ESN Reduces Nitrate Leaching in Minnesota Potato Production

This study comes from a potato grower’s field, which was split in half. Half of the circle was fertilized with ESN at planting; the other half was fertilized with a conventional program consisting of pre-plant urea plus the bulk of the required nitrogen (N) applied thru the center pivot with irrigation water on a regular basis (total of eight fertigation applications). Suction lysimeters are a device used to extract the soil solution for the purpose of measuring soluble nutrients and other elements that are in the soil. When placed at different depths in the root zone, they are useful for monitoring the downward movement of mobile nutrients such as nitrate-nitrogen. The conventional program of ‘spoon-feeding’ N thru irrigation has been demonstrated to be an excellent N management practice as long as irrigation is properly managed. In this case, a single application of ESN with one supplementary fertigation resulted in less leaching loss plus saved the grower time and money, increased yields, and improved crop quality, a very attractive value package for the grower.

Figure 1. Nitrate Concentration in Suction Lysimeters. ESN reduced leaching of N in a Minnesota potato field compared with the grower’s conventional fertigation program.
Source: Dr. Carl Rosen, University of Minnesota

This Minnesota study compared ESN applied at emergence or at planting with multiple applications of conventional urea. ESN produced significant increases in marketable yield in three out of four years. Split urea application included 100 lbs N/ac at emergence, 20 lbs N/ac at hilling, and four post-hilling applications of 20 lbs N/ac at approximately 2 week intervals. ESN was broadcast and incorporated. N rate shown includes 40 lbs N/acre at planting from DAP.

Figure 2. ESN increased Russet Burbank yields over conventional split applications in this multi-year Minnesota study.
Source: Dr. Carl Rosen, Univ. of Minnesota.