Application of soil and tissue analyses in fertilization practice in Czechoslovak orchards

Periodic estimation of cation exchange capacity saturation and its complementation towards optimal proportions is a basis of calcium, magnesium and potassium fertilization policy. Calculation of the complementary rates: K kg.ha-1 = 0.06 . 1 (Kaim - Kactual), analogically Ca and Mg with coefficients 0.03, 0.02, respectively; in paranthesis there is the difference between the aimed and the actual proportion in per cent of the C.E.C. saturation, 1 is the layer in cm to be complemented. As for phosphorus, there is necessary to supply the soil profile before planting sufficiently for the whole life of the orchard: P kg.ha-1 = 0.5. 1 (110-Pactual), Pactual is the estimated content in ppm (by Egner). As a rule there in no need of fertilization with phosphorus in the course of the orchard existence if the soil content exceeds 50 ppm, the leaf content does not decline below 0.19 per cent in several successive years' average, and the tree performance is proper. Even in instances of presumable defficiency, the efficiency of the phosphorus fertilization should be tested in a limited part of the orchard. Nitrogen requirement is planned with respect to the climatic and soil conditions as well as to the yielding level of the orchard. The requirement is realized in three successive partial rates, the proportions being differentiated regarding the climatic regions. Possible reductions of the particular rates are defined respecting: actual content of mineral N (NH4- + NO3+) in the soil at start of the budding and after blossom, actual fruit set after blossom and after fruitlet drop, growth vigour and leaf N content in previous summer. Leaf (or other tissue) analysis is an important aid to determination of the nutrition status of the tree, but it is no basis of fertilizer rates assessment.