Indian Agricultural Research Institute, New Delhi-110012
*Present address: Division of Fruit Crops, Directorate General of Horticulture, Zaafaraniya Experiment Station, Baghdad, Iraq.
In general, nitrogen, phosphorus and potassium concentrations were maximum in young twigs which decreased with the increasing age of the twigs. C/N ratio was low in young twigs and maximum in all flushes before the initiation of spring growth and bloom.
A marked decrease in nitrogen content occurred in October, corresponding to initiation of second flowering in Columbia and initiation of Autumn flush in both the varieties. After October, there was an increase in nitrogen content reaching maximum in early spring. The ash and calcium showed increasing trend with the increasing age of the leaf, with some decrease in November, reaching maximum in early spring. Earlier flushes showed more of calcium and ash than the flushes which appeared later.
The concentration of magnesium was found to build upto a maximum and then showed wide fluctuations. However, definite decrease in its concentration was quite evident in early March. The concentration of phosphorus and potassium was quite high in bearing shoots as compared to non-bearing shoots of different flushes.
