Organic fertilizers are made from organic material such as grass clippings, leaves, manure or even table scraps added to compost pile or sometimes used directly like farmyard manures. The biggest advantage of using an organic fertilizer is that organics are less harmful to the environment. While chemical fertilizers can contaminate the water table, organics break down into natural components that are recycled by the soil. They dissolve more readily than chemical fertilizers and release their nutrients over a longer period of time. This steady feeding provides plants with an extended application of nutrients during all stages of growth. The results of various research works have been summarized in simple language to assist farmers on the use of organic fertilizer.
(i) Organic fertilizers reduce the density of soils such as heavy clay, allowing for better air circulation around the roots
(ii) Good organic mulch also prevents weeds from getting a foothold.
(iii) Good organic fertilizers promote earthworm activity and also promote the growth of beneficial organisms
(iv) Organic fertilizer add the basic nutrients plants need for the best growth and development–nitrogen, phosphorus and potassium
(v) Organics also promote stronger plants and better production. They help the environment since they do not contain harsh chemicals that are hazardous to humans and animals.
(vi) Organic fertilizers have a very positive impact on the environment and they provide the nutrients necessary for growth and help plants overcome disease.
3.0 PRINCIPLE OF COMPOSTING
Composting may be defined as a biochemical process by which diverse and mixed group of microorganisms breaks down organic materials to humus. Therefore, optimum conditions should be maintained during composting to maximize the microbial activity in the compost production system. All the following points should be considered in composting:
(i) C: N (Carbon to Nitrogen) ratio in raw materials
(ii) moisture content
(vii) microbial activity, and
(viii) nutrient supply
4.0 METHODS OF COMPOSTING
The followings are the four methods of composting 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;
• it accelerates decomposition and allows for easy penetration of air
• it allows for easy turning of the compost materials
• it makes it easy to maintain optimum moisture content
• it is very popular among those producing for commercial purposes
• during the process, cover heap with suitable covering material like 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
• it is adaptable for small scale compost production
• there is poor aeration and slow decomposition
• there is difficulty in maintaining optimal moisture contents during the rains
• there is difficulty in turning compost materials, and
• the cost of making pits are high
4.3 CAGE METHOD
If you adopt this method;
• you can collect raw materials to be used on a daily basis
• you do not need any systematic arrangements of collected materials
• you can open cage for air and rain although you cover the top of the cage from direct rain impact
• decomposition in this method is low and turning of materials is not needed
• it is suitable for home gardens and small farm lands
4.4 BARREL METHOD
If you adopt this method;
• it is suitable for home gardens particularly in urban areas
• you can collect materials to be used on daily basis
• this method is like the cage method in many aspects
• but barrels are costlier than the cage.
5.0 STEPS IN COMPOST PRODUCTION
5.1 Selection of site for compost production
In selecting site for compost production, make sure:
• raw materials are available readily
• water source is available
• the site should not be in the close vicinity to drinking water source.
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 stone and unwanted materials
• Level the site if possible
5.3 Collection of raw materials
In collecting raw materials for compost
• locally available raw materials should be used like weeds, banana leaves and trunk, sow dust, crop residue and kitchen wastes.
Heap and Pit methods
• maintain the maximum height of the layer up to 15 – 30 cm to accelerate the decomposition of raw materials
• use as the 1st layer weeds or tree loping or leaf fall or any other suitable raw materials
• use as the second layer green leaves or grass.
• add water if raw materials are dry or do not contain sufficient moisture.
• use as the 3rd layer banana leaves.
• use as the 4th layer leaf fall or related materials.
• use as the 5th layer Animal wastes.
• use as the 6th layer pieces of chopped banana trunk.
• use as the 7th layer various leaves available.
• make the pit or heap with different raw materials up to a reasonable height.
• add enough water and cover the heap or pit with a covering material.
• in the heap method always keep a space between the cover and the ground for ventilation.
• open the cover and check the moisture content every 4-5 days by inserting a pole in to the compost heap or pit.
• add enough water if moisture content is low and cover the heap or pit again.
• remove the cover and turn the heap or pit properly after 3-4 weeks (1st turning).
• during the turning add inoculants to increase the decomposition again.
• cover the heap or pit again as mentioned earlier.
• Similarly, check the moisture every 4-5 days and add water if necessary.
• remove the cover and turn properly after 7-8 weeks (2nd turning)
• at this stage also add inoculants to increase the decomposition.
• during the 2nd turning too if moisture content is not sufficient water should be added.
• after the 2nd turning too, check the moisture content every 4-5 days interval and if moisture is not sufficient add water.
• remove the cover and turn compost properly after 11-12 weeks (3rd turning).
• after mixing, make the heap or pit again and cover as earlier.
• after 3 months in many occasions materials are well decomposed and compost can be used for crop production.
Cage and barrel methods
• prepare a cage with stakes or placed a compost barrel or compost bin in a suitable place.
• the advantage of these methods is that raw materials can be added at any time.
• fill Cage or barrel with different raw materials alternatively according to their decomposition rate.
• in addition, add inoculants to increase the decomposition of raw materials.
• since drying is fast in the cage method, add water regularly to maintain the reasonable moisture content inside the cage.
• cover the top of the cage with coconut frond or with suitable covering materials to maintain the optimum moisture content inside the cage.
Produced compost could be collected from the bottom of the cage or barrel.
The followings are the benefits of using compost on farmlands or gardens
• Increase yield.
• Improve overall soil fertility.
• Provision of humus or organic matter.
• Provision of vitamins, hormones and plant enzymes which are not supplied by chemical fertilizers.
• Useful as buffer to changes in soil pH.
• Compost is free from pathogenic organisms, weeds and other unwanted seeds.
• Compost nutrients are readily available.
• Easy to apply when compared to other organic manures.
For further enquiry, contact the 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 organic fertilizer production, packaging and utilization for backyard farming or vegetables production.