Seasonal variation of nutrients in mango (Mangifera indica) trees on three soils of the dry Pacific region of Costa Rica. I. Macronutrients.
Ponchner S., Rojas R., Bornemisza E.
Author Affiliation: Estación Experimental Agrícola Fabio Baudrit Moreno, Facultad de Agronomía, Universidad de Costa Rica, Alajuela, Costa Rica.
Agronomía Costarricense 17 : 21-30
Abstract : Nutritional status and seasonal variation of N, P, Ca, Mg, K and S were evaluated in mango trees (cultivars Irwin and Tommy Atkins) at 3 sites (the 3 most important mango-producing areas in Costa Rica) with different soil types - Atenas (Ustic Humitropept), Orotina (Typic Dystropept) and Liberia (Typic Ustropept). The leaves sampled were either terminal (new), intermediate or old, i.e. representing each of the last 3 growth flushes, and samples were taken each month. N, P, K and Mg concentrations increased as leaf age decreased, demonstrating the mobility of these elements. In contrast, S concentration did not differ significantly between leaves of different ages and Ca concentration was lower in new leaves than in intermediate or old ones. It was concluded that S and Ca were immobile. N, P, K and Mg concentrations were higher and Ca concentration lower in Irwin than Tommy Atkins. N, P, Mg and S deficiencies were observed in all 3 orchards. In the case of P, Mg and S, the low foliar concentrations corresponded to low soil concentrations. Leaf N, P, K, Mg and S concentrations were low during flowering and fruiting, while Ca concentration decreased after the end of the rainy period. Based on the results, sampling intermediate-aged leaves after harvest was recommended for the most homogeneous sample.