Tuesday, November 1, 2016

5.1 describe how glasshouses and polythene tunnels can be used to increase the yield of certain crops

 Glasshouses and polythene tunnels can be used to grow crops because they increase the rate of
photosynthesis and increase crop yields. Since conditions can be controlled they can provide an
environment that increases efficiency/allows the process to be sped up.

Glasshouses and polythene tunnels allow farmers to manipulate an artificial environment with optimum
conditions. The limiting factors of photosynthesis (carbon dioxide concentration temperature + light
intensity) and plant growth (availability of light + water, temperature and nutrition) can be maintained to
optimum conditions resulting in a greater yield.

Glasshouses and polythene tunnels mimic the greenhouse effect and provide warmth in the growing area
to increase the rate of photosynthesis (optimum temperature).

Glasshouses:
Glasshouses increase yield of crops by protecting plants from the weather and pests. Heaters can be used
to control temperature (provides warmth) and can also control CO2 levels. Lamps can provide light day
and night, the extended periods of light maximizes photosynthesis and therefore also increases rate of
growth.

-        Greenhouse gas effect increases the temperature inside the glasshouse and allows the enzymes in the plant to work at optimum temperature.
-        Provides shelter against harsh weather e.g. strong storms/wind
-        Prevents water loss through transpiration
-        Constant conditions
-        Can be warmed through the burning of fossil fuels which will also provide carbon dioxide (one of the requirements of photosynthesis)

Polythene tunnels:

Polythene tunnels can provide some protection against the weather and pests, they are cheaper than
glasshouses and cover a greater area of land so more crops can be grown in them. While they provide less

shelter for the plants, they are sometimes preferred over glasshouses because they are adjustable.

No comments:

Post a Comment