Assessment of Potential Nutrient Release from Phosphate Rock and Dolostone for Application in Acid Soils  

作　　者：Rogério Borguete Alves RAFAEL María Luisa FERNáNDEZ-MARCOS Stefania COCCO Maria Letizia RUELLO David C.WEINDORF Valeria CARDELLI Giuseppe CORTI 

机构地区：[1]Department of Rural Engineering, University Eduardo Mondlane [2]Department of Agriculture, Food and Environmental Sciences, Università Politecnica delle Marche [3]Department of Soil Science and Agricultural Chemistry, Universidad de Santiago de Compostela [4]Department of Materials, Environmental Sciences and Urban Planning, Università Politecnica delle Marche [5]Department of Plant and Soil Science, Texas Tech University

出　　处：《Pedosphere》2018年第1期44-58,共15页土壤圈（英文版）

基　　金：supported by the "Applied Research and Multi-sectorial Program" (FIAM) (No. 5.2.1) granted by the Italian Cooperation and Development Agency (ICDA) to the Universidade Eduardo Mondlane;the Polytechnic University of Marche, Italy for the PhD scholarship provided to the first author as well as research funding for this work

摘　　要：Finding alternative local sources of plant nutrients is a practical, low-cost, and long-term strategy. In this study, laboratory column experiments were conducted in a completely randomized design to evaluate the feasibility of using phosphate rock and dolostone as fertilizers or acid-neutralizing agents for application in tropical acid soils. The dissolution rates of different particle-size fractions(0.063–0.25, 0.25–0.5, and 0.5–2 mm) of both rocks were studied by citric acid solution at p H 4 and 2 and water, with extraction times of 1, 3, 5, 7, 12, 24, 72, 144, 240, and 360 h. The results showed that the dissolution of both rocks depended on the particle size,leaching solution, and extraction time. The dissolution rate of rock-forming minerals increased as the specific surface area increased,corresponding to a decrease in particle size. In all cases, the release kinetics was characterized by two phases: 1) a first stage of rapid release that lasted 24 h and would ensure short-term nutrient release, and 2) a second stage of slow release after 24 h, representing the long-term nutrient release efficiency. Both rocks were suitable as slow-release fertilizers in strongly acid soils and would ensure the replenishment of P, Ca, and Mg. A combination of fine and medium particle-size fractions should be used to ensure high nutrient-release efficiency. Much work could remain to determine the overall impact of considerable amounts of fresh rocks in soils.Finding alternative local sources of plant nutrients is a practical, low-cost, and long-term strategy. In this study, laboratory column experiments were conducted in a completely randomized design to evaluate the feasibility of using phosphate rock and dolostone as fertilizers or acid-neutralizing agents for application in tropical acid soils. The dissolution rates of different particle-size fractions（0.063–0.25, 0.25–0.5, and 0.5–2 mm） of both rocks were studied by citric acid solution at p H 4 and 2 and water, with extraction times of 1, 3, 5, 7, 12, 24, 72, 144, 240, and 360 h. The results showed that the dissolution of both rocks depended on the particle size,leaching solution, and extraction time. The dissolution rate of rock-forming minerals increased as the specific surface area increased,corresponding to a decrease in particle size. In all cases, the release kinetics was characterized by two phases： 1） a first stage of rapid release that lasted 24 h and would ensure short-term nutrient release, and 2） a second stage of slow release after 24 h, representing the long-term nutrient release efficiency. Both rocks were suitable as slow-release fertilizers in strongly acid soils and would ensure the replenishment of P, Ca, and Mg. A combination of fine and medium particle-size fractions should be used to ensure high nutrient-release efficiency. Much work could remain to determine the overall impact of considerable amounts of fresh rocks in soils.

关 键 词：citric acid dissolution rate leaching solution particle-size fraction release kinetics slow-release fertilizer 

分 类 号：S158[农业科学—土壤学]