Agriculture
No description yet. This curated deck is ready for daily study.
Card preview (24)
What does agriculture involve?
it involves the control of ecosystems o divert energy and nutrients into the human food chain
What are the key principles of agriculture?
Selection of species Control of abiotic and biotic features manipulation of food species to improve productivity
Why is a suitable temperature needed in agriculture?
Needs to be warm enough for growth Some crops need frost-free periods Evaporation impacts: higher temp=more water Biochemical reactions are increased by higher temps Keeping animals warm reduces heat loss so more energy is used in growth
What is the thermal growing season?
The season in which temperatures are warm enough to sustain growth
What species can grow in frost?
Raspberries are not affected by frost
How can temperature be controlled in agriculture?
Greenhouses, heated with solar or gas Candles or large fans to disperse the cold air in orchids during frosts Woven plastic cloth over fields to retain warm air close to the ground Livestock kept warm by providing shelter or them being kept inside during the winter
Why else would livestock be taken in over the winter?
Lack of food as grass doesn’t grow in temperatures below 5 degrees
Why is light important in agriculture?
Light affects photosynthesis, therefore daylength affects photosynthesis
What is photoperiodism?
Daylength
What crops need longer days/more light?
Oats
What crops need shorter days/less light?
Maize
How are livestock affected by daylengths?
Long day lengths increase milk production. Poultry grow best with short days but egg production is increased in longer days. Sheep mate in shorter day lengths
How can lighting be controlled?
Artificial lighting to extend the growing season
Why is water important in agriculture?
A solvent for chemical reactions Nutrients absorption Cell water provides support Water used to replace water lost in transpiration Used for transport of minerals Gaseous exchange
What is the hydrological growing season?
The time during the year that there is sufficient water to sustain growth
What crops have high water needs?
Rice needs flooded fields
What crops have low water needs?
Cereal crops like wheat
What happens to tomatoes in irregular rainfall?
Their skin expands and splits
What do humid conditions attract?
Fungal diseases
What problems are caused by waterlogged soils?
Higher risk of fungal diseases Soils become anaerobic so mor denitrifying bacteria, less nitrogen in soils
How can waterlogged soils be reduced?
Drainage Deep ploughing Avoidance of soil compaction Provision of conditions for worms
What are problems of water shortages?
Lack of water means crops close their stomata so no absorption of CO2, therefore no photosynthesis so plants stop growing. Increases trampling by livestock as they have to travel further to find water which can lead to desertification and erosion
What methods can be used to increase water?
Drip irrigation Soil mulching to reduce evaporation Provision of conditions for worms for increased infiltration Less compaction by less machinery or smaller stocking densities Adding OM to increase water retention
What is soil fertility?
The ability of soil to sustain growth