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A review of farm-scale nutrient budgets for organic farms as a tool for management of soil fertility

Watson, C.A.; Bengtsson, H.; Ebbesvik, M.; Loes, A-K.; Myrbeck, A.; Salomon, E.; Schroder, J. and Stockdale, E.A. (2002) A review of farm-scale nutrient budgets for organic farms as a tool for management of soil fertility. Soil Use and Management, 18, pp. 264-273.

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Online at: http://dx.doi.org/10.1079/SUM2002131

Summary

On organic farms, where the importation of materials to build/maintain soil fertility is restricted, it is important that a balance between inputs and outputs of nutrients is achieved to ensure both short-term productivity and long-term sustainability. This paper considers different approaches to nutrient budgeting on organic farms and evaluates the sources of bias in the measurements and/or estimates of the nutrient inputs and outputs. The paper collates 88 nutrient budgets compiled at the farm scale in 9 temperate countries. All the nitrogen (N) budgets showed an N surplus (average 83.2 kg N ha-1 year-1). The efficiency of N use, defined as outputs/inputs, was highest (0.9) and lowest (0.2) in arable and beef systems respectively. The phosphorus (P) and potassium (K) budgets showed both surpluses and deficits (average 3.6 kg P ha-1 year-1, 14.2 kg K ha-1 year-1) with horticultural systems showing large surpluses resulting from purchased manure. The estimation of N fixation and quantities of nutrients in purchased manures may introduce significant errors in nutrient budgets. Overall, the data illustrate the diversity of management systems in place on organic farms, and suggest that used together with soil analysis, nutrient budgets are a useful tool for improving the long-term sustainability of organic systems.


EPrint Type:Journal paper
Keywords:Nutrient budgets, Nutrient use efficiency
Subjects: Soil > Nutrient turnover
Soil > Soil quality
Research affiliation: UK > Scottish Agricultural College (SAC)
Deposited By: Buchan, Mrs Elizabeth
ID Code:8061
Deposited On:07 Apr 2006
Last Modified:12 Apr 2010 07:33
Document Language:English
Status:Published
Refereed:Peer-reviewed and accepted

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