A MODEL FOR CALIBRATION OF DRIP-TUBE NITROGEN FERTILIZATION OF GREENHOUSE CUCUMBERS USING LEAF COUNTS

The half-monthly nitrogen (N) absorption and growth parameters of drip-fertilized autumn cucumber were estimated by destructive analysis.
The amount of N absorbed was estimated using the following formula:
The amount of absorbed N (g/a/14days) = the increased number of leaves (number / m²/14days) x 3.83 + 185.8
This formula was tested in a practical cultivation experiment.
One fourteenth of the result of the formula was applied as N fertilizer through a drip tube daily.
Although the amount of N applied was only 77% that used in the conventional method, the cucumber yield remained the same.
Plant growth using five training methods with different patterns of leaf-increase was compared.
The savings in N fertilizer were 28 to 34% over the conventional method, although the yield differed widely with the training method.
Our method saved N, costs, and labor in a field experiment.
Furthermore, surplus N in the soil was controlled and the distribution of EC was equal throughout the field.
These results suggest that this is a practical formula for controlling N application using drip fertilization.

VII International Symposium on Protected Cultivation in Mild Winter Climates: Production, Pest Management and Global Competition

T. Sato, K. Matsuura, J. Narimatsu, N. Mizuno, A. Kitabatake, M. Okamoto, R. Takayanagi

cucumber, drip irrigation, nitrogen, growth diagnosis, fertilization

https://doi.org/10.17660/ActaHortic.2004.659.77