Generation of artificial crop rotation schemes as cyclic permutations

By I.N. Athanasiadis, A.E. Rizzoli, S. Janssen & M.v. Ittersum
In Farming Systems Design 2007: Methodologies for Integrated Analysis of Farm Production Systems , (M. Donatelli, J. Hatfield & A. Rizzoli, ed.) , pp. 225-226 , Catania, Italy, 2007.

Abstract:
Cover image Farm production planning involves the simulation and evaluation of crop succession alternatives, known also as crop rotations. A crop rotation is a succession of crops in time and space, that are applied cyclically on the same piece of land. Artificial crop rotations schemes are typically generated as all possible rearrangements of the available crops that are agronomically feasible with respect to crop frequency and succession (suitability filters). Given a set of c crops and a desired length of rotations r, the traditional approach requires the evaluation of all possible combinations of crops in a solution space, sized c to the power of r. This practice limits the length of rotations to be evaluated as the size of crop rearrangements expands exponentially. In this paper we present a more efficient and faster alternative generation algorithm that excludes cyclically equivalent rotations from the solution space. The algorithm represents each crop rotation cycle as a number in the c-based numeral system, and is capable of excluding the generation of cyclic equivalent rotations, through a single modulo operation. After the generation of all non-cyclically equivalent crop rotations, the suitability filters are applied for obtaining agronomically feasible rotations, which form the basis of followup assessments.

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