CNAS Research & Extension

You are here: Home / Soils of Guam

Soils of Guam

Where Found: Soil Name: Search:

Ylig series

Description

    Soil Origin: Volcanic

    Soil Texture: The surface layer has dark brown clay with moderate fine subangular blocky structure.

    Soil Classification: Silty Clay
    Click Here to See Soil Classification Diagram

    Where Found: Inarajan, Merizo, Santa Rita, Talofofo, Umatac
    Description: Generally, it can be recognized as low-lying areas covered with kariso or sedges. It can also be seen on concave hillsides and in drainageways. These soils formed in alluvium derived from weathered tuff and tuff breccia. The soils are hummocky in some areas. Slopes are 0 to 15 percent. The surface color changes from dark brown to reddish brown at 36 cm., turns grayish and yellowish brown at 56 cm., reddish gray at 99 cm. , yellowish red at 114 cm. and back to grayish brown at 140 cm.

    Habitat and Land Use: This soil is suitable for fruit production such as watermelon and pineapple. Paspalum species, a number of forbs such as Buttonweed, Ground orchid, False verbena, Bahiagrass, Townsville stylo, and Centro are suitable in this type of soil. It is also well suited to pond construction. If adequate fertilizer and lime are used, napiergrass or guineagrass is suitable.

Soil Health

Acidity Water Permeability/Runoff Fertility and Management
    Very strongly acid (pH 4.5) to slightly acid (pH 6.3)   
    Very deep, somewhat poorly drained, moderately slowly permeable soil. It has moderately and very high water holding capacity.   
    Leaching of Nitrogen in the soil is not so serious. Ammonium is not recommended as a Nitrogen source because it tends to acidify the soil. The problem of Calcium deficiency and Aluminum toxicity can be corrected by applying lime. This type of soil provides the best opportunities for intensive rangeland management.

    Content Sources: USDA Soil Conservation Service Soil Survey of Territory of Guam, SoilWeb: An Online Soil Survey Browser
    Other sources of information on Guam Soils: WERI Watershed Atlas
    Date of Update: February 16, 2016

Yigo series

Description

    Soil Origin: Limestone

    Soil Texture: The surface layer has dark reddish brown silty clay with moderate very fine granular structure, very friable.

    Soil Classification: Silty Clay
    Click Here to See Soil Classification Diagram

    Where Found: Dededo, Malojloj, Mangilao, Yigo
    Description: These soils formed in sediment overlying porous corraline limestone. Slopes are 0 to 7 percent. The surface color changes from dark reddish brown to dusky red at 15 cm. and turns to dark red at 41 cm. deep.

    Habitat and Land Use: Fruit trees are suitable for this soil type and the dominant forest trees that thrive in it include Tangantangangan, Mapunao, Nunu, Faniok, Faia, Lagundi, Chopak, Yoga, and Pisonia. Subdominant trees are Kafu, Pahong, Paipai, Fadang, Fago, and Macaranga thompsonii.

Soil Health

Acidity Water Permeability/Runoff Fertility and Management
    Slightly acid (pH 6.5) to neutral (pH 6.8)   
    Deep and very deep, well drained, moderately permeable soils in depressional areas on plateaus.   
    This soil is deep and virtually inert without organic matter.

    Content Sources: USDA Soil Conservation Service Soil Survey of Territory of Guam, SoilWeb: An Online Soil Survey Browser
    Other sources of information on Guam Soils: WERI Watershed Atlas
    Date of Update: February 16, 2016

Togcha series

Description

    Soil Origin: Volcanic

    Soil Texture: The surface layer has dark reddish brown silty clay with moderate very fine granular structure.

    Soil Classification: Silty Clay
    Click Here to See Soil Classification Diagram

    Where Found: Inarajan, Merizo, Santa Rita, Talofofo, Umatac
    Description: These soils formed in slope alluvium derived from weathered tuff and tuff breccia. Slopes are 3 to 15 percent. The soil color changes from dark reddish brown to dark red at 13 cm., changes to yellowish red at 28 cm and turns back to red beyond 36 cm. deep.

    Habitat and Land Use: Watermelon and pineapple is best suited for this type of soil.

Soil Health

Acidity Water Permeability/Runoff Fertility and Management
    Strongly acid (pH 5.2) to medium acid (pH 5.6)   
    Very deep, well drained, moderately permeable soils on volcanic uplands. It has moderately and very high water holding capacity.   
    Erosion is a serious concern for this type of soil. However, leaching of Nitrogen in the soil is not so serious. Ammonium is not recommended as a Nitrogen source because it tends to acidify the soil. The problem of Calcium deficiency and Aluminum toxicity can be corrected by applying lime. This type of soil also provides the best opportunities for intensive rangeland management.

    Content Sources: USDA Soil Conservation Service Soil Survey of Territory of Guam, SoilWeb: An Online Soil Survey Browser
    Other sources of information on Guam Soils: WERI Watershed Atlas
    Date of Update: February 16, 2016

Shioya series

Description

    Soil Origin: Volcanic & Limestone

    Soil Texture: Dark brown loamy sand with few very fine very dark grayish brown pockets, single grain.

    Soil Classification: Loamy Sand
    Click Here to See Soil Classification Diagram

    Where Found: Hagåtña
    Description: These soils formed in water-deposited coral sand. Slopes are 0 to 5 percent. The soil color changes from dark brown to very pale brown beyond 25 cm. in depth.

    Habitat and Land Use: In this type of soil, the forest species are tolerant of salinity such as Gago, Binalo, Pahong, Hunek, Nonak, Putting, Panao, Niyog, Talisai, Da’og, and Ifil.Tangantangan also grows in disturbed areas of this soil type.

Soil Health

Acidity Water Permeability/Runoff Fertility and Management
    Mildly alkaline (pH 7.8) to moderately alkaline (pH 8.4)   
    Deep and very deep rapidly permeable, excessively drained soils on coastal strands.   
    It is close to the ocean and any structure built on it should be designed to withstand high winds and waves.

    Content Sources: USDA Soil Conservation Service Soil Survey of Territory of Guam, SoilWeb: An Online Soil Survey Browser
    Other sources of information on Guam Soils: WERI Watershed Atlas
    Date of Update: February 16, 2016

Saipan series

Description

    Soil Origin: Limestone

    Soil Texture: Dark reddish brown silty clay with weak medium subangular blocky structure.

    Soil Classification: Silty Clay
    Click Here to See Soil Classification Diagram

    Where Found: Barrigada, Chalan Pago-Ordot, Ipan, Malojloj, Mongmong-Toto-Maite, Sinajana, Yona
    Description: These soils formed in sediment overlying porous corraline limestone. Slopes are 0 to 7 percent. The soil color changes from dark reddish brown to yellowish red at 15 cm., turns red at 70 cm. and goes back to yellowish red at 100 cm. deep.

    Habitat and Land Use: Watermelon is suitable with this soil. Dominant forest trees suitable with this soil type include Tangantangangan, Mapunao, Nunu, Faniok, Faia, Lagundi, Chopak, Yoga, and Pisonia. Subdominant trees are Kafu, Pahong, Paipai, Fadang, Fago, and Macaranga thompsonii.

Soil Health

Acidity Water Permeability/Runoff Fertility and Management
    Neutral (pH 6.9 – pH 7.3)   
    Deep and very deep moderately permeable, well drained soils on uplifted limestone plateaus. The available water capacity is moderate.   
    This soil is virtually inert without organic matter. It is suitable for use as rangeland.

    Content Sources: USDA Soil Conservation Service Soil Survey of Territory of Guam, SoilWeb: An Online Soil Survey Browser
    Other sources of information on Guam Soils: WERI Watershed Atlas
    Date of Update: February 16, 2016

Ritidian series

Description

    Soil Origin: Limestone

    Soil Texture: The surface layer has dark reddish brown extremely cobbly clay loam with strong medium granular structure.

    Soil Classification: Clay Loam
    Click Here to See Soil Classification Diagram

    Where Found: Dededo, Mangilao, Yigo
    Description: These soils are found on plateaus and escarpments. They formed in slope alluvium, loess, and residuum derived from sediment overlying corraline limestone. Slopes are 3 to 99 percent. The soil color changes from dark reddish brown to yellowish red at 3 cm. deep.

    Habitat and Land Use: The dominant forest trees suited with this soil type include Tangantangangan, Mapunao, Nunu, Faniok, Faia, Lagundi, Chopak, Yoga, and Pisonia. Subdominant trees include Kafu, Pahong, Paipai, Fadang, Fago, and Macaranga thompsonii.

Soil Health

Acidity Water Permeability/Runoff Fertility and Management
    Mildly alkaline (pH 7.6) to moderately alkaline (pH 7.9)   
    Well drained, moderately rapidly permeable soils that are very shallow to limestone.   


    Content Sources: USDA Soil Conservation Service Soil Survey of Territory of Guam, SoilWeb: An Online Soil Survey Browser
    Other sources of information on Guam Soils: WERI Watershed Atlas
    Date of Update: February 16, 2016

Pulantat series

Description

    Soil Origin: Limestone

    Soil Texture: The surface layer has very dark grayish brown silty clay with strong fine and medium granular structure.

    Soil Classification: Silty Clay
    Click Here to See Soil Classification Diagram

    Where Found: Agana Heights, Asan, Barrigada, Chalan Pago-Ordot, Dededo, Hagåtña, Ipan, Malojloj, Mangilao, Mongmong-Toto-Maite, Piti, Santa Rita, Sinajana, Talofofo, Tamuning, Yigo, Yona
    Description: These soils are found on upland plateaus and hills. They formed in residuum derived from argillaceous corraline limestone. Slopes are 3 to 60 percent. The soil color changes from very dark grayish brown to black and dark brown at 3 cm. and lighten up into brown color at 18 cm. deep.

    Habitat and Land Use: Foxtail, guineagrass, and Tangantangan, which is a nutritious forage plant are suitable in this type of soil. Shallow-rooted vegetables can also be planted during the rainy season since it is more feasible to farm at this time of the year. The dominant forest trees suited with this soil type include Tangantangangan, Mapunao, Nunu, Faniok, Faia, Lagundi, Chopak, Yoga, and Pisonia. Subdominant trees include Kafu, Pahong, Paipai, Fadang, Fago, and Macaranga thompsonii. Palma brava also appears to spread in this type of soil.

Soil Health

Acidity Water Permeability/Runoff Fertility and Management
    Slightly acid (pH 6.5) to moderately alkaline (pH 8.2)   
    Well drained, slowly permeable soils that are shallow over limestone. The water capacity is very low.   
    It is a very fertile soil with a slightly acidic surface horizon that becomes alkaline in the subsoil due to the influence of the limestone parent material. It has high levels of organic matter in the surface horizons, and it is rich in Calcium throughout the profile. This soil can also be converted to improved pasture by applying fertilizer and then seeding adapted grasses and legumes such as guineagrass, napiergrass, and Calopogonium mucunoides.

    Content Sources: USDA Soil Conservation Service Soil Survey of Territory of Guam, SoilWeb: An Online Soil Survey Browser
    Other sources of information on Guam Soils: WERI Watershed Atlas
    Date of Update: February 16, 2016

Kagman series

Description

    Soil Origin: Limestone

    Soil Texture: The surface layer has dark brown clay with moderate fine subangular blocky structure and friable.

    Soil Classification: Silty Clay
    Click Here to See Soil Classification Diagram

    Where Found: Barrigada, Mangilao, Talofofo, Yona
    Description: These soils formed in sediment overlying argillaceous limestone. Slopes are 0 to 15 percent. The soil color changes from dark brown to strong brown beyond 14 cm., turns yellowish red at 50 cm and back to strong brown color at 127 cm. deep.

    Habitat and Land Use: Foxtail, guineagrass, and Tangantangan, which is a nutritious forage plant, are suitable in this soil. Watermelon can also be planted in this type of soil. The dominant forest trees compatible with this soil include Tangantangangan, Mapunao, Nunu, Faniok, Faia, Lagundi, Chopak, Yoga, and Pisonia. Subdominant trees are Kafu, Pahong, Paipai, Fadang, Fago, and Macaranga thompsonii.

Soil Health

Acidity Water Permeability/Runoff Fertility and Management
    Slightly acid (pH 6.3) to neutral (pH 6.8)   
    Deep and very deep, well drained, moderately slowly permeable soils on uplifted limestone plateaus. The available water capacity is moderate.   
    Erosion can be a problem particularly where excessive field traffic and cultivation have created a tillage pan in the dense clay below the surface layer. Water can accumulate and flow across the top of this layer, eroding away the surface even in gently sloping areas. This soil is suitable for use as rangeland.

    Content Sources: USDA Soil Conservation Service Soil Survey of Territory of Guam, SoilWeb: An Online Soil Survey Browser
    Other sources of information on Guam Soils: WERI Watershed Atlas
    Date of Update: February 16, 2016

Inarajan series

Description

    Soil Origin: Volcanic

    Soil Texture: The surface layer has dark gray clay with many fine red mottles and moderate medium subangular blocky structure.

    Soil Classification: Silty Clay
    Click Here to See Soil Classification Diagram

    Where Found: Agat, Chalan Pago-Ordot, Merizo, Piti, Talofofo, Umatac
    Description: This soil formed in alluvium. Slopes are 0 to 4 percent. The soil color changes from dark gray to dark yellowish brown beyond 25 cm. in depth.

    Habitat and Land Use: It is suitable for fruit production such as banana and watermelon. During rainy season, removal of excess water with ditches and subsurface drains could significantly lengthen the cropping season. The dominant species found in this soil type are water-tolerant grasses such as paragrass, guineagrass, and Paspallum species. These are palatable grasses that provide excellent high protein forage for cattle, goats, and carabao. Tangantangan also provides browse and shade. Adapted legumes are feasible such as Desmodium intortum. This soil is restricted to tree species that can tolerate intermittent flooding and wetness such as Pago, Screw pine, Langasat, and Ifil.

Soil Health

Acidity Water Permeability/Runoff Fertility and Management
    Strongly acid (pH 5.3) to neutral (pH 6.7)   
    Deep and very deep, somewhat poorly drained, slowly permeable soil on broad valley bottoms and coastal plains. It has a seasonal high water table.   
    Erosion is not a problem. Use of the land for grazing is relatively minor however, it is locally very important. Cross-fencing, periodic mowing, and dragging improve the range. For this soil type, stock ponds can also be developed.

    Content Sources: USDA Soil Conservation Service Soil Survey of Territory of Guam, SoilWeb: An Online Soil Survey Browser
    Other sources of information on Guam Soils: WERI Watershed Atlas
    Date of Update: February 16, 2016

Guam series

Description

    Soil Origin: Limestone

    Soil Texture: It is cobbly clay loam with moderate very fine granular structure and crumbles easily when dry.

    Soil Classification: Clay Loam
    Click Here to See Soil Classification Diagram

    Where Found: Agana Heights, Agat, Barrigada, Dededo, Hagåtña, Mangilao, Merizo, Mongmong-Toto-Maite, Piti, Santa Rita, Sinajana, Tamuning, Umatac, Yigo
    Description: The Guam series is the dominant soil type on northern Guam. It is found on uplifted plateaus and formed from sediment overlying porous corraline limestone. Slopes are 0 to 15 percent. The soil color changes from dark reddish brown to dusky red beyond 5 cm. in depth.

    Habitat and Land Use: This soil is dominated by foxtail which provides high quality palatable forage. Agricultural crops such as tomato, eggplant, and bell pepper are best suited with this type of soil. The dominant forest trees include Tangantangangan, Mapunao, Nunu, Faniok, Faia, Lagundi, Chopak, Yoga, and Pisonia. Subdominant trees include Kafu, Pahong, Paipai, Fadang, Fago, and Macaranga thompsonii.

Soil Health

Acidity Water Permeability/Runoff Fertility and Management
    Neutral (pH 7.1) to mildly alkaline (pH 7.5)   
    Shallow and well-drained, moderately rapidly permeable soil that is very shallow to limestone bedrock. It has poor water holding capacity.   
    Erosion is not a problem however, split applications of Nitrogen in the soil are necessary because it is quickly leached out of the soil. The soil can be converted to improved pasture by applying fertilizer and then seeding adapted grasses and legumes such as guineagrass, napiergrass, and Calopogonium mucunoides.

    Content Sources: USDA Soil Conservation Service Soil Survey of Territory of Guam, SoilWeb: An Online Soil Survey Browser
    Other sources of information on Guam Soils: WERI Watershed Atlas
    Date of Update: February 16, 2016

Chacha series

Description

    Soil Origin: Volcanic

    Soil Texture: The surface layer is dark brown clay with moderate medium subangular blocky structure parting to strong fine subangular blocky.

    Soil Classification: Silty Clay
    Click Here to See Soil Classification Diagram

    Where Found: Barrigada, Dededo, Malojloj, Mangilao, Tamuning, Yigo
    Description: These soils are formed in alluvial sediment and volcanic saprolite overlying limestone. Slopes are 0 to 7 percent. The soil color changes from dark brown to mixed dark brown and dark yellowish brown after 10 cm. A strong brown color can be seen beyond 20 cm. in depth.

    Habitat and Land Use: Foxtail, guineagrass, and Tangantangan, which is a nutritious forage plant are suitable in this soil. Watermelon is also best suited in this type of soil.

Soil Health

Acidity Water Permeability/Runoff Fertility and Management
    Medium acid (pH 6.0) to mildly alkaline (pH 7.8)   
    Very deep, somewhat poorly drained, slowly permeable soils in concave basins on limestone plateaus. Water is moderately drained and collected in the surface during heavy rains.   
    During rainy season, removal of excess water with ditches and subsurface drains could significantly lengthen the cropping season. It is also suitable for use as rangeland.

    Content Sources: USDA Soil Conservation Service Soil Survey of Territory of Guam, SoilWeb: An Online Soil Survey Browser
    Other sources of information on Guam Soils: WERI Watershed Atlas
    Date of Update: February 16, 2016

Atate series

Description

    Soil Origin: Volcanic

    Soil Texture: The surface layer is dark reddish brown silty clay with moderate very fine granular structure.

    Soil Classification: Silty Clay
    Click Here to See Soil Classification Diagram

    Where Found: Agat, Asan, Inarajan
    Description: These soils are formed in residuum derived from tuff and tuff breccia. Slopes are 0 to 60 percent. The soil color changes from dark reddish brown to yellowish red after 30 cm. and turns dark red after 56 cm. in depth.

    Habitat and Land Use: It is used as wildlife habitat and watershed, for grazing purposes, subsistence and commercial farming, homesite and recreational development.

Soil Health

Acidity Water Permeability/Runoff Fertility and Management
    Strongly acid (5.5) to slightly acid (pH 6.2)   
    Very deep, moderately permeable, well drained soil. Medium runoff.   
    Atate series is an Alfisol with intermediate fertility. It has lower Calcium than Pulantat but not as Calcium depleted as the Akina series. Compost can be applied to improve its fertility. Crushed coral limestone can be mixed into the soil to provide Calcium and reduce soil acidity. Tree species compatible with this type of soil include Gago, Pago, Screw pine, Betel nut, Da’og, Chosga, Ilang-ilang, and Langasat. Ifil, which has commercial value used for hand-carved furniture and handicrafts and Palma brava also appears to spread in this type of soil.

    Content Sources: USDA Soil Conservation Service Soil Survey of Territory of Guam, SoilWeb: An Online Soil Survey Browser
    Other sources of information on Guam Soils: WERI Watershed Atlas
    Date of Update: February 16, 2016

Akina series

Description

    Soil Origin: Volcanic

    Soil Texture: The surface layer is dry with moderate fine granular structure.

    Soil Classification: Silty Clay
    Click Here to See Soil Classification Diagram

    Where Found: Agat, Asan, Inarajan, Merizo, Santa Rita, Talofofo, Umatac, Yigo
    Description: These soils are formed in residuum derived from tuff and tuff breccia. Slopes are 0 to 99 percent. Soil color changes from dark reddish brown to dark red beyond 10 cm. in depth.

    Habitat and Land Use: These soils are mainly used for wildlife habitat and watershed. Watermelon and pineapple are also suited in this type of soil and tree species that are compatible include Gago, Pago, Screw pine, Betel nut, Da’og, Chosga, Ilang-ilang, and Langasat. Ifil is also of commercial value used for hand-carved furniture and handicrafts. Palma brava also appears to spread in this type of soil.

Soil Health

Acidity Water Permeability/Runoff Fertility and Management
    Very strongly acid (pH 4.9) to strongly acid (pH 5.3)   
    Very deep, well drained moderately slowly permeable soils with moderately and very high water holding capacity.   
    It is the least fertile soil on Guam. Erosion is a serious concern and has infertile subsoil that should not be exposed. Leaching of Nitrogen in the soil is not so serious. Ammonium is not recommended as a Nitrogen source because it tends to acidify the soil. The problem of Calcium deficiency and Aluminum toxicity can be corrected by applying lime. Farming across the slope, strip cropping and using terraces, diversions, and grassed waterways can be used to reduce erosion. Intensive rangeland management can also be done in this type of soil.

    Content Sources: USDA Soil Conservation Service Soil Survey of Territory of Guam, SoilWeb: An Online Soil Survey Browser
    Other sources of information on Guam Soils: WERI Watershed Atlas
    Date of Update: February 16, 2016

Agfayan series

Description

    Soil Origin: Volcanic

    Soil Texture: The surface layer is dry with black clay and has strong fine granular structure.

    Soil Classification: Silty Clay
    Click Here to See Soil Classification Diagram

    Where Found: Agat, Asan, Inarajan, Merizo, Santa Rita, Talofofo, Umatac
    Description: This soil covers approximately 0.8 percent of Guam's total land area. These soils are formed in residuum derived from marine-deposited tuff, tuff breccia, and tuffaceous sandstone. Slopes are 7 to 99 percent. The soil color changes from black to mixed black and yellowish brown as it go beyond 20 cm. in depth.

    Habitat and Land Use: The use of this soil as wildlife habitat and watershed can be enhanced by protecting the soil from wildfires and by planting adapted trees.

Soil Health

Acidity Water Permeability/Runoff Fertility and Management
    Slightly acid (pH 6.4) to neutral (pH 7.0)   
    Well-drained, moderately slowly permeable soils that are very shallow and shallow to strongly weathered tuff. Water is rapidly drained in the clay and very slowly in the gray portion. In high areas, drainage is rapid. Lower areas have poor drainage.   
    Tree species compatible with this type of soil include Gago, Pago, Screw pine, Betel nut, Da’og, Chosga, Ilang-ilang, and Langasat. Ifil, which has commercial value used for hand-carved furniture and handicrafts and Palma brava also appears to spread in this type of soil.

    Content Sources: USDA Soil Conservation Service Soil Survey of Territory of Guam, SoilWeb: An Online Soil Survey Browser
    Other sources of information on Guam Soils: WERI Watershed Atlas
    Date of Update: February 16, 2016