Nutrient Demand of Oil Palm Hybrids in Tropical America

The second phase of this study was initiated at three locations including Astorga (Tumaco Department), Hacienda La Cabaña (Casanare), and Unipalma de los LLanos (Meta) plantations. The soils at these locations were acidic (pH from 4.3 to 4.8) with very low P (3 to 5 ppm) and variable percent exchangeable Al (30 to 70%). In each location, two OxG planting materials were evaluated: “m1” from La Cabaña and “m2” from Unipalma. The plants were transplanted in the second semester of 2011, and the first fruit yield is expected only by the end of 2013 or in the first semester of 2014. Accordingly, only measurements of plant growth as height, leaf area of reference (9th) leaf (LA9), leaf number (LN), and transversal section area at the petiole base (PTS) have been collected so far. Also, measurements of leaf mineral content were obtained from samples taken from LA9, as the regularly used 17th leaf is not recommended measurements in young plants.

At all three locations, m2 plants had larger LA9, but remarkably, similar PTS areas for both materials (m1 and m2). Mineral concentrations of N, P and K for leaf 9 were similar for both materials, but Ca and B were higher for m1 compared to m2 by 20% and 33%, respectively. The larger biomass of m2 produced a disproportionately larger total absorption of N, P and K than m1 (about 20% increase). At the Astorga location, responses to N and P rates were observed. For example, about a 20% increase in plant height was observed with the highest N rate compared to the lowest N rate. The other two locations did not show a significant response to N or P. Boron did not affect the response of the plants, and B leaf concentration varied with B fertilizer rate only in m1, which suggested that m1 is a larger B accumulator than m2. The commercial dose recommended for conventional oil palm may be sufficient for m1 and small crosses like this, but as our analysis suggested, it is not adequate for larger breeding lines such as m2. Colombia-16