Soil analysis: what it is, types and how to do it

Soil testing is an essential process for agriculture, gardening and construction projects as it provides detailed information about the composition and health of the soil.

Understanding soil characteristics allows for better decision-making for fertilization, management and cultivation, thus ensuring greater productivity and sustainability.

Here, we will talk more about soil analysis, learn how to do it correctly and all its types.

What is soil analysis?

When we talk about agriculture, there is no way not to talk about soil analysis. That is why today we are going to teach you what this method is all about.

This practice makes it possible to evaluate all soil attributes, whether biological, physical or chemical.

It is used to determine soil fertility, identify nutrient deficiencies, measure pH and other important characteristics that influence plant growth and environmental health.

This process is relevant not only in agriculture, but also in areas of environmental management, gardening and civil construction.

It can help gardeners choose plants suitable for the available soil and adjust growing practices.

For environmental management, it can contribute to the monitoring and remediation of contaminated areas, also helping with soil conservation. In the construction industry, this analysis will assess the suitability of the soil for structures.

Types of soil analysis

There are several types of soil analysis and each of them will focus on different properties. Therefore, let's understand more about each of them to know what your soil really needs. See what the types are:

Chemical analysis

The chemical analysis can be divided into parts or carried out completely, in which case tests are carried out to evaluate the macro and micronutrients present in the soil.

The complete version is usually more suitable for farmers who do not have stored soil data, to start building a database and be able to analyze fertility.

It can also be carried out when the farmer wants to adopt a new production system or expand into new areas.

Soil analysis is used to assess the presence of important nutrients, such as nitrogen, phosphorus, potassium, and more. It also assesses the ability to retain and exchange cations, and the acidity or alkalinity of the soil.

Physical analysis

Physical analysis is performed to determine the physical properties of the soil. The test aims to reveal information regarding fertility, but also soil texture, density, which affects soil compaction and aeration, and porosity.

This will help you understand how to manage your land, which crops will do well and last longer.

Soil structure can also be determined by physical soil analysis, which examines whether soil particles are clumped together or aggregated.

Biological analysis

Biological soil analysis is a set of methods used to evaluate the activity and presence of living organisms in the soil, such as bacteria, fungi, protozoa, and other microorganisms.

These organisms play important roles in soil health, including decomposing organic matter, cycling nutrients, and promoting soil structure.

Step by step guide on how to perform soil analysis

Now, let's understand how soil analysis can be done step by step, see:

1 – Preparation

Start by dividing the land into homogeneous areas, that is, areas that have similar characteristics, such as topography, history of use, soil, vegetation and management.

Avoid carrying out soil analysis and preparation on days of heavy rain, as this can make it difficult to collect samples and alter the analysis results. Choose seasons with lower soil moisture.

2 – Sample collection 

The samples collected in the analysis can be composite or simple, which can generate different results. Composite samples are the combination of several simple samples taken from a homogeneous area.

While the simple sample is taken from a single place, it is normally used for specific analyses.

For this process, you need to use a hoe to collect soil samples, and the depth will depend on the type of analysis. For chemistry, the ideal is 0 to 20 centimeters, and for physics, the ideal is 20 to 40 centimeters.

3 – Preparation of identification and shipping

Place the sample in a clean plastic bag or suitable container, ensuring it is dry and tightly sealed.

Label each one with the name, date, depth, area identification, and any relevant observations.

And it must be sent to the laboratory as quickly as possible to avoid changes in the soil characteristics.

By following these steps you can ensure that your soil analysis is useful for making informed decisions about land management and soil fertility.

FAQ

1. What is soil analysis?

Soil testing is a process that assesses the composition and health of soil, providing information about its biological, physical and chemical properties. This process is essential for determining soil fertility, identifying nutrient deficiencies, measuring pH and other characteristics that influence plant growth and environmental health.

2. Why is soil analysis important?

Soil testing is crucial because it helps optimize agricultural management, improve crop productivity, select plants suitable for available soil, and monitor and remediate contaminated areas. In construction, it assesses the suitability of soil to support structures.

3. What are the main types of soil analysis?

• Chemical Analysis: It evaluates macro and micronutrients present in the soil, such as nitrogen, phosphorus and potassium, in addition to the cation exchange capacity and pH.
• Physical Analysis: Examines properties such as soil texture, density, compaction, aeration and porosity.
• Biological Analysis: Assesses the presence and activity of living organisms in the soil, such as bacteria and fungi, which are essential for soil health and fertility.

4. How to perform soil analysis?

• Preparation: Divide the land into homogeneous areas and avoid collecting during heavy rains.
• Sample Collection: Use a hoe to collect soil samples at different depths depending on the type of analysis. Composite samples are a combination of several single samples from a homogeneous area.
• Preparation and Shipping: Place samples in clean containers, label them appropriately, and send them to the laboratory as soon as possible to ensure accurate results.

5. How can soil analysis benefit agriculture?

Soil testing allows farmers to adjust cropping practices, choose the right fertilizers, and improve water management. This results in higher productivity, more efficient use of inputs, and more sustainable practices.

6. What is the recommended depth for soil samples?

• For chemical analysis: Samples should be collected from 0 to 20 centimeters deep.
• For physical analysis: Samples should be collected from 20 to 40 centimeters deep.

7. What are common mistakes in collecting soil samples?

Common mistakes include collecting samples in unsuitable weather conditions, not following the recommended depth, or not ensuring samples are properly labeled and dry before shipping.

8. Where can I get soil analysis?

You can have your soil analyzed in specialized laboratories, which can be found in agricultural institutions, rural cooperatives or environmental analysis companies.

9. How often should I perform soil analysis?

The frequency of analysis depends on specific crop needs and management practices. Generally, it is recommended to perform an analysis every 2 to 3 years to maintain the soil in optimal condition.

10. How to interpret soil analysis results?

Results should be interpreted based on recommendations provided by laboratories and adjusted to the specific needs of the plants or projects in question. Consulting an agronomist or soil specialist can help you better understand the data and make informed decisions.