Masters Theses

Date of Award

5-1996

Degree Type

Thesis

Degree Name

Master of Science

Major

Plant, Soil and Environmental Sciences

Major Professor

Michael D. Mullen

Committee Members

John T. Ammons, John Foss

Abstract

A pedological study of tropical soils in and around the Mayan Biosphere Reserve in Peten, Guatemala was undertaken in order to study the characteristics and potentials of different soils for the better management of natural resources. The objectives of this research were: i) to describe the main characteristics of selected soils in the Peten; ii) to better understand the genesis of these soils; iii) to classify the soils according to the U.S. soil taxonomy system; and iv) to determine the potentials and management of the soils.

With the cooperation of several Guatemalan institutions, six sites were chosen and the soils at each site were fully characterized. After field characterization, the soil samples were transported to the laboratory for physical and chemical analysis. The analysis includes: pH, total carbon and total nitrogen contents, organic carbon, calcium carbonate equivalent, total elemental analysis, exchangeable bases, cation exchange capacity, KCI exchangeable aluminum and exchangeable acidity, archeological extract, and particle size analysis.

The first three soil sites were located in the Yaxja area. A soil-landscape position relationship was established; Mollisols occupied upland and sloping positions and Vertisols occupied depressional areas in the lowlands. The rest of the sites were scattered in other areas inside, as well as outside, the Mayan Biosphere Reserve.

The soil orders found in the research area were Mollisols, Vertisols and Alfisols. The Mollisols and Vertisols developed from calcareous parent materials and the Alfisol from alluvial deposits. The soils developed from the carbonated rocks are rich in clay, especially montmorillonitic clay. The pH ranged from strongly acid (Alfisol) to moderately alkaline. The average organic matter content of the topsoil of the different sites (4.84%) is comparable to those of temperate climates. The abundance of clay and organic matter resulted in high CEC values for the first five soil sites; however, the total elemental analysis showed serious deficiencies, especially in phosphorus, potassium and nitrogen.

The soils were classified as Aquic Hapludolls, Typic Endoaquerts, Typic Rendolls, Eutrochreptic Rendolls, and Typic Paleudalfs. In terms of the land capability classification, the soils were classified as: site 1: llw, site 2: lllw, site 3: Vie, site four: lie, site five: IVe and site six: llf.

The soils, as well as other natural resources in the Peten, are rapidly being degraded. Mismanagement, improper use and deforestation are depleting the soils. A management system based on land layout, mulches, management of cracking, fertilization, and liming was proposed to improve the productivity of the soils. This, along with sustainable agricultural practices will reduce the degradation of the natural resources.

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