Seasonal changes in mineral nutrients of olive leaves in an arid region of Argentina (San Juan): nitrogen, phosphorus, and potassium

LUIS BUENO; ENRIQUE SANCHEZ; PETER S. SEARLES

Lisboa, Portugal

Congreso; International Horticultural Congress; 2010

International Society of Horticultural Science

The objective of this study was to determine the time of year when nitrogen (N), phosphorus (P), and potassium (K) are most stable in leaves from current season shoots in var. ‘Arbequina’ olive trees in San Juan, Argentina (31º58’06” S – 69º35’37” O). The concentration of foliar N, P and K was evaluated monthly over 4 years, on 8-year-old trees in a commercial orchard with a density of 357 trees per hectare. Samples were taken from three replicate plots of 10 trees each. Leaf nitrogen concentration was highest in March (late summer in the Southern Hemisphere) and minimum values were found in the spring months of September, October, and November. For P, maximum and minimum concentrations were found in August-September (late winter) and December-January (early summer), respectively. Lastly, the minimum concentrations of K were detected in October (spring) similar to nitrogen, while maximum values occurred in November. Statistical analyses indicated minimum values of standard deviation and of the coefficient of variation for both N and K in the spring (October) and for P during the winter. In that N and K are the nutrients most likely to be deficient in this region, the period prior to flowering in the spring appears to be the most appropriate for foliar nutrition sampling given the stability of these nutrients at that time of year.