Answer to Question #256360 in General Chemistry for G6ix

Question

soil organic matter is repeatedly stressed as the key factor in sustainable land management. briefly discuss

Answer 1

Soil organic matter has long been recognized as an important indicator of soil productivity. The Soil organic matter refers to the organic fraction of the soil exclusive of undecayed plant and animal residues. It plays a crucial role in maintaining sustainability of cropping systems by improving soil physical (texture, structure, bulk density and water holding capacity), chemical (nutrient availability, cation exchange capacity, reducing aluminum toxicity and allelopathy), and biological (nitrogen mineralization bacteria, dinitrogen fixation, mycorrhizae fungi and microbial biomass) properties. The preservation of soil organic matter is crucial to ensure long term sustainability of agricultural ecosystems. Improvement/preservation of soil organic matter can be achieved by adopting appropriate soil and crop management practices. These practices include conservation tillage, crop rotation, use of organic manures, increasing cropping intensity, use of adequate rate of chemical fertilizers, incorporation of crop residues, liming acid soils and keeping land under pasture. Organic matter can adsorb heavy metals in the soils which reduce toxicity of these metals to plants and also their escape to ground water. Similarly, SOM also adsorbs herbicides, which may inhibit contamination of surface and ground water. Furthermore, soil organic matter also functions as a sink to organic carbon and mitigates carbon dioxide (CO2) gas escape to environment. Globally, soil organic matter contains about three times as much carbon as found in the world's vegetation. Hence, organic matter plays a critical role in the global carbon balance that is thought to be the major factor affecting global warming. Overall, adequate amount of soil organic matter maintains soil quality, sustainability of cropping systems and reduces environmental pollution.