Due to the increased use of dwarfing rootstocks and fertilizer experiments dressings increased from 90-120 kg N/ha in 1958 to 170-270 kg in 1965. In deciding on the quantity of nitrogen dressing its interacting effects on growth and fruit production as well as the influence of soil, weather and undergrowth were studied. Some of the experiments were carried out in pots, the others in the field.
The discussions cover the availability of nitrogen in the soil and the nitrogen requirements of the trees, especially in relation to competition with a full grass cover and grass strips. The system with grass strips and mulched bare tree strips is considered a case of fertilizer placement since the soil under the grass strip is extremely low in nitrogen during the greater part of the season.
|Qualification||Doctor of Philosophy|
|Award date||1 Jun 1973|
|Place of Publication||Wageningen|
|Publication status||Published - 1973|
- nitrogen fertilizers
- plant nutrition