Thursday, 23 May 2013

SOIL ORGANIC SUBSTANCES AS A SOURCE OF CARBON AND MINERAL NUTRIENTS OF PLANTS


The utilization of elements in carbon and mineral nutrition of plant is the conditions of biological and geological cycles of substances. The accumulation of scattered elements of the atmosphere, hydrosphere and soil crops in the form of the living substance of autotrophic and heterotrophic organisms and the liberation of those elements through their living activities as well as after death is enormous in scale and importance, the biological cycle develop the part of the geological cycle.

In the admission of nutrient from the great geological cycle into the small biological cycle and the reverse process does not possess the character of a closed cycle. The decomposition of plant and animal organisms after death does not also proceed completely to final product of mineralization, but it is accompanied by the new formation of organic substance. In many cases of complex nature, it possesses a greater resistance to decomposition than the original organic substance. The reverse of organic carbon is these formations, including also the organic substances of living organisms and their dead residues.

However, the principal source of the carbon dioxide required by plants during photosynthesis is the atmosphere, where the water content is approximately 0.03 percent or about 0.57mg per 1 of air and its reserve, about 2.1 billion tons. When one considers that land plants of the earth is fix annually, during photosynthesis about 20,000 million tons of carbon or approximately 80,000 million tons of water which then lead to the total carbon dioxide content of the atmosphere which would be sufficient to last only for a few decades.

But it is a well known fact that the water of the air is continually being replenished from other reserves including the hydrosphere, the surface of which it mingles freely with the atmosphere. In the air and in the waters of the earth, the total amount of carbon dioxide which are available to land plant exceed 10 tons, which is sufficient to satisfy the carbon dioxide requirements of plants for thousands of years. The most important source of replenishment of the carbon dioxide of the atmosphere is the soil. During the cause of the day, particularly during the hours of intensive photosynthesis, there may occur a time when the carbon dioxide concentration in the air layers surrounding the plant is lower than normal and this will result in a decrease in the intensity of photosynthesis.

No comments:

Post a Comment

Understanding Soil Fertility and Why It's Important

Soil isn't dirt, it's a living, breathing ecosystem that sustains life on the planet. Among the many attributes of soil, fertility i...