Compost always has a neutral pH thereby stabilising soil pH in contrast to a number of inorganic fertilziers that acidify soil.
Compost has a negative electric charge. This is an important quality as it enables soil to mobilize the postitively charged nutrients and to exchange them with the crop. This is called Cation-Exchange-Capacity. Soils devoid of this may be rich in nutrients but will still be unable to provide them to the crop.
Compost also improves soil structure, water holding capacity and aeration of the soil. This supports crops by providing sufficient water to crops and at the same time avoiding root rot. Soil rich in compost will be crumbly and easy to till while at the same time protected from erosion.
Compost is rich in beneficial microorganisms. They play an important role in crop health and nutrient uptake.
Sufficient amounts of high quality compost together with regular homemade liquid fertilizer applications will supply your soil with adequate amounts of all necessary nutrients to grow a plentyful, strong and healthy crop.
How does compost happen?
Think of these microorganisms as your "Soil-Cattle". They need feed, drinking water, air to breath and shelter to protect them from heavy rain or burning sun. If you remember this you know almost everything there is to know about compost making. Just as your cattle produces manure in its shed, your microorganisms will produce organic fertilizer in the compost heap.
If you take good care of them they will take good care of you by providing you with just what you need to grow your crops.
What do microorganisms feed on?
Microorganisms can only digest Nitrogen-rich materials though, if they have acess to Carbon-rich materials at the same time.
Carbon-rich material is organic matter that is dried up, yellow or brown material like dry leaves, straw, harvest residues, maize stover, etc.
In our compost we need to provide the microorganisms with a balanced mix of both Nitrogen-rich, green materials and Carbon-rich, brown materials.
All plants contain different amounts and combinations of nutrients and micronutrients. To get a good amount and variety of all nutrients into our compost it is important to use a good variety of different organic matter sources (e.g. weeds) in our compost.
What do you need to make compost?
Besides that choose a location that is protected, e.g. under a tree. This is important to shelter your compost (and the microorganisms) from heavy rain and sun.
The spot you choose should also enable to you to make a number of compost heaps next to each other, either in a row or in a circle. The compost will be ready for harvest within 3 months. Therefore you need enough space to make a number of compost heaps over a period of 3 months. After that you can remove the first compost heap and make the new heap in the same space. So if you make 1 compost per week, you need 12 square meters for the heaps and a bit of space for you to move around. Making composts next to each other in a succession will allow microorganisms to move quickly from one heap to the other according to the development stage the heap is in as different microorganisms are needed at different stages.
This brings me to the next point - make your compost on soil. Do not make your compost on concrete or a polythene sheet as the microorganisms need to be able to move in and out of the heap freely. That does not mean that you have to clear the ground or even dig a whole. Microorganisms are so small that they cannot be seen with the naked eye. They can easily move past roots and grass, no need to remove them first.
Constructing a compost in a whole might even be harmful as it would obstruct air movement within the heap. We have to ensure good air movement as our microorganisms need oxygen.
During heavy rains water would collect in a whole and the bottom part of the compost would drown. Microorganisms need water, but they don't like to go swimming :-)
The bottom layer of rough branches will assist in air circulation. Air can easily move in through the rough branches at the bottom of the heap.
Making best use of fresh manure
Building the compost heap
It does not matter how thick these layers are exactly or if you mix up all materials and decide not to layer at all. Just remember that microorganisms are tiny and need both kinds of materials together, so don't make the layers too thick. About the height of a hand is a good guideline.
Layering just helps to assess if the blanace between Nitrogen-rich and Carbon-rich materials is about right. If you add too little Nitrogen-rich materials the decomposition process will not get started.
Enriching the compost
Don't use too much ash as it would dry out the microorganisms.
Other things that MUST NOT be added to a compost are inorganic (artificial) fertilizers. They are salts and salts kill microorganisms. Fats and oil also kills microorganisms and should not be added to the compost. Also ensure that no manmade materials end up in your compost. Batteries, plastic and metal rubbish can be toxic and poison your compost. You also don't want to cut yourself on pieces of glass or wire in your compost.
Lime does not need to be added to a compost. Compost naturally has a neutral pH. Lime is needed in your soil to neutralize Hydrogen cations in the soil, not in the compost. So always incorporate lime directly into the soil in your field.
These steps: Nitrogen-rich layer of fresh, green weeds and fresh dung or chicken manure, Carbon-rich layer of dry matter and harvest residues, enrichments like ash, a thin layer of soil and water we call 1 layer in a compost. You can either build 1 such layer per day every time you clean out your cowshed for example, continously adding more layers daily, or you keep layering in one go until your compost heap reaches up to about your hip. It could be higher of course but I find it gets hard to work any higher than that. And I like to keep my compost making easy and enjoyable. If you want to develop a good habit of routinely making compost e.g. on a weekly basis, you should always try to keep it simple and easy. If it becomes complicated or hard work you are less likely to actually do it.
The final touches
To protect your compost heap properly from drying out too fast and also fom heavy rain or sun, it should be covered with some blanket material. This can be long grass, banana leaves, even palm leaves or keiapple hedge branches, which will also keep out curious chickens.
Do not cover the compost with a polythene sheet. Remember, it needs air circulation, which would be stopped by a polythene sheet.
What you should do though is checking if decomposition processes are well under way in your compost heap. The first phase is dominated by microorganisms that will heat up your compost heap to around 60*C. By day 3 you should be able to see steam coming out of the "chimney" if you check early in the moning. If you place your hand inside the chimney you will feel the heat coming out. You could also stick your machete (panga) into the heap and leave it there for a few seconds. When you pull it out the blade will be hot. These are all good signs that tell you that everything is going well in your compost heap. Around day 10 the second phase starts and the heap cools down. Different microorganisms now take over the task.
If your compost heap does not go through this heating up and cooling down cycle you have done something wrong and need to take it apart and start over. The most common mistakes if it does not heat up are: use of too little Nitrogen-rich material or too little water. Add both and try again. If on the other hand it takes a long time to cool down you might have added too much Nitrogen (which is not a problem but a waste of Nitrogen-rich material) or too much water and fungus might have taken over your compost heap. In that case open the compost heap. A tale-tell sign for fungus activity are white streaks growing through the compost. Add some more Carbon-rich materials, try not to compact the materials too much and start over.
Parts of the composted materials will not be decomposed completely. They were either too large or too dry or solid Carbon. They will take a little longer to decompose fully. They need to be seperated from the finished compost. That is best done by throwing the compost through a large sieve. To construct such a sieve we have build a large wooden frame and covered it with chicken wire. If you lean it against a tree or a stick at an angle you can easily throw the compost against it. The finished compost falls through the wire piling up as a neat heap of beautiful compost, and the bigger, not decomposed parts will remain in front of the sieve. These parts can be used instead of topsoil in the next compost heap and will just continue to decompose until they have also turned into beautiful compost.
You can also use it in your field immediately. You can apply it broadcast and incorporate it into your soil during land preparation. You can also fill it into your planting rows or holes. It does not burn seeds or plants. You can also use it any time as a mulch/ topdressing between the rows in a standing crop. It is a safe product. No protection is needed during handling.
A word about weeds...
Of course we don't want to spread weeds through our compost. Therefore weeds should always be weeded before they go into seed stage. If you wait until it has gone into seed a lot of the nutrients that were originally stored in its leaves will actually have moved into the seed and the value of the leaves for compost making will be minimal. Secondly, when you do your weeding at seed stage a lot of the seeds will fall to the ground and multiply. By weeding at an early stage you will subsequently reduce the need for weeding in the following years.
However, even if seeds enter the compost heap, that is not a problem. As the compost heap heats up to around 60*C for several days, this will kill most seeds. Cells of most organisms burst at temperatures over 42*C and will thus be destroyed. This is also true for a good number of crop diseases. They will not be spread through compost. It is as if the composed material has been sterilized. Some notorious diseases like bacterial wilt though do not get destroyed by heat. Tomatoes, capsicums and potatoes affected by bacterial wilt MUST NOT be composted.