wind and tillage erosion

Question 1

how does soil erosion by wind occur?

Answer 1

detachment and transport via wind is known as Aeolian erosion, occurs through two processes - deflation (removal of loose fine grained particles by turbulent wind) and abrasion (wearing down of surfaces by grinding action or sand blasting

Question 2

deflation landforms?

Answer 2

they are usually hollows or blowouts, often originate from vegetation destruction, limited by water table (wets sands resits deflation

Question 3

what are abrasional landforms?

Answer 3

abrasion of surface by sand particles, abrasion of soil surface when particles fall onto, and particles hit other particles and break into smaller ones, the landforms are Yardang (streamlined bedrock) and ventifacts (polished or flattened stones)

Question 4

what is Aeolian transport?

Answer 4

saltation (0.1-0.5mm bounce along surface, impact loosens other particles, 50% of Aeolian transport), creep (rolling and sliding along surface, 0.5-2mm, 25%of Aeolian), suspension (very fine silt and clay <0.1mm, travels long distances, 25% of transport)

Question 5

what are the depositional landforms?

Answer 5

ripples (small sand waves length around 1m)

dunes (stable or advancing landform)

Question 6

what are the effects of drought?

Answer 6

wind erosion on fields occurs in dry periods, less rain = less vegetation = less protection, sand is less coherent, more soil loss

Question 7

what were the 1930s dust bowl?

Answer 7

8yrs of dust storms in US, top soil blown off fields, due to drought and land use practice, natural prairie grass was removed for wheat which cant cope with drought conditions

Question 8

what are the time scales of erosion?

Answer 8

it either occurs incrementally or dramatically, large storms produce huge erosion events, incremental erosion small common events have a huge overall impact

Question 9

what is tillage erosion?

Answer 9

caused by humans from tillage in agricultural practices,(its the agricultural preparation of soil by mechanical agitation) tractors move the soil gravity exacerbates this, tillage causes topsoil to be removed exposing subsoil, eventually subsoil covers whole field, bad for growth (50% yield reduction on clay soils), it will also exacerbate water erosion