AGROECOLOGY
- COMPOSTING
Making
your own compost is one of the best ways to reduce the volume of organic waste,
while preparing an excellent fertilizer for your crop or your garden.
In
woody crops it is normal, but not generalized, to grind the wood from pruning,
to leave it on the spot, restoring to the soil the majority of mineral elements
extracted by plants. This practice of grinding, with or without burial, is also
practiced in many annual crops.
But
some situations may require that this grinding is not carried out. This is the
case of certain diseases, or the requirements of certain types of mechanization
(such as the harvesting of almonds). There are also farmers who simply don't
want to do it or are not equipped with grinders.
In
these situations, the most common practice is to get the wood out of the plot
using a large rake harnessed to a tractor, and burn it.
It
is an economical and rapid technique, but burning is an agronomic, energy,
nutritional, environmental and even economic contradiction, at least in areas
with temperate climates. Indeed, the benefits of the contributions of organic
matter are numerous (see http://culturagriculture.blogspot.com.es/2015/10/54-organic-matter-in-soil.html).
To systematically burn this source of restitution accelerates the
impoverishment of the agricultural soil and forces the farmer to purchase
considerably superior quantities of fertilizers to what he would need by
restoring this organic matter.
In
situations where local grinding of plant remains is not done, the best solution
is composting. These remains are collected on an open area, coarsely grinded,
organized in piles, wetted and stirred periodically.
The
process is simple, economical, but requires some organization and rigor. Composting
in pile will go through a thermophilic phase, during which the core temperature
can reach 70ºC for a few days, producing a sterilizing effect by eliminating
almost all fungi, bacteria and insects. Even coming from diseased plants,
composted vegetal remains are transformed into a healthy and economical source
of organic matter, and thus an organic fertilizer for crops.
In
some areas, there are groups or companies specialized in the collection of
strictly plant remnants (especially of urban origin), to transport them to
farms where farmers become owners of them and process them by composting for
their own use. Waste collectors see volumes to be treated reduced, farmers
obtain an amount of plant remains that they are unable to produce on their farms,
and they make their own organic fertilizer.
I
have a friend and former colleague adviser who specialized in this activity, in
Provence, by creating the company Terre et Compost. Hi Eric!
If
the composting has a good quality and the plant remains too, the compost
obtained can even obtain the organic label (but it depends mainly on the
national legislation).
Composting
is a very old technique, simple, economic and ecological to dispose of high
quality organic matter on the farm.
I
found an interesting article on this subject on a French-speaking Facebook page
(from Quebec, therefore from the French-speaking part of Canada), highly
recommended to all those interested in soils, Sols Vivants Québec (https://www.facebook.com/groups/1643973612487835/?ref=group_header).
You will find a lot of information, with a dose of science, a dose of lived
experiences and a good dose of ideology and militancy. Everyone will be able to
find their account. I don't always agree with the ideas, but it does not
detract from the interest of most publications.
The
following text was published on Agronouvelles.com, the blog of the Agronomists
Board of Québec http://www.agronouvelles.com/2017/06/le-compostage-domestique-passion-volonte-and-knowledge-techniques-requises/
"Domestic
composting: passion, will and technical knowledge required.
Composting is a fascinating field
that is practiced at large, medium and small scale and is aimed at
industrialists, agricultural producers and amateur gardeners alike. In short,
to all those interested in the environment, agriculture or horticulture.
While urban agriculture is
attracting an increasing attention, domestic composting is still part of the
tools that are available to the urban horticulturist as a mode of production of
living matter (the compost) and more recently, from an environmental
perspective, as a mode of ecological management for certain residues generated
at home.
In so doing, the transport of these
organic materials and all the disadvantages and the impacts that it entails are
thus minimized. Using compost at home, organic matter and nutrients essential
for plant growth are returned to the soil. In spite of these noble objectives,
it takes horticultural passion, environmental convictions, a bit of will, and a
minimum of time and technical knowledge to make domestic composting a perennial
adventure.
What is
composting?
It is often argued that composting
is a natural process. Despite the similarities we see between composting in
pile and decomposition processes observed in nature, we must note that the
stacking over several feet of organic matter of various origins that is placed
on a limited surface or in a closed place does not occur in nature.
Composting should therefore be seen
as a process that is controlled and is different from a pile in the field or
from a stack of organic residues that we let be decomposed and which, over the
course of months and years, ends being transformed into a material that seems
to be black earth.
In specialized literature such as
standards and guides, composting is synonymous with "a directed process of
bio-oxidation of a solid organic substrate including a thermophilic
phase". This definition implies maintaining aerobic conditions within the
mass and achieving thermophilic temperatures (corresponding to Tº> 45ºC)
throughout the mass. This notion of reaching high temperatures is important, in
particular for large-scale composting, because it makes possible to obtain a
hygienisation effect. Thanks to the high temperatures, the composting process
reduces the level of pathogenic micro-organisms and the destruction of weed
seeds, reducing the risk of contamination and spread. The term
"compost" should logically be understood as the product obtained from
composting, i.e. a stabilized, hygienized and deodorized material that is beneficial
to plant growth.
Should it be deduced that compost
from domestic composting without temperature rise is not of quality? Absolutely
not! By following the rules of the art, it is possible to produce a compost of
good quality; It is necessary, like in the case of production of wines or beers
at home, to take the trouble to learn, because there is a limit to be able to
reconcile ease and quality when processes involved are complex.
Small scale
composting
Composting at different scales and
the use of composts have been the subject of numerous books and publications.
Here in Quebec, the recent book entitled "Le compost: Pourquoi?
Comment?" (Compost: Why? How?) of the agronomist Lili Michaud addresses
the subject in a clear and detailed way and provides a wealth of useful, if not
essential, information for those interested in domestic composting. It is
unnecessary, therefore, to repeat here information already amply dealt with.
Regardless of the scale at which
composting is practiced, the processes that involve the work of micro-organisms
are the same and the purpose of the composter is to satisfy the requirements of
the micro-organisms so that the work is adequately carried out. If
micro-organisms don't care about the size of operations, they need a good
environment (moisture, oxygen) and food (carbon, nitrogen) to do their jobs and
survive in the microbial jungle.
The choice of quality residues is
crucial and this is especially true in the absence of high temperatures. This
mode of "cold" transformation requires a minimum of vigilance. For
example, materials that may contain pathogens (animal feces, diseased plants)
and plants considered to be weeds (rhizomes or seeds) should be avoided.
Furthermore, for reasons of
quality, materials that may contain metals or non-biologically degradable
compounds (e.g. pesticide residues, treated wood ash, plastics) or materials
that generate unpleasant odors (for you and for your neighbors) such as fish,
meat and crustaceans are also to be avoided for small-scale operations.
Finally, some materials can be composted, but in small quantities (eggshells,
moist fresh grass, ash).
Compost is primarily an organic
soil amendment and is advantageously used primarily as a source of organic
matter which, by decomposing in the soil, will provide the nutrients essential
for plant growth. The quality of composts is a complex field, both in the
multitude of parameters to be taken into consideration and in the complexity of
the processes involved, from the compost to its use.
A greying teacher once said to a
young agronomist: "Know that it takes more than a thermometer to do
composting." It's my turn to say, "It takes more than a pH meter to
assess the quality of the compost."
Organic matter content, humus,
water retention capacity, C/N ratio, nitrogen, phosphorus, potassium,
oligoelements, pH, maturity and pathogens are just a few examples of the
terminology associated with the concept of quality of composts.
These parameters are important for
those whose job is to ensure good plant growth while preserving the quality of
the soil and the environment. Welcome to
the agronomists beds!
Agronomist since 1982, Denis Potvin
[author of
the article] is specialized in the
management of biomass and fertilizer residual materials of various origins,
notably by composting. He joined the Institute for Research and Development in
Agri-Environment (IRDA) in 2012 as project manager for biomass recovery. Denis
Potvin now works as a technology transfer agent while continuing to be involved
in projects that bring his expertise to bear."
If you want
to make your own compost, learn more about the process. It's simple, but there
are a few rules to follow.
You will
find many useful links, for example by typing on your search engine "make
your own compost".
At work!
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