Mathematical models, tables and nomograms to establish the technical optimal rates (TOR) of N, P sub 2 /sub O sub 5 /sub and K sub 2 /sub O in strawberry, comparison with some erroneous models.

摘要

A series of mathematical models and agrochemical tables and nomograms in strawberry is presented and these can be used in order to establish the Technical Optimal Rates (TOR) of N, P2O5 and K2O as function of maximum expected yield, Ym, and the specific soil agrochemical indexes (nitrogen index: IN; mobile phosphorous: PALc; mobile potassium: KAL). The TOR of a nutrient is the rate which allows to obtain the maximum yield under given conditions concerning the soil supply of the regarded nutrient, and that allows a sustainable horticulture. The paper presents the logical deduction of the TOR mathematical model, derived from a modified Mitscherlich response function. The TOR system uses the same equations for nutrients action coefficients and soil nutrient supply as the Economically Optimal Rate (EOR) system. The FERTEXPERT software version 3 has been used for TOR calculations. When exact values of TOR are desired, the mathematical model has to be used; when operative settle of TOR are desired, the practical agrochemical tables and nomograms can be used by farmers. The agrochemical tables and nomograms will be accessed online on a specific website. The paper also presents comparative results between the reasonable nutrient rates calculated with the TOR model and the absurd nutrient rates calculated with some erroneous models.