Farming Practises And Productivity Flashcards
Info on intensive farming
Involves changing an ecosystem by controlling the biotic and abiotic factors, eg the presence of pests or the amount of nutrients available, to make it more favourable for crops or livestock. Means intensively farmed crops or livestock can have greater net productivity (greater amount of biomass) than organisms in natural ecosystems. Energy input might be greater eg given food that higher in energy then their natural food. Or it might be the same as a natural ecosystem eg a field of crops still receives the same amount of sunlight as a natural field
What is a natural ecosystem and what is its energy input
Am ecosystem that hasn’t been changed by human activity. Energy input is the amount of sunlight captured by the producers in the ecosystem
In which ways does intensive farming increase productivity
Can increase efficiency of energy conversion, more of the energy organisms have is used for growth and less is used for other activities eg recovering from disease or movement.
Can remove growth limiting factors, more energy available can be used for growth
Can increase energy input, more energy added to ecosystem so there is more energy for growth
What are the 3 main intensive farming practises
Killing pests
Using fertilisers
Rearing livestock intensively
What are pests
Organisms that reduce the productivity of crops by reducing the amount of energy available for growth. Means crops are less efficient at converting energy
3 ways that farmers reduce pest numbers
Using chemical pesticides, biological agents or intergrated systems
Chemical pesticides info
Herbicides kill weeds that compete with agricultural crops for energy. Reducing competition= more energy so will grow faster and become larger, increasing productivity. Fungicides kill fungal infections that damages crops. Crops can use for energy for growing and less for fighting infection so grow faster, become larger, increasing productivity. Insecticides kill insect pests that eat and damage crops. Killing means less biomass is lost from crops so grow larger increasing productivity.
Environmental issues with using chemical pesticides
Directly affect other non-pest species eg butterflies
May indirectly affect other non-pest species eg eating a lot of primary consumers that each contain a small amount of chemical pesticide can be enough to poison a secondary consumer
Economic issues with using chemical pesticides
Expensive, may not be profitable for farmer to use them, their cost greater than extra money made from increased productivity
Biological agents info
Reduce number of pests, crops lose energy and biomass, increasing productivity. Natural predators introduced to ecosystem eat pest species. Parasites live in or lay their eggs on a pest insect. They either kill the insect or reduce its ability to function. Pathogenic bacteria and viruses used to kill pests
Environmental issues with using biological agents
Natural predators introduced may become a pest species themselves
Can affect other non-pest species
Economic issues with using biological agents
Less cost effective, may increase productivity less in short term for same amount of money invested
Intergrated systems info
Use both chemical pesticides and biological agents. The combined effect of using both can reduce pest numbers even more than either method alone, meaning productivity is increased even more. They can reduce costs if one method is particularly expensive, expensive method used less. They can reduce the environmental impact of things like pesticides because less is used.
What are fertilisers
Chemicals that provide crops with minerals needed for growth eg nitrates. Crops use up minerals in the soil as they grow, so growth is limited when there aren’t enough minerals. Adding fertiliser replaces lost minerals so more energy from ecosystem can be used to grow, increasing the efficiency of energy conversion.
Natural fertilisers are….
Organic matter, include manure and sewage sludge
Artificial fertilisers are…
Inorganic, contain pure chemicals (eg ammonium nitrate) as powders or pellets
Environmental issues with using fertilisers
Can be washed into rivers and ponds killing fish and plant life due to eutrophication
Changes the balance of nutrients in soil, too much of a particular nutrient can cause crops and other plants to die
Economic issues with using fertilisers
Farmers need to get the amount of fertiliser they apply just right. Too much and money is wasted as excess fertiliser is washed away (causing eutrophication). Too little and productivity won’t be increased, so less money can be made from selling the crop
What does rearing livestock intensively involve
Controlling the conditions they live in, so more of their energy is used for growth and less is used for other activities, the efficiency of energy conversion is increased so more biomass is produced and productivity is increased.
Examples of how animals would be intensively reared
May be kept warm, indoor pens where movement restricted so less energy wasted keeping warm and moving around
May be given feed that higher in energy than their natural food, increases energy input so more energy available for growth
Advantage of rearing livestock intensively
More food produced in shorter space of time, often a lower cost
Disadvantage of rearing livestock intensively
Raises ethical issues, some people think the conditions that they are kept in causes pain, distress or restricts their natural behaviour so it shouldn’t be done
Advantages of using natural fertilisers
Nutrients released slowly
Improves soil quality
Reduces eutrophication
Improves soil aeration
Advantages of using artificial fertilisers
Known nutrient content
Nutrients available immediately
Nutrients distributed easily
Easy to store
