Split nitrogen fertilization and in row application in the potato crop

Residual soil nitrate after the harvest of potatoes is often too high. Nitrogen (N) efficiency of potatoes is low. This is among other things due to the poorly developed root system of the plants. N uptake by potatoes from soil layers deeper than 60 cm is poor and plant roots in adjacent rows overlap barely. By means of fertilization in the row, the fertilizer is better positioned (near the seed potato). This should lead to a better utilization of the given nitrate and a lower residual soil nitrate while maintaining yield and quality. Another efficient method is to give about 70% of the total need by planting and the other 30% 6 weeks after planting. This should also lead to a better utilization of the given N with less risk of nitrate leaching in spring by heavy precipitation. In the framework of the project “Bring N to the potato to utilize N more efficient” (financed by the Flemish Government), 5 field trials were set up in 2012. On this fields, the use of fertilization in the row in potatoes was demonstrated whether or not in combination with splitting in to 2 gifts. Some trials showed that nitrate fertilization in the row was clearly positive and that a lower N fertilization with this method was sufficient while maintaining yield. In other locations this technique gave little or no added value. On 4 locations was explicitly focused on splitting of the N-fertilisation. Split application proved in 2012 often its usefulness.