Technology Keys
Introduction
Compost is decomposed organic matter that has been broken down by micro-organisms, especially bacteria and fungi. We refer to Farming God's Way compost as black gold and it is the best plant food on the planet. By putting back good quality compost into the soil, farmers can reap sustainable profitability for the long term. Compost builds up organic nutrient levels in the soil and helps restore natural biotic balances in the soil profile. We suggest a compost pile size of 2m x 2m x 2m. When complete this will drop down to about 3.5m3, which is enough for 1 acre or 1/2 ha of maize inputs. It is not recommended that you reduce the starting size of the pile to below 1.5m long x 1.5m wide x 2m high, to ensure you get the necessary heat and decomposition. Start collecting compost materials at crop canopy closure, or when there is plenty of green material around. Make as many compost piles as you need for your field size. For large commercial farms simply join compost pile together in long lines.
Ingredients
Compost is made up of four main ingredients - nitrogen, green, woody and dry components.
1) Nitrogen
• 10% of your pile - 15 x 50kg bags of fresh manure
• If there is no manure use 4m3 of legumes
• This component is the fuel of the compost pile and gets the bacteria going.
2) Green
• 45% of your pile – about 8m3
• Anything that is green when cut. Preferably use within 3-4 days.
3) Woody
• 22.5% of your pile – about 4m3
• Woody material encourages the fungal growth e.g. maize cobs, stalks, branches, cardboard and wood shavings.
4) Dry
• 22.5% of your pile – about 4m3
• Dry material adds bulk e.g. thatch grass, leaves and weeds
If making compost for vegetable plantings, please see the Vegetable Guide for guidelines on compost ingredient ratios.
Building the Pile
Collect the dry, woody and manure ingredients first and pile them separately before collecting the green materials.
• Maintaining correct ratios is very important
• Build the pile layer by layer with the 4 main components - start with 10cm of woody, then 10cm of dry, then place 20cm of green, then 2 bags of fresh manure on top of that. Apply 50-60 liters of water using buckets onto this completed layer. This makes up one complete layer
• Continue repeating complete layers and watering in until you get to the 2m height. There are usually 8-9 complete layers in a pile.
Turning the Pile
• 1st turn after 3 days or when the temperature reaches 68°C
• Mix the pile into the adjoining 2m*2m position using a pick, fork or a hoe, bringing the outside material into the inside and moving the inside material to the outside
• This turning process maintains the correct temperature, mixes ingredients, brings material on the outside to the inside so that it also gets exposure to high temperatures, aerates the pile with oxygen and allows for moisture levels to be checked and adjusted if necessary
• If the pile is not turned it will become anaerobic, have a bad smell and result in poor quality compost
• A simple guideline is to turn every 3 days for the first 3 turns and every 10 days for the next 2 or 3 turns. That is 5 or 6 turns
• After 2 months the turning process is complete
• Once complete, leave the compost to cure thoroughly for another 4 months
Temperature
• Ideal temperature range is between 55°C to 68°C
• Maintaining that temperature range will kill all seeds and unwanted pathogens
• You can use a temperature probe for accurate readings. A cheap alternative is to use an 8mm steel rod instead. After inserting it into the pile for a few minutes, see if you can hold on it for 5 seconds. If you can the temperature is less than 68°C. If you cannot, it’s ready for the pile to be turned
• If you allow the temperature to get above 68°C, desirable microbes get killed and carbon gets burned up and wasted
• After the 5th or 6th turn, the compost will only get warm not hot and then drop further to ambient temperature during curing
Moisture Content
• Moisture is lost as steam and needs to be replaced
• Try to keep the moisture content of your compost at 50%. You can test this by squeezing it in your hand.
If moisture drips out, it is too wet. If no water drips out, but on opening your hand the material does not hold its shape, then it is too dry, so add a bucket of water after every 50cm layer. If squeezed, no extra moisture drips out and on opening your hand the material holds its form, then it is close to the desired 50% moisture content
• If you get excessively high rainfall, leave a gentle slope on the top of the pile and place thatch grass or grain bags on top to keep excess rain water off the pile, which can cool the pile too much
Indicators of Good Compost
• Dark brown colour
• Sweet and rich smell
• Crumbly structure
• You should be able to see thick fungal strands
Compost can be stored as is for years, without degrading or losing its nutrients and the cost of producing it, is only labour. Compost is the input that we should see on every farm field as we express faithfulness with what God in His all sufficiency has put in our hands.