Articles
THE EFFECT OF FERTILIZATION ON LEAF AND SOIL ANALYSES OF RIBES RUBRUM L. AND RIBES NIGRUM L.
The six regimes of nitrogen fertilization of red currant cv.
Rotes Wunder were: N O, N 21 kg/ha in spring (beginning of May), N 21 kg/ha in spring + N 25 kg/ha in July (at ripening of berries), N 21 kg/ha in spring + N 50 kg/ha in July,N 21 kg/ha in spring + urea spraying (0.7%) three times after blooming and micronutrient fertilizer (0.5%) + urea spraying four times after blooming.
The fertilization treatments of black currant cv. Öjebyn were: N 25 kg/ha in the beginning of May, N 45 kg/ha in the beginning of May and N 25 kg/ha in the beginning of May + N 20 kg/ha in June after blooming.
After eight yield seasons there was no significant difference between fertilization treatments in the red currant trials.
Also in black currant the soil and leaf characteristics were commonly within the recommendation range applied in Finland, though the fertilization rates varied greatly.
According to these results, the older recommendation ranges seem to be too wide to give sufficiently information about fertilizing red and black currants.
The new leaf analysis recommendations are obviously more useful in practice, but on condition the samples have been taken at the right time of the growing season twice instead of once.
The correlations of macronutrient contents between leaves and soils varied from 0.020 (B) to 0.568 (K), when pH correction had not been taken into account.