Precision Agriculture, 2, 265᎐279, 2000
ᮊ 2001 Kluwer Academic Publishers. Manufactured in The Netherlands.
The ‘‘Null Hypothesis’’ of Precision
B. M. WHELAN AND A. B. McBRATNEY firstname.lastname@example.org
Australian Centre for Precision Agriculture, McMillan Building A05, Uni
ersity of Sydney,
NSW 2006, Australia
Abstract. As precision agriculture strives to improve the management of agricultural industries, the
importance of scientific validation must not be forgotten. Eventually, the improvement that is imparted
by precision agriculture management must be considered in terms of profitability and environmental
impact both short and long term . As one form of precision agriculture, we consider site-specific crop
management to be defined as: ‘‘Matching resource application and agronomic practices with soil and
crop requirements as they vary in space and time within a field.’’ While the technological tools
associated with precision agriculture may be most obvious, the fundamental concept will stand or fall on
the basis of scientific experimentation and assessment. Crucial then to scientifically validating the
concept of site-specific crop management is the proposal and testing of the null hypothesis of precision
agriculture, i.e. ‘‘Given the large temporal variation evident in crop yield relative to the scale of a single
field, then the optimal risk aversion strategy is uniform management.’’ The spatial and temporal
variability of important crop and soil parameters is considered and their quantification for a crop field is
shown to be important to subsequent experimentation and agronomic management. The philosophy of
precision agriculture is explored and experimental designs for Precision agriculture are presented that
can be employed in attempts to refute the proposed null hypothesis.
Keywords: experimentation, spatial variability, management zone
Precision agriculture PA should be considered as a philosophical shift in the
management of variability within agricultural industries. It must be aimed at
improving profitability andror environmental impact both short and long term .
As with all such endeavours to further knowledge in science-based disciplines, the
concepts and acceptance of the PA philosophy will ultimately rest on the successful
completion of scientific experimentation and assessment.
As one form of PA, Site-Specific Crop Management SSCM can be defined as:
‘‘Matching resource application and agronomic practices with soil and crop re-
quirements as they vary in space and time within a field.’’ This definition implies
that assessment should have both an economic and environmental component, and
that considerable effort or risk is associated with management of the often complex
cropping system. It also requires that the variability in soil and crop requirements,
across space and time, be correctly characterized.
Figure 1 provides an example of the PA decision process that could then be
employed following a study of field variability. This model begins with the premise
that variability in crop yield is the initial signal that variable-rate treatment might
be warranted. Another model might begin with the observation of soil variability.