The Role of Organic Matter in Soil for Improving Crop Productivity and Soil Health

Soil organic matter (SOM) is one of the most important natural resources and the basis of soil fertility. The term SOM generally refers to the total organic carbon (C)- containing substances in soil. The total mass of organic C in soils has been estimated at 22 × 1014 kg, similar to the total of all other C reservoirs on the earth’s surface (21 × 1014 kg). 1 SOM contents range from less than 1% in sandy and desert soils to 1%-5% (w/w) in the surface horizons (top 15 cm) of typical mineral and agricultural soils, to almost 100% in organic soils. Even at the lowest levels, the role of SOM in all processes occurring in the soil is ascertained to be highly relevant. SOM plays a crucial role in the global carbon balance that largely governs global climate change, and organic matter in soil profiles contains four to six times as much carbon as all of the world's vegetation. These include enhancing soil aggregation, boosting nutrient exchange, retaining soil moisture, decreasing compaction and surface crusting, and increasing water infiltration into the soil. Since SOM is the best way to incorporate natural soil production, it ought to be used as a soil quality indicator. Therefore, boosting SOM pools in agricultural ecosystems is crucial for reestablishing soil health, ensuring sustainable crop production, and storing CO2 in the atmosphere. To increase the biomass production required to raise the SOM level in the soil, it is, therefore, crucial to implement practices like crop rotation, minimizing tillage operations, using cover crops, applying animal manures, green manures, crop residues, and composts, as well as using chemical fertilizers.