San Bernardino, California, features a diverse array of soil types, each with distinct characteristics impacting soil health and land use. This article examines six notable soil types in the San Bernardino area, focusing on their properties relevant to soil health.
Bernardino Series
The Bernardino series is prominent in San Bernardino, characterized by very deep, well-drained soils formed from fan alluvium of igneous and sedimentary rock. These soils are typically found on fan terraces with slopes of 0 to 30 percent, at elevations of 3,500 to 5,500 feet.
Soil Health Characteristics:
- Texture: Ranges from gravelly clay loam in the upper layers to gravelly sandy loam in the lower layers, supporting good water retention and drainage.
- Organic Matter: Dark brown surface layers indicate moderate organic matter, beneficial for soil health.
- pH: Slightly alkaline to moderately alkaline (pH 7.5 to 8.0), generally favorable for nutrient availability and microbial activity.
- Drainage: Well-drained, promoting good aeration and root development.
- Permeability: Slow, requiring careful water management to prevent waterlogging.
The Bernardino series supports diverse vegetation, including grasses and mesquite. However, its slow permeability and potential for runoff may necessitate erosion control measures, especially on steeper slopes.
Hanford Series
Found primarily in western San Bernardino County, the Hanford series is another significant soil type.
Soil Health Characteristics:
- Texture: Coarse sandy loams providing excellent drainage and aeration.
- Erodibility: Slightly erodible, showing good resistance to erosion.
- Wind Erodibility: Moderately susceptible, with a wind erodibility group of 3 and an index of 86.
- Expansion Potential: Low, indicating stable soil structure with minimal shrink-swell behavior.
- Corrosion Potential: Low for concrete and moderate for steel, indicating relatively favorable conditions for infrastructure.
The coarse texture promotes good drainage, but rapid water infiltration and potential nutrient leaching require careful irrigation and nutrient management.
San Emigdio Series
Present in various parts of San Bernardino County, the San Emigdio series shows different subtypes with slightly varying characteristics.
Soil Health Characteristics:
- Texture: Varies from gravelly sandy loam to fine sandy loam, balancing drainage and water retention.
- Erodibility: Generally low, indicating good erosion resistance.
- Wind Erodibility: Moderate susceptibility, with wind erodibility groups ranging from 3 to 5 and indices from 56 to 86.
- Expansion Potential: Low, suggesting stable soil structure.
- Corrosion Potential: Low for concrete and high for steel, necessitating careful material selection for construction.
San Emigdio soils support diverse plant types. The low erodibility is advantageous for soil conservation, though wind erosion in some areas and high steel corrosion potential may require specific management practices.
Tujunga Series
The Tujunga series, occurring in parts of San Bernardino County, is known for its sandy texture.
Soil Health Characteristics:
- Texture: Sandy, promoting excellent drainage but potentially limiting water retention.
- Organic Matter: Generally low, affecting nutrient retention and soil structure.
- Fertility: Often low due to rapid leaching.
- Erosion Potential: Susceptible to wind erosion due to sandy texture.
Management practices, such as increasing organic matter through cover cropping or organic amendments, can improve soil structure and nutrient availability. Erosion control measures may be necessary to protect against wind erosion.
Greenfield Series
Another soil type in San Bernardino County is the Greenfield series.
Soil Health Characteristics:
- Texture: Typically sandy loams, offering a good balance between drainage and water retention.
- Fertility: Moderately fertile with better nutrient retention than sandier soils.
- Drainage: Well-drained, aiding root development and aeration.
- Organic Matter: Moderate levels contribute to soil structure and fertility.
Greenfield soils are promising for agriculture due to their balanced properties. Maintaining organic matter through crop residue management or cover cropping and careful irrigation can enhance soil health.
Ramona Series
The Ramona series is also present in San Bernardino County.
Soil Health Characteristics:
- Texture: Ranges from sandy loams to loams, providing good water retention and drainage.
- Fertility: Moderately fertile with good nutrient-holding capacity.
- Drainage: Well-drained, supporting healthy root development.
- Erosion Potential: Susceptible to erosion on steeper slopes.
- pH: Slightly acidic to neutral, favorable for most plants.
Ramona soils offer good agricultural potential due to their balanced texture and fertility. Erosion control measures on slopes and maintaining organic matter levels can further enhance soil health.
Conclusion
San Bernardino County's diverse soil types offer both opportunities and challenges for soil health management. Key considerations include:
- Organic Matter Management: Essential for improving soil structure, water retention, and nutrient availability, especially in sandier soils like the Tujunga series.
- Erosion Control: Necessary on steeper slopes and in areas prone to wind erosion.
- Water Management: Careful irrigation is needed to prevent waterlogging and excessive nutrient leaching.
- Nutrient Management: Tailoring fertilization to specific soil needs optimizes plant growth and minimizes environmental impacts.
- pH Management: Monitoring and adjusting pH ensures optimal nutrient availability.
- Soil Structure Preservation: Conservation tillage and minimizing compaction help maintain good soil structure.
By understanding each soil type’s unique characteristics and implementing appropriate management practices, land managers and agriculturists in San Bernardino County can support sustainable land use, agricultural productivity, and ecosystem health.
