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Browsing Theses & Dissertations by Author "Acevedo-González, Melisa A."
Acevedo-González, Melisa A.; Román-Paoli, Elvin; College of Agricultural Sciences; Román Pérez, Félix; Valencia, Elide; O'Farril-Nieves, Hipólito; Department of Crops and Agro-Environmental Sciences; Santana, Carmen
Pineapple [Ananas comosus (L.) Merr.] is an important fruit crop in many tropical countries around the world. Its production has decreased dramatically in Puerto Rico by 77% since 1965. This reduction may be due to problems with nutrients and water management. Pineapple plants require large amounts of N and K to maximize yield, therefore, proper management is required. Although pineapple has a low water requirement (60 mm/month), large periods of drought can affect yield. An experiment was conducted to assess how methods of fertilization and water management affect pineapple production. Two pineapple cultivars „MD-2‟ and „Cabezona‟ were established in a randomize complete block design at Isabela on a Oxisol soil with a plant density of 40,617 plants/ha and at Lajas on a Ultisol soil with a plant density of 17,943 plants/ha, respectively. The treatments applied were: i) application of granular fertilizer 12-6-10-3 at 2, 5, and 9 months after planting (896 kg/ha); ii) application of 150-150-120-45 kg/ha plus twenty foliar applications of urea and potassium sulfate (50 kg/ha) every three weeks; iii) the same nutrient amount as treatment 2, but with drip irrigation every three weeks; iv) same nutrient amount as treatment 3, but applied throughout fertigation; and v) the same nutrient amount as treatment 2 but N was applied as a controlled release formulation every 6 months. In Lajas, foliar nitrogen concentration from the „D‟ leaves for treatment 2 and 3 were the highest with 1.3% (α ≤ 0.05), however, even though treatment 5 was not significantly different (α ≥.0.05), it showed a heavier fruit with 0.8 kg (14 MT/ha) The low yield was primarily due to the high infestation of mealybug Dysmicoccus brevipes (Order Hemiptera) in the entire field and poor root development. In Isabela, treatments 2, 3 and 5 showed the highest fruit weight with the maximum value of 2.5 kg (101 MT/ha) and 1.5% of N concentration in the foliar tissue of the „D‟ leaves (α ≤ 0.05) Treatments 2, 3 and 5 also showed the highest plant growing variables. Brix value was higher in Treatment 5 with 15.5°. Although the application of nutrients to the foliage showed the highest values in almost all variables, I recommended the use of controlled release fertilizers to eliminates the need for frequent foliar applications without compromising yield.