Composting for Small-scale Farmers – by Darryl & Hazel Edwards.
Compost is an exceptional alternative to fertiliser which builds up not only the organic nutrient levels
in the soil but helps to restore the natural biotic balances which occur in the soil profile.
2Corinthians 9:8 And God is able to make all grace abound to you, that always having all sufficiency
in everything, you may an abundance for every good deed.
God’s Word is true, He has made a way even for the poorest of the poor to make the best quality soil
supplement by making & utilising compost as a superior substitute for fertiliser. This makes possible
the fulfilment of the Principle of “sowing bountifully & with joy” for the poor who can’t afford
fertiliser. By putting back into the soil good quality compost they can reap the same if not better yields
in the long term as compared to fertiliser usage with the application of knowledge & faithfulness.
What is compost?
It is the Aerobic decomposition by BACTERIA and FUNGI of a mix of organic material.
1) Thermal compost
2) Worm or Vermi-compost (cold composting)
3) Static compost
All three of these methods are suitable for the small-scale farmer. There are pros and cons for all:
Thermal composting is the most reliable to guarantee a product that is weed and pathogen free, it also
is very fast (7 to 8 weeks).
Worm composting provides excellent product (worm casts, which are higher in plant available
nutrients), but requires large numbers of worms and does not eliminate weed seeds.
Static compost is the easiest but most unreliable due to the uncontrolled environment leaving risk of
pathogens, seed and it is very slow. (Can take up to a year).
Thus thermal compost is the most suitable method, but it requires diligence and training to achieve the
The minimum size of a thermal compost heap is about 1.5 m cubed. Thus I have developed a 2x2x2m
pile, which will ensure the required volume for the required temperatures that must be attained. It is
also small enough for a single person to work in a few hours. In a small-scale or garden situation it is
also not too difficult to accumulate or gather enough raw material to build a heap of this size. This
volume of compost, if made correctly and the right quality attained should easily be able to sustain a
hectare of maize.
-High Nitrogen (legumes, manures)
-Green (anything cut green, even if it has dried. Diversity is good)
-Woody/Dry. (At least 5% should be greater than 3cm in size includes cobs & maize stalks).
For a bacterial dominant compost (preferred by most annuals such as vegetables)
25% High N
For a fungal dominated compost (preferred by most perennials and maize)
25% High N
a. Building the pile.
It may take an extended period for enough material to be gathered to build a pile of the desired
size. This is not a problem. The materials should be piled separately until such time as enough of
each material has been accumulated.
When the pile is to be constructed it is important that the right ratios are attained. The most simple
way to achieve this is to divide the height of the pile into 10 x 20cm layers. Then alternate the
materials in the desired proportions (30% equates to 3 separate layers). An example follows:
Woody (10 cm)
High N (10 cm)
Woody (20 cm)
High N (20 cm)
Green (20 cm)
Woody (20 cm)
High N (20 cm)
Green (20 cm)
Woody (20 cm)
b. Activating the Pile.
Once the pile has been built it needs to be mixed. The best way to do this is to begin slicing away
at the heap. Mix the different materials thoroughly and wet them at the same time. Now begin to
rebuild the 2x2x2 pile next to the original (layered) pile. The objective of this initial turning
process is to thoroughly mix the entire pile and to wet it to at least 50% moisture. If some of the
mixed, wet material is squeezed in the hand and moisture drips out, it is too wet. If when squeezed
and no water drips out, but on opening your hand the material does not hold its shape then it is too
dry. Thus if squeezed, no extra moisture drips out and on opening the hand the material holds its
form then it is close to the desired 50% moisture content.
The composting process has now begun.
c. Temperatures and turning.
The compost will begin to get hot very quickly. Under ideal conditions the temperature can reach
70°C within 48 hours. This is undesirable. If the temperature in the pile reaches 70°C it becomes
too hot for the microbes, which are creating the heat, to exist. Carbon also begins to be burnt and
this is wasteful. This heat is created by the reproduction of thermophilic bacteria and will only
occur if there is adequate water and oxygen.
Heat is however essential to kill all seeds in the compost and all undesirable pathogens. This is
achieved in the temperature range from 55°C to 68°C. The temperature needs to be maintained in
this range for at least 3 days. All parts of the pile need to be exposed to this heat. This heat
however only exists on the inside of the pile (the outer 40cm is much cooler). This is one of the
reasons why turning is important. Each time you turn the pile you should attempt to move material
from the outside to the inside, and visa verse.
If the temperature of the pile is too high (ie. Approaching 70°C) then the only way to reduce it is to
turn the pile. When turning the pile gauge whether the moisture content is still adequate. A lot of
moisture is lost as steam and this needs to be replaced. The adding of water can also cause
The simplest way to determine what the temperature within the pile is, is by using a temperature
probe. For rural folk this would be difficult to obtain or purchase, thus some simple method of
ascertaining the approximate temperature by touch needs to be devised.
The turning process has thus achieved three things:
1. Exposed new material to the required heat,
2. Aerated the pile with oxygen, essential for the heat process and
3. Allowed for the lost moisture to be replaced.
At this point it is important to note that if the pile is not turned it will become anaerobic. This
means that it will run out of oxygen. If this happens the desirable bacteria will die off or go
dormant and undesirable anaerobic bacteria will become dominant. If this happens the
temperature will drop and often a bad smell will be noticed.
Compost Temperature Cycle.
The temperature cycle of the compost heap will follow a similar trend to that displayed in the graph
below. The temperature will continue to rise until the pile is turned, when it temporarily drops. It then
slowly begins to rise again. This will continue until all the nitrogen in the pile has been utilized. If
your compost does not get hot it generally indicates that there is not enough nitrogen present. Be
careful not to add too much Nitrogen, this will prevent the compost from maturing within the 7 to 8
week period as desired. The temperature can continue rising for many more weeks depending on how
much nitrogen there is. In this situation it also means that after the 7-8 week period, when the compost
should have matured, you would have to continue tending it. The temperature would need to be
continually checked and the pile turned when the temperature reached close to 70°C. If however the
correct ratios are achieved at the start of the process and the compost begins to cool after 5-6 weeks
then the conditions are ideal. After the compost has matured it can then be stored in situ for long
periods without further turning. The mature compost will also not degrade nor will nutrients leach out
of it. It will be in the form of a stable organic fertilizer and inoculum.
Indicators of good compost.
•Smell If it smells bad, it is bad! This is due to the presence of alcohols, Acetic acid, butyric
acid, valeric acid and putrescine. All of which are produced in anaerobic conditions.
•Color NOT BLACK
Deep, rich brown indicates humics
Tan, honey color means fulvics
•Texture Crumbs, air passages, aggregates visible
•Fungal Strands Visible thick threads, in compost, not aerial, not fuzz
Utilising the compost
The compost can be used by placing 90-100ml per planting station. This allows for holes to be dug at
around 8cm as compared to the 15cm depth when using manure due to the fact that the seed can be
placed on the compost without the necessity of a layer of soil separating seed from fertilizer & manure
as is usually the case. Both points taken into account the time saving in digging shallower planting
stations & not having to cover the inputs are considerable over an expansive area.
Hi Farming God’s Way Trainers- Fertilizers
I have had many questions asked about fertilizer names, compositions & uses, so have
compiled a very basic outline for your information so you don’t look or feel stupid in front of
your class of 500 people. ☺
Fertiliser is made up of 3 main components.
N is Nitrogen
P is Phosphorus
K is Potassium
They also throw in some micronutrients such as Molybdenum (Mo) & cobalt (Co) if the soils &
crop type so require.
Fertiliser types include:
1) Basal fertilizers – these are placed in the soils first depth or A horizon.
They usually contain high P or Phosphates. Phosphates move very slowly in the soil profile &
as a result cannot really be “leached” thru the soil profile as they bind to soil particles. High
acidity ie low ph soils fix nutrients like phosphates in a form that is not readily able to be taken
up by plants. Hence the application of lime to up the ph for easier release of nutrients.
Commercial names include: Superphosphates, 23:21 & also DAP (DiAmmonium phosphate –
2NH4Po4 which is high in both N & P)
Basal fertilizers often also contain what is usually a balanced ration of nutrients in the form
such as 2:3:2 (NPK) (30%) ie 30% of the fertiliser is in the form of Nitrogen 2/(2+3+2) or
2/7*30/100 ie (8.5% N) : (13%P) : (8.5%K). ie of 50Kg 8.5% is pure Nitrogen & so on.
Commercial names include: 2:3:2 & various other mixtures usually soil & country specific.
2) Top dressings
These are usually a high Nitrogen content application in the form of ammonium, Nitrites
(NO2) & Nitrates (NO3).
They move rapidly thru the soil profile & are easily leached out of the soil after heavy rains.
Commercial names include:
a) AN – Ammonium Nitrate NH4NO3 – other common names for the same include LAN (RSA
call it Limestone ammonium nitrate), CAN (Calcium Ammonium Nitrate) or KAN (Kalsium
ammonium nitrate) but it is the same thing – the Limeston (high calcium content) or Calcium
only serves as a temporary carrier for the Ammonium Nitrates or N portion. AN has 28% N &
is very potent hence the 10cm or handwidth away from seedlings application. AN is better
than Urea in that it contains N in a form more readily taken up by plants & “volatilizes”
(releases N to atmosphere) less due to it’s make up & it’s bond with the Calcium. It is
however much more expensive than Urea.
b) Urea (NH2)2CO is much higher in N at 46% but it is also much more problematic if
it is applied too close to plants, it moves & is leached more readily from the soil in
heavy rains, & is volatilises very easily & therefore should almost without exception
be buried unless almost guaranteed wetting occurs through irrigation or rainfall. It is
however very cheap in comparison to AN
God bless you all for considering the poor & gaining knowledge of a field outside of your own.
I trust this is useful for your training or answering of questions.
Yours in His service
Farming God’s Way