Cellular respiration is the process of breaking down food molecules to obtain energy and store it in the form of adenosine triphosphate (ATP) molecules.
Plant cells, after creating sugar molecules through photosynthesis, undergo cellular respiration to create ATP molecules.
Only plants can photosynthesize, but both plants and animals depend on respiration to release the chemical potential energy originally captured through photosynthesis.
The figure illustrates how closely photosynthesis and respiration are linked. As you can see, thanks to these two life-sustaining processes, plants and animals depend on each other to survive.
Organic Matter Stability
Stability is the measure of how rapidly carbon is altered in OM. Some organic matter is extremely stable. Diamonds and graphite are pure carbon, but a diamond will not change its composition for thousands of years. There are three basic facets of OM stability. If mixed with the soil, will OM take nutrients away from plants? If stacked, will OM heat up? If left on the soil surface, will OM create odors, draw flies, or invite larger animals to feed?
We have already shown how C:N ratio is used to predict immobilization in soil. A direct method to predict autoheating ability of solid manure or compost is to place a sufficient quantity of material into an insulated container, add water to bring moisture content to approximately 50 percent, and measure temperature rise in the container after one day. A step by step procedure to use this method is given in OSU Factsheet, BAE-1761, The Icebox Test: an Easy Method to Determine Autoheating Potential of Compost and Byproduct Materials.
Putrescibility is a measure of a waste’s ability to release noxious odors and attract flies. The general definition of a non-putrescible waste is that it cannot undergo “significant biological transformation.” Decomposing animal bodies undergo a huge transformation from muscle protein to soil organic matter. Composted manure is non-prutescible because it lies at a much lower energy state. First, the animal removed energy from the feed before it was excreted. Then, microorganisms removed more energy from the manure during composting. We generally rely on other indirect measures, such as the ability of the material to autoheat to determine the putrescibility of wastes. It is difficult to predict the autoheating potential of OM — especially with liquids. Therefore, the energy level of OM, as measured as resipiraiton rate, is usually used to indirectly measure putrescibility.
The Solvita™ compost stability test is a commercial product that uses respiration and ammonia volatilization rates to estimate stability. The mass of CO2 and NH3 released by a compost sample in an airtight container is measured using standard color changing panels. Organic matter stability is determined by consulting standard charts (Figure 4).
As a result, they carry out photosynthesis to release oxygen, then absorb the oxygen to carry out respiration and release carbon dioxide, then absorb this carbon dioxide and carry out photosynthesis and so on, in a never ending energy production cycle.