MSU Extension

As fertilizer prices continue to climb, it becomes even more critical that growers take inventory of soil nutrients through soil testing. Soil tests are the best way to evaluate soil nutrient levels and based on their results, nutrients should be applied so that plant roots can most effectively recover them. Often soil test levels indicate adequate nutrients available for a growing crop; however, test results may overestimate small plants’ ability to adequately explore the soil for needed nutrients for rapid early season growth. Applications of starter fertilizer in a 2 by 2 placement on sugarbeets can supply a portion of fertilizer needs and increase early season growth which often results in improved yield.

The trial results that will be discussed in this article reflect the general experience that the Sugarbeet Advancement program has had with multiple field trials in Michigan in the last several years. Because of the differences in climate, soil test levels, organic matter, Ph, and soil texture, results may be different in other production areas. In the Great Lakes production area Median Bray P1 Phosphorous levels are typically high at approximately 90-100 lbs per acre. Organic matter is less than 2%, soil Ph is greater than 7.2, and average soil texture is loam. Growers are generally planting into light- colored soils that are slow to warm in the spring. Pre-plant nitrate tests generally only give a credit of 20-40 lbs/acre.

Field scale trials were conducted in Michigan between 2002 and 2006 comparing low rates (generally 3 gallons/acre) of high-phosphate, in-furrow pop-up fertilizers to a check and/or in-furrow application in conjunction with 2 by 2 placement of nitrogen. Generally, in-furrow fertilizers offered small, but insignificant, increases in yield. However it was observed that 2 by 2 placement of nitrogen in conjunction with in-furrow fertilizer typically improved early season growth and improved tonnage. Occasionally, in-furrow fertilizers have been shown to contribute to slower emergence or reduced stands when compared to no in-furrow applications. Because of potential seed sensitivity, rates and types of in-furrow nutrients applied with seed are limited.

It needs to be restated that these trials were done on fields with high phosphorous levels. Research conducted in other beet production areas has generally shown more benefit of phosphate containing in-furrow pop-fertilizers on soils with low phosphorous test levels.

Recent research conducted by Sugarbeet Advancement has concentrated on 2 by 2 placements of fertilizers. These applications have some advantages over in-furrow and broadcast fertilizers. Two by 2 applications allow early and strategic placement of fertilizer in the root zone, gives producers the option to use any nutrient and to increase nutrient amounts. It also reduces fertilizer seed sensitivity issues and can improve efficiency of uptake of nutrients. The main disadvantage for 2 by 2 placements is equipment cost and the fact that some planters are not conducive to equipment installation.

In Michigan it is common to use a combination of broadcast/side dress fertilizer in conjunction with 2 by 2 placement of starter fertilizer. There’s often an early season growth response to the 2 by 2 placement of 10-15 gallons of 28% nitrogen, 10-34-0, or a mixture of the two. This growth response is most obvious when planting beets into chisel plowed cornstalks when no broadcast pre-plant nitrogen is applied and/or when planting very early into cold soils.

Trials conducted in high phosphorous fields have generally shown increased yield/visual response from the 2 by 2 placement of nitrogen and less often from phosphorous. From Sugarbeet Advancement observations it might be suggested that a 2 by 2 starter mix have a minimum of 30 (and preferably 40) pounds of nitrogen and 20 pounds of phosphorous. Many growers who use 2 by 2 starters often add micro and secondary nutrients to the combination. If you choose to do this, make sure all ingredients are compatible and agitate them if required to prevent separation. Michigan yield response has normally been between one-half and 2 tons per acre with the various combinations used.

Every production area and soil type is different in its ability to supply needed nutrients for top sugar beet yields. Adequate nutrients are normally present in fields once beet roots begin to spread out into the soil. In the early growth stage, roots may be slow in their ability to find and take up nutrients. Placing fertilizer in a 2 by 2 band enables young beets to take up needed nutrients and improve early growth. Under Michigan’s high-phosphorous soil conditions, the largest share of the early growth response is from the nitrogen portion in the 2 by 2 placed fertilizer. Placement in this manner can improve efficiency of nutrient uptake, improve early growth, and may improve yields.

As with any production strategy, taking time up front to conduct soil tests and study research recommendations can be well worth the investment.