Manure Management
 
Environmental Issues

Animal manure management is defined as a decision making process aiming to combine profitable agricultural production with minimum nutrient losses from manure, for the present and in the future. Good manure management will minimize the negative and stimulate the positive effects on the environment. Gas emission and leaching of nutrients, organic matter and odor have undesirable effects onto the environment. The contribution of manure to plant nutrition and build up of soil organic matter is considered to have a positive effect. An indirect positive effect is that the use of animal manure may save non renewable resources used in inorganic fertilizer production. 

Negative and positive aspects of manure are closely interrelated because emissions at an early stage inevitably have repercussions on positive effects on the soil and any crops at a later stage. This is schematized in Figure 1. The amounts of nutrients sucgh as N, P and K taken up by the crop determine the agricultural value of the manure and depend on the amounts of nutrients emitted during the path from animal to crop. The greater the nutrients loss the lower agricultural value of the manure.
 
Figure 1

Possible nutrient losses from manure between excretion and crop uptake.

Source:  redrawn from Brandjes et al., 1996.

Click on the figure to view a larger version

Techniques

The manure management systems are highly diverse:

Manure deposit by kraaling. North Senegal. Photo: Yasmina Lemoine
  • Lagoons: Liquid manure, either before or after separating parts of the solids, is treated in anaerobic lagoons. Organic material is decomposed, thereby mineralizing part of the nutrients. The liquid phase is either discharged into surface water or used for irrigation. 

  • Emission of NH3, CH4 and N2O.

    [See also: Greenhouse Gas Emission]

Photo: Arend Nell
The photo shows storage of manure in a lagoon 
- without any lining and without any cover
Targeted Livestock Systems

All livestock production systems are concerned, but industrial systems are the most implicated because of the large amount of manure produced. The mixed systems generally include processing and utilization of manure in farming procedures.

Grazing System
LGA LGS1 LGS2 LGS3 LGH1 LGH2 LGH3 LGT1 LGT2 LGT3
y y y y y y y y y y

Mixed System
MCG MCR MCC MFF MEF
y y y y y

Industrial System
IFP IPL IPG IRM IDU ISL ITN IMP
Y Y Y Y Y Y Y Y

Impact

  • Positive environmental impact
    • Negative environmental impact
    • Ammonia emissions: before and during storage, and during application in the field.
    • Emission of NOx: this is formed as a by-product of the denitrification process.
    • Emission of methane, formed upon decomposition of manure under anaerobic conditions.
    • Runoff of manure and manure components into surface water, contributing to water pollution.
    • Leaching of nitrate and phosphorus into the ground water, contributing to underground water pollution.
    Overflow from manure pit on open water. Photo: Arend Nell
    Overflow from manure pit onto 
    open water - a negative impact 
    of poor manure management
    Context of Application References

    Brandjes P.J., de Wit J., van der Meer H.G., van Keulen H., 1996. Environmental impact of animal manure management. Livestock and the environment ? Finding a balance. International Agriculture Centre, Wageningen (the Netherlands), pp. 53.

    H.J.M. Hendriks and A.M. van de Weerdhof. Dutch Notes on BAT for Pig- and Poultry Intensive Lifestock Farming. August 1999. Information Centre for Environmental Licensing, P.O. Box 30732, NL-2500 GS The Hague, The Netherlands. Tel: +31 70 3610575; Fax: +31 70 3633333; Internet: “www.infomil.nl”. Click here to view document in Acrobat format.

    See Also

    Manure Storage

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