Die Bodenkultur - Journal for Land Management, Food and Environment
L. BOESE, R. JAUERT, H. MICHAEL and K. WALOSZCZYK:
Optimal First Spring Nitrogen Application for Winter Wheat and Barley in Relation to the Different Crop Situation
Field experiments for optimal first spring nitrogen application, considering the specific situation of the stands, were carried out on winter wheat and winter barley during four years on a dry site (Calcic Cheronzem) in the central region of Germany. At the beginning of the vegetation period and after tillering, respectively, three amounts of nitrogen fertilizer were applied to different stands, produced within the trials by variation of seeding date and rate.
No evidence was found for the necessity of different N rates at the beginning of vegetation period in dependence on number of plants per square meter and the reached phonological stage of the plants. In literature also no reliable evidence exists for the superiority of different N fertilizer rates for different developed crops. In consequence, corresponding recommendations have to be judged critically.
The optimal amount of the first N rate in spring depended on the yield formation conditions of the year concerned, in particular on weather conditions. It did not depend on the amounts of soil mineral nitrogen (Nmin) in spring. The sum Nmin (0 to 60 cm depth) + amount of fertilizer N (first rate) that led to the maximum yield in the year concerned, varied from 100 to 348 kg N/ha, nearly independently from the special crop. The delay of the first spring n rate until the end of tillering resulted, as a rule, in a yield decline.