Organic Matter: The source of life for the Soil

Soil organic matter is the living fraction of the soil and consist of about 6% of the total soil composition. It is a major determinant of the soil productivity and crop performance because of the crucial role it plays is maintaining equilibrium among plant nutrients and the microbial population of the soil. In the light of this key benefits, it’s therefore necessary to be adequately informed about the proper applications of organic matter in crop production in order to maximize crop yield.

What is Soil organic matter?

Soil organic matter is the fraction of soil that consist primarily of 3 major components:

  1. Plant Residue and Living Microorganism: this fraction of organic matter significantly influences the fertility of the soil because of the role of microbial biomass in the decomposition of the plant residue to release primary nutrients (Nitrogen, Phosphorus, Potassium) that are required by the crop for effective performance.
  • Detritus: this is also referred to as the active organic matter because it is the fraction of the organic matter that hosts the microorganism responsible for the decomposition and remineralization of the soil. It consists mainly of dead animal residue and wastes, as well as some plant residues
  • Humus: this is the stable fraction of the organic matter resulting from the decomposition of the plant and animal residue has less influence on soil fertility because it is the final product of decomposition. However, it is important for soil fertility management especially with respect to the cation exchange capacity of the soil.

Benefits of Organic matter and The Challenges associated with the Lack thereof:

When it comes to the benefits of Organic matter to the plant, they can be categorized into 3 major classes due to the complexity of the composition of organic matter and the effect of its deficiency are also categorized according its nature:

  1. Physical Benefits: organic matter plays a crucial role in improving the stability of the soil aggregate, improve water infiltration and soil aeration. All of which are important for growth and establishment of the plant root system and root performance.

Soils that are poor in organic matter are difficult to cultivate due to the high possibility of sticking of clay, crusting and run off, which consequently affect the generic potential of crops grown under such condition

  • Chemical Benefits: Organic Matter improves the Cation exchange capacity (CEC) of the soil. CEC of the soil determines the availability of nutrients to the plant and supply of these nutrient over time. Soil poor in CEC suffer significantly from leaching of fertilizers, as a result growers incur losses in input and productivity of the crop.

Organic matter improves the ability of a soil to resist pH change [Buffering capacity], this is very important because the appropriate pH ensure the nutrients remain soluble in soil solution and readily available for uptake by the plant root. Unfavorable pH lead to the precipitation of the nutrients and making them unavailable for uptake, though present in the soil.

  • Biological Benefits: due to the presence of living organism in the soil organic matter composition which are beneficial for the breaking down of plant and animal residues to release essential nutrients usable by the plant. Humus also provides food in the form of organic acids for living organism in the in soil which helps to Improves the population, Biodiversity, and activities of microbes which creates a healthy environment for the development of plants. Without activities of the biological agents, the fertility and performance of the soil is significantly impaired and the crops become susceptible to disease and pest attacks. 

As presented alongside the benefits of soil organic matter, we can learn that the consequences of the poor organic matter management are far-reaching and would tell on the profitability obtainable by growers. It is therefore recommended that organic matter amendment fertilizers be an integral component of any crop production fertilization program to ensure continuous peak performance of the soil over a long period of time.