The content of basic nutritive elements in apple leaves dependening upon fertilizing and other agents
1999
Haak, E. (Estonian Agricultural University, Tartu (Estonia). Polli Horticultural Inst.)
The content of basic nutritive elements in leaves were investigated (1991-1997) at the Polli Horticultural Institute in the apple cultivar 'Talvenauding' and (1969-1997) in the cultivars 'Cortland' and 'Tellissaare' on the occasion of fertilizing. Different fertilizer doses and ways were used in (1) pre-planting and (2) yearly fertilizing. The nitrogen and potassium content in leaves varied in great extent between the years even in one fertilizing variant, depending for example upon the yield level. In the case of abundant yield the nitrogen was at high level and potassium at low level. The phosphorus content in leaves was relatively stable and only little dependent upon fertilizing and other agents. It became evident that leaf diagnostic method is not practical in Estonian changeable weather conditions: the content of basic nutritive elements in leaves depends more upon other agents than on the content of nutritive elements in soil and upon fertilizing
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