No, it slows it down.
You could say that, if you consider eating dead animals to be speeding up decomposition.
lava
light will produces heat which will speed up the rate of decomposition.
Warmth usually speeds decomposition. Also burying what you want decomposed will expose it to more bacteria and insect activity which will also speed it along.
No. It is neither a bacteria nor a fungi.
Exposing it to heat and UV light.
A dehydrated salt can be rehydrated.
For example, by increasing the temperature, by grinding the material, treating with chemicals.
how might a modern farming speeding up the decomposition of matter in soil affect the nitrogen cycle
Salt is highly corrosive and will speed up the rust process.
Warm the water
Sugar will speed up the decomposition process because sugar does not melt, it will decompose. Decomposing sugar produces oxygen and water that certain bacteria and microbes love and then they are attracted to the area causing more decomposition in that area.