Soil Fertility And Replenishment Nutrients: Factors, Nutrients Replenishment

The top layer of the Earth's crust is called soil. Mineral nutrients, humus, water, air, and microbes come together to make good soil. It provides different n nutrients to life forms. For photosynthesis, growth, development, and other metabolic activities, plants require a variety of nutrients contained in the soil. The loss of soil fertility is caused by the plants' use of nutrients. The replenishment of nutrients in the soil is necessary to preserve the fertility & nature of the soil.

Read More: Manures and Fertilizers

Key terms: Soil, Replenishment, Nutrients, Texture, Organic, Mineral, Composition, Atmospheric nutrients

What is Soil Fertility?

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Soil fertility is defined as the soil’s capacity to sustain a plant’s life, with all the required nutrients. Highly fertile soil can yield more than double in the same span. The fertility of the soil is lost, when the soil has been used extensively without the replenishment of its nutrients. Thus the soil is replenished with its nutrients. 

There are certain factors that can affect soil fertility such as Mineral composition, the pH level of the soil, texture of the soil, and organic matter. Methods like growing leguminous plants, adding manure, and fertilizers that can be used to replenish soil fertility. 

The fertility of the soil plays a very important role to maintain the growth of the plants of that area. Soil fertility is the potential or the ability of the soil of a particular region to maintain plants growth. The more the soil fertility, the more is the plant’s growth of that region. 

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Factors Affecting Soil Fertility

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There are four main factors that affect soil fertility. These are Mineral composition, soil pH. Soil Texture and Organic Matter:

The following factors affect soil fertility:

Mineral Composition

For the soil to be fertile, the soil needs to maintain a certain mineral composition. This mineral composition can be maintained by applying proper fertilizers and manures. If the mineral composition of the soil is perfect, then only the soil will be fertile, and the crops or the plant’s growth will be good.

Soil pH

The pH of the soil is another important factor, due to which, soil fertility gets affected. The required pH level for the soil to be fertile is 5.5 to7.

Soil Texture

The texture of the soil is also responsible for affecting the soil’s nutrients. The clayey soil has the ability to retain more nutrients and therefore acts as a nutrient reservoir. Thus making the soil more fertile.

Organic Matter

Organic matter is a very good source of nitrogen and phosphorus for the soil. These organic matters can be mineralized and given to the plants.

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Depletion of Soil

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Depletion of soil is the process in which the top soil gets eroded. This occurs due to several reasons, but one of them is that the nutrients of the soil get reduced. This further leads to a decrease in the yield. Thus the soil needs to be replenished at a regular interval so that the soil can maintain its yield.

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Methods of Replenishment of Nutrients in Soil

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Replenishment of soil nutrients is very important, as the soil losses its fertility in being used for repetitive cultivation of crops. Thus, in order to overcome soil fertility, replenishment of nutrients is very important.Replenishment of nutrients means some minerals nutrients are to be added to the soil in order to maintain its fertility.

There are some methods that can be used to replenish the soil nutrients.

1. Addition of Manures: 

Manures are organic materials, which can be used as organic fertilizer in agriculture. There are three types of manures. They are:

• Compost: Composts are decomposed organic matter, which is added to the soil for improving the soil structure. The composts are formed by the slow decomposition of the animal excreta and leftovers of plants. Then it is added to the soil. This further acts as a source of various minerals such as nitrogen, phosphorus, sulfur, etc which improves the soil structure by increasing the water holding capacity thus increasing the soil fertility.
• Vermicompost: It is a compost where the worms like earthworms and red wigglers live in the soil, decompose the organic wastes, and excrete the macronutrients like oxygen, carbon, and hydrogen with other micronutrients in the soil. Thus the oil is replenished in this process.
• Green Manure: It is the key to organic gardening. Green Manure is the cover crop that is grown to maintain the fertility and structure of the soil. Some of the examples of green manure are Alfalfa, cowpea, fenugreek, and buckwheat. It is the major source of nitrogen and phosphorus in the soil. This improves the soil structure, prevents soil erosion, and inhibits the growth of weeds. 

2. Adding Fertilizers: 

The chemical substances that help the soil to increase the yield of the crops are called fertilizers. The two main fertilizers are Urea and NPK. 

• Nitrogen is used in the soil for improving the growth and development of the crop
• NPK stands for three minerals, Nitrogen, Phosphorus, and Potassium. Thus it replenishes the soil with these three nutrients. These three minerals have different importance. Nitrogen is essential for plant growth, phosphorus is essential for root development and potassium mainly focuses on the quality of the plant and other resistance to microbial diseases.

3. Growing Leguminous Plants: 

Leguminous plants are those plants, which can convert atmospheric nitrogen into ammonia. This is called nitrogen fixation. 

Our surrounding air contains a large amount of nitrogen, but plants can absorb the atmospheric carbon dioxide but they cannot absorb the atmospheric nitrogen. The leguminous plants are able to absorb this atmospheric nitrogen. 

• The bacteria that inhabit the leguminous plants, perform the nitrogen fixation.
• Rhizobium is one such bacteria, which shows a symbiotic relation with the legumes. This bacteria lives in the root modules of the legumes and absorbs the atmospheric nitrogen and converts them into water-soluble ammonia.
• The water-soluble ammonia are captured in the soil water and replenish the soil with nitrogen when needed and also make it available for plant use.

4. Cropping Patterns: 

Different Cropping patterns can retain soil fertility without using artificial inputs. There are three main types of cropping patterns:

• Crop rotation: It is the process of where crops are grown one after the other in the same field.
• Intercropping: It is the process of growing two or more crops in a definite pattern.
• Mixed cropping: It is the process where seeds of two or more are intermixed and spread over the field.

The main purpose of these cropping patterns are:

• The plants not only obtain the nutrients from the soil but also add some of the nutrients to the soil, those are the results of their metabolic activities.
• There is a different requirement for different crops, and thus the metabolic wastes of one crop can serve as the key nutrients for another crop.
• By growing different types of crops simultaneously or alternatively, can maintain the balance of mineral nutrients in the soil.

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Things to Remember

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• Soil fertility is the strength of the soil that helps in the growth of the crop or plant.
• More the soil fertility, more is the yielding of the crop
• Factors like pH level, organic matter affect soil fertility.
• There are certain methods that can be used to replenish soil fertility.
• The methods are Cropping pattern, Addition of fertilizers, and Addition of manures.
• It is very important to maintain soil fertility in order to receive a better yield.

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