W5 - Topic 10 - Soil Improvement Flashcards
What is soil improvement?
Modifying soil properties to optimize conditions for plant growth.
What is the best approach to soil improvement?
Matching plants to existing soil conditions.
What are the key components of site analysis?
- Profile Assessment
- Site Considerations
What does profile assessment include?
- Topsoil depth
- Texture
- Structure
- pH
- Drainage/aeration
- Compaction
What aspects are considered in site considerations?
- Aspect
- Rainfall patterns
- Temperature range
- Existing vegetation
What are the symptoms of soil compaction?
Hard soil, poor water infiltration, stunted root growth.
What are solutions to soil compaction?
- Decompaction/ripping
- Tillage/cultivation
- Adding organic matter
- Avoiding traffic on wet soils
- Confining traffic to designated areas
What are symptoms of poor soil structure?
Hard clods, waterlogging, crusting.
What solutions can improve poor soil structure?
- Adding organic matter
- Adding gypsum
- Mixing soil layers
- Cultivating at appropriate moisture content
What are symptoms of inadequate topsoil depth?
Shallow rooting, poor plant establishment.
What solutions can address inadequate topsoil depth?
- Adding topsoil
- Mounding
- Terracing
- Selecting shallow-rooted plants
What symptoms indicate water management issues?
Waterlogging, runoff, water repellence.
What solutions are available for water management issues?
- Improving subsurface drainage
- Applying wetting agents
- Decompacting to improve infiltration
- Adjusting irrigation schedules
What are the symptoms of pH problems in soil?
Nutrient deficiencies, poor growth.
What solutions can be used to adjust soil pH?
- Adding lime to raise pH
- Adding sulfur to lower pH
- Selecting plants adapted to existing pH
What symptoms indicate nutrient deficiencies?
Yellowing, stunted growth, poor flowering.
What solutions can address nutrient deficiencies?
- Adding appropriate fertilizers
- Incorporating organic matter
- Balancing pH
What are the symptoms of salinity issues in soil?
Leaf burn, wilting despite adequate moisture.
What solutions can help with salinity issues?
- Improving drainage to leach salts
- Flushing soil with fresh water
- Selecting salt-tolerant plants
What are symptoms of disturbed/inverted soil profiles?
Unnatural texture changes, buried organic layers.
What solutions can be implemented for disturbed/inverted profiles?
- Mixing layers
- Adding organic matter
- Installing drainage
What are the benefits of compost/soil conditioners?
- Improves soil structure
- Increases water-holding capacity
- Enhances nutrient storage
- Stimulates biological activity
What is the application guideline for compost?
Apply up to 100mm thick, cultivate into top 200mm of soil.
What types of manures are commonly used?
- Cow and sheep
- Chicken
- Horse
What is the application guideline for manures?
Use more sparingly than compost (10mm max).
What is green manure?
Growing plants specifically to dig into soil.
What are the benefits of using green manure?
- Adds organic matter
- Improves soil structure
- Can fix nitrogen
- Suppresses weeds
What are the benefits of using mulches?
- Soil insulation
- Reduces evaporation
- Prevents erosion
- Improves infiltration
- Suppresses weeds
- Adds organic matter over time
What are the application guidelines for mulches?
Apply to 75mm maximum depth, keep away from plant stems.
What are the requirements for turf?
- Good drainage
- Resistance to compaction
- Adequate topsoil depth (minimum 100mm, 200mm preferred)
What strategies can be employed for annual and vegetable beds?
- Ensure minimum 200mm topsoil depth
- Regularly add organic matter
- Minimize excessive digging
- Implement crop rotation
What are the requirements for shrub beds?
- Adequate topsoil depth (300mm minimum)
- Good drainage
- Appropriate soil structure
What are the strategies for trees in soil improvement?
- Select trees suited to site conditions
- Decompact large area
- Ensure adequate drainage
- Consider mounding or terracing
- Mulch around trees
What is structural soil composed of?
80% rock (20-200mm diameter) and 20% filler soil.
What are the limitations of structural soil?
- Low effective soil volume
- Drought-prone
- Low nutrient content
What is the purpose of drainage solutions like agricultural drain pipe?
Removes gravitational water and creates space for excess ground water.
What causes perched water tables?
- Finer textured layer over coarser layer
- Compacted layers
- Hardpans
What should be considered in a problem-solving approach for soil improvement?
- Identifying limiting factor(s)
- Choosing appropriate intervention
- Long-term management
What is a practical solution for inadequate topsoil depth for trees?
- Add topsoil
- Create mounding
- Add subsurface drainage
- Consider terracing
True or False: The most sustainable approach to soil improvement includes selecting plants well-adapted to existing conditions.
True
Fill in the blank: The most sustainable approach often combines modest soil improvements where necessary and _______.
selecting plants well-adapted to existing conditions.
