System Boundaries P .2 Crop Selection Our over-arching goals for crop selection were to pick crops that would be marketable and profitable, relatively easy to grow, and contribute to a functioning, diverse ecosystem. We devised a three step process for crop selection, which used a combination of quantitative and qualitative analyses. The three steps are outlined briefly here, and then described in greater detail in the analysis: of the data sets before using this process to generate an actual Polydome design. One of our primary limitations was the fact that we didn’t have complete yield and price figures for all crops of interest, which necessarily pushed them out of our working pool even though they may have been valuable additions. Analysis 1. System incompatibility We began by eliminating plants with problematic physical features. This was not a comprehensive elimination process. In an actual Polydome design, we would recommend developing these first elimination criteria in a much more systematic manner. • Excessive height For all tree species, we chose to eliminate those tending to grow over 10 meters tall. Dwarf cultivars were considered an option in certain cases. Exceptions were also made for varieties of trees that perform well when pruned for smaller size, or that can be espaliered. • Allelopathy For all species, we chose to eliminate crops that are strongly allelopathic or poorly performing when planted in polyculture. For example, walnut secretes a chemical in its root zone that prevents any other crops from settling nearby. Fennel and wormwood have similar properties in that they generally interfere with the growth of surrounding crops. 1. • • • 2. • • • System incompatibility Excessive height Long maturation period Allelopathy Economics Basic crop value and yield potential General labor requirements Prioritizing for perennial plants 3. Supporting Elements • Selecting beneficial companion plants • Selecting elements that provide required functions or material flows Each of these steps is described in greater detail in the upcoming analysis. The data we used for this process were as complete and up to date as we could find within our time constraints. However, we would recommend improving the completeness and quality of some 2. Economics • Basic crop value and yield potential Because one of the primary goals of the Polydome greenhouse is for it to be economically sustainable, our first round of elimination was geared at filtering the crops by economic productivity. As a Polydome: High Performance Polyculture Systems 59 Pagina 58

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