Evaluation of the spatial uncertainty of agro-ecological assessments at the regional scale : The phosphorus indicator in northern Italy
Articolo
Data di Pubblicazione:
2009
Citazione:
Evaluation of the spatial uncertainty of agro-ecological assessments at the regional scale : The phosphorus indicator in northern Italy / N. Castoldi, L. Bechini, A. Stein. - In: ECOLOGICAL INDICATORS. - ISSN 1470-160X. - 9:5(2009 Sep), pp. 902-909. [10.1016/j.ecolind.2008.10.009]
Abstract:
Agro-ecological indicators are simple conceptual models to carry out agro-environmental
assessments. Their use requires data that need to be obtained at low cost, frequently
avoiding direct measurements. The quality of input data thus may limit the usefulness
of the indicators. One source of uncertainty is the spatial interpolation of inputs, used to
provide indicator values throughout an area. This paper explores the uncertainty of the
inputs, and its effect on the output of one indicator, the phosphorus indicator (IP). The
indicator evaluates the appropriateness of phosphorus (P) use by farmers, assigning bad
scores to over- and under-fertilization. We evaluated its use for P management in the Sud
Milano Agricultural Park (northern Italy). We used data contained in a large database of soil
and farm properties as well as crop management information at the cadastral parcel level to
calculate IP values. The uncertainty of a single input variable (extractable soil P) was tested
to quantify the corresponding uncertainty of the indicator. The results show that the
variability of IP is high and within 80% of the analyzed area excessive applications of P
fertilizers are made, in particular in animal farms. In most cases, uncertainty is not relevant,
as it is either very low, or (if high) it is related to extremely low indicator values: in these
cases, the assessment of P management is unaffected by the uncertainty of the indicator.
The results show that in this area P fertilizers should be applied at lower doses, or not
applied at all. An extension service might help farmers with fertilizer management, reducing
resource use, environmental pollution and costs. This study shows that uncertainty
analysis is a crucial component of environmental assessments, and that the importance of
uncertain input data needs to be evaluated on a case-by-case basis.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Animal manure; Crop management; Database; Fertilizers; Kriging; Soil fertility; Spatial interpolation
Elenco autori:
N. Castoldi, L. Bechini, A. Stein
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