Nutrient uptake of sugar beet. Part II: Development of nutrient export from field

The development of nutrient content and the quantities of nutrient exported with sugar beet was investigated using long standing trials. Numerous fertilization trials were conducted by the State Institute for Agriculture in Hessen, Germany, and the Southern German sugar industry from the years 1994 until 2013. In order to show the development and to reduce annual variations, the results were summarized from four experimental years each at the beginning (1994–1997), in the middle (2002–2005) and at the end of the investigation period (2010–2013). Macro- and micro nutrients were used in the investigations.

The nutrient content of almost all the elements in the beet (except for calcium) was lower at the end of the investigation period than at the beginning. It ranged between 74% (nitrogen, sulphur) and 83% (potassium) relative to the value in 1994–1997. The reason for this is assumed to have its origin in the breeding progress and the optimizations of the cultivation of sugar beet as well as the physiology of beet plant. Even for micro nutrients, lower levels were found during the investigation period of 20 years. Despite the increase in beet yields of 36% during the investigation period, the nutrient uptake of the beet was nearly constant. It is important to note that today, with regard to the beet, the export of nitrogen, phosphorous, magnesium and sulfur per unit of area is comparable to the nutrient export 20 years ago. Only the export of potassium increased slightly. The fertilization can follow largely independent from yield level.