Manure Management Planning: The Essentials

Take home messages:

• Producers should consider developing a nutrient management plan (NMP) for their operations because it provides a framework for producers to obtain the greatest benefit from the economic and agronomic value of their manure, while protecting environmental quality at the same time.
• An important component of any NMP is gathering information about the physical features of the site or field that is to receive manure application. This will allow the producer to identify potential limitations or risks associated with manure application.
• Another key piece of a NMP is collecting information about the characteristics of the manure (i.e., physical form, nutrient content). Published values for manure production and nutrient content are averages and may not reflect the composition of manure on a given operation. Manure testing is the optimal situation.
• Nutrient application comprises determining nutrient application rates and pattern based on the identification of sensitive areas, crop rotation and cropping system, soil test information and manure nutrient content. This component is perhaps the most critical piece of the NMP.
• Producers should consider as part of their NMP implementing beneficial management practices (BMPs) to reduce the environmental risks associated with manure application. Alberta Agricultures BMP manuals outline several such practices that producers can implement.
• Record keeping is a key component of an NMP and allows producers to demonstrate due diligence with regards to nutrient management. Certain manure management records must be kept in accordance with the Agricultural Operation Practices Act (AOPA).

• On January 1, 2005, all the requirements for manure application limitations, record keeping, and soil testing came into full effect under the Agricultural Operation Practices Act (AOPA).
• Confined feeding operations (CFOs) must keep records, soil test and apply manure according to AOPA requirements.
• Custom manure applicators and cow/calf producers must also apply manure according to AOPA requirements and keep records only if they handle over 500 tonnes of manure per year.
• Anyone that can not meet the land base requirements, nitrogen and salinity limits, and setbacks under AOPA must receive an authorized Nutrient Management Plan (NMP) to use alternative practices that will provide equal or better protection to the environment.
• The regulations in AOPA protect livestock producers by ensuring that they protect water quality (surface/ groundwater), maintain livestock producers’ right to farm and by reducing livestock operations impacts on neighbours.

Nutrients and their fate in the environment: key learnings from long term field experiments at the Lethbridge Research Centre (full article)
Chi Chang and Xiying Hao, Lethbridge Research Centre, Agriculture and Agri-food Canada

Take home messages:

• Animal manure is an excellent crop nutrient source: Animal manure is not waste and it contains plant available nutrients such as N, P, K, Ca, Mg, S, Cu, and Zn etc.
• Nutrient management for animal manure is very complicated: Plant nutrients in the manure are not proportional to meet the crop requirements resulting in over apply for some nutrients and under apply for others.
• Crop nutrients could be potential contaminants for soil, water and air: If nutrients applied to soils in excess of crop uptake can potentially move into water resource and volatize into air, the nutrients become pollutants.
• Improper management of animal manure could cause negative Environmental impacts: If manure is not properly managed either in the feeding and other facilities or land application, the nutrients in the manure could move away from the target area to cause harmful effects on land, water and air.

• Nutrient management is a balance between production/economics and environment.
• Soil testing provides a means of checking the soil nutrient account and monitoring excessive nutrient accumulations. Benchmark or topographic landscape sampling will provide the best soil sampling results for temporal and spatial variability.
• Crop nutrient requirements are functions of the crop, yield potential, soil nutrient levels, soil pH, soil salinity, moisture conditions and agro-climatic zones.
• Nutrient use efficiencies are affected by the nutrient source, time of application, methods of application and the specific nutrient biological and chemical interactions with the soil.

• When generating a farm-specific manure nutrient content database, manure should be sampled for 3 to 5 years so as to account for variation due to climatic differences from year to year, which have a significant impact on nutrient losses during storage. Once a historical average has been generated from this database, the need for annual sampling diminishes.
• Manure should be sampled immediately prior to application, where possible. Samples taken at this time will closely approximate what is being applied to the field.
• Representative sampling is crucial when sampling manure. Although solid and liquid manure both present challenges to obtaining representative samples, producers should remember that the laboratory analysis will only be as good as the quality of the sample. A procedure for sampling manure is outlined in the environmental beneficial management practices (BMP) manuals put out by Alberta Agriculture.

• Basic components of a manure nutrient management plan include soil testing, fertilizer recommendations, quantity of manure, nutrient content of manure, Agricultural Operation Practices Act (AOPA) requirements, and record keeping.
• Nutrient availability in manure is not known exactly and can only be estimated based on certain assumptions. This represents a major practical limitation to nutrient management planning.
• Applying the AOPA nitrogen limits may result in over application of nitrogen relative to crop requirements, which poses a potential risk to environmental quality. It is preferable to apply nutrients based on crop requirements.
• Phosphorus-based application of manure requires a much larger land area compared to nitrogen-based application. This is because the N to P ratio in manure is different than the ratio required by the crop. This has special significance to producers operating on a limited land base.

• What are you trying to avoid losing? – or in other words, where are the savings? The method of manure application depends on the volume and consistency of the manure. Decisions and costs associated with broadcast spreading, field incorporation, and other management such as liquid injection or composting, are changing.
• The environmental risk of manure stems from over - application causing nutrient build up in soil, water contamination from runoff, and atmospheric changes (ie: greenhouse gasses). Along with the weather, residual or excess soil nitrogen is unstable and difficult to predict. Concern for phosphorous and salinity levels compound the problem of using manure as a nutrient replacement for crop production. When calculating manure application rates, a balance must be found between the expected soil nutrient levels and the potential crop demand.
• Crop nutrient content of manure is low by percentage of weight or volume. Think handling costs and fertility efficiency –Manure can be a disposal problem before it is a crop nutrient… as an organic soil amendment, fertility is a bonus.
• New manure application methods conserve soil and enhance crop nutrient goals. We need consensus on the definitions and standards for injection and compost, but relative to the splash & dash associated with pig poop plowing, or the intensity involved with raw feedlot manure management, I see no down side to a head-on approach that dares the nay Sayers to prove us wrong - in terms of the benefits of injection and composting… I've always said that if you want to understand something, try and change it!

• Intensive livestock operations generate large amounts of manure, which is generally not transported far from source. Over-application of manure can lead to soil, water and air quality problems.
• Composting is a means of reducing water content and mass of raw manure and potentially moving nutrients further away from source.
• A lot of different materials are called ‘compost’. Composts are quite variable in terms of chemical properties.
• Open-air windrow composting of solid feedlot manure is fairly ‘low-tech’. Other technologies include anaerobic digestion for production of biogas.
• Until now, cheap natural gas has precluded widespread adoption of anaerobic digestion in Canada.

• Manure nutrient content is ultimately a result of the feeding program. By concentrating on improving the efficiency of the feeding program we can also influence the nutrient profile of the manure.
• Nutrients in animal rations exceeding animal requirements are excreted in the urine and feces, making economical and environmentally responsible manner more difficult. Producers can address this situation through precision diet formulation, based on feed test information, credible animal nutrient requirements and careful selection of ingredients.
• The real benefits of precise ration formulation are not realized until coupled to the implementation of animal management practices designed to achieve maximum feed efficiency, such as phase/group feeding and managing feed wastage.
• Optimizing particle size of feed ingredients, using enzyme products such as phytase to enhance digestion, and using ionophores in ruminants are examples of advanced strategies that are not only effective at reducing manure nutrient excretion, but in certain cases can further reduce feed costs.
• Not all practices designed to reduce manure production or manure nutrient content will be feasible on all operations. Producers and those that are working with producers to must carefully assess what is appropriate for a particular operation.

• Nitrogen-based application rates of manure will cause phosphorus to accumulate in soil. Excess phosphorus in soil poses a significant risk to surface water quality.
• To be sustainable, the agriculture industry must shift to an integrated nutrient management strategy that results in a balance between nutrient inputs and outputs.
• A shift from nitrogen-based to phosphorus-based application rates of manure will require a much larger land base to accommodate manure.
• Producers will incur increased costs to transport and spread manure to meet phosphorus-based application rates.

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