Project

Best practice for long-term field storage of sugar beet under Nordic climate conditions

Goal: To investigate management options that allow the clamp (field-store) temperature to be maintained within the ideal range, given the Swedish climate.

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William English
added 3 research items
Long term storage of sugar beets in clamps can be challenging due to high accumulation of degree days, frost or excessive moisture. This may cause an increased growth of molds, spread of rots, and rates of respiration , which in turn leads to high sugar losses during storage. With support from the agricultural European Innovation Partnership (EIP-AGRI) a novel farm scale clamp ventilation system has been developed and tested. The aim of this system is to reduce the amount of degree days and improve the storage climate by pushing air through the clamp when the ambient temperature is lower than the temperature inside of the clamp. The project has included the development of an automatic control system based on wireless technologies, and a ventilation pipe that can be inserted into an A-shaped pile. The results of commercial scale trials of the system show that both the amount of degree days and storage losses can be reduced. Three years of data from six ventilated clamps will be presented at the congress.
Rates of harvest damage in various vegetable crops has been linked to soil water content at harvest and the resulting cell turgor. Casual observation in sugar beet suggests that rates of surface cracking at harvest are similarly linked to soil water content. The rates of damage during harvest and handling of sugar beet has also been linked to their mechanical properties. It is, however, unclear that the standard metrics used for quantifying sugar beet mechanical property will capture the dimensions on which cell turgor affects mechanical properties. A small exploratory study was undertaken in Sweden during 2021. Sugar beets were taken from a field grown under commercial conditions. Two treatments were applied in the field in four replicates during the six weeks prior to harvest and assessment; grown under a shelter, or irrigated twice. A third and separate treatment of dehydration through high airflow over the one week period prior to assessment was also applied. Untreated beets were taken as the control. Mechanical properties were assessed with the standard pseudo-static measures of puncture resistance and tissue firmness. Mechanical property assessment was extended to also include the apparent elastic modulus, plus a dynamic falling-ball test. Damage from the dynamic test was assessed as degree of surface abrasion and cracking. The results showed that the irrigated sugar beets had a lower puncture resistance compared to both those grown under a roof and the dehydrated beets. The falling-ball test showed that irrespective of dry or wet conditions immediately prior to harvest, the sugar beets cracked at the same incidence. The puncture resistance of the dehydrated sugar beets did not differ from the control, but rates of damage were greatly reduced. The dehydrated beets also returned lower tissue firmness and higher elastic behaviour than the other treatments, suggesting a link between damage during dynamic impacts and these traits.
The rate of airflow through a sugar beet clamp is central in the thermodynamic processes that occur during storage. It determines the rate at which ambient air and the air inside the clamp exchange through advection, and the rates at which heat and moisture transfer between the beets and the air. Computational Fluid Dynamics (CFD) is a method commonly used by engineers to model fluid dynamics and heat transfer processes in complex systems. Thanks to increased computing power and generous open source software communities, programming high-resolution CFD models is a much more accessible research avenue. Using the open source software programs R and Blender (physical model creation), OpenFOAM (CFD modelling), and ParaView (results visualisation), a series of CFD models of stylised sugar beet clamps were developed. Clamp size was modelled as either 7 m, 8 m, or 9 m wide at the base. The clamp was modelled as either uncovered, or covered with TopTex. Ambient wind velocity was taken as either 1, 5, or 10 m/s normal to the clamp length. The porous medium approach was adopted, and Darcy-Forchheimer (D-F) parametrization applied. The D-F values for the clamp region were fixed at values derived from previous research (Tabil et al, 2003), for small, large and mixed beet sizes. D-F values for TopTex were supplied by TenCate Industrial Fabrics. An additional model of a clamp with active ventilation was developed. The steady airflow profiles of eleven models are presented.
William English
added a research item
Methodology for analysing textural properties of sugar beet roots in the laboratory has previously been established. It has been shown to be reliable and of value in exploring relationships between textural properties, damage rates, and storability of varieties. In this paper, a methodology for the assessment of textural properties in-field, prior to harvest, using an inexpensive handheld penetrometer is examined. Three sugar beet varieties were grown in Belgium, the Netherlands, and Sweden during 2019. Textural properties were assessed in-field with the handheld penetrometer 2, 1 and 0 months prior to harvest, and with the laboratory penetrometer directly after harvest. Comparison of the results showed generally strong correlations. A power analysis suggests a difference in mean Handheld Pressure of 0.10 MPa could be found significant within a large trial with a block design. The reliability of the handheld penetrometer was further assessed in the Swedish national variety trials over three years (2019-2021). Correlation coefficients of 0.86 and 0.94 were found between mean Handheld Pressure for 2019 and 2020, and 2020 and 2021 respectively. The handheld penetrometer can be applied as an economic means of quantifying differences in textural properties of sugar beet varieties. Clear operating procedure and training must exist.
William English
added a research item
What is the role of temperature in the long-term storage of sugar beets, including on the sugar loss mechanisms of respiration and rot. Rates of mechanical damage are also considered.
William English
added 2 research items
OBJECTIVES 1. Investigate the size of impact stresses that sugar beets may be exposed to during harvest and transport: Force, contact area, & pressure; Differences between beet types; Differences between beet size 2. Further develop assessment method, inc.converting dynamic to static
CONCLUSIONS • The correspondence between the handheld and the laboratory penetrometers was high • The magnitude of values from the handheld penetrometer were most similar to Puncture resistance • The rank order of pressures recorded in season with the handheld penetrometer was stable over time
William English
added an update
One important factor in the maintenance of quality of sugar beets in storage is the level of damage they sustain during harvest and handling. We've being doing some fun tests around how impacts result in bruising across different varieties. Read more about it here: www.meran.se/droppin-beaets/
 
William English
added a project goal
To investigate management options that allow the clamp (field-store) temperature to be maintained within the ideal range, given the Swedish climate.