Bacteria-rich liquid fertiliser
A bacteria-rich liquid fertiliser is a liquid "fertiliser" that provides little nutrients to crops but still manages to improve the quality of the soil due to the beneficial bacteria they contain.
Types of bacteria-rich liquid fertiliser
Compost tea can be made by mixing green manure with water and aerating this for 24 to 48 hours using a (DIY) compost extractor. This is then diluted (1 part of this mixture on 10 parts water). Some 22 to 30 liter are given per 100m². Compost tea does not have high amounts of nutrients, but contain much bacteria which help plants increase their defenses to fight diseases. 
Bokashi liquid fertiliser
Bokashi liquid fertiliser is made by pre-composting organic waste through an anaerobic fermentation process. A bokashi bin is designed to not smell, for use inside an apartment or anywhere where odor would be a problem. The output of a bokashi bin can be further processed into compost through traditional composting, vermicomposting, or direct placement in soil.
Fermented animal/human urine
Animal/human urine can be collected and stored in a bucket or pot and covered and left to ferment for a few weeks. It can then be diluted and added to close to plants to promote healthy growth. The degree of dilution can vary between 1:1 and 1:5, depending on the crop and the amount of fertiliser (carbon/nitrogen) you already supplied to the crop using other fertilisers.
Fermented manure/water mix
Placing animal manure in a large sack and then suspending it in water, creates a rich manure that can be added to plants and improve growth. See diagram below
If you use chicken manure, then in 7-14 days the nutrients from the manure have passed through into the liquid and it is ready to be used
Fermented plant/water mix
Fermented plant/water mix or "plant tea" is made from large, soft and sappy plants which quickly break down (e.g Tithonia, lantana camara, acasia, stinging nettle) Generally, plants are steeped in cold or warm water for a certain period. The liquid is then sifted through a linen cloth and then sprayed on the crop or on the nearby soil. Most extracts contain trace elements and/or plant hormones that strengthen the cell walls and reinforce the plant's defenses. A number of them also contain substances that kill off or slow down the targeted pest organism. Treatment should thus be often repeated from the start of the cultivation.
It is made as follows:
- A small or medium size container is packed 2/3 full with the leaves of the plants above (avoid using stalks)
- A large amount of wood ash is added to aid in the breakdown of the leaves
- The pot is filled up with water.
- The pot is then covered and left to stand for 7 to 14 days
Note that you need to open the pot every three days. and The stir the mixture with a stick. If there is a strong smell, then more wood ash also needs to be added. When it's done, it can be used for plants or poured onto compost to speed up breakdown
Useful plants for making fermented plant/water mixes
- Wormwood: the poisonous tannins that the plant contains make the crop unpalatable for insects. Effective against aphids and mites. Extract: 200-300 g of dried wormwood is mixed with boiling water. After 1 day, water is added so that 10 liter is obtained. Sift and and spray on the crop.
- Tansy: animals find the odor and taste of this plant unpleasant and will not eat from it. Usable against various insects. Extract: 300g fresh plant parts per 10 liters of water. Cook briefly first and then allow to rest for 24 hours. Sift and spray.
- Stinging nettle: the active substance is formic acid. It is the most known, softest cure for aphids, not usable against other insects. Extract: steep 1kg fresh nettles per 10 liter of cold water. Then sift after 24 hours and spray undiluted. Stinging nettle manure: the same mixture is left to stand for about 5 days. Stir regularly and add rock meal. Dilute 10 times and then pour on the soil. The slurry is used as a strengthening fertilizer.
- Equisetum arvense: This herb contains much silica which strengthens the cell walls. An extract of horsetail has a good efficiency against fungal diseases. Extract: 1 kg of fresh or 150 g of dried horsetail is boiled for 15 minutes in 10 liter water. Let rest for a few hours, sift, and dilute 5 to 10 times before spraying.
Seaweed extract: extracts of brown and blue-green algae contain a high content of trace elements, magnesium and potassium. Their growth-promoting value it attributed to the vitamins, plant hormones and enzymes. It increases resistance to disease and promotes growth.
Derris and kwassia: harmless to humans but it is less effective as an insecticide.
Advantages of liquid fertilisers
- due to the use of a liquid, more on-the-spot fertilisation can occur (meaning the space between the plants would have less weed growth) and the system may be automated.
The method of application of the liquid bio-fertiliser is easy (foliar or drip)
- Abstracts_on_Sustainable_Agriculture_5#1._Green_manure_crops_in_irrigated_and_rainfed_lowland_rice-based_cropping_systems_in_south_Asia -Abstract on green manure crops in south Asia