University:
Sam Houston State University
Course:
GEOL 1405 | Geologic & Environmental Hazards
Academic year:

2019
Views:

422

Pages:

13
Author:

Clint W.

Soil Formation Soil Physical Properties • Slope is defined as the angle of the soil surface from horizontal. • It is expressed as the % of rise over run. Soil Physical Properties • Slope effects the productive potential in numerous ways: Rain runoff, soil erosion, the use of farm machinery, and contour farming. Soil Physical Properties • Texture refers to the proportions of sand silt and clay in the soil. • Course-textured soils are and sandy and do not hold water well, while fine-textured soils contain clay and tend to hold more surface moisture. Soil Physical Properties • Flood hazard refers to the likelihood that the soil will flood. • This may occur in flood plains near rivers and greatly reduce plant production. Soil Physical Properties • Erosion as a soil property, refers to the degree that the soil has already been damaged. • May range from none to severe. Soil Physical Properties • A field used for crop production that has little or no erosion can continue to be used for crops. • But a severely eroded field may need to be turned into pasture where it is always covered. Soil Texture • Soil Texture • What is Soil Texture? – It is the proportion of three sizes of soil particles. • Which are: – Sand (Large) – Silt (Medium) – Clay (Small) Soil Texture Effects of Particle Size? Soil particle size affects two important soil features: They are internal surface area The numbers and size of the pore spaces Soil Texture What is the internal surface area ? It is the area of soil that the total surface are of the particles in the soil. So the smaller the soil particles the greater the internal surface area will be. Soil Texture Pore size and number: this depends on the particle size. So there are more pores that are found between the larger particles. Soil Texture What is a Soil Separates? They are categories that scientist have divided up into three groups The three groups are: Sand Silt Clay Soil Texture What is Sand? It is the largest and is further divided into four subcategories. They are: Very coarse sand Coarse sand Medium sand Fine Sand