This page of the Methodologies section gives information and links to procedure for estimating the nitrogen budget of cropping systems.
Data input sheet for estimating soil-surface N budgets
Here is a spreadsheet which is aimed to help you calculate a comparative 'soil-surface N-balance' analyse (c.f. OECD 2001; Parris 1998) for experiments which gather data from functionally distinct crops or cropping systems, for example with and without legumes.
The N-balance analysis includes an assessment of N surplus [N inputs - N outputs] and N use efficiency [NUE, N outputs/ N inputs] (c.f. OECD 2008). The N-balance data sheet in the file accessible below allows data to be described in relation to productivity using biomass and monetary value for a main crop only or main-crop/sub-crop combinations where co-cropping has occurred as part of a cropping sequence or rotation.
OECD (2001) Environmental indicators for agriculture: methods and results. Vol 3. OECD, Paris, France.
OECD (2008) Environmental performance of agriculture in OECD countries since 1990. OECD, Paris, France.
Parris K (1988) Agricultural nutrient balances as agri-environmental indicators: an OECD perspective. Environmental Pollution 102, 219-225.
File for download: Excel (19 kb) DataInputSheet_SoilSurfaceNBudget [Link to file pending. ]
