Soil Health And Fertilizer Management Flashcards
What role does healthy soil play in plant health?
- mechanical support
- Absorbs, holds and releases water
- exchanges gases
- Convert nutrients tied up in organic matter to nutrients available for plants
- Resist erosion
- Suppresses insect pests and plant pathogens
- Sustains biodiversity
What’s the difference between soil health and soil quality?
Soil quality is the ability of soil to function for a purpose, such as agriculture or building material. Soil health is an assessment of the state of the soil regarding specific subjective goals and soil management.
What are the distinct principle layers of most soils and what is the collective term for?
Soil profile
Four distinct horizons:
- Horizon A: Topsoil
- Horizon E: subsurface
- Horizon B: subsoil
- Horizon C: parent material
What is the most common soil material in PA?
Transported soil materials: alluvium, colluvium, glacial till.
Which horizon has the most organic matter and the greatest concentration of plants roots?
Surface soil - Horizon A and E
What color is the subsoil?
Shades of red brown, yellow, and gray
What part does parent material play in soil health?
It influences soil, texture, natural, fertility, acidity, and depth.
Based on the content of organic matter, what are the two types of soil?
Mineral soils: containing less than 20% organic matter
Organic soils: containing more than 20% organic matter
What is the soil make up of most soil’s in Pennsylvania?
Most soils in Pennsylvania are minerals soils because of the presence of sandstone, shale, and limestone sedimentary rocks.
What are some factors influencing a soils physical properties?
- Climatic factors: e.g. rainfall temperature
- Relief: e.g. Slope and direction of the land surface.
- Vegetation
What are some physical properties of soil?
Texture, color, structure, internal drainage, depth
What determines the kind of crop is grown vs what determines the expected yields?
Soil properties determine the crop, yields depend on fertility level.
What causes the color of the soil?
Organic matter content, drainage, conditions, degree of oxidation/extent of weathering
What might light surface soil color indicate?
Lower organic matter content, coarse, texture, bleached conditions, or high annual temperatures.
What might dark surface soil color indicate?
Poor drainage, low annual temperatures, high organic matter content, slow oxidation, parent material.
What are some dark surface soil temperature-related properties?
Absorbs heat more rapidly during the day, lose heat faster at night, generally warmer than light soils during the warm seasons.
What do subsoil colors indicate?
Air, water, and soil relationships, degree of iron oxidation in the soil.
Red/brown: soil allows relatively free, movement of air and water
Gray/yellow: slow, internal drainage, too little oxygen
What determines the soil texture?
The amount of sand (>0.05 mm), silt (0.002-0.05mm), and clay (<0.002mm) present in the soil.
What are the five general textural classes most PA surface soils fall into?
- silt loam
- loam
- Silty clay loam
- Sandy loam
- Clay loam
How does bigger soil particles alter the properties of the soil?
Allow water to enter faster, water can move more freely, warm up faster because of air present between the particles.
What are peds or aggregates?
Soil particles group together in soil formation processes.
Why is strong soil structure favorable and how can we promote it?
Strong structure allows good movement of air and water. Strong structure in surface soil is promoted by adequate supply of organic matter and working the soil when it’s not too dry/wet.
What are the types of soil structure?
- Granular: characteristic of horizon A
- Platy: commonly occurs in horizon E
- Blocky: found in horizon B but may occur in horizon A
- columnar: usually found in horizon B most common in arid regions
- Prismatic: usually found in horizon B, most common in arid regions
Why is soil structure linked to the biological health of the soil?
Most beneficial soil organisms can only live in the existing pores and channels in the well aggregated soil.
What are some minute processes that produce granular aggregate?
- plants roots enlarge the openings in the soil
- Organic matter formed from decaying roots serve as a cementing agent.
- soil bacteria producing stable exudates and develop small electrostatic charge
- Fungal hyphae knit particles together
How do large soil organisms help soil health?
They can move the soil and create macropores in the soil. Their feeding pattern and waste products also contribute.
What is internal drainage?
The rate an extent of water movement in soil across the surface as well as downward.
What are the different effective soil depths?
- very shallow: soil is less than 10” to a layer that restricts root development
- shallow: 10-20”
- Moderately deep: 20-36”
- Deep: 35-60”
- Very deep: > 60”