52 IPNI Interpretive Summaries
<strong>Americas</strong> <strong>and</strong> <strong>Oceania</strong> <strong>Group</strong> Northern Latin America Dr. Raúl Jaramillo Colombia Nutrient Dem<strong>and</strong> of Oil Palm Hybrids for Tropical America Project Leader: Dr. Jose Alvaro Cristancho, Fedepalma, Cenipalma Soil, Water <strong>and</strong> Mechanization Program, Villavicencio, Meta Columbia. E-mail: acristancho@ceripalma.org Project Cooperators: Diego L. Molina, Jorge S. Torres, Isaac T. Vera, Eloina Mesa, <strong>and</strong> Edna M. Garzón This study examines the nutrient dem<strong>and</strong>s of the OxG hybrid oil palm <strong>and</strong> the most adequate tools to calibrate crop fertilization (e.g. foliar critical levels for different nutrients). The nursery phase was initiated in 2010 with two sets of plantlets growing in two locations of Colombia. In each location two parallel studies were carried out with rates of: 1) N, P, <strong>and</strong> K; <strong>and</strong> 2) Mg, Ca, <strong>and</strong> B. <strong>Plant</strong> growth, nutrient absorption, <strong>and</strong> leaf physiology were evaluated. The first phase of the study involved independent studies on nursery plants (before transplanting) at two locations. The nursery experiments were carried out in Tumaco (southwest Colombia) having alluvial, relatively high organic matter soils <strong>and</strong> continuous rainfall; <strong>and</strong> Meta (center east Colombia) having low organic matter oxisols <strong>and</strong> seasonal raining. The OxG materials used were accessions obtained from crosses made with Elaeis oleifera collected in Brazil. Two different crosses were evaluated in each nursery experiment. In general the phase I results showed that N controlled the growth of plantlets for the two materials tested in both locations. But for the other nutrients, the response was specific for each OxG material tested, for instance, the dem<strong>and</strong> of K <strong>and</strong> B in one of the tested materials was larger than the recommended rate for E. guineensis, but the second OxG accession had similar requirements of the African oil palm. As well, the calculated nutrient dem<strong>and</strong> for P <strong>and</strong> Ca were material specific. The use of K, Mg <strong>and</strong> B did not produce significant decreases or increases in plant growth (leaf number, leaf area, plant height) in the nursery phase. In the case of B, slight increases were found with the largest quantities used; again, this response was material-specific. In summary, these results suggest very specific dem<strong>and</strong>s of the crop as a function of the material planted, which in practical terms means that each plantation or region may need to develop site-specific studies to fully underst<strong>and</strong> the actual dem<strong>and</strong>s of the different OxG materials. The experimental design used may serve as a model for further nursery studies. The second phase of the study was initiated with the transplant of independently managed plantlets at three locations: the Astorga (Tumaco), Hacienda La Cabaña (Casanare), <strong>and</strong> Unipalma de los LLanos (Meta) plantations. Columbia-16 Global Maize Initiative, Colombia Project Leader: Dilia M. Coral, Fenalce Soils <strong>and</strong> <strong>Nutrition</strong> Management Program Cota, Cundinamarca. E-mail: dcoral@fenalcecolombia.org Project Cooperators: Henry Vanegas (FENALCE General Manager), Carlos E. Molina, <strong>and</strong> Gustavo Lemos In 2011, this study completed four consecutive crop cycles at Villa Escocia, <strong>and</strong> the fifth cycle was planted on October 27. The study had following specific objectives: 1) measure yield differences among different nitrogen management strategies <strong>and</strong> 2) compare the ecological intensification (EI) management against traditional maize technology. In 2009-B, the first planted cycle, the average yield in the intensive management was 7.30 t/ha <strong>and</strong> the traditional management yield average was 5.49 t/ha. Only the treatment with intense management with N in all cycles showed a significantly higher yield (8 t/ha), but this was possibly an artifact as many other treatments suffered from plant lodging. Overall, this cycle indicated a high fertility soil, with small differences within N strategies tested with high or low planting densities. Cycle 2010-B showed the lowest yield overall as a result of extreme rainfall, this was also the cycle in which the treatments with reduced N application (2/3 cycles) did not receive N. The average grain yield in 2010-B with intensive management was only 6.45 t/ha, while the traditional management average was 5.53 t/ha. The maximum yield was obtained with traditional management N applications in all cycles (8.77 t/ ha), which was slightly higher than intensive management with N in all cycles (8.45 t/ha). It was noticeable IPNI Interpretive Summaries 53