If forest fires are good for forests,...could farmers use ash to enrich their soil?

Question

What happens in the soil that results in such a burst of plant growth afterwards?...like after a forest fire.

Could Farmers use ash for a natural fertilizer, to help grow crops?

Answer 1

From the very beginning the purpose of slash and burn agriculture was to fertilize the soil with the ash as well as clear the land and control weeds. After one or two years they would have to leave the area when the fertility dropped and slash and burn a new area. Of the three major nutrients, potassium is also called potash because the major source was from from ashes of hard wood fires. So, as you can see, ashes are a good source of plant nutrients. If you use ashes on your garden or flower beds it is a good idea to put them into your compost pile and add them diluted in the compost because ashes can be a very "hot" fertilizer and burn your plants. Also they can make the soil acid if applied in large amounts.

Answer 2

Slash-and-burn used to be a sustainable system - still is in very sparsely populated areas - when populations were still very low in many rural areas. These days, there is not enough land for the "rest" that the soil needs - to regenerate. Remember, soil formation is a process that takes many, many years, but we can destroy soil in a short span of time, even by the malpractices in agriculture. Fires simply makes room for the underbrush to burst through when the canopy is cleared, and probably break the dormancy of some seed that have lain in the forest litter for a long time. This is the reason why managed forests are logged or even "burned" periodically, to make way for new growth. But this is - and must be - very controlled and purposive.

As to the value of ash, it is yes, mostly carbon, and is used as a soil conditioner. It can be useful to raise the pH of really acidic soils, if your crop requires it. I have also seen farmers use ash to keep away ants in a seedbed.

Answer 3

Forest fires are not necessarily good for a forest, but they are a natural part. In some cases though, they are essential. For example, some pine cones (known as seratonous cones) won't open and release seeds unless there is a fire to melt the resin.

Ash is not a good fertilizer. It can be a good soil amendment though. Ash is very acidic. If farmers dumped ash on their fields, the ground would be too acidic to grow many crops. But if the soil is already very basic, ash could help.

Around the world people slash and burn forests to plant crops. What you must realize is they have to keep moving because the soil is only good for one or two crops after that. In rain forests, trees uptake nutrients from the soil as fast as the leaves decompose. In most cases, you only have a couple inches of topsoil. Contrast that to the US Midwest, where there are 10 to 20 feet of top soil.

Answer 4

When a forest fire occurs, the nutrients that are locked up in the organic matter on the ground (limbs, leaves, etc.) are released into the soil. This allows for a rich environment for the next generation of trees and flowers.

The problem is that most agricultural fields are farmed every year and do not have that buildup of organic matter to burn. In fact modern agriculture is more comparable to strip mining the soil. In order to replenish the soil nutrients have to be brought in (fertilizer, manure) as opposed to released by fire. The organic matter that is in the soil is important to water holding capacity, preventing compaction, and reducing soil erosion. So burning off that OM would cause even more problems.

So no, farmers can not use fire to enrich soils.

Sugar cane fields are burnt to remove the leaves and prepare the cane for harvest. There is little advantage to the soil to do this.

Answer 5

You are correct forest fires and crop burning is good for the land. It gets rid of bugs and makes the land "virgin" again much better then any chemical will ever do.
We live in the land of volcanic ash. Our soil is rich in many nutrients that makes this part of Oregon one of the best for growing.
Have you seen what Mount Saint Helen's now looks like?

Many of the bagged soil you buy at the store comes from such places as you describe. VERY good for growing ! Farmers by such stuff, but in bigger quantities, even liquefied.

Without forest fires (hopefully controlled) we would not have healthy tree's nor many species of underbrush we see. Volcanos are not great, but just look at the land where valcanos are. Hawaii is known to have the best soil around!

Answer 6

Most definitely. I know that the sugar cane fields in Hawaii are burned off every year, in order to make room for new plants, and to enrich the soil.

However, the value of this is going to depend on what you want to grow. Different plants do better with different types of soil - some like acidity, some don't, etc. So the ash may help some plants, but might also hurt others.

Answer 7

As a child, our house was heated with a wood stove. All winter we would dump the ashes in a pile in the garden, then come spring we would work them into the soil.

wood ashes make an excellent fertilizer. So the short answer to your question is Yes

Answer 8

Fires are good for forest and praires only in that;

Pine cones open and release their seeds better if heat treated.
Eradicates dead material.
Sometimes the living survives.

Ash contains mostly carbon, possibly just a soil ammendment.
But also minerals which new seedling can use.
e.g. they slash and burn in the amazon and elsewhere.
Quicker than plowing and composting.
but top soil is thin and only good for a couple years.

The new plants grow better becuase of the nutrients and there is nothing else around competeing for nutrients, space, sun etc.
Grasses then bush type plants will usually grow first because they grow faster and more seed yield per acre than big trees.
Trees will eventually grow through and outcompete smaller plants.
Compost would be better because it also contains organic nutrients and N-compounds.
Soils, fertilizers, and plants need a good N:C ratio

Decomposition may destroy some harmful biological agents.
Thorough burning will more likely destroy all harmful insects, viruses, bacteria, fungus or chemicals (herbicides, organic toxins).

Answer 9

In old forests the ground is littered with plant debris. On decomposition, the pH tends towards acidic. The ash helps to neutralize the soil. The potassium fertilizes.

Ash is rather harsh. Generally, it is not good to use it alone.

Answer 10

My Grandfather smoked a pipe. He grew his own tobacco. He would pile brush then burn it then plant his tobacco seeds directly in the soil under the burned ash. He had the best crop of tobacco in his area of that time. The bad part was, he died of cancer at the ripe young age of 52. My answer is, you bet!