fertilizer application can be designed within a range for
which the amounts of phosphate and potassium application are not reduced below the required rates.
(2) The data of variable fertilizer application rates are input
into an application (App), compatible with the Android
mobile operating system, that was developed by our
company (Zukosha co., Ltd). This app can determine
the present location using GPS and send the fertilizer
application rate of the present location to the fertilizer
applicator via a wireless LAN.
(3) By using a variable fertilizer applicator that can receive
fertilizer information from the app, variable fertilizer
application can be performed automatically.
The effect of our system was investigated in sugar beet in
three Andosol fields in the Tokachi area of Hokkaido in
2015. Experimental plots were established in each field. The
areas of each plot were more than 1 ha. Conventional fertilizer application (CF) and variable fertilizer application
(VF) treatments were applied to the plots, and the fertilizer
application rates and sugar yields for both treatments were
compared.
For the VF treatment, the nitrogen fertilizer application
rate was reduced by an average of 25% in each field compared with the CF treatment. Moreover, the sugar yield was
higher in each field for the VF treatment than for the CF
treatment, with an average of 9% higher yields (Table 5.21).
Fig. 5.14 Outline of variable fertilizer application system. Figure supplied by Katsuhisa Niwa
5 Hokkaido Region
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