Greenhouses and polythene tunnels provide the right conditions for plants to grow. The transparent material allows natural light in for photosynthesis; however, additional light can help especially during the winter. The greenhouse effect also happens in greenhouses. Short wave radiation entering the greenhouse becomes longer wave radiation. These cannot leave the greenhouse so easily, heating up the greenhouse as a result.
Adding lime to acidic soils. An unsuitable soil pH can affect crop growth as it reduces the uptake of mineral ions. It can also denature enzymes in the plant.
2.Carbon Dioxide and Temperature
Burning fuels produce carbon dioxide and heat. These increase the rate of photosynthesis so plants have more food and therefore, fewer plants die, increasing yield of crops. However, when heating, the farmer must heat to the optimum temperature for photosynthesis. Any hotter and it’d be a waste of money as there would be no further increase in yield due to the denaturing of enzymes and other factors.
Burning fuels also produces water vapour, which maintains a moist atmosphere and reduces water loss by transpiration.
For photosynthesis – light can enter the glass or transparent material.
- Organic fertilisers – are made from animal faeces mixed with straw.
- Inorganic fertilisers – carefully formulated to yield a specific amount of nitrate or some other ion.
Using fertilisers mean that extra mineral ions are available in the soil to be taken up by plants and used to make proteins and other compounds for growth.
Also, when crops are sold, the nitrogen in the proteins in plants goes with them and is lost from the farm ecosystem. To replace the lost nitrogen (so it won’t affect the nitrogen cycle in the farm), fertiliser is added.
However, fertilisers can also cause problems. The ions in them are very soluble, and as a result, are easily leached (carried out with water) from the soils and can enter lakes and rivers from sewages. This increases the level of nitrates and other ion and causes eutrophication.
- As nitrate levels rise, algae use them to make proteins and reproduce rapidly, forming an algal bloom.
- This prevents light from penetrating further in the water. Submerged plants cannot photosynthesise as a result, and die.
- The algae also die as they run out of nitrates.
- Bacteria decay the dead plants and algae, releasing more nitrates and allowing the cycle to repeat. As they reproduce more and more due to the large amount of dead matter, their respiration uses up more and more oxygen. Because of the depletion of oxygen, all life in the water will die.
That's the end of the topic!
Drafted by Joey (Biology)