Agricultural Practices
Biology: AQA A Level, topic 5.3.3
Primary Productivity in Farming
Farming practices attempt to maximise productivity by increasing the efficiency of energy transfer. Ways to improve primary productivity are described below.
Efficiency of energy transfer
- Farming practices are used to maximise the efficiency of energy transfer.
- This increases how much energy is available for human consumption.
- Efficiency of energy transfer is increased by:
- Simplifying food webs.
- Reducing respiratory losses.
Overcoming limiting factors
- Overcoming limiting factors to photosynthesis helps to maximise primary productivity. This can be done by:
- Maximising plant exposure to light.
- Using warmer temperatures in greenhouses.
- Irrigation to maximise water supply.
Fertilisers
- Fertilisers can be sprayed on fields to maintain nutrient levels in the soil.
- High nutrient levels in the soil help plants convert energy to biomass efficiently.
Pesticides
- Using pesticides removes any pests that might spoil the crop.
- Removing pests prevents the loss of biomass.
- Herbicides kill weeds and reduce competition for resources like sunlight or soil nutrients.
- Fungicides prevent fungal diseases.
Secondary Productivity in Farming
Farming practices attempt to maximise productivity by increasing the efficiency of energy transfer. Ways to improve secondary productivity are described below.
Reduce energy loss
- The efficiency of energy transfer can be improved by reducing energy lost through heat from respiration or other means. E.g. -
- Limit movement of animals.
- Use heating in barns.
- Antibiotics - prevents energy lost to pathogens.
Increase growth rate
- Increasing growth rate helps maximise the rate of production of biomass. E.g. -
- Selective breeding to produce breeds with higher growth rates.
- Steroids to increase growth rates and the accumulation of biomass.
- Harvest when young - most of an animal's energy is used for growth when young so accumulation of biomass is maximised.
Test yourself on Agricultural Practices
Which of these are NOT a technique used to maximise primary productivity?
What are the two techniques for improving secondary productivity?
Which of the following are NOT ways to reduce energy loss in secondary productivity?