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Twenty-six soil profiles were characterized and classified as Ultisols in the middle-upper watershed of Pirrís River. These soils developed on Pleistocene to Oligocene undulated to strongly undulated mountainous landscapes, on: 1) marine sediments, 2) volcanic andesitic-basaltic materials and 3) colluvial materials, all of them covered by natural vegetation of wet to very wet tropical forest in an ustic soil moisture regime. The soils are deep, possess an argillic horizon and are of fine to very fine texture. Soil reaction is acid to strongly acid and may possess a horizon high in manganese concretions associated to ancient water levels of the Pirrís River watershed, on geologic materials high in manganese content. Clay content, CEC, particle density and bulk density of the soils vary with parent material, while base content and phosphorus fixation are not so related. According to Soil Taxonomy, 2 suborders were recognized: Humults and Ustults. Five great groups: Haplustults, Paleustults, Haplohumults, Palehumults, Rhodustults; and 9 subgroups: Typic Haplustults, Aquic Haplustults, Typic Paleustults, Andic Haplohumults, Aquic Haplohumults, Aquandic Haplohumults, Ustic Haplohumults, Andic Palehumults, Typic Rhodustults. The Andic and Aquandic subgroups exhibit, in superficial horizons, depositions of volcanic ash materials dated around 700 years of age. Buried clayey subsoils of Talamanca Ultisols are much older than their over laying horizon, being dated as old as 9000 to 65 000 years of age. [ABSTRACT FROM AUTHOR]

This experiment was conducted to evaluate the response of alder trees (Alnus acuminata (H.B.K.) O. Kuntze) to liming in Andisols of 2 sites of the Virilla River upper watershed, Costa Rica. The first experiment was set up in 2002 at the Hospicio farm, Vista de Mar, Goicoechea County, at 1542 masl; on a soil classified as Typic Udivitrands. A second experiment was carried out in 1997 at Dorval farm, Las Nubes, Vásquez de Coronado County, at 1925 masl, on a soil classified as Thaptic Udivitrands. Liming treatments were: 0 (check), 750, 1500 y 2250 kg.ha-1 of calcium and magnesium carbonate (Dolomite), 1500 kg.ha-1 of calcium carbonate (Calcita) and 1500 kg.ha-1 of calcium sulfate (Gypsum). Dasometric variables measured were diameter at breast height (DBH) at 1.3 m, total height of trees, and volume was estimated using the formula: V(m³)=2.71828 -- 10.0557 + ln(d)*2.0369 + 0.927718*ln(h) as proposed by Segura et al. (2005), where d represents DBH (cm) and h is total height (m). None of the liming treatments significantly affected DBH annual increment, total height, average height annual increment, total volume and total volume annual increment in any of the 2 farms. Nor liming affected any tree growth variable by season (dry vs. wet season). No significant differences were found among dasometric variables due to the addition of different liming sources. The lack of response to the soil amendments compared demonstrates that the soil available Ca, Mg and S was enough to provide these nutrients in quantities that allow alder optimum growth. None of the soils studies showed acidy problems large enough to adversely affect alder tree growth. [ABSTRACT FROM AUTHOR]

Andisols, Inceptisols and Entisols of the Pirrís River watershed, Los Santos, Talamanca, Costa Rica. Eight soil profiles were described and classified on volcanic ash deposits at the upper Pirrís River watershed. The soils were classified as Andisols and Inceptisols of the suborders Ustands, Udands and Ustepts; at the great group level the soils were classified as Haplustands, Placudands and Dystrustepts, belonging to the subgroups Dystric Haplustands, Humic Haplustands, Aquic Haplustands, Typic Placudands and Andic Dystrustepts. The topsoil characteristics of many of these soils are fragile, vulnerable to erosion and landslides. In general, these soils are acid, of low fertility status and present recent surface horizons (Holocene), but could be underlain by argillic horizons formed during the Pleistocene. On recent alluvial terraces from the Holocene, another group of seven soil profiles were described. These show little morphological development; major soil- forming processes in these positions include detachment in the highlands and deposition of particles through river flooding in the lowlands. These soils were classified in the orders Entisols and Inceptisols, suborders Fluvents y Ustepts, great groups Ustifluvents, Dystrustepts and Haplustepts, finally belonging to the subgroups Typic Ustifluvents, Fluventic Dystrustepts, Fluventic Haplustepts and Humic Dystrustepts. Most Entisols present coarse textures (sandy loam) while in the Inceptisols the clay content is dominant (clay loam, sandy clay loam and clayey textures). A third group of soils were described in a rim around intrusive materials of Miocene to Pleistocene origin, dated to be 8 to 11 Ma. On these metamorphic materials Inceptisols were formed, showing high rock and stone contents. Most of these soils are shallow, acid and of yellowish colors, due to the illuviation, lixiviation, humus formation, weathering and erosion dominating soil forming processes in this area. [ABSTRACT FROM AUTHOR]

Soils from 11 watersheds planted with banana in the aluvial valleys of the Caribbean zone of Costa Rica were chemically characterized and classified. Two major soil areas were identified based on their morphological and chemical properties and taxonomic criteria. One of the areas consisted mainly of Inceptisols formed from fluvio-volcanic materials with andic properties (Andic Eutrudepts, Aquandic Endoaquepts), dystric Inceptisols (Fluventic Dystrudepts) and Andisols (Typic Hapludands), most with good drainage, medium textures (sandy loam, loam, silty loam), sum of bases 10 to 19 cmol.l-1, CEC 13 to 28 cmol.l-1 and clays with permanent charge. The adjacent zone consisted mainly of Inceptisols formed from aluvial sedimentary materials deposited by frequent river floods (Fluventic Endoaquepts, Dystric Fluventic Eutrudepts, Fluvaquentic Eutrudepts, Fluvaquentic Endoaquepts), with a sum of bases 18 to 46 cmol.l-1, CEC 19 to 46 cmol.l-1, without Andic properties, textures fine to medium (clay loam, silty clay loam, clay, silty clay) and in some case with poor drainage (Endoaquepts, Epiaquepts, Fluvaquentic). Geographically, the 2 zones were separated by the watersheds of Vueltas-Silencio-Parismina Rivers; the northwest area is highly influenced by volcanic ash deposits and has its medium fertility characteristics, while the southeast area is not influenced by volcanic ejecta and has high fertility characteristics. [ABSTRACT FROM AUTHOR]

This study includes the characterization of the clay mineralogy of banana soils from 11 watersheds of the Caribbean alluvial lowlands, using RX diffraction and dissolution methods. These results confirm the abundance of montmorrillonite, metahalloisite, vermiculite and plagioclases, together with small amounts of allophane, gibbsite and iron oxides like hematite, maghemite and magnetite. Chlorite was not detected but illite was found in some samples. The use of dissolution and estequiometric techniques allowed us to identify amorphous materials, probably allophane, in soil RE-16 in the Tortuguero river basin. Soils northwest of the watershed of rivers Vueltas, Silencio and Parismina, were dominated by metahalloisite and montmorrillonite; they were classified as Inceptisols with Andic properties (Andic Eutrudepts, Aquandic Endoaquepts), Dystric Inceptisols (Fluventic Dystrudepts) and Andisols (Typic Hapludands). Soils southwest of that watershed were dominated by montmorrillonite, vermiculite and metahalloisite; they were classified as Eutric Inceptisols of alluvial origin (Fluventic Eutrudepts, Dystric Fluventic Eutrudepts, Fluvaquentic Eutrudepts, Fluventic Endoaquepts) and Inceptisols with drainage problems (Fluventic Endoaquepts, Fluvaquentic Epiaquepts). The montmorillonite, vermiculite and allophane are formed in the hillsides of the watershed (cordilleras Central and Talamanca) and later deposited in the lowlands by river flooding; metahalloisite is formed by transformation of halloisite and gibbsite developed from allophanic materials. [ABSTRACT FROM AUTHOR]