Spatial optimisation of cropped swaths and field margins using GIS

This paper(1) proposes an elementary method for optimising the spatial configuration of cropped swaths within agricultural fields while creating space for field margins,and (2)assesses its feasibility with respect to input data requirements. The approach assumes straight, non-overlapping swaths and attempts to relocate areas of inefficient machine manoeuvring to boundary strips by minimising the costs of area loss and additional swaths minus any subsidy received for field boundaries. Optimisation involves an exhaustive search over a discrete set of swath orientations and positional shifts that are derived from measured field geometry. The method was implemented using an open source GIS library to facilitate spatial overlay operations and data input and output. Testing involved the stability of the optimal swathing pattern and economic evaluation of farming alternatives under changes in the cost values used in the objective function. The method requires accurate field geometry data, but for optimising the spatial configuration of swaths and margins, the cost values only need to be roughly known. However, economic evaluation of the option of compulsory buffer strips versus voluntary field margins requires accurate cost estimates. The method is being used to support regional plans concerning biodiversity and societal demands in the Hoeksche Waard (The Netherlands). (C) 2009 Elsevier B.V. All rights reserved.