Germination stage prior to emergence. Emergence will occur within a few days of germination. Sugarbeet growth can take between 20 and 24 weeks depending on location and growing conditions.
A pair of cotyledon leaves have emerged and no evidence of first or second leaf. The cotyledons usually yellow and drop off the plant by the fifth or sixth leave stage. At this stage, the tap root is developing and nitrogen in the soil is accessed by the plant roots for leaf (canopy) development. Sugarbeets are unique in their nitrogen requirements. Too little nitrogen results in poor leaf canopies, premature yellowing, and reduced yields, while too much nitrogen leads to a reduced sucrose content, increased impurities, and lowered sucrose extraction. Proper nitrogen fertilizer use increases root and sugar yield. Early root growth is characterized by elongation of the tap root with limited lateral root growth. Nitrogen and phosphorus availability in the seedling root zone are a key determinant of yield potential.
Cotyledons and first and second leaf are just visible. These leaves appear simultaneously, and although they seem to be oppositely arranged, they are alternates. One leaf is developmentally behind the other but stage separation between the two leaves is not possible.
Cotyledons are present and at least 50 percent of the next leaves are unrolled.
Cotyledons are present and at least 90 percent of the next leaves are unrolled, but not completely. Timing of herbicide application is extremely important for maximizing weed control and recoverable sucrose per acre. Weeds must be controlled when they are very small (less than 1 inch high). The first post-herbicide treatment should be applied when weeds are in the cotyledon to early two-leaf growth stage. Nutrient deficiencies, especially nitrogen, during these early stages can limit yield potential by slowing the rate of leaf expansion.
Two leaves are unrolled and the third leaf is not visible.
Two leaves are unrolled and the third leaf is just visible.
Two leaves are unrolled and the third leaf is 50 percent unrolled.
Two leaves are unrolled and the third leaf is 90 percent unrolled.
As crop development progresses beyond V2.0 leaf stage, two or more developing leaves are always present. Therefore, true V3.0, V4.0, etc. growth stages are not possible. A decimal fraction of each leaf stage is used to allow for better separation between leaf stages and increase accuracy of GDD (Growing Degree Days) predictions. The fraction represents the percentage of amount of the next emerging leaf that has unrolled (e.g., if a plant has three fully unrolled leaves and the fourth is 60 percent unrolled, the stage is V3.6).
At later leaf stages when several unrolled leaves may be present, use the most advanced leaf of the recent emerged pair in the estimate (do not count cotyledons). The sugarbeet plant has a taproot system that utilizes water and soil nutrients to depths of 5 to 8 feet.
The sugarbeet plant grows until harvested or growth is stopped by a hard freeze. Sugarbeets primarily grow tops until the leaf canopy completely covers the soil surface in a field. This normally takes 70 to 90 days from planting. At this time, the taproot begins to expand and sugar is stored in the root. Root and sugar yield is maximized when canopy closure is achieved by early summer to maximize photosynthesis during the longest days of summer. There is no stage in the plant’s growth when it may, physiologically, be considered to have undergone any ‘ripening’ process. Cool weather and diminishing nitrogen supply enhance sugar accumulation. Excess nitrogen supply later in the season can encourage greater vegetative growth at the expense of sugar storage in the root. Nitrogen should be managed to promote rapid early leaf growth while becoming depleted in late summer to avoid excessive vegetative growth and maximize sugar storage.
The taproot grows about 8 inches deep and is harvested for sucrose. There are two stages to harvesting sugarbeets: plant defoliation occurs first, followed by digging of the beets. The later the crop is harvested, the higher the yield and quality should be. The exception is if a severe frost kills most plant foliage, stopping yield and quality improvement.