In the plant world, the quality of the soil and what generally makes the soil fertile is usually measured by the crops that will be grown. For someone who is now starting to learn about soil, it is important to know the differences between soil fertility and soil productivity.
While soil fertility means focusing on conventional agriculture, organic agriculture focuses on soil productivity; it has the goal of improving the overall soil fertility and maintaining it for a long period of time. In this article, we will focus on and explain soil fertility and soil productivity, the factors that influence them, and how we can achieve each one of them.
What Makes the Soil Fertile?
Fertile soil can offer crop yields, and in agriculture, we take into consideration all its biological, chemical, and physical characteristics. Adding the right nutrients to the water supply and having the correct soil structure or the right living organisms are a few characteristics that must be met.
Fertile Soil vs. Productive Soil
Since the terms are frequently used interchangeably, it is logical to be confused. Let’s compare the two to see the differences:
- A measure of available nutrients to plants.
- The main factor for crop yields (water supply, temperature, and rainfall are additional ones)
- Used as a potential status for the soil to produce crops
- Able to be analyzed in the lab
- Depends on the physical, biological, and chemical factors of the soil
- Depends on the nutrients
- It is an inherent quality
- Can be the same in all climates
- Fertile soils can be characterized as not productive
- Used broadly when crops are considered
- Interaction of all factors
- Only assessed under particular climate conditions
- A result of various factors that influence the soil
- Depends on location, fertility, physical conditions
- Not an inherent quality
- Can be different according to climate and location
- Productive soils are 100% fertile
Components of Soil Fertility
The key ingredients of soil are 5% organic matter, 25% water, 25% air, and 45% salt, and the soil needs to have all of the above to be fertile. Think of it as a coordinator that distributes the nutrients to plants. In further detail:
- Good air circulation provided – The flows freely with no further issues. Water evaporation and transpiration carry on with no disruption.
- Microorganisms can live there with no issue – The microbes and the bacteria can perform their fundamental functions freely (nutrient cycling, plant growth stimulation, breaking down crop residues).
- All nutrients provide a benefit to the plant overall – They help with the creation of new cells and plant tissue organization effectively.
- Drainage is available, and the water holding capacity is great – When it is necessary, the soil is well aerated, and when it is needed, it can flush out the unwanted wanted water easily.
Balance of all ingredients is the key to making fertile soil.
What Is the Most Fertile Soil?
The most fertile soils are thick in texture with a good number of nutrients, they are well aerated, and there is enough organic matter. The soil particles have good water drainage and can use the nutrients effectively.
If we have all these factors together, how can we achieve the fertility of the soil?
How to Achieve Fertile Soil
There are several ways you can improve fertility and the soil's overall health. Here are a few:
- Offering fertilization and nutrients – The soil is fertilized and gets all the nutrients necessary to grow the crops. It also supports the plants effectively.
- Crop rotation / Mixed cropping – Annual crops are selected and grown, so the soil can remain protected and not depleted.
- Adequate tillage – Used mostly to get a good soil texture without causing erosion.
- Feeding of the soil organisms – Supplying the soil with compost and earthworms, for instance. They highly appreciate the organic material.
- Protection from the weather conditions – Strong winds and heavy rains can cause many issues. Plant coverage may be necessary to protect crop yields. It also preserves water moisture.
As you can see, achieving fertile soil is not a complex task but requires some knowledge.
Factors Influencing Soil Fertility
The most well-known factors that can influence the fertility of the soil are:
- The supply of nutrients – Like nitrogen, phosphorus, calcium, magnesium, and potassium sulfur. These nutrients have to be there and in the right amounts.
- The supply of water – In adequate amounts, the water has to enter the soil through the pores until it reaches the roots efficiently while using organic matter and minerals.
- The pH – It can be alkaline or acidic. It needs to be ready for the plants at hand to offer the right conditions. Some plants need more acidic soil, while others need more alkaline soil. The soil needs to be managed to host the plant’s needs.
- Soil structure – The structure should allow some good drainage and the right air circulation.
- The depth of topsoil – In order for the plants to establish their roots, they will need more than 10 cm depth. If the topsoil is less than 10cm, it is considered to be shallow.
- Supply of organic matter – Mulch, coconut coir, humus, or dead leaves will do. It helps with moisture.
- Density – Loose and fluffy soil will allow the plants to reach for the nutrients they need.
- Existence of clay – It will help with the retention of nutrients and will act as a buffer to the soil by protecting it from becoming highly acidic.
- Saline groundwater in close proximity – Salt water can help with overall fertility by providing moisture to the yields and strength to the plant overall (bigger leaves and stems).
While we have the organic factors that can influence fertility, some non-fertility factors are proven to affect fertility over time.
Non-Fertility Factors That Can Impact Soil Production
We also have to consider other factors that might be affecting the overall soil fertility in general. Some of those are:
- Climate and weather – Since it can change from one place to another, it is one of the factors that either can enhance fertility or completely decrease it.
- The use of fertilizers and pesticides – Whether they are used or not, they can create a big difference. A balanced supply of fertilizers, pesticides, and organic matter is the way to go.
- Weeds and pests – Weeds and pests need to be removed and controlled since they can affect the overall plant health and nutrient supply.
- If genetically modified plants are used – Since they contain newly contained genes, they can disrupt the overall flow of nutrients and organic material in the soil.
One reading all the factors together may wonder how they can achieve to make the soil more fertile. There 2 ways we currently know that can do that.
Ways to Make the Soil Fertile
We have two ways to make this happen, either the organic way or the inorganic way.
The Organic Way Includes:
- Coverage – Using mulch or dead leaves/stems, the moisture is kept for longer periods of time. It also facilitates the flow of nutrients.
- Cover crops – This will help with the air circulation and provide nutrients and minerals through the decomposed leaves.
- Minimizing tillage – While it is helpful to fix the structures, tillage overall exposes the lower layers, and as a result, the water gets evaporated.
- Soil Analysis – It helps to know which nutrients are in abundance and which are missing. It also helps with the planting and where to place each crop directly.
- Organic matter use – While it provides nutrients, it might contain diseases and pests, which we do not favor.
- Crop Rotation – It helps with the regulation of weeds, mobilization of nutrients, and retention of moisture.
The Inorganic Way Includes:
- Fertilizers – It is suggested to use only the amount needed since, over time, it can kill and eliminate all the microorganisms that are in favor of plant growth.
- Compost Tea – Known for its wide benefits, it can improve water retention, loosen the compact soil, and help the microbes that fight off pests and diseases even more.
- Alfalfa meal – The triacontanol hormone in there can help with plant growth and photosynthesis. It also absorbs the extra water and provides good drainage.
And now, the upcoming question comes to the surface. How do we maintain it?
How to Improve Soil Fertility and Maintain it
Since all the factors interconnect between fertility and productivity, some main key factors can help with the maintenance:
- Slow release fertilizers – They offer a good amount of micronutrients and macronutrients, like nitrogen and phosphorus.
- Presence of organic matter – Mulch, decomposed leaves, and stems can add nutrients while helping with the right levels of moisture.
- Water supply – Rainfall can contribute to this from time to time. The manually adjusted water supply to the soil should be provided and aligned with the plant’s needs.
- Additional nutrients in the soil – Rock powder, when used after tillage, can correct any soil deficiencies. Fertilizers that contain calcium and sulfur can be of great use to provide some additional help to the microorganisms as well.
- Absence of toxic substances – The absence of chemicals and pollutants should be checked and monitored. They can change the mineral conditions and disrupt the microorganism’s cycle.
Fertility maintenance requires constant attention but is easy to follow.
How to Improve the Soil Structure
The most important thing here is to maintain the soil structure is to perform the necessary activities to maintain the plant root health, air circulation, and boost microorganisms. The activities below will help overall:
- Use of mulch/leaves and stems for cover – By using the mulch and the leaves (or stems and branches), it helps the soil maintain moisture. Once they decompose completely and get metabolized, the soil overall becomes more loose and fluffy.
- Help with microorganisms – By avoiding the use of unnecessary fertilizers (or using too much), the organisms in the soil are able to find shelter while providing air circulation to the roots.
- Use of compost and additional materials – Compost is known for improving the overall texture by making the soil softer. It adds additional moisture and loosens the tight parts of the soil overall.
While soil structure is essential, there is one more key ingredient that can make all the difference in the world which is organic matter.
Soil Organic Matter and its Importance
Organic matter plays a huge role in soil fertility. The functions it carries can affect a plant and crop growth and health overall. Let’s see below why:
- It prevents any extra acidity in the soil – by maintaining the pH levels stable, the soil remains fertile and suitable for all the crops there available.
- It helps with the retention of nutrients and their slow release – Since it is able to retain the necessary nutrients, it can make the soil a better provider of nutrients to the plants at hand while keeping stable the air circulation and the humidity.
- Food for the microorganisms and earthworms – Organic matter is a great food source for the earthworms found in the soil. They decompose it and metabolize it. The end result is a rich, dense and soft soil texture, rich in nutrients.
- Acts as a “glue” – It can act as a sponger and tie up the soil particles together. This works like wonder in clay and sandy soils.
- Water retention mechanism –This can help a lot, especially in drier periods. Organic matter can hold water up to 5 times its own weight, helping with the overall moisture.
- Acts as a wall to the soil structure – By helping with the overall structure, it can result in better soil pores and better air circulation. It can also help the roots penetrate the soil further.
Maintaining organic matter value is crucial for controlling the growth of the plant.
How to Increase Organic Matter in the Soil
Since the organic matter is always metabolized and decomposed, it is suggested to be used over and over again over time for better results. This can create questions about how the matter can be increased and maintained. Here’s how:
- Avoid the overall tillage and erosion – Since it can expose the lower levels of soil and cause water evaporation, it is best to avoid it if it is not needed.
- Crop rotation – Rotating the crops with deep roots or can build up organic matter can be very helpful.
- Use of cover crops – Cover crops can increase the level of nutrients, especially young ones. They increase the overall biomass from the roots to the stems and then the leaves.
- Mulching – Mulching can help with additional fiber, which can stay for a really long time in the soil. It can also help with erosion.
- Application of compost – Same as mulching, it can stay there for a long time, offering the right nutrients to the plants.
- Application of organic manures – They can help increase the organic matter since they can be a nitrogen source.
- Leaving the yields residue on the field – By not throwing them away or burning them, leaving them in the soil can increase the biomass over time and give strength to the plants.
As you can see, there are numerous manageable ways to increase the organic matter in the soil.
Why Is Productive Soil a Fertile Soil?
Productive soil is always fertile because we know it can produce, support, and grow plants in it. While fertility focuses on many biological, chemical, and physical properties of the soil, the productivity of the soil is much more concerned with looking at the overall ability of the soil to grow plants.
What Makes a Productive Soil?
Productive soil has the right texture, air circulation, compost availability, and water supply. All the factors are studied and maintained to produce the end result: strong plants and healthy crops.
Which Material Gives the Soil Its High Fertility?
Organic matter is known to give a high soil fertility rate by decomposing. It can protect the soil’s pH, keep the microorganisms happy, and keep the soil structure healthy. However, its large amounts and imbalance in structure may be the reason why might soils rich in the organic matter not be fertile.