The Use of Fertilisers in Farming

The Use of Fertilisers in Farming

Plants or in this case crops make their own food through

photosynthesis, but in order to do so require nutrients. These come in

two main forms: Macronutrients and Micronutrients.

The primary nutrients that plants use include nitrogen, phosphorus and

potassium, of which are usually depleted first in the soil because

plants use large amounts of them for their growth. Secondary nutrients

are calcium, magnesium and sulphur, but there are usually enough of

these nutrients in the soil.

Micronutrients include boron, copper, iron, chloride, manganese,

molybdenum and zinc of which are all elements essential for plant

growth but are only required in small amounts.

In order to produce a good harvest plants need ideal conditions to

grow. This includes having the right amounts of light, water, an

appropriate temperature and a supply of inorganic ions such as

nitrate, phosphate and potassium.

(3 and 9)

In farming the crop plants are harvested. Thus, nutrients are removed

from the soil instead of allowing the inorganic ions present in the

plants to decompose back into the soil. Unlike natural ecosystems

fertilisers are needed to restore nutrient levels in the soil to

provide optimum plant growth conditions to maximise yields. Under

natural conditions the soil nutrients are recycled. Once the plant

dies, it is decomposed by bacteria/putrefying bacteria, which breaks

down organic molecules and releases the nutrients back into the soil.

In natural ecosystems, plants obtain their nitrogen from nitrogen

fixing bacteria in the soil. Dinitrogen gas (N2) in the atmosphere can

be used by soil microorganisms and converted into forms that can be

used by plants, either symbiotically or non-symbiotically. Leguminous

plants that contain Rhizoium bacteria may fix enough N2 to meet almost

80% of the plants nitrogen needs.

The nitrogen cycle represents one of the most important nutrient

cycles found in terrestrial ecosystems. Nitrogen is used by living

organisms to produce a number of complex organic molecules like amino

acids, proteins, and nucleic acids. The largest store of nitrogen is