1.0 INTRODUCTION
Organic fertilizers are made from organic material like grass clippings, leaves, manure, or even food scraps that are added to the compost pile or sometimes used directly as farm manure. The biggest advantage of using an organic fertilizer is that organic ones are less harmful to the environment. While chemical fertilizers can contaminate the water table, organic ones break down into natural components that are recycled by 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 papers have been summarized in simple 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 for better air circulation around the roots.
(ii) A good organic mulch also prevents weeds from taking hold.
(iii) Good organic fertilizers promote earthworm activity 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 COMPOST
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 compost production system. All of the following points must be considered in composting:
(i) C:N (carbon to nitrogen) ratio in raw materials
(ii) moisture content
(iii) ventilation
(iv) reaction
(v) crushing
(vi) spinning
(vii) microbial activity, and
(viii) nutrient supply
4.0 COMPOSTING METHODS
The following are 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;
• accelerates decomposition and allows easy air penetration
• allows easy turning of composting materials
• facilitates maintenance of optimal moisture content
• is very popular among those who produce for commercial purposes
• during the process, cover the pile with a suitable covering 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 optimum moisture content during the rains
• there is difficulty converting composting materials, and
• the cost of drilling wells is high
4.3 CAGE METHOD
If you adopt this method;
• you 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 farmlands
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 must not be near a source of potable water.
5.2 Preparation of a production site
To prepare the site for composting.
• Provide shade and ensure adequate drainage of the area.
• Clean 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 trunks, planting dust, crop residues and kitchen waste should be used.
6.0 PROCEDURE
Heap and Pit methods
• keep the maximum layer height down to 15 – 30 cm to speed up the decomposition of raw materials
• use weeds, tree pruning, 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 a third layer.
• Use leaves or similar materials as a 4th layer.
• Use animal waste as a 5th layer.
• Use chopped banana trunk pieces as the 6th layer.
• use as 7th layer several sheets available.
• make the pit or pile with different raw materials up to a reasonable height.
• add enough water and cover the pile or hole with a covering material.
• In the pile method, always keep a gap 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 the moisture content is low and cover the pile or hole again.
• Remove lid and turn pile or pit properly after 3-4 weeks (1st turn).
• during turning add inoculants to increase decomposition again.
• cover the pile or hole again as mentioned above.
• Similarly, check humidity every 4-5 days and add water if necessary.
• remove the lid and turn properly after 7-8 weeks (2nd turning)
• at this stage also add inoculants to increase decomposition.
• during the second turning, also if the moisture content is not enough, 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, re-mound or pit 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
• Set up 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 decomposition rate.
• 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
The following are the benefits of using compost on farmland or gardens.
• Increase performance.
• Improve general soil fertility.
• Supply of humus or organic matter.
• Contribution of vitamins, hormones and plant enzymes that are not provided by chemical fertilizers.
• 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 extension agents in your community or visit Isoya Rural Development Project, Department of Agricultural Extension and Rural Development, 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.