Changes in the NO3-N content of the soil in farm orchards of apricot and plum.
1992
Toth, T. (Kerteszeti es Elelmiszerip. Egyet. (Hungary))
In orchards planted on humous sandy soil with the apricot variety Magyar kajszi and the plum variety Stanley, the Nitrate-N supply of the soil after early spring N fertilization or without N fertilization became stabilized at a value of ca. 100 kg N/ha from late April onwards. In the case of late spring N treatment, there was an intense increase in the nitrate N supply of the soil for a brief period, but considerable fluctuations were later observed due to fixation and liberation. During the vegetation period examined, 2 nitrate peaks could be observed; the 1st in early spring (this was intensified by N fertilization) and the other in the autumn months. The natural N-supplying capacity of the soil, with possibly a very low rate of N-fertilization, is sufficient to develop the yield levels achieved so far. Only a very weak positive correlation could be demonstrated between the early spring nitrate-N supply from the soil and the N contents of apricot and plum leaves.
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