Soils Flashcards
(6 cards)
Types of Soil erosion
Wind erosion
Water erosion:
-rain splash erosion
-surface runoff
-slumping and landslides
Methods of reducing soil erosiom
Long term crops
Zero tillage cultivation:
Minimises soil disturbance and reduces soil erosion, direct drilling of seed > ploughing
Contour ploughing:
Ploughing at 90 degrees to the slope means less water flow carrying the soil is lost
Tied ridging:
Cross cross shape to retain water
Multi cropping
Windbreaks
Increasing soil organic matter
Features of fertile soil
Water content - good draining so not waterlogged but still retains water
Soluble material-fertile soils contains macronutrients (N,P,K)
Air content- most living organisms in soils are aerobic so well aerated soils are likely to be more fertile
PH- (5.5-7) range of tolerance. In acidic soils leaching will increase and damaged root cell membranes, alkaline conditions phosphates become insoluble
Soil biota - detritivores (woodlice) break up DOM and release nutrients into the soil
Decomposers(fungi+bacteria) break down DOM- they rely on detritvores to make the DOM smaller
Soil texture
Soil structure - soil particles form aggregates called peds, the ped type affects soil properties and fertility
Soil depth
How does vegetation reduce soil erosion
Natural windbreak
Plant leaves reduce impact of raindrops
Plant roots hold the soil together
Plants help to increase infiltration of water into the soil, reducing the rate of run off
Human activities increase soil erosion
Vegetation removal
Ploughing vulnerable soils-breaks soil structure exposing it to rain or wind erosion
Overgrazing- livestock density is to high then plants are eaten quicker than they can grow
Reduced soil biota-ploughing and use of agrochemicals reduce soil biota
Soil compaction-heavy machinery compacts soil, reducing aeration so more surface runoff after rainfall so more erosion
Universal soul loss equation uses
Estimate rate of soil erosion
