Classification of Nutrients for Crop Production & Role of Macro-Nutrients in Crop Production

Classification of Nutrients for Crop Production & Role of Macro-Nutrients in Crop Production:

In addition to light and water the plants needed essential elements for their survival. Element can be defined as a substance that cannot further subdivided. These elements called nutrients for plants and essential to complete plant life cycle. Each nutrient/element has to perform some specific function or plays some basic roles in plant growth and life cycle like cell division, structural support, and reproduction process to maximize the yield.

The Nutrients required for plant growth (Crop Production) can be categorized based on the demand for optimum growth and maximize the yield.

The nutrients divided into three classes given below.

Macro-nutrients

Secondary nutrients

Micro-nutrients

Macro-Nutrients:

The nutrients required in abundant quantity and without them, a good crop stand is not possible.

These nutrients are Carbon(C), Hydrogen(H), Oxygen(O), Nitrogen(N), Phosphorus(P), Potassium(K), and then further sub-divided into two groups.

In the First group the nutrients are obtained from water and air. In this group the Carbon(C), Hydrogen(H), Oxygen(O) are the macronutrients, and plants can take them from air and water independently, so they are not sold as fertilizer in the market. 

In the second group the nutrients are needed to provide as supplement fertilizer. In this group the Nitrogen(N), Phosphorus(P), Potassium(K), are the macronutrients and plant need in abundant and provided in the form of compound fertilizers available in the market.

In general concept nitrogen is responsible for the physical growth of the plant and essential part of each cell in the plant.

The phosphorus supports the growth of the roots system or we can say phosphorus is responsible for the root part and supports in the formation of a healthy stem.

The potassium is also a very important macro-nutrient that regulates the movement of water inside the plant and for photosynthesis responsible for the opening and closing of stomata to uptake CO₂.  

Nutrients levels of soil can be assessed to some extent by its type (based on textures) will be discussed in a separate blog.

If any of the macro-Nutrients shortage reaches to critical deficiency level, then crop yield will drop drastically.

Secondary-Nutrients:

The nutrients are essential for plant growth but required in comparatively less amount than macro-nutrients and required in larger quantity than micro-nutrients, which are called secondary nutrients.

Calcium (Ca), Magnesium (Mg), and Sulfur(S) are categorized as Secondary nutrients for plants.

Although plant uses these nutrients in plant growth, compounds of one or more of these elements are also used as soil conditioner rather than strictly used for plant nutrients.

Secondary elements affect the PH of the soil as well, Ca. and Mg. increases the soil PH on the other hand Sulfur increases the soil PH from some source.

Availability of Ca, Mg, and Sulfur in soil depends upon the nature and category of the Soil at your farm.

Understanding of the availability of the secondary nutrients in the soil can be assessed based on soil type will be discussed in a separate blog in the future.     

Micro-Nutrients:

 These essential elements for crop optimum growth/yield but are required in smaller amounts hence called micronutrients. Each has it is specific            

Zinc (Zn), Iron (Fe), Copper (Cu), Manganese (Mn), Nickle (Ni), Boron (B), Cholerine (cl), Molybdenum (Mb), Cobalt (Co)

Basic Role of supplement nutrients in crop health:

1      Nitrogen(N):

Major Role of Nitrogen in Plants Health is mandatory for photosynthesis, the shortage of nitrogen leads to a shortage of chlorophyll, in that case, plants cannot use sunlight as a source of energy to perform the function of the nutrient’s uptake.

Nitrogen is a basic component of vitamins, amino acids, and energy systems which contributes to the formation of protein. In this context nitrogen and protein has a directly proportional relationship with each other in the plant body. 

Plant can uptake Nitrogen in the form of NH₄⁺ and NO₃^-. Nitrogen is a mobile element in the plant and can easily move from older leaves to new leaves. In case of mild deficiency mature leaves color will become yellowish-green and when deficiency becomes severe old leaves will become yellow.   

Phosphorus (Ph):

Major Role of phosphorus in Plants Health is very critical especially at the time of germination, phosphorus promotes the early root development and seedling growth.

Phosphorus encourages the development of the root, increases the strength of stalk and stem moreover it promotes the flowering and seed formation processes in the plant.

It plays an important role in capturing the sunlight and converts it into useful compounds for plants.

In young plants the highest amount of P is found in tissues at a growing point, as the crops mature the P moves to seeds or fruits.

Plant can uptake phosphorus in the form of H₂PQ₄^-, HPQ₄^2- or PO₄^3-. The actual form of anion depends upon the PH level of the Soil.

Identification of the Shortage of P in the plant structure is slightly complex. In some crops like corn crop discoloration is a symptom but some crops get the dark green color in a severe shortage of Phosphorus.

The deficiency of P in the soil can be diagnosed by soil test.

The availability of P to the plant from the soil has a strong relationship with the PH level of the soil, PH value of soil from 5.5 to 6.5 is the most suitable range to release the phosphorus to plant, out of this range availability of Phosphorus is much lower to plants.    

Potassium(K):

Major Role of Potassium in Plants Health is to boost the enzymic activities helping in the process of photosynthesis and food formation. Plants take up potassium in abundance, In high yielding crops K uptake is comparable to the N uptake. It helps in the formation of cellulose and translocation of the sugars and starches. It plays a vital role in producing starch-rich grains.

Potassium is also known as quality nutrient because it has a strong effect on the fruit features like size, shape, color, fiber content, taste, and shelf-life parameters.

Plant can uptake potassium in the form of K⁺ ion.

Potassium has a very important role in turgor (the ability of the plant to be straightened and leaves to be widely spread to get maximum sunlight) of the plant.

It improves immunity against drought, extreme temperatures, and less susceptible to pest attack and nematode attack.

The availability of a desirable quantity of K promotes roots development and improves drought tolerance ability of the crop. 

Deficiency of K appears on mature leaves as edges burning and before maturity of leaves white spots as mild deficiency and brown spots reflect severe potassium deficiency. 

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