Land Evaluation and Site Assessment (LESA)

LESA is an analytical tool, consisting of two components, Land Evaluation (LE) and Site Assessment (SA), designed to provide systematic and objective procedures to rate and rank sites for agricultural importance. LESA provides a national model with consistent terminology and a set of classification procedures using soil-based and other site factors while offering a great deal of local flexibility. The uniqueness of the LESA system is that, while it is established by technical experts, using factors and weights to rate and rank agricultural land, the latter will only be accepted if they and the resulting LESA scores make sense to local farmers and officials. Therefore LESA can be considered an example of participatory tool development in which involvement of knowledgeable local people in formulating a LESA system is vital.

Once it is determined that a LESA system is needed for a particular state or locality, the following steps are taken: (i) appointing a LESA committee, (ii) specifying one or more factors measuring soil quality for the LE component, (iii) specifying another set of factors relating to non-soil site conditions for the SA component, (iv) assigning ratings for each factor (scale 0-100), (v) assigning weights to each of the factors (scale 0.00-1.00) in response to their perceived importance , (vi) tallying the weighted factor ratings to obtain a LESA score, and (vii) preparing score thresholds for decision making. All computations needed are done in spreadsheets to ensure full transparency and understanding of the stakeholders. The rating of soil-based qualities is done by applying one or more land classification systems as LE factors, such as Soil Potential Ratings, Soil Productivity Ratings, Land Capability Classification, and the Farmlands Classification.

Factors used for site assessment include factors other than soil-based qualities measuring limitations on agricultural productivity or farm practices, (ii) factors measuring development pressure or land conversion, and (iii) factors measuring other public values, such as historic or scenic values. Once established, a draft LESA system will need to be field tested, perhaps several times, to adjust the factor scale values and weights.