ISHS Acta Horticulturae 506: International Workshop on Ecological Aspects of Vegetable Fertilization in Integrated Crop Production
ESTIMATION OF NITROGEN UPTAKE OF FIELD VEGETABLES |
| Authors: | C. Feller, M. Fink |
| Keywords: | Kohlrabi, Brassica oleracea var. gongylodes L., white cabbage, Brassica oleracea L. var. capitata f. alba, fertilizer recommendation, BBCH scale, growth stages |
| Abstract:
Some fertilizer recommendation systems for field vegetables are based on estimated nitrogen (N) uptake curves. The estimation of nitrogen uptake should be as accurate as possible, in order to avoid recommendations being too high or too low. Therefore, the accuracy (standard error of difference between measured and estimated values, sd) of two estimation methods was compared. Comparison was carried out with measured nitrogen uptake curves of kohlrabi (Brassica oleracea var. gongylodes L.) and white cabbage (Brassica oleracea L. var. capitata f. alba). For kohlrabi, the use of observed growth stages resulted in a small estimation error (sd=14kg N ha-1). This method is recommended since it is accurate and easy to use. The estimation that depended on time-after-planting, showed a larger estimation error (sd=28kg N ha-1). For white cabbage, both methods tested were not suitable because estimation errors were too high (63 and 51kg N ha-1, respectively). | |
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