ISHS Acta Horticulturae 428: Ecological aspects of Vegetable Fertigation in Integrated crop Production in the Field
CONSIDERATION OF NITROGEN MINERALIZATION FROM HARVEST RESIDUES IN THE CALCULATION OF FERTILIZER RECOMMENDATIONS |
| Author: | M. Fink |
| Keywords: | vegetables, model, decision support system, N-Expert |
| Abstract:
A field experiment was carried out in order to test if nitrogen (N) mineralization of harvest residues is considered correctly in the fertilizer recommendations given by the decision support system ‘N-Expert’. Kohlrabi (Brassica oleracea convar. acephala var. gongylodes L.) was grown with 4 levels of mineral nitrogen and 4 levels of lettuce (Lactuca sativa L.) harvest residues. For each level of harvest residues a recommendation for mineral fertilization was calculated by N-Expert. As the amount of harvest residue increased, recommended N fertilizer decreased from 200 to 100 kg/ha N. Calculation of nitrogen balance showed that the amount of nitrogen that mineralized from harvest residues was less than estimated by N-Expert. Despite this estimation error no fertilizer recommendation of N-Expert resulted in significant yield losses in this experiment. This was shown by regression models, which were fitted to yield of kohlrabi in dependence on mineral fertilizer. | |
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