soils and mineral nutrition Flashcards
(15 cards)
What is plant-available water?
water that can be absorbed by plants from the soil
Which type of soil has the highest capacity to store water?
Clay
Which soil texture is ideal for plant growth?
balanced mixture of sand, silt, and clay
What is the effect of compaction on soil?
- reduces soil porosity
- lowers storage of water
- decreases hydraulic conductivity
- restricts water infiltration
- reduces oxygen exchange
- impairs root function
What is soil endemism?
limited marginal soil types that are too challenging for most species
What are the components of soil organic matter?
- organic solutes
- organic insoluble debris
- live roots
- microbes
- fungi
- invertebrates
What is soil erosion and how does it come about?
removal of topsoil due to wind, water, or human activity
Why is soil erosion bad for plant growth?
- reduces fertility
- reduces organic matter
- reduces water-holding capacity
What are the top two most important minerals that plants need?
- nitrogen
- phosphorus
Which nutrient is most limiting in young versus old soil?
- young soils - nitrogen
- older soils - phosphorus
What does Liebig’s law of the minimum say?
growth of a plant is controlled by the resource that is in the shortest supply relative to the plant’s need
How do many plants adapt their growth pattern between low nutrient and high nutrient environments?
- allocate more resources to root growth in low-nutrient environments
- invest more in shoot growth and leaf expansion in high-nutrient environments
What two types of symbiosis do plants form to improve mineral nutrition?
- Symbiosis with Rhizobia
- Symbiosis with Mycorrhizae
Which mineral do Rhizobia help improve for plants?
nitrogen (N₂) into ammonium (NH₄⁺)
What do Mycorrhizae enhance for plants?
- uptake of phosphorus (P)
- uptake of nitrogen
- sometimes water
