1.0 INTRODUCTION
Organic fertilizers are made from organic material such as grass clippings, leaves, manure, or even food scraps that are added to the compost pile or sometimes used directly as farmyard manure. The biggest advantage of using an organic fertilizer is that organic ones are less harmful to the environment. While chemical fertilizers can pollute the water table, organic fertilizers break down into natural components that are recycled through the soil. They dissolve more easily than chemical fertilizers and release their nutrients over a longer period of time. This constant feeding provides plants with an extended application of nutrients during all stages of growth. The results of various research works have been summarized in plain language to help farmers in the use of organic fertilizers.
2.0 MEANING
(i) Organic fertilizers reduce the density of soils such as heavy clay allowing better air circulation around the roots.
(ii) A good organic mulch also prevents weeds from taking hold.
(iii) Good organic fertilizers promote the activity of earthworms and also promote the growth of beneficial organisms.
(iv) Organic fertilizers add the basic nutrients that plants need for better growth and development: Nitrogen, Phosphorus and Potassium.
(v) Organic products also promote stronger plants and better production. They help the environment as they do not contain harsh chemicals that are dangerous to humans and animals.
(vi) Organic fertilizers have a very positive impact on the environment and provide the necessary nutrients for growth and help plants overcome diseases.
3.0 PRINCIPLE OF COMPOSTING
Composting can be defined as a biochemical process by which a diverse and mixed group of microorganisms breaks down organic materials into humus. Therefore, optimal conditions must be maintained during composting to maximize microbial activity in the composting system. All of the following points should be considered in composting:
(i) C:N (carbon to nitrogen) ratio in raw materials
(ii) moisture content
(iii) ventilation
(iv) reaction
(v) shredding
(saw) turning
(vii) microbial activity, and
(viii) nutrient supply
4.0 COMPOSTING METHODS
The following are the four composting methods that farmers could adopt for maximum productivity.
(1) Heap method
(2) pit method
(3) cage method
(4) Barrel Method
4.1 HEAP METHOD
If you adopt this method;
• speeds up decomposition and allows easy air penetration
• allows easy turning of composting materials
• facilitates the maintenance of optimum moisture content
• is very popular with those who produce for commercial purposes
• during the process, cover the battery with a suitable cover material, such as nylon, as shown below
4.2 PIT METHOD
If you adopt this method;
• it is very tedious but it is very suitable for dry areas
• is adaptable for small-scale compost production
• there is poor aeration and slow decomposition
• there is difficulty in maintaining optimal moisture content during rainy seasons
• there is difficulty converting composting materials, and
• the cost of drilling wells is high
4.3 CAGE METHOD
If you adopt this method;
• can collect raw materials to use daily
• does not need systematic arrangements of collected materials
• you can open the cage for air and rain even if you cover the top of the cage from the direct impact of rain
• decomposition in this method is low and it is not necessary to turn the materials
• is suitable for home gardens and small farmland
4.4 BARREL METHOD
If you adopt this method;
• is suitable for home gardens, especially in urban areas
• can collect materials to use daily
• this method is like the cage method in many ways
• but the barrels cost more than the cage.
5.0 STEPS IN THE PRODUCTION OF COMPOST
5.1 Site selection for compost production
When selecting the site for compost production, make sure that:
• raw materials are readily available
• the water source is available
• the site should not be near a source of drinking water.
5.2 Preparation of a production site
To prepare the site for composting.
• Provide shade and ensure adequate drainage of the area
• Clean up the site
• Remove stones and unwanted materials
• Level the site if possible
5.3 Collection of raw materials
In the collection of raw materials for compost.
• Locally available raw materials such as weeds, banana leaves and stems, planting dust, crop residues and kitchen waste should be used.
6.0 PROCEDURE
Heap and Pit methods
• keep the maximum layer height up to 15 – 30 cm to accelerate the decomposition of raw materials
• use weeds, tree trimmings, fallen leaves or any other suitable raw material as a first layer.
• use green leaves or grass as a second layer.
• Add water if raw materials are dry or do not contain enough moisture.
• Use banana leaves as the third layer.
• Use as a 4th layer of fallen leaves or similar materials.
• Use Animal Waste as the 5th layer.
• use chopped banana trunk pieces as the 6th layer.
• use various available sheets as the 7th layer.
• make the pit or pile with different raw materials up to a reasonable height.
• add enough water and cover the mound or hole with a covering material.
• In the heap method, always keep a space between the deck and the ground for ventilation.
• Open the lid and check the moisture content every 4-5 days by inserting a post into the compost heap or hole.
• add enough water if moisture content is low and cover the pile or hole again.
• Remove the lid and turn the heap or pit properly after 3-4 weeks (1st turn).
• during turning add inoculants to increase decomposition again.
• cover the mound or hole again as mentioned above.
• Similarly, check the humidity every 4-5 days and add water if necessary.
• remove lid and turn properly after 7-8 weeks (2nd turn)
• at this stage also add inoculants to increase decomposition.
• During the second turning, also if the moisture content is not sufficient, water should be added.
• also after the second turning, check the moisture content every 4-5 days and if the moisture is not enough, add water.
• remove the cover and turn the compost properly after 11-12 weeks (third turn).
• after mixing, remake the mound or hole and cover as before.
• after 3 months in many cases the materials are well decomposed and the compost can be used for crop production.
Cage and barrel methods
• Prepare a cage with stakes or place a compost barrel or compost bin in a suitable location.
• The advantage of these methods is that raw materials can be added at any time.
• fill the cage or barrel with different raw materials alternately according to their rate of decomposition.
• In addition, add inoculants to increase the decomposition of raw materials.
• Since drying is rapid in the cage method, add water regularly to maintain a reasonable moisture content within the cage.
• cover the top of the cage with coconut leaves or suitable covering materials to maintain optimum moisture content within the cage.
The compost produced could be collected from the bottom of the cage or barrel.
7.0 BENEFITS
Following are the benefits of using compost on farmland or gardens.
• Increase performance.
• Improve the general fertility of the soil.
• Supply of humus or organic matter.
• Contribution of vitamins, hormones and plant enzymes that chemical fertilizers do not provide.
• Useful as a buffer against changes in soil pH.
• The compost is free of pathogenic organisms, weeds and other unwanted seeds.
• Compost nutrients are readily available.
• Easy to apply compared to other organic fertilizers.
Advisory services
For further inquiries, please contact the extension agents in your community or visit the Isoya Rural Development Project, Agricultural Extension and Rural Development Department, Obafemi Awolowo University, Ile-Ife, Nigeria for questions, clarifications, new knowledge and capacity building in the production of organic fertilizers. packaging and use for backyard agriculture or vegetable production.