Tackling the future challenges of Organic Animal Husbandry - vTI

! Agriculture and Forestry Research, Special Issue No 362 (Braunschweig, 2012) ISSN 0376-0723
Download: www.vti.bund.de/en/startseite/vti-publications/landbauforschung-special-issues.html
(Sundrum et al. 2008). In general, requirements for external N inputs on livestock farms can be reduced
by improving N utilisation (Paul & Beauchamp 1995). However, farmers often do not have a
clue about the amounts and quality of nutrients, flowing through the different sub-systems of their
farms, and on how to strive for possible savings in expenses and nutrient losses, simultaneously.
Thus there is a need for more orientation, data and criteria to deal with.
Table 1. Mean and min-max values of N-efficiency in relation to the whole farm system, to
different sub-systems, and to feed efficiency on organic dairy farms
Due to the ban of mineral N fertiliser, N is the first limited factor for growth processes in plant cultivation
in organic farm systems. Limitations in the purchase of cheap N sources enclose an inherent
incentive to increase the efficiency of N, available within the farm system and to reduce N losses
to a minimum when striving for an increased productivity. Hence, N-efficiency serves as a production
goal and simultaneously as key criteria to estimate the potentials for reducing inputs and
nitrogen losses while increasing productivity.
In the current study, average farm-gate N surplus and variation were similar, compared to those
found by Haas et al. (2007) on organic dairy farms in Germany. However, farm-gate nutrient balance
assessments provide very little information with respect to improvements of the nutrient management
while at the same time bear the risk of leading to unjustified self-content or misinterpretation.
Although the number of farms investigated in the current study was small, the data indicate both
large variation in N efficiency between sub-systems and farms and a considerable potential for improvements.
The investigations gave reasons for the assumption that the knowledge of organic
farmers concerning the farm specific nutrient flow might be low.
Farm specific data on N-efficiency in sub-systems provide helpful information about the weak
points in the nutrient management. Whether the farmer is well recommended to implement specific
measures to increase N-efficiency depends on the effectiveness and the cost-benefit relationship of
the measures in the specific situation. Due to the fact that both effectiveness and efficiency are the
result of complex interactions between various factors within the farm system, estimations cannot
be deduced from general knowledge derived from scientific results or from text books. Instead,
management decisions should be based on the farm specific boundary conditions and on sound data
that reflect the nutrient flow and the transformation processes of nutrients within and between subsystems.
Suggestions to tackle the future challenges of organic animal husbandry
Data from organic dairy farms indicate a large potential to increase N efficiency while at the same
time enhancing profitability. The systemic approach proved to be a powerful tool to identify weak
points in nutrient management within the farm system. Main challenges in nutrient management are
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Organic dairy farms (n = 9) Efficiency (in %)
Whole farm system
(N-input / product related N-output)
Sub-systems
Livestock
44 (23 - 72)
84 (79 - 87)
Dung storage/distribution 65 (49 - 88)
Arable land/pasture 62 (40 - 81)
Feed storage/distribution 87 (59 - 95)
Feed efficiency (N-feed / N-milk) 14 (10 - 18)