Agriculture - Soil Formation and Preparation

Agricultural Soil

A branch of science dealing with the study of soil and edaphic conditions related to the food and fiber production is called agricultural soil science. Agricultural soil is the soil which is loamy and fertile and it is considered so because soil can be of varieties and many exist that do not suit for agriculture purpose. Soil that suits the best can be termed as agricultural soil. Soil being the backbone of agriculture, it should be the most suitable one for growing different crops and giving better yield and best quality plants. 


Which Soil is Suitable for Agriculture?

An ideal agricultural soil has the following characteristics:

  1. Proper aeration

  2. Great water holding capacity

  3. Soft or fertile

  4. Good texture or consistency

  5. Balanced alkaline or acid content

  6. Rich in micronutrients and macronutrients

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Soil Formation

How is Soil Formed?

Soi formation takes place through various processes including weathering of rocks and mixing of the rock materials with organic debris which is generated by the decay of plants; the other process is a slow chemical alteration of water that seeps through the weathered rock material after rains. Let’s understand what is weathering! Weathering is the process by which rocks will be broken down to form smaller particles ultimately forming soil that also includes geological sediments and organic debris. It takes over 500 years for the formation of just 1 cm of soil from harder rocks.

Combined processes of physical, chemical and biological factors including weathering of rocks under environmental conditions lead to the formation of soil. It can be said that soil is a mixture of biotic and abiotic components. It  is composed of a wide range of materials including worms, minerals, decaying organic matter, microorganisms, hummus, water and air. All of these altogether make soil fertile which is suitable for the growth of plants or agriculture. 


Types of Soil

  • Sandy Soil: It is light, warm, dry and also tends to be acidic and is low in nutrients. 

  • Clay Soil: It is a heavy soil type that benefits agriculture from its high nutrients. 

  • Silt Soil: It is a light and highly fertile soil with good moisture and consists of medium sized particles and therefore holds moisture well and is well drained.

  • Peat Soil: Peat, the term is given to that soil that forms with the help of wetland vegetation, mosses, shrubs and sedges. It is formed when plant material is not able to fully decay in acidic and anaerobic conditions. It is great for acid loving plants like blueberries.

  • Chalk Soil: Chalky soil is also called lime-rich soil which is heavy or light and made up of calcium carbonate. It is very alkaline with a pH of 7.1-8.0. Meditteranean plants grow well in chalky soil.

  • Loam Soil: Loamy soil is an ideal plant-growing soil which is a combination of equal parts of sand, silt and clay. It has desirable characteristics for agriculture as it has features of all.


Preparation of Soil

To meet the objectives of land preparation for agriculture, we need to undergo various steps to make it the best for cultivation. Soil fertility often needs to be replenished as it loses its nutrient richness with time. So, prior to sowing of seeds, the following steps are taken which are the methods of agricultural soil preparation.


  1. Ploughing

This step includes the loosening and digging of soil. During ploughing, we can loosen the soil and bring deep rich nutrients of the soil to the top. It also increases the aeration of soil that leads to better air circulation and better root health. Other benefits of ploughing include removal of weeds, integration of manure, avoiding infectious pathogens and insects. Equipment used for ploughing include wood or iron made ploughs and hoe is also used to uproot weeds and break the soil.


  1. Levelling

This step of soil preparation is done after ploughing the agricultural fields and it helps in evenly distribution and levelling of soil. It is done with the help of a plank of wood or iron. This process helps in uniform water distribution preventing water logging while irrigating the fields.


  1. Manuring

Manuring is the step of soil preparation undertaken after ploughing and manuring. It helps in replenishing the soil with rich nutrients; Nitrogen, Phosphorus and Potassium are considered the major nutrients and manuring ensures it is added to the soil to enhance the productivity. Besides, many other nutrients and organic fertilizers are supplied via manuring. Regular addition of compost and other manure helps in improving the soil structure, moisture-holding capacity of the soil, soil aeration and water infiltration.

FAQ (Frequently Asked Questions)

1. Which is the Best Type of Soil for Agriculture?

The best soil for agriculture considered to be highly effective for crop productivity is loamy soil which is the mixture of silt, clay and sand. It helps in providing multiple benefits to the crop with better nutrient availability, water holding capacity and high organic matter for their enhanced growth.

2. How Does Soil Recycling Take Place?

Soil has to be replenished during certain intervals as it may lose its nutrient richness with time. When plants grow in the soil, they use the nutrients present there in the soil and after their life cycle, they die and get decomposed with the help of microorganisms. It helps in recycling the nutrients in the soil and after another agricultural preparation, the crops can take up these nutrients and grow.

3. What Are the Variables in Soil Which May Change Depending Upon Its Types?

The different kinds of soil variables include soil texture, aeration and porosity, water content, drainage, water potential, fertility, soil biota and soil acidity or soil pH. To increase soil fertility, scientists suggest to include compounds of Nitrogen, Phosphorus and Potassium to the soil in the form of manure. Soil porosity is also an important factor to enhance its productivity as small pores serve as reservoirs of water supply to plants and microorganisms in the soil, helpful in scanty rainfall days. And during heavy rains, large pores help in draining out the water by insertion of drainage pipes. Porosity is an important factor for supplying oxygen to the roots of plants and other living beings living in the soil. These points highlight the importance of soil in agriculture.