THE COMPOSITIONAL NUTRIENT DIAGNOSIS OF ONIONS

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 (I_N, I_P, I_K, I_Ca, I_Mg) and an index for filling value between 100 % and the sum of nutrient concentrations (I_R). 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< I_N <0.93 and –1.0 < I_X <1.0 for other nutrients.
More constrained CND-r² values must reduce I_X² values proportionally when independent I_X² 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.

XXVI International Horticultural Congress: Toward Ecologically Sound Fertilization Strategies for Field Vegetable Production

L.E. Parent, L. Khiari

Alium cepa L., foliar analysis, macro-elements, micro-elements, organic soils, nutrient imbalance

https://doi.org/10.17660/ActaHortic.2003.627.32