ISSUE #319

319 - Potassium Nutrition of Sugarbeet - Potassium is an essential


element in the life of the sugarbeet and performs many complex functions within the plant related to the metabolic process and enzyme reactions. It, also, maintains an electrical balance in the plant. Sugarbeet has a high requirement for potassium and absorbs more of this nutrient than any other mineral nutrient. This can be noted on the beet sample tickets at harvest. While essential for plant growth, potassium in the beet root together with sodium and amino-nitrogen, are the major impurities in the factory process. These elements along with their associated salts will prevent a certain amount of sugar from crystallizing and this remains in the molasses. This is referred to as percent sugar loss to molasses and is measured on a fresh beet basis on all grower beet samples at harvest. Growers can minimize this loss by not applying excess amounts of potash and/or nitrogen fertilizer.

Most soils in the Red River Valley are well supplied with potassium. The 1995 fields soil tested for potassium, shown in the table, indicate that 78 percent of the fields tested high to very high; 14% tested medium and only 8% tested low to very low. The data also confirms that sugarbeet growers are generally fertilizing according to recommendations and that high testing fields are not being over fertilized like they were in past years. When adequately fertilized, the low and very low soil K fields produced high sugarbeet yields and quality.

1995 Sugarbeet Yield and Quality By Soil K Level

Harvested Acres*Soil Test KK20 AppliedTons/ASugarSLMRecoverable per TonSugar Per Acre
2,535 73 V. Low 75 19.0 16.45 1.56 298 5,662
26,339 155 Low 45 20.5 16.26 1.63 293 6,007
48,870 240 Med. 21 20.4 16.49 1.64 297 6,059
261,247 540 High 5 19.0 16.41 1.63 296 5,624
9,347 1,140 V. High 2 19.7 16.59 1.64 299 5,890

* 81% of total acres (Representative fields - beets delivered on correct contract)