• Written By Monica_Kumari
  • Last Modified 24-01-2023

Plant Nutrients in Soil


Plant Nutrients in Soil: Soil is an important source of nutrients for plant growth. Nitrogen (N), Phosphorus (P), and Potassium (K) are the three major plant nutrients. They are known as NPK when they are all together. Calcium, magnesium, and sulphur are also important nutrients. Plants also require trace elements such as iron, manganese, zinc, copper, boron, and molybdenum, which are only required in trace amounts by the plant.

The role of these nutrients in plant growth is complex. Plants create their own food, whereas animals and humans do not. We directly or indirectly depend on plant nutrients for our food needs. Read this article to know more.

Modes of Plant Nutrition

Nutrition is the process of getting food and accessing it to grow, stay healthy, and repair any damaged body parts. Plants produce food by utilising raw materials found in their environment, such as minerals, carbon dioxide, water, and sunlight. Nutrition is classified into two types:

  • Autotrophic – Plants use autotrophic nutrition and are referred to as primary producers. Light, carbon dioxide, and water are used by plants to synthesise food.
  • Heterotrophic – Animals and humans are both heterotrophs because they rely on plants for food.

Major Plant Nutrients Elements

Experienced gardeners, as well as farmers, learn the precise nutrients required at any stage of growth, for health and even taste. Furthermore, they can detect what plants require through a variety of signs and indicators, diagnosing illnesses, pest problems, and nutrient deficiencies.

What nutrients are you supposed to be looking for in fertilisers? What do your plants actually require? Let’s take a look at major elements one by one:

1. Nitrogen (N)

Nitrogen is essential for plant growth. It is found in all plant cells, as well as in plant proteins, hormones, and chlorophyll. Soil nitrogen is derived from atmospheric nitrogen.

Some plants, such as legumes, fix atmospheric nitrogen in their roots; otherwise, nitrogen from the air is used to produce ammonium sulfate, ammonium nitrate, and urea in fertiliser factories. When nitrogen is imposed on soil, it is transformed into the mineral form nitrate, which plants can absorb.

Soils with a high organic matter material, such as chocolate soils, have a higher nitrogen content than podzolic soils. Heavy rain easily leaches nitrate from the soil, resulting in soil acidification. Nitrogen must be applied in small amounts regularly so that plants can use it all, or in organic forms, such as composted manure, to decrease leaching.

2. Phosphorus (P)

Phosphorus aids in the transfer of energy from sunlight to plants promote early root and plant growth and accelerate maturity.

Few Australian soils contain enough phosphorus to support continuous crop and pasture production, and the North Coast is no exception. Superphosphate, which is formed from rock phosphate and sulfuric acid, is the most common phosphorus source on the North Coast. Phosphorus is present in all manures; manure from grain-fed animals is an especially rich source.

3. Potassium (K)

Potassium boosts plant vigour and disease resistance, aids in the formation and movement of starches, sugars, and oils, and can improve fruit quality.

Potassium levels are low or insufficient in many of the North Coast’s sandier soils. In addition, soils utilised for intensive grazing and rigorous horticultural crops can experience significant potassium loss (such as bananas and custard apples). The most common potassium sources are potash muriate and potash sulfate.

Plant Nutrients: Nitrogen, Phosphorus, and Potassium

4. Calcium (Ca)

Calcium is required for root health, the development of new roots and root hairs, and the growth of leaves. It is usually limited to the acidic soils of the North Coast. Calcium is found in lime, gypsum, dolomite, and superphosphate (calcium phosphate and calcium sulfate mixture). Lime is the most affordable and appropriate option for the North Coast.

Dolomite is beneficial for magnesium and calcium deficiencies, but if used for an extended period of time, it will unbalance the calcium/magnesium ratio. Superphosphate is effective in cases where calcium and phosphorus are required.

5. Magnesium (Mg)

Magnesium is an essential component of chlorophyll, the green pigment found in plants, and required for photosynthesis (the process by which the sun’s energy is converted into food for the plant). Deficiencies occur primarily on sandy acid soils in high rainfall areas, particularly when intensive horticulture or dairying is practised.

Heavy potassium fertiliser applications can cause magnesium deficiency, so banana growers must monitor magnesium levels because bananas are heavy potassium users.

Magnesium deficiency can be treated with dolomite (a magnesium-calcium carbonate mixture), magnesite (magnesium oxide), or Epsom salts (magnesium sulfate).

6. Sulfur (S)

Sulfur is a component of amino acids in plant proteins and is engaged in plant energy generation processes. It is the source of many flavours and odour compounds in plants, including the aroma of onions and cabbage.

In soils high in organic matter, sulfur deficiency is not a problem, but it leaches easily. Seaspray is a major source of sulfur in the atmosphere along the North Coast. The main fertiliser sources are superphosphate, gypsum, elemental sulfur, and ammonia sulfate.

Trace Elements in Plants

Check out the list of trace nutritions elements in plants below:

  • Iron (Fe): Iron is a component of many compounds that control and boost growth.
  • Manganese (Mn): Manganese facilitates the photosynthesis process.
  • Copper (Cu): Copper is a necessary component of enzymes in plants and is widespread in North Coast soils, though it can be lacking in red soils.
  • Zinc (Zn): Zinc contributes to the manufacturing of a plant hormone that promotes stem elongation and leaf expansion.
  • Boron (B): Boron enables the formation of cell walls in rapidly growing tissue. Calcium deficiency minimises calcium uptake and inhibits the plant’s ability to use it.
  • Molybdenum (Mo): Molybdenum is essential for legumes because it aids bacteria and soil organisms in the conversion of nitrogen in the air to soluble nitrogen compounds in the soil. It is also required for the synthesis of proteins from soluble nitrogen compounds.

Stay tuned to Embibe for a better understanding of other Biology concepts.

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