S13 - Session P2 - Silicon application influence imbalance between nitrogen and potassium fertilization in young olive plant

Authors: Inmaculada Martos-García *, María Benlloch-González, Ricardo Fernández-Escobar

In many olive orchards from the Mediterranean Basin are frequently observed nutritional imbalances associated to an excess of nitrogen fertilization and low levels of potassium in leaves. It has been observed that Si application positively affects many aspects of nitrogen nutrition (uptake, assimilation, and remobilization) and alleviates the negative effects of potassium deficiency in many crops. However, the relationship between silicon and olive nutrition is poorly documented. In order to elucidate whether Si, applied through the irrigation water, improves the vegetative growth in young olive plants treated with different N and K doses, a preliminary experiment was performed with the cultivar `Picual´ growing under shade-house conditions in Cordoba, Southern Spain. Plants received weekly two levels of Si (0 or 20 mg/L,) through the irrigation water. When differences in silicon leaf content were observed, the treatments resulting from the combination of different levels of nitrogen (0, 100 y 400 ppm N, Ca(NO 3 ) 2 ) and potassium (0.05 y 2.5 mM KCl) were started. The experiment was arranged in a completely randomized block design, with five blocks and 12 treatments. The results obtained show that the application of Si promoted both the vegetative growth and N uptake in those plants under 0 or 100 ppm N levels independently of the KCl treatment. However, Si application decreased the accumulation of K in plants grown under the combination of low or high levels of N and KCl (0 ppm and 0,05 mM or 400 ppm and 2,5 mM, respectively). N nutrition was not affected by the KCl levels, but it was affected by Si treatments while K nutrition depended on the Si and N level the plant received.