ISHS Acta Horticulturae 627: XXVI International Horticultural Congress: Toward Ecologically Sound Fertilization Strategies for Field Vegetable Production
THE COMPOSITIONAL NUTRIENT DIAGNOSIS OF ONIONS |
| Authors: | L.E. Parent, L. Khiari |
| Keywords: | Alium cepa L., foliar analysis, macro-elements, micro-elements, organic soils, nutrient imbalance |
| Abstract:
Mineral analysis of plant tissue is the basic numerical information for making a nutrient diagnosis. It is instrumental in adjusting the fertilization to specific soil-plant systems in order to maintain balance between nutrients and achieve high-yield levels. The compositional nutrient diagnosis (CND) provides a multi-ratio, nutrient balance, approach that generates linear variables adapted to any linear model and easy to diagnose from generic statistical distribution patterns. Our objective was to develop a method to derive CND norms from an onion survey dataset. A nutrient imbalance index was computed as the sum of squared values of 5 CND nutrient indexes (IN, IP, IK, ICa, IMg) and an index for filling value between 100 % and the sum of nutrient concentrations (IR). Using the X2 distribution as generic model, CND norms were elaborated from the dataset. The CND nutrient imbalance index (CND-r2) and the corresponding chi-square value for 6 degrees of freedom were both. Critical CND nutrient indexes were found to be –0.93< IN <0.93 and –1.0 < IX <1.0 for other nutrients. More constrained CND-r2 values must reduce IX2 values proportionally when independent IX2 values, as found here, are additive to CND-r2 values. This CND approach can be easily updated with new data for improving soil and crop management in specific agroecosystems. | |
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