Soil nutrients for optimal plants growth and production

Soil nutrients for optimal plants growth and production

Healthy and fertile soil needs adequate supply of nutrients for optimum plants growth. The major nutrients in the soil for plant growth are Nitrogen (N), Phosphorus (p) and Potassium (K) which make up the trio known as N-P-K. These nutrients are absorbed by the plants for root development (N & P), growth (N), flowering (P) and fruiting (K). Other important nutrients are Calcium (Ca), Magnesium (Mg) and Sulphur (S). Plants also need trace elements like Iron (Fe), Manganese (Mn), Zinc (Zn), Copper (Cu), Boron (B) and Molybdenum (Mo). These nutrients should be constantly replace else production will decline with decreasing amount of soil nutrients. These nutrient must be balance. A deficiency of one nutrients cannot be compensated by the surplus of the other.

Essential soil nutrients for optimum plants growth

The concept of limiting factor states that plants growth is always controlled by the mineral nutrients in shortest supply, even when sufficient quantity of the other nutrients exist. Imagine a wooden bucket with staves of different length. If water is filled in the bucket, it can be filled only to the height of the shortest stave – the limiting factor. In nature, N is almost always limiting in plant growth.

Liebig's law of limiting factor

Major element (N-P-K)

Nitrogen (N): Nitrogen is found in plant cells, proteins, hormones and chlorophyll. It is a very essential element in plant growth. The main source of soil N is from the atmosphere. Legumes fix atmospheric nitrogen in their roots thereby helping to convert atmospheric N into soil nitrate that plants can easily absorb. Dark soils usually contain more N than light brown soil. Heavy rain usually leached out nitrate from the soil, so it should be added in small amount that plant can effectively use it – preferable in organic form like composted manure which release the nitrate slowly.

Phosphorus (P): Phosphorus stimulates early root development, photosynthesis and plant growth. It also transfer energy from sunlight to plants and hasten maturity of plants as it helps plant to produce flowering site and produce large buds. Manure contains P especially grain-fed animal manure like chicken manure.

Potassium (K): Potassium helps plant to resist diseases and increase flowering and fruit production. It enhance strong root growth, water intake and helps to form and move starch, sugar and oil in plants. It enhance plants vigour, disease resistant capacity and yield. Cassava and bananas are big potassium users.

Secondary nutrients (Ca-Mg-S)

Calcium (Ca): Calcium is vital for healthy roots and leaves development. It helps produce strong cells and root walls.

Magnesium (Mg): Magnesium is a key component of chlorophyll which makes leaves green. Chlorophyll is vital for converting sun’s energy to food for the plant in a process call photosynthesis. Magnesium also helps with production of carbohydrates and sugars to enhance flowering. Deficiencies occur mainly on sandy acid soils in high rainfall areas.

Sulphur (S): Sulfur is a major constituent of amino acids in plant proteins. It is involved in energy-producing processes in plants. It helps produce chlorophyll and play a vital roles in foliage and root development. It is responsible for many the flavour in many plants like onions, cabbage, garlic etc. Sulfur deficiency is not a problem in soils high in organic matter.

Micro- nutrients: These are trace elements that are needed in small quantities for healthy plant growth

Iron (Fe): Iron regulate and promote growth, components of enzymes, essential for chlorophyll synthesis, photosynthesis

Manganese (Mn): Manganese helps with photosynthesis, chloroplast formation, cofactor in many plant reaction, activate enzymes

Copper (Cu): Copper is an essential element of plant enzymes, involved in photosynthesis

Zinc (Zn): Zinc supports the production of plant hormones and auxins activity which are responsible for stem elongation and leaf expansion

Boron (B): Boron enhances the formation of cell wall in growing tissues. Important in sugar transport, cell division and amino acid production

Molybdenum (Mo): Needed by soil organism and bacterial in the nodules of legumes to convert atmospheric nitrogen into soluble nitrogen compounds in the soil like nitrate. It is vital in proteins formation from nitrates.

Chlorine (Cl): Used in turgor regulation, aid photosynthesis, resist diseases

Symptoms of nutrients deficiency in Plants 

Plants need the right combination of nutrients to live, grow and reproduce.  They often show symptoms of being unhealthy when they lack these nutrients. Below are some of the symptoms of nutrients deficiency that can be identify on the plant. 

Nutrients imbalance

Too little or too much of any one nutrient can cause problems of nutrients imbalance. So it is good to fertilize lightly and monitor or you test the soil before adding much fertilizer. Nutrients interacts with each other either synergistically to increase the uptake of one another or antagonistically to fight each other and lock each other out. Check the soil to make sure nutrients are not locked out of the plants and building up in the soil before adding supplemented nutrients. The Mulder’s chart specifically shows which nutrients in the soil increases (synergy) or decreases (antagonism) availability of the other nutrients in the soil.

Important plant nutrients across different growth stages 

Since different nutrients have different functions, the nutrient needs of a plant also changes from propagation to early vegetation, late vegetation to flowering. It begins with strong root development which require N. At early vegetation stage, the need of N and K increase to produce more leafy growth, horizontal branching and tight internodes. When flowering time arrives, N levels drops off and P intake increases slightly as the focus now is to produce dense, potent flowers. When the fruits are about to ripe, the need for K start increasing.

We recommend that you you stick to a N:K ratio of 5:4 during vegetative stage and drop it gradually to 2:3 during flowering. Research have shown that too much phosphorus during flowering may leads to many smaller nuts, but not bigger nuts and the need for P is pretty low throughout plant's life cycle. The Ca:Mg ration should be kept at 3:1 to balance charges and enhance uptake of plant nutrients. 

Change of nutrients requirement over different plant stages

In our next write-up, we shall discuss how to add these nutrients to the soil in naturally. We shall be uploading videos soon on our youtube channel. Subscribe to our channel, like, comment and hit on the notification button to keep up with update. Like our facebook page and follow us on instagram and twitter