Rock Phosphate Recapitalization: A P Fertilizer for Mature Oil Palm (Elaeis Guineensis Jacq.) in the Semi- Deciduous Forest Zone in Ghana
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Date
2011-08-12
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Abstract
The study focused on direct application of phosphate rock (PR) as an alternative source of phosphorus (P) to the use of superphosphate (triple superphosphate) for mature oil palm (Elaeis guineensis Jacq.) in the semi-deciduous forest zone of Ghana. The objectives of the study were to assess the fertilization effect of phosphate rock (PR) on the growth, development and yield of oil palm. The experiment also aimed at studying the influence of PR on soil microbial activity under oil palm as well as the influence of PR on soil nutrient changes, The economic benefit of using PR under oil palm was examined.
A field experiment was conducted between 2003 to 2007 at the Oil Palm Research Institute (OPRI), Kusi in the semi-deciduous forest zone of Ghana. The study was carried out on the soils
of Nzema series classified as Ferric Acrisols (FAO) and Typic Hapludult (USDA). The oil palm
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trees selected were 8 year old tenera (DXP ex OPRI). Each plot measured 17.6 m x 17.6 m and had 6 palms. There were four treatments, consisting of; 1). TSP - OPRI fertilizer recommendation - 222 kg of AS + 222 kg of TSP + 296 kg of MOP / ha / yr (control); 2). PR1 - PR 715 kg + 222 kg of AS + 296 kg of MOP / ha - Yr 1. PR 358 kg + 222 kg of AS + 296 kg of MOP / ha - Yr 2. PR 358 kg + 222 kg of AS + 296 kg of MOP / ha - Yr 3; 3). PR2 - PR 1428 kg + 222 kg of AS + 296 kg of MOP / ha applied once in every 5 years; 4). PR3 - PR 142.85 kg / ha +222 kg AS / ha + 296 kg of MOP / ha applied twice in every 5 years.
Chemical analysis of the soil indicated that application of treatments influenced the soil chemical properties to a varying extent. Soil pH ranged from extremely acidic (3.73) to acidic (5.43). Available K was as high as 125 mg/kg with available P recording 9.55 mg/kg which was slightly below the medium range of available P for oil palm production. The use of PR improved soil chemical properties especially increasing exchangeable Ca, Mg, K and ECEC.
The results showed that treatment PR2 was effective and gave the highest oil palm fresh fruit bunch yield of 62.8 t/ha whiles the TSP was the least effective with a production of 53.7 t/ha. Development, growth and yield response of P fertilization by palms followed the trend: PR2 > PR3 > PR1 > TSP. This trend could be attributed to sustainable supply of P to palm trees by PR than TSP. Microbial C, N and P were higher at the 4th year of study than during the 1st year of study. PR2 recorded the highest microbial C and N values, with PR3 holding more available phosphorus at the end of four year period.
The cost benefit ratio in a declining order were: 3.4, 3.1, 2.9 and 2.4 for PR3, PR2, PR1 and TSP respectively. The study has clearly shown that, agronomically and economically it is sound to use PR under matured oil palm.
Description
A thesis submtitted to the Department of Crop and Soil Sciences, Kwame Nkrumah University of Science and Technology in partial fulfilment of the requirement for the award of the degree of Master of Philosophy in Soil Fertility/Plant Nutrition, 2009