During three years between 2004 and 2006 different levels of nitrogen including various strategies of temporal partitioning were studied with the chicory variety Vintor. The objectives of these experiments were to assess the impact of N fertilization on the development and quality of the chicory roots and thereafter on the performance of the roots at forcing in the following year. Chemical analyses performed on samples of petioles in advanced stages of crop development revealed increasing accumulation of nitrate with progressive rates of N fertilization. Whereas root diameter did not respond to N fertilization, concentration of total N in the harvested roots was significantly increased by progressive N fertilization. Moderate rates of N fertilization positively affected yield and quality of the chicons. A strategy including a first application of 30 kg N/ha at sowing followed by 3 split applications of 15 kg N/ha, spread between the 5th and the 11th week of the crop, mostly led to the highest yield of marketable chicons. Shape and solidity were negatively affected by excessive N fertilization, which led to an increased share of loose-packed chicons with half-open tips. Based on our investigations a maximum total rate of 90 kg/ha can be recommended for soils of the type sandy loam depending on the natural availability of nitrogen (Nmin). Split application of nitrogen between sowing and the mid of August meet the demand for nitrogen of the chicory crop best.
Optimized N-fertilization in the production of chicory