Compost question.

Can someone tell me why leafmould is so less nutritional to the soil than homemade garden compost.
It is said that leafmould is a good soil conditioner,which I agree(lovely stuff)but it is good organic matter as is garden compost so why the big difference?

 

hi rod- I found some information which may be useful (compagniadelgiardinaggio.it)

In the same way as plants, also micro-organisms need a balanced supply of nutrients.

In a good compost heap the ratio between the carbon (C) and nitrogen (N) must be a number between 20 and 30.
A good C / N ratio is obtained by mixing nitrogen-rich compounds with other carbon-rich.

The compost heap does all the work for you!
If there is too much carbon (hence the C / N ratio is greater than 30), the process of composting will be slowed down until the excess carbon will disappear.

In this case one can intervene adding elements nitrogen-rich (very easy to find) or urea.

If the C / N ratio is low, that is, there is too much nitrogen, the excess is converted into ammonia (which is a gas smelling of urine), so you will loose fertilizing power, and produce produce bad smell.

Another issue is the humidity. The right moisture level is that of a sponge soaked and squeezed. If you squeeze a handful of compost, it should not be dripping water nor be dry and in pieces.

Also in this case it is possible to mix elements rich in water with dry elements to obtain the right moisture point.

Here is a table with the C / N ratio and the degree of humidity of certain waste:
Material---- -------Humidity---- C / N ratio
Kitchen waste---- High--------- 12-20
Clippings---------- High--------- 12-15
Animal manure----Medium------ 15
Offal--------------- High--------- 15-18
manure--------------------------- 20
tea and coffee remains----- Good------ 25-30
dry leaves------------------- poor------- 25-60
Conifer needles------------- Poor --------30
Straw------------------------ Poor------- 50-100
pruning residues------------ poor------- 100-150
Paper and cardboard (uncoated)------ Very poor -----200-500
Wood (chips and sawdust)------------ poor----------- 100-500

It is not necessary to make complicated calculations to get a good compost, just alternate dry elements (they are carbon-rich)
to wet elements (richer in nitrogen)...

as you become experienced you wll be able to judge what needs adding: carbon or nitrogen, moisture, or dry material.

Moisture and oxygen are indispensible for microorganism to work, this is why one has to keep the whole compost areated by turning it from time to time and wet it if necessary.

 

If I remember back to my school days (a long time ago), it goes something like this.

Leaf mold turns into humous. Basically fibre. The nutrients are there but are not released freely because of lignin I think. Its main purpose is to provide structure for the soil, to keep gases (including air) flowing about, and therefore keep the soil healthy. Over a long time, much longer than is the case with decomposition of softer materials, fungi will work on the humous and eventually overcome the lignin, and release the nutrients in the humous, but in nature, by that time that happens, that layer will be several inches down and lots of new layers will have been added on top because of successive autumns, with each layer providing its own ecosystem (this autumn's layer being used by all sorts of beetles for example to hibernate under, last autumn's one being munched on by worms etc).

 

I think the primary benefit I get from leaf mould is from the mycorrhizal fungi that take up residence and then, hopefully, get incorporated in the soil where I spread it. That and the fibre in the rotted leaves.

I would expect Compost to have far more nutrients - it includes plant matter that was growing vigorously when composted, and things like Nettles and Comfrey that are very efficient at hauling up nutrients from deep in the soil into their leaves.

Whereas leaves are "dead" - the plant they were on will have done its best to extract any goodness from them into its over-Winter storage so as not to waste the energy that went into producing them in the first place. So I would expect that there is less nutrient value in leaf mould [than compost]

 

Now that does make sense.