The overall aim of this research project was to increase the preparedness of the sugar beet industries of Sweden and other nations for long-term post- harvest storage under dynamic conditions. This includes the increased ability to respond to changes in available varieties, the pricing model, industry structure, technology used to harvest and transport the crop, and the climate. The individual studies were to target the key areas identified as drivers of successful long-term post-harvest storage. On top of this and as far as possible, the research was to be: applied; result in practical tools or recommendations; collaborative; consider ongoing developments in industry such as active ventilation; and, remain applicable even if longer post-harvest storage campaigns do not eventuate.

In this context, the specific objectives of this thesis are;

  • Assess the impact of nitrogen and water availability during the growing season on the mechanical properties of sugar beet roots, the subsequent rates of damage at harvest, and on quality loss during post-harvest storage (Paper I). This will support commercial agronomic decisions in the face of variation in input prices.
  • Assess the reliability of a simple handheld penetrometer in the assessment of sugar beet root mechanical properties (Paper II). This will support the rapid assessment of relative storability of new varieties through the development of a practical and standardised methodology for in-field assessment of mechanical properties.
  • Increase understanding of the impact of the movement of air, and of temperature and humidity on the movement of water and on quality parameters in sugar beet post-harvest storage systems (Paper III). This will give insight into how airflow can be managed to improve quality parameters in commercial operations. It will also support the further development of models of sugar beet post-harvest storage systems.
  • Develop a spatial-temporal numerical model of airflow and temperature within a bulk of sugar beet roots (Paper IV). This will give deeper insight into the distribution and dynamics of temperature in clamps. It can also support future research into the management of the sugar beet post-harvest storage environment including studying actively ventilated systems.
  • Explore possibilities for measuring alternative mechanical properties of sugar beet roots (Supplementary Studies (SSs)). Specifically, explore methods for the assessment of dynamic forces (SS1 and SS2), and explore the need for the inclusion of the modulus of elasticity in future assessments of mechanical properties (SS2). The SSs were designed only as exploratory studies and do not reach the standards of academic publication.

Papers I and II, and both supplementary studies focus on the first principle of long-term post-harvest storage of sugar beet roots: plant health. Papers III and IV focus on the second principle: the post-harvest storage environment.