ISHS Acta Horticulturae 383: Mineral Nutrition of Deciduous Fruit Plants
INTERPRETATIVE POSSIBILITIES OF PLANT ANALYSIS BY THE DOP INDEX. |
| Authors: | L. Montañés, E. Monge, J. Val, M. Sanz |
| Keywords: | Apple, foliar diagnosis, Malus sp., nutritional status, plant nutrition, reference values |
| Abstract:
Since plant analysis was developed as a tool to assess the nutritional status of plants, those involved have used many concepts based on nutrient contents in plant material, including ratios and balances, to interpret the analytical values. However, none of the interpretative methods, if used separately, provides a clear picture of the real nutritional status. In this paper, an index (DOP: Deviation from Optimum Percentage) to interpret plant analysis data is described. The DOP index is defined as the percentage deviation of the concentration of an element (on dry matter basis) in analyzed plant tissue relative to the concentration of a reference value. The DOP index is therefore calculated by applying the following general formula: DOP=[(Cx100)/Cref]-100. C is the concentration of a given element in the analyzed sample, and Cref is the reference nutrient concentration. The absolute value of a DOP index indicates the importance or severity of an anomalous nutritional status. When a given element is at its optimal concentration the DOP index for this element is equal to zero. A large absolute value in a DOP index indicates a large deviation from the optimum situation. For any given element, a negative DOP index indicates a deficiency, whereas a positive DOP index indicates an excess. To illustrate the method of calculation of the index for fruit trees, a practical example is given. By calculating the DOP indexes for each of the mineral elements a nutritional status for the plant or crop is obtained. The DOP method permits the ranking of nutrients in the order in which they are limiting as well as identifying particular limitations, including deficiency and excess. | |
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