ISHS Acta Horticulturae 428: Ecological aspects of Vegetable Fertigation in Integrated crop Production in the Field
NITROGEN UPTAKE AND NITROGEN LOSSES IN FIELD TRIALS WITH CARROTS |
| Authors: | J. Rühlmann, Y. Kuzyakov, B. Geyer |
| Keywords: | nitrogen balance, simulation model, mineralization, carrots |
| Abstract:
The aim of the investigations presented in this paper is to demonstrate the influence of nitrogen supply on nitrogen uptake, Nmin value at the end of cultivation period, and nitrogen losses in carrot production. The results of 13 field trials were used to calculate an N balance and to indicate N losses. The inputs of the N balance were the Nmin value at the beginning of cultivation, N fertilization, atmospheric N deposition and net nitrogen mineralization. The outputs were the N uptake by plants and the Nmin value at the end of cultivation. The net nitrogen mineralization was calculated by the CArbon Nitrogen DYnamics Model “CANDY” (Franko 1989). The results showed that an increase of N supply from 120 to 390 kg/ha was related to
Linear regression indicated that 75% of variation in N uptake was caused by variation of N supply including all components of N balance input. Regression results were compared with the recommendation of the “KNS” system for N fertilization of carrot and for calculating N mineralization. Both the regression method and the “KNS” system recommended give nearly the same N-supply to get an N uptake of 160 kg/ha. | |
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