Role of EC, Nitrogen, Phosphorus, Potash and pH for best crop production
To keep the humanity alive, it is very important that the Earth is cultivated with crops as these plants provide food, fibre, housing and many other benefits to the human population and for this process Fertilizers play a key role and as expected that the population will rise rapidly in the coming years, so there is more and more requirement of fertilizers to boost the production of crops so that the people are fed with food and remain healthy.
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The growing plants need 17 essential elements which are called macronutrients and micronutrients for their growth and out of these 17, 14 are absorbed by the plants through the Soil while the remaining three come from air and water. Nitrogen, Phosphorus and Potassium or NPK are the “big 3” primary nutrients in the commercial fertilizers which plays a key role in the nutrition of plants.
The crop productivity also depends on the pH and Electrical Conductivity or EC of the Soil. All the nutrients, major or minor, have their own significance and importance in production of crops. So it is very important to add proper nutrients in the proper time and proper amount to get quality and optimum yields.
Here, we will focus on these basic nutrients and their Role in production of Crops.
Role of Nitrogen, Phosphorus and Potassium in the process of crop productivity
These three major elements Nitrogen, Phosphorus and Potassium contribute to the growth of crop and these “big 3” Soil nutrients are also known as NPK where each letter stands for the element’s symbol on the periodic table, where N stands for Nitrogen, P stands for Phosphorus and K stands for Potassium.
We will understand these one by one.
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Nitrogen is one of the main chemical elements that is required for the growth of plants and in the Photosynthesis process, it is an integral part of all the proteins. The availability of usable Nitrogen is the most limiting factor for the growth of crops in many agricultural conditions.
The crop absorbs it either through Ammonium or Nitrate through the root system of the crop. The plant then utilises Nitrogen as a building block to produce protein in the form of enzymes which is very important in the Photosynthesis process and the crops then move Nitrogen around their plant systems from the high Nitrogen density area to the areas where it is deficient.
Nitrogen is a mobile element and it gets relocated from older tissue to younger tissues during the time of a deficiency and this is the reason for the yellow colour in the older leaves which is the sign of Nitrogen deficiency. The deficiency also occurs from the overuse of fertilizers which causes lock out of nutrients in the Soil.
The plant absorbs more Nitrogen than any other plant and therefore, it is considered to be the most important nutrient. It is very essential in making the plants healthy as they help in the development of the fruits and make it nutritious after they are harvested. They help in the formation of protein and these proteins make up much of the tissues and most of the living things.
Read more: Importance of Potash for Crop Production.
Phosphorus is the second of the “big 3” important nutrients required for the growth of plants and it is linked to a plants ability to use and store energy including the photosynthesis process. It is also needed in helping the plants to grow and develop normally.
It is vital for strong growth and the Soil can cause stunted, spindly crops due to the insufficient amount of Phosphorus. It breaks into separate ions when combined with water which is absorbed by the plants root system and is then used for the photosynthesis and energy or nutrient transport.
Phosphorus helps in the yield of crops in a greater quantity and it also creates healthier stocks and root systems. It also helps in maturing of the crops much more quickly than the plants without Phosphorus.
The insufficient supply of Phosphorus can cause green and purple discolouration, wilting, small fruits and flowers. It creates a strong root base and produces strong crops all through the season.
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Potassium is the 3rd key nutrient of the “big 3” fertilizers and it helps in strengthening the plants abilities to resist the disease and plays a very important role in increasing the yield of crops and its overall quality. The nutrient also protects the plant during the cold or dry season and strengthens the root system and prevents it from wilt.
Potassium is naturally found in the Soil in two forms: one of the forms is absorbed into the plant and the other is unavailable to the plant. Potassium is water soluble in many of the agricultural products which allows it to be absorbed by the crops through the nutrient rich Soil.
The healthy plant uses Potassium in the cell system which uses water and it also aids the plant in using this water efficiently which prevents many diseases and damage from heat. It also helps the cycle of nutrients through leaves, roots and stems.
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Soil pH – Role and Effects
Soil pH is the measure of acidity and alkalinity in a Soil and it is one of the most vital factors which determines the yield of the crops. The pH regulates and controls many chemical and biochemical processes within the Soil and it plays a major role in making the plant nutrients available and it also has an effect on the chemical forms of the nutrients.
The Soil pH has an enormous influence on the biogeochemical processes within the Soil and is therefore described as the ‘master Soil variable’ which influences the biological, chemical and pHysical properties of the Soil and its processes and affects the plant growth and its yield.
The pH of the Soil measures the concentration of Hydrogen ions in the Soil solution. The Soil becomes acidic when the basic elements such as Calcium, Magnesium, Sodium and Potassium are held by Soil colloids and are replaced by Hydrogen ions.
The increase in acidity of the Soil results because of the reduction in pH of Soil. The pH ranges from 1 to 14 with 7 being the neutral. We can say that the Soil which has a pH of 4 has 10 times more acid than a Soil with a pH of 5 and 100 times more acid than a Soil having a pH of 6.
The optimum range for the growth of plants varies among crops. Some of the crops grow best in the range of 6 to 7 while others grow under slightly acidic conditions. The properties of the Soil influences the need and response to nutrients and it varies by region, so it is very important that you have the knowledge of Soil and crop to manage the pH of the Soil for getting best crop results.
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Effects of Soil Acidity
- Acidic Soils restrict the water and nutrient access to the roots and all the major plant nutrients i.e Nitrogen, Phosphorus, Potassium, SulpHur, Calcium, Manganese and also the trace element Molybdenum becomes unavailable and if available then it is only in insufficient quantities. Due to this, the plants start showing deficiency symptoms.
- The dropping of Soil pH makes Aluminium soluble and this retards root growth which restrict the access to water and nutrients and the effect of aluminium toxicity on crops restrict access to stored sub Soil water for grain filling as well and reducing the growth and yield.
- The pH also has an effect on the persistence of herbicides.
- Low PH in the Soils affects the microbial activity decreasing the legume modulation.
Effects of Alkalinity
Alkaline Soils exhibit deficiency symptoms because the solubility of minerals are reduced and the deficiency of Iron, Manganese, Zinc, Copper and Boron are commonly observed in high pH Soils. Also, there is deficiency of a major nutrient Phosphorus. Calcium also gets deposited in high amounts which accumulates and inhibits the uptake of Potassium and Magnesium nutrients.
Electrical Conductivity (EC)
Electrical Conductivity is a measure of the “total salts” concentration present in the nutrient solution. The mapping of Electrical conductivity depicts a variety of Soil characteristics which are highly correlated to the productivity of crops. Some of the Soil properties that affect electrical conductivity include Soil particle size distribution, Soil organic matter, Soil nutrient levels, Soil compaction, Soil drainage, CEC, Soil water holding capacity and Soil salinity.
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Electrical conductance exists because of the particles having electrical charge that are loosely bound to specific positions within the materials and are capable of conveying electric charge. Liquid water is a conductor and it contains some form of dissolved ions which are movable charged particles. On the other hand, Soil is also a composite conductor in which the water, solid particles and air are present in variable quantities in which the electric charge carriers are dissolved. These ions are usually the major inorganic ions, i.e cations Na+, Mg 2+, Ca 2+, and K+ ; and anions Cl –, SO42-, HCO3–, CO32-, and NO3 –.
When there is no electric field the ions move randomly within the field and no net electric current is observed. On the contrary, when there is an electric field applied, the cations move to the lower potential areas and anions move to higher potentials and therefore, the water or the Soil system starts conducting electricity. Therefore, Electrical conductivity is a pHysical quantity which indicates its ability to conduct electric current and is the reciprocal of the resistivity of the material.
Importance of Monitoring EC
The Electrical conductivity within the nutrient solution influences the growth and development of a plant. During winter months, higher Electrical conductivity is used as it restricts the uptake of water which results in smaller, thicker and stronger cell walls and in this situation, the plants use relatively more energy in the formation of flowers and fruit. Similarly, a low EC during winters produces too much leaf growth and too little fruit growth in the plants.
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During Summers, high EC restricts water absorption too much and therefore it restricts the ability of the plant to cool itself via transpiration. This makes the crop stressed.
The electrical conductivity also influences the production and quality of fruit and generally, a higher Electrical conductivity leads to lower production and smaller fruit size because the cells and the fruits take up less water resulting in a lower fresh weight. However, a high EC also results in better fruit taste.
EC measures the salinity of the Soil which affects the nutrient readiness in the Soil and prevents its absorption by the plants. The more salinity transforms the productive Soil to a less productive Soil.