(6.4) Fertilisers

Question 1

Natural organic fertilisers

Answer 1

Dead/decaying remain of plant & animals waste, manure & bone meal

Question 2

Artificial (inorganic) fertiliser

Answer 2

Mined from rocks & deposits converted into diff forms & blended together contain: N/P/K

Question 3

How do fertilisers increase productivity?

Answer 3

Plants = minerals for growth 
N = essential for proteins & DNA 
\+Nitrates avail = +plant growth & +larger leaf SA + Photo + productivity 
Combination of inOrg & org = best 
Until LF reached

Question 4

Environmental consequences of N fertilisers

Answer 4

-Reduced species diversity; N rich soil favour fast growing species (grass/nettles etc) outcompete o/ species - only survive when N is low

• Leaching; pollution of water course
• Eutrophication; Leaching of fertiliser to H20 course

Question 5

Leaching

Answer 5

Nutrients removed from soil
Rain water dissolve soluble nutrients (nitrates) carry deep into soil beyond reach of plant root
Leached nitrates = run into streams/rivers/lakes
High nitrates in water = prevent 02 transportation & stomach cancer
Leached nitrates can also cause Eutrophication

Question 6

Eutrophication

Answer 6

Nutrients build up in lakes!

Question 7

Eutrophication process (11)

Answer 7

1) little nitrate in river = nitrate LF for plant/ algae growth
2) leaching = +Nitrate conc = algae plant GROW exponentially
3) Algal bloom; algae grow @ surface
4) dense algae @ surface absorbs light ; prevents it reaching lower depths
5) ☀️ = LF for low algae - they die
6) Lack of dead plant/algae NOT a LF for S algae = GROW EXPONENTIALLY
7) SO need 02 for respiration
8) 02 conc reduced & nitrates released from decaying orgs
9) 02 = LF for aerobic orgs (fish) - DIE :(
10) anaerobic pop grow EXPONENTIALLY
11) Anaerobic org further decompose dead material; release + nitrates & toxic waste - hydrogen sulphide = water is putrid

Question 8

Need for fertiliser

Answer 8

Contain mineral ions
Mineral ions in soil are removed when crop is eaten!
Natural ecosystem ; death will return mineral ions to soil
Agricultural ecosystem ; the dead remains/urea usually not returned to same place
-Mineral ions will become LF and reduce productivity