Soil fertility means the ability of a soil to sustain plant growth by providing essential plant nutrients and favourable chemical, physical and biological characteristics as a habitat for plant growth.
Soil Fertility is defined as “the quality that enables a soil to provide the proper compounds, in the proper amounts, and in the proper balance, for the growth of specified plants when temperature and other factors are favorable”.
- A fertile soil will contain all the major nutrients for basic plant nutrition (e.g., Nitrogen, Phosphorus, and Potassium), as well as other nutrients needed in smaller quantities (e.g., Calcium, Magnesium, Sulfur, Iron etc.). Usually a fertile soil will also have some organic matter that improves soil structure, soil moisture retention, and also nutrient retention, and a pH between 6 and 7.
- Soil fertility is a manageable soil property and its management is of utmost importance for optimizing crop nutrition to achieve sustainable crop production.
Factors Governing Soil Fertility
Some factors are involved in soil fertility. These are as follows:
- Parent material: Fertility of a soil depends on the chemical composition of parent material from which it derived.
- Topography: Soils on the upper slope are less fertile than the soils on lower slope because high leaching and erosion on upper slope.
- Climate: In tropical climate decomposition of organic matter is faster than temperate climate. Thus soils of tropical regions are less fertile when compared to temperate region.
- Depth of Soil Profile: Deep soils are more fertile than the shallow soils and the roots are spread well enough in deep soils than the shallow soils.
- Physical Condition of Soil: The soil texture and soil structure influence the soil fertility.
- Artificial Factors: Water logging, cropping system, toxic chemicals and pesticides in the soil etc.
Importance of Soil Fertility
Soils with high fertility-
- Mobilize soil nutrients from the reserves.
- Transform fertilizer nutrients into easily available forms.
- Store water-soluble nutrients in easily available forms, thus preventing leaching.
- Offer the plants a balanced nutrient supply due to its self-regulating system.
- Store and supply sufficient water.
- Maintain good soil aeration for the oxygen requirements of roots.
- Do not ‘fix’ nutrients, i.e. convert them into available form.
- Improve crop use efficiency of nutrients and resources such as water and light.
A term comes with soil fertility, that is soil productivity, what is soil productivity?
- Soil Productivity is defined as the capability of a soil for producing a specified plant or sequence of plants under a specified system of management.
- The main factors governing productivity are soil fertility, climate, pests, disease, genetic potentials of the crop and man’s management (tillage, planting date, irrigation schedule etc.). Thus, soil productivity is an expression of all the factors, soil and non-soil, that influence crop yields.
- Soil Productivity is basically an economic concept and not a soil property. Three things are involved: (1) inputs (a specified management system) (2) outputs (yield of particular crops), and (3) soil type.
Are Soil Fertility and Soil Productivity Same?
A question arises, are all the highly fertile soils productive?
The answer is, ‘No’. Because-
For a soil to be productive it must be fertile. But It does not follow, however, that a fertile soil is productive. For example, many fertile soils exist in arid regions, but they are not productive due to lack of irrigation or favorable temperature.
So, all highly fertile soils are not productive, but all productive soils are highly fertile.
Difference Between Soil Fertility and Soil Productivity
Soil fertility and soil productivity are not same, there are some basic differences:
|Soil Fertility||Soil Productivity|
|1. It is an index of available nutrient to plants.||1. It is used to indicate crop yields.|
|2. Influenced by the physical, chemical and biological factors of the soil.||2. Depends upon fertility and location.|
|3. It is the function of available nutrients of the soil.||3. It is the function of soil fertility, management and climate.|
|4. All fertile soils are not productive.||4. All productive soils are fertile.|
|5. It is an inherent property of the soil.||5. It is not the inherent property of the soil.|
This article is based on the class lecture by Md. Bayazid Hossain, Lecturer, Department of Soil, Water & Environment , University of Dhaka.
Some information have been added by the author. Any mistake, error and other related things found in this article are only author’s to blame.
- Saifun Nahar Smriti on 5 December, 2020.