Research Report 1.2

Nitrogen and Carbon transformations in
Conventionally-Handled Livestock Manure

Dr. G. Kachanoski, Environ. Soil Services,
605 Arkell Rd., Arkell, ONT N0B 1C0
COESA Report No.:  RES/MAN-002/97

Objectives & Expected Outputs

Interpretative Summary

Photo Gallery

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Objectives and Expected Outputs

Objectives:

Document the state of our knowledge of nitrogen and carbon transformations which occur during conventional storage and handling of solid and liquid livestock and poultry manures; to investigate various manure storage and handling techniques with respect to N and C changes during storage and handling while recognizing nutrient conservation and availability for plant growth; to provide a comparative economic assessment of costs associated with manure handling, the nutrient content and value of the final product.

Expected Outputs:

Nitrogen and carbon components in the feed, bedding and excrement of livestock will be tracked during handling and storage. Recognizing the changes which are certain to occur after application of the manure to the land consideration will be given to techniques which involve incubation of manure with soil. Consideration will also be given to monitoring the losses from the greenhouse gas perspective. It is anticipated that useful information will be obtained enabling the prediction of manure nitrogen availability for plants and losses of environmental importance.

Type:

Open Bid, Industry                             

Spending Profile:

93-94: $113.2 K,   94-95: $133.6 K,   95-96: $130.0 K,   96-97: $122.7 K,   Total: $500 K

Status:

Available March 1998

 

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Interpretive Summary

One objective of this project was to investigate various manure storage and handling systems with respect to nitrogen (N) and carbon (C) changes during storage and handling. A literature review found few definitive studies done specifically on this topic. These transformations determine the nutrient content and losses from the handling system. Thus, a primary goal of the project was to measure C and N of the animal feed, fresh faeces, and the various states of transformation of the manure as it moved through the handling system. The magnitudes of the various losses of C and N between the handling stages were also measured. Thus, methods of estimating the mass balance had to be devised. Since the economics of the systems also had to be assessed the study was done on "operational sized units".

Six manure handling systems were chosen to track the mass balance of C and N for a defined set of inputs and outputs. The systems included:

  1. solid poultry manure,
  2. solid top-loading beef,
  3. liquid swine (high water use),
  4. liquid swine (low water use),
  5. solid dairy, and
  6. liquid alley-flush dairy.

The study allocated considerable resources to chemical analysis, to form a reference database of chemical composition of manure from as many components of the different systems as possible. This characterization included aerobic incubation of sand-soil-manure mixtures in the laboratory to measure mineralizable C and N. Full nutrient analysis (N, P, K, C) are given along with selected analysis of C and N compounds (lignin, acid digestible fibre, volatile fatty acids, etc ). The data given are average values for major time periods (fall, winter, etc ), but sampling was usually done on a weekly or bi-weekly basis. Measurements of greenhouse gas flux rates were made to rank stages of the handling system with respect to their potential to generate these gases. Usually the greenhouse gas losses (except CO2 ) were negligible with respect to mass balance of C and N. However, the magnitudes of the losses are important from an environmental perspective.

The fate of the C and N inputs varied depending on the manure, but there were also many similarities. The amount of N excreted as fresh faeces was consistently 70 - 80% of applied feed N. Final plant available manure NH4-N amounts as a percentage of N inputs were:

  1. solid poultry manure = 7.5 to 10%,
  2. solid top-loading beef = 8%,
  3. liquid swine (high water use) = 38%,
  4. liquid swine (low water use) = 40%,
  5. solid dairy = 19%, and
  6. liquid alley-flush dairy = 40%.

Additional amounts of organic N were in the manure, but it varied from 1% (liquid swine) to 45%(solid dairy) of input N. Gaseous loss of N from NH3-N volatilization was the major pathway of N loss. The loss occurred very quickly from fresh manure leaving few management options for reducing N loss.

A second major objective of this research was to provide a comparative benefit-cost assessment of the six manure-handling systems. A questionnaire was designed for collection of bio-physical and economic data from farmers, through on-farm interviews or mailing out. A spreadsheet system was developed to analyse the farm data and produce a profile of total annual manure production, total capital investment in manure-handling facilities and equipment, annual costs of ownership and operation of manure-handling, economic benefits from manure, and total net costs or benefits from manure operations. Five of the six farms displayed net costs of manure operations (i.e. costs exceeded benefits) ranging from $4.13 to $124.28 per tonne of manure applied per year. The sixth farm showed a net benefit of $0.06 per tonne of manure applied per year. These results concurred with previous research results, which typically showed a net cost for manure operations.

Results from this study are being used by a manure systems team at the University of Guelph to aid in development of an expert system for managing animal waste. The final manure generated from the different systems was used in a different study evaluating plant uptake of the manure nutrients. This study is a separate AAFC Green Plan Report No. 1.4 (Principle Investigator, Dr. E. Beauchamp, Univ. of Guelph), but the combination of the studies gives a complete summary of the fate of C and N and other nutrients.

 

Photo Gallery

A poultry barn where they raise chicks to broilers on sawdust litter. We monitored changes in litter composition due to excrete during a summer and winter production cycle. The farmer removes the resulting manure from each crop of birds and spreads it or piles it outdoors. For manure stored over winter, core samples were collected in the spring to detect changes in composition in the pile.

A poultry barn

A dairy barn using a gutter cleaner for manure removal. Samples of manure were collected from gutters just before cleaning so that we-could learn amount and composition of fresh manure. Samples of urine, faeces, and feed were also collected periodically.

A dairy barn using a gutter cleaner

Solid dairy manure removed by a gutter cleaner and top-loaded onto a cement pad. Where the manure pile accumulated over several months, cages containing a known weight and composition of fresh manure were periodically added in* the pile. We retrieved these at the time of spreading to detect changes in composition and losses during storage. Pile volume was determined by surveying and bulk density by cutting measured blocks with a hedge trimmer.

Solid dairy manure removed by a gutter cleaner

An exercise alley in a cow-calf barn at a beef production unit. Manure in the alleys is scraped daily into a gutter and top-loaded onto a cement pad. The pad also receives packed straw-manure mixtures from the bedded areas. Runoff from the alleys and storage pad is collected in an underground covered storage tank. We monitored volume and composition of the stored runoff, and collected solid manure samples throughout the spreading operation to detect variability in manure composition.

An exercise alley in a cow-calf barn

The grower barn at a farrow-to-finish swine farm. Liquid manure below slatted floors was sampled for weaner pigs, starters, growers, and sows, and feed samples were also collected periodically. We monitored depth of stored manure to learn amounts produced by animal type. Sometimes a sampler was left below the floor for 24 hours to collect fresh manure.

Grower barn at a farrow-to-finish swine farm

The top of a 12-meter high manure storage tower. Samples from various depths are collected with a kemmerer bottle. Profile samples were also collected if the liquid storage was not more than 4 meters deep.

Top of a 12-meter high manure storage tower

Monitoring gas flux from a floor-grating over manure storage in a swine barn. We calculated emission rates through the grating from the rate of increase in gas concentration in the chamber. This chamber was designed for floating on liquid manure. We used another closed chamber for monitoring gas flux from solid manure piles. Gas samples were analyzed for carbon dioxide, methane, nitrous oxide, and ammonia.

 


 

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