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Background and aims: In oil palm, similar fertilization treatments can result in leaflet potassium and magnesium concentrations that vary significantly from one progeny to another. This hinders the development of standardized fertilizer recommendations for this crop, as they are usually calculated based on optimum leaflet nutrient concentrations.Methods: 4-high-yielding oil palm progenies with contrasting leaflet K and Mg concentrations (C1, C2, and C3 of Deli x La Mé origin and C4 of Deli x Yangambi origin) were treated with combinations of 3-levels of KCl and MgSO4, in a completely randomized split-plot factorial design with 6-replicates, where progenies were a sub-factor.Results: For a given level of KCl or MgSO4, different leaflet K and Mg concentrations were found between progenies (p < 0.0001). Leaflet K concentration and yield response to KCl applications revealed that the four oil palm progenies have different optimum leaflet K concentrations. In our study period (5-8 YAP), progenies C1 and C3 showed their highest fresh fruit bunch (FFB) yields (13.62 and 16.54 t ha-1 year-1, respectively) at K2, whereas progenies C2 and C4 showed their highest yields (14.62 and 12.39 t ha-1 year-1, respectively) at K1. Conclusion: Our study highlighted specific optimum leaflet K and Mg concentrations for different oil palm progenies in a given environment. It paves the way for adopting K and Mg fertilizer application rates adapted to specific requirements of each type of oil palm planting material.

We compared four oil palm (Elaeis guineensis Jacq.) progenies’ morphological growth characteristics to reveal genotypic differences in plant growth and assess their adaptability in Nigeria’s environment in response to different levels of potassium chloride (KCl) and kieserite fertilizer applications. The studied progenies (C1, C2 and C3 of Deli × La Mé origin and C4 of Deli × Yangambi origin) represent a wide genetic diversity of oil palm and have shown among a population of 116 different progenies, a contrasting K and Mg leaflet concentrations that covered the extreme ranges of leaflet concentrations in these minerals. The trial consisted of a completely randomized split-plot factorial design with six replicates, where progenies, considered as sub-factor were treated with combinations of 3 levels of potassium chloride (0, 1.5, 3.0 kg of KCl palm−1 year−1) and kieserite (0, 0.75, 1.5 kg of MgSO4 palm−1 year−1) fertilizers (main factor), respectively. Growth characteristics differed significantly among progenies, but not in all studied years. In all progenies, KCl treatments significantly increased the average annual collar girth increment and projected canopy area. Adding 3.0 kg palm−1 year−1 of KCl significantly increased the total leaf area of progeny C4. Kieserite applications did not have an effect on progenies’ growth characteristics whereas potassium showed to be the main mineral needed for oil palm growth. It was shown that with equal amounts of fertilizers applied, progeny C3 had better morphological traits than the other progenies, suggesting that the effective nutrient requirements should be assessed for each individual progeny and that fertilization should be adapted accordingly.

Oil palm fertilizer requirements are based on leaflet mineral concentrations. Four oil palm progenies representing a wide genetic diversity of Elaeis guineensis species and with contrasting K and Mg leaflet concentrations were tested in Indonesia and Nigeria, environments which differ predominantly in climate. During 5 years, we compared oil palm progenies’ leaflet mineral concentrations between both countries under abundant fertilizer applications to investigate the extent to which they depend on the environment. In the two studied environments, leaflet concentrations significantly differed between progenies for K, Mg and Ca, but the country effect was not found significant (p = 0.352) for any leaflet mineral’s concentration. In both countries, progenies ranked similarly in their mineral categories (lowest and highest cation concentrations within the 4 progenies population), indicating that leaflet mineral concentrations in the tested oil palm progenies are mainly determined by their genetic background. For each progeny, with abundant fertilization, K, Mg and Ca proportions to total leaf cation charge (TLCC) were similar, irrespective of the environments in which the palms were cultivated. We have strong indications that foliar concentrations of K, Mg and Ca are determined by genetic factors which dominate the environmental effect. However, it remains uncertain whether differences in oil palm foliar concentrations between different oil palm progenies imply that they require specific fertilizer amounts to attain an optimal production.