1.1 POST-HARVEST FIELD STORAGE SYSTEM

Storage systems employed for food crops range from the harvested crop being housed in highly controlled environments, through to the crop being left in-situ post maturity until it is taken to the next stage in the value chain. The choice of storage system is a combination of the per unit volume value of the crop, and the crop’s tendency to degrade in the available environments (Wills et al., 2007a). For sugar beet, three storage systems are in common use. Two of these are post-harvest storage systems, including the smaller clamp system located in-field (Figure 1), and the large pile system located at the processing factory. A clamp is an old technology used for the post-harvest storage of root crops, consisting simply of a bulk of the crop piled on the earth and covered as necessary with a protective material such as straw or soil (Aliou, 1998). A pile consists of a bulk of harvested roots that can be five meters high and 40 meters wide, or larger (Bugbee, 1982; Gaddie & Tolman, 1952; Shaaban, 2020). The third storage system sees the sugar beet crop left in-situ in the field beyond the end of the period of seasonal growth, where it is protected by the soil and plant canopy. In-situ storage can be employed where mild winters are expected, and harvest occurs just prior to delivery. If clamp formation occurs, it is usually only for a short period. In some environments where sugar beet is grown, post-harvest storage is strongly discouraged owing to the unfavourable environment (Orleans & Cotton, 1952).

The research project this thesis describes was focused on the clamp system of post-harvest field storage, but this thesis also has application to the pile post-harvest storage system. A large component of the research referenced in the following discussion on the principles of successful post-harvest storage of sugar beet was conducted in the context of pile storage. A distinction between these two systems is generally not made here, as both are the post-harvest storage of bulks of sugar beet roots. The in-situ storage system is generally ignored.