Agriculture

Question 1

when planting crops you need to consider

Answer 1

space availability
seasonality
demand
weather conditions

Question 2

abiotic agricultural factors

Answer 2

temperature
light
water
soil pH
carbon dioxide
soil fertility
soil salinity

Question 3

abiotic factor: temperature

Answer 3

• optimal growing season temperature and length of season
• frost free period or frost resistant crops
• drought and water availability
• shelter for warmth e.g:
  greenhouses trap heat in
  gas burners in orchards to keep trees warm
  transparent covers over trees
  barns for animals

Question 4

abiotic factor: light

Answer 4

• photosynthesis rate
• can provide artificial light
  Eg’s of light affecting:
• longer days -> longer farming days
• more light -> more reproductive rate
• longer day -> more milk production
• shorter day -> faster chicken grows (battery hens in semi darkness)
• longer day -> more egg production

Question 5

abiotic factor: water

Answer 5

• transpiration -> temp regulation
• turgidity (flaccid)
• reliability of rains
• pH of water e.g acid rain
• water logged soil can drown crops
• water can create fungal growth
• irrigation systems e.g sprinklers
• water shortage -> cell damage -> death

Question 6

abiotic factor: soil pH

Answer 6

• most plants between pH 5 and pH 7
• increase pH by adding crushed lime (calcium carbonate)
• decrease pH by spreading powdered sulfur

Question 7

abiotic factor: carbon dioxide

Answer 7

• limiting factor in rate of photosynthesis
• can pump CO2 into greenhouses by burning carbon based fuel e.g gas

Question 8

abiotic factor: soil fertility

Answer 8

• nutrients affect soil growth
• fertilisers add nutrients
• too many fertilisers can lead to eutrophication
  common primary macronuntrients:
  nitrogen -> manufactures proteins
  phosphorus -> root growth
  potassium -> ion and seed development

organic fertiliser - manure
inorganic fertiliser - chemicals

advantage of inorganic - know exactly how many nutrients
dis - toxic to animals eg worms, can be washed away (eutrophication)

Question 9

abiotic factor: soil salinity

Answer 9

• how salty soil is (do not want)
• osmotic dehydration of roots
• reduce by irrigating more but greatly increases water consumption

Question 10

hydroponics

Answer 10

no soil but growing plants in a controlled manor. Means crops can be grown all day so grow more quickly and can be more efficient with space

Question 11

biotic factors

Answer 11

fungus
bacteria
pests

Question 12

biotic factor: fungus

Answer 12

rot plants
cant use rotted plants

Question 13

biotic factor: bacteria

Answer 13

mad cow disease, over 300 people killed

Question 14

biotic factor: pests

Answer 14

• pests –> pesticides
• insects will eat and damage crops
  e.g termites eat trees, tree dies
  e.g rabbits, rats, mice, birds, weed, snails and slugs (molluscs), nematode worms
• scarecrows can keep crows away

deal with pests by:
crop rotation - changing crops annually/ seasonally
companion crops - growing 2 crops together to deter pests
pest attraction - planting desirable crops to deter pests
flowering plants - attracts bees, increases pollination
predator habitats - attract predators to kill pests
sterile male - release sterile insects to kill off fertile insects
pheromone traps - lures insects into trap and kills them
genetic modification - modify crop dna to resist pests
pesticides - chemical but shows results much quicker*

perks of pesticides:
toxicity
specific - target specific pests not all animals
persistent
insoluble - could enter water system
contact - kills when comes into contact with pest
systematic - absorbed into crop so when bitten it kills
plant antibiotic - kills bacterial pests in plants, as well as animal pests