieve all these objectives when composting beef cattle manure by incorporating zeolite into the compost windrow. The goal is to produce a high-quality Compost that can be used as a bio-based soil amendment. Along with nutrient value, compost also can help improve Soil quality characteristics.

“Preliminary results of earlier research suggest that when zeolite is ingested by cattle through feed, it may reduce methane production in the rumen,” explains Abiola. “With this project, We intend to show We can achieve a similar reduction in greenhouse gases by adding the compounds to feedlot manure in the composting process. By retaining more of the nitrogen in the compost, less is released as nitrous oxide, a greenhouse gas. Naturally occurring zeolites are commonly used in a number of industrial applications. Zeolites, which can filter, remove odour and absorb gas, are often used in water softeners  Zeolite part of a larger group of compounds known as aluminum silicates and silicates are derived from silicon. “If you think of carbon as being the backbone of life, then silicon is the backbone of soil,” says Abiola. “The key characteristic of zeolites are their ability to perform filtering, odour removal and gas absorption tasks.” Methane and nitrous oxide are two of the greenhouse gases produced during the composting process. Both gases are more potent than carbon dioxide. Aluminum silicates can sequester reactive ions such as nitrates, sulfates and hydrogen ions, which may reduce methane and nitrous oxide production during the composting process. It has been estimated that the use of aluminum silicates may reduce methane and nitrous oxide emissions by 20 percent. Assisting Abiola on the project is Tanya McDonald, a research technician at the Olds College School of Innovation. McDonald says despite the tough year agricultural producers have experienced, there is still the need to examine manure management options.

“As agriculture moves towards larger farm sizes and increased animal numbers, there is a greater need for effective methods of dealing with manure,” she says. “Composting is one management strategy that results in improved nutrient retention, reduced odour and pathogen content, and reduced volume of manure to be handled.”
Turning manure into rich compost
The first year of the project is intended to produce a nutrient-rich compost suitable for use as a bio-based soil amendment, using a process that reduces production of greenhouse gases such as methane. “Properly composted material should not produce methane gas,” says Abiola. “Methane is only produced under an anaerobic environment (without oxygen), while proper compost is made in an aerobic environment (with oxygen).”

The Olds College demonstration site involves a 10,000 m2 clay-based pad for the compost windrows. Manure and bedding material from the college feedlot will form four composting windrows. The windrows will be approximately two meters tall, four meters wide and 50 meters long. The zeolite will be added to the windrows. Three windrows will contain zeolite in various percentages, with the fourth windrow being the control. 

“Zeolite has proven benefits in many industries,” says McDonald. “Zeolite is used in everything from plant growth media, health applications, feed additives, Wastewater filtration and composting. It has an excellent ability to bind ions.” It is also widely used in horticultural, construction and industrial applications. It can improve aeration and moisture retention, which makes it a useful product to include in the demonstration. A Scarab compost windrow turner will work the product into the manure. Windrows will be monitored to ensure that temperatures reach 55C, needed for the destruction of pathogens and weed seeds, and the windrows will be turned five times within the first fifteen days. Gas monitoring will be done on the first day of the project, and then again on days 10 and 30. Gas samples are collected using a flux chamber situated on the top of the compost pile. These samples are analysed for carbon dioxide, methane and nitrous oxide Concentrations. These measurements will be related to the various amounts of Zeolite added.

“Our objective is to not only show how the Zeolite works in reducing greenhouse gas emissions, but also to determine the economics,” says Abiola. “We need to determine the economic ratio of aluminum silicates for the amount of manure being composted and the benefits achieved.” Once the active phase of composting is complete, the compost will be left to cure. Samples will be analysed for nutrient content prior to field application of the product as a bio-based soil amendment.

Using the product
In the second year of the project, team leaders will use the manure compost as a bio-based soil amendment for field crops and compare the results with synthetic fertilizer. The compost will be divided into four equal parts. Half the compost will be broadcast applied to the pasture, with split applications of the material in the fall and spring. This application will not be incorporated. The other half of the compost will be used on barley silage with the same split application timing, but the compost will be incorporated.

Project leaders expect a comparison between compost and commercial fertilizer applications will showcase the performance of compost against synthetic fertilizer infield crop applications. “Zeolite is an excellent product for enhancing plant growth,” says McDonald. It provides aeration and improved moisture retention. Zeolite acts as a slow release fertilizer, releasing nutrients as they are required by the crop. It should perform very well in the field.

The benefits

Adding zeolite to the composting manure is an effective way to manage manure, says Abiola. Essential nutrients are retained while greenhouse gases naturally produced during the composting process are minimized. Odour from the manure is also greatly reduced.
Producers will be able to see first hand the economic benefits of adopting such a process for their operations. Confined feedlot operators will be able to maximize the value of manure as a bio-based soil amendment on their own land. There’s also potential to market composted manure as a commercial product.

“Composting beef manure provides a cost effective solution to many manure management issues, such as volume and odour reduction,” says Abiola. He adds that there may be an opportunity for producers to trade carbon credits if that market develops.

Abiola notes the success of these two projects will have national implications. If shown to be both practical and economical, livestock producers across Canada would be able to implement the system. The GHGMP supports a broad range of projects across Canada.
Aluminum Silicate (Zeolite) Reduces Manure Odour & Cuts Greenhouse Gas Emissions
Olds, Alta., September 15, 2004

The Olds College School of Innovation will demonstrate that adding an aluminum-based mineral to composting beef manure will help reduce odour and greenhouse gas emissions, while retaining valuable nutrients, providing moisture and aeration.

The aluminum silicate product is a volcanic mineral called Zeocan Zeolite. This naturally occurring mineral is also commonly used in a number of industrial applications. “Preliminary results of earlier research suggest that when this mineral is ingested by cattle through feed, it reduces methane production in the rumen,” explains Dr. Abimbola Abiola, project leader. “With this project, we intend to show we can achieve a similar reduction in greenhouse gases by adding the compounds to feedlot manure in the composting process.” The process will produce a high quality compost, to be used as a bio-based soil amendment. Along With nutrient value, Compost also helps improve other Soil quality characteristics. The demonstration project is being funded in part by the Greenhouse Gas Mitigation Program for Canadian Agriculture (GHGMP). The federal program is designed to promote awareness of agricultural practices that reduce atmospheric levels of greenhouse gas or increase carbon storage in soils. The Canadian Cattlemen’s Association (CCA) administers the delivery of the beef sector component of the program.

The project site is located at the Olds College Composting Technology Centre. In the first year of the project, four windrows were assembled using manure from the Olds College feedot, says Abiola. One windrow, without any treatments, will be used as the control, while the other three windrows include a combination of manure and zeolite in various percentages. The windrows will be turned at specific times to ensure effective aerobic composting. Gas emissions Will also be monitored to measure methane, Carbon dioxide and nitrous Oxide production. Gas measurements will be related to the amounts of zeolite added to the Compost. Our research is not only to show how the silicates work in reducing greenhouse gas emissions, but also to determine the economics,” says Abiola. “We need to determine the economic ratio of zeolite for the amount of manure being composted and the benefits being achieved.” Once the active composting process is complete, the compost will be left to cure. In the second year of the project, the treated and untreated composts will be applied to field crops and pastures and compared to commercial fertilizer. Abiola says adding zeolite to the composting manure is an effective way to manage manure. Essential nutrients are retained, while greenhouse gases naturally produced during the composting process are minimized. The Olds College demonstration is intended to show the environmental and economic benefits of composting. He says feedlot operators will be able to expand their manure management options and use this valuable bio-based soil amendment on their land. There may also be opportunities to sell the composted manure as a commercial product.

“Composting beef manure could provide a cost effective, environmentally friendly solution to many manure management issues such as volume, odour and timing of application,” says Abiola.
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Greenhouse Gas Mitigation Program for Canadian Agriculture

Beef Sector Administered by the Canadian Cattlemen’s Association.

References