THE CANGES OF NO3-N CONTENT IN THE SOIL OF ORCHARDS WITH DIFFERENT SOIL CONDITIONS

ISHS Acta Horticulturae 383: Mineral Nutrition of Deciduous Fruit Plants

THE CANGES OF NO₃-N CONTENT IN THE SOIL OF ORCHARDS WITH DIFFERENT SOIL CONDITIONS

Authors:	T. Tóth, J. Papp, Z.I. Ibrahim
Keywords:	N_min-method, nitrogen supply, fruit crops
Abstract: The rationalization of nitrogen application in orchards is required both for environment protection and profitable crop production. Moderate nitrogen dressing is the most important requirement in integrated fruit production. At present in most Hungarian orchards there is unbalanced tree nutrition primarily because of overfertilization of nitrogen. For this reason we have been conducting some experiments on nitrogen application and soil testing in orchards with different types of soil. The objective of these investigations was to obtain information on whether the determination of NO₃-N content of the soil by the N_min-method is suitable to characterize the nitrogen status of orchards in order to decrease nitrogen-dressing and leaching. We used the N_min-method by Scharpf and Wehrmann 1976, taking soil samples from the end of winter to the begining of November to a depth of 80 cms in 20 cm layers. The experiments were carried out on three locations with different soils including on alluvial clay loams, sandy loam and clayey loam. The fruit crops were apple, plum, and raspberry. The main results of the 3-year experiments can be summarized as follows: The N_min-method is promissing in order to characterize the quantity of NO₃-N in the soil for estimating the adequate nitrogen level of orchards. The NO₃-N content of the soil fluctuates much less within a year in the clayey loam and alluvial clay loam than the sandy loam. There are two peak periods in the NO₃-N content of the orchards soil under the Hungarian climatic conditions, one in early spring, the other in autumn. Among the tested fruit crops only raspberry showed a positive relationship between NO₃-N content of soil in early spring and the content of nitrogen in leaves.
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