Sugarbeet yield gains at the end of the season
Sugarbeets will continue to grow and significantly increase tonnage and sugar content in the last two months prior to harvest.
Sugarbeets are a unique crop in Michigan’s Saginaw Valley agriculture crop mix. They are the only crop in this area that has a biennial life cycle. They will continue to grow vegetatively and increase tonnage and store sugar until harvest or freeze up. Sugarbeets normally will not survive the harsh winters in Michigan. However, if they could, they would produce seed the following year. Speed of growth and amount of sugar produced is dependent on moisture, sunlight and temperature, along with plant health. Growth will slow or stop during dry periods and resume at a rapid pace when moisture returns. Over the years we have experienced many dry summers, and when moisture returned in early fall, good yields were achieved by harvest.
In recent years, Michigan has produced large beet crops, which require starting harvest and processing as early as mid-August. Growers often question how much the yield gain would be if harvest was delayed until permanent piling of beets in late October. In 2010 and 2011, Michigan State University Sugarbeet Advancement and Michigan Sugar Company researchers conducted six date-of-harvest studies. Sugarbeets were harvested at regular intervals for yield and quality starting at early harvest to early November. Weekly yield increases from these trials ranged from 3/4 of a ton to approximately two tons per acre. When averaged over all conditions, yield increases were about 1.2 tons per week.
The largest yield increases occurred when adequate rainfall followed a period of dry conditions. In this situation, rehydration and rapid growth occurred with healthy beets. The lowest weekly gains occurred with insufficient rain or unhealthy beets from nematode and disease issues.
Sugar contents were highest after October 15. Percent sugar content varied over the testing periods, but typically had an increase of two to five percentage points from early to late harvest. Harvesting beets within three days after rainfall usually produced lower sugar contents due to beet rehydration.
Based on research, Michigan Sugar Company has developed a payment formula for early delivery to compensate for the loss of yield and quality. This can be accessed through their website. Growers are able to plug in different yield scenarios to calculate potential revenue. Based on general scenarios, it appears the payment formula should adequately compensate most growers for early dig yield and quality loss.