THE INFLUENCE OF K:CA:MG:NA RATIO AND TOTAL CONCENTRATION ON YIELD AND FRUIT QUALITY OF SOILLESS-GROWN TOMATOES: A MODELLING APPROACH

This study describes an application of Systematic Variation method (SV) for optimizing cation proportions (K, Ca, Mg, Na) and the total element concentration of hydroponically-grown tomatoes.
A randomized complete-block design with 5 replications (3 plants per experimental unit) was used to compare a factorial combination of 4 proportions of K:Ca:Mg:Na and 2 total concentrations of elements (30 and 60 meq L^-1). Each of the cation proportion treatment was defined by a high proportion of one cation (V=0.64) and an equally low proportion of the others (v=0.12) for a total amount of one (V + 3v = 1). The highest total and marketable yield were obtained in treatment with high proportion of K (avg. 2.94 and 2.72 kg plant^-1, respectively) and Ca (avg. 2.84 and 2.65 kg plant^-1, respectively), while treatments with high proportion of Mg (avg. 2.59 and 2.22 kg plant^-1, respectively) and Na (avg. 2.21 and 2.09 kg plant^-1, respectively) gave the lowest values.
The highest incidence of blossom-end rot was observed in treatments with high proportion of Mg and K (avg. 10.8 % and 3.7 % of total yield, respectively). Fruit quality (soluble solids, titratable acidity, EC) improved by increasing the proportion of K and Na and the total concentration.
The SV method showed that for maximise the marketable yield it is necessary to include a large amount of K and Ca in the nutrient solution.

International Symposium on Soilless Culture and Hydroponics

S. Fanasca, Y. Rouphael, M. Cardarelli, G. Colla

Lycopersicon esculentum L., Systematic Variation method, mineral nutrition, quality

https://doi.org/10.17660/ActaHortic.2005.697.43