1. Coir compost
The largest by products of coconut is coconut husk from which coir fibre is extracted. This extraction process generates a large quantity of dusty material called coir dust or coir pith. Large quantity of coir waste of about 7.5 million tones is available annually form coir industries in India. In Tamil Nadu state alone 5 lakh tons of coir dust is available.
Coir pith has gained importance owing to its properties for use as a growth medium in Horticulture. Because of wider carbon and nitrogen ratio and lower biodegradability due to high lignin content, coir pith is still not considered as a good carbon source for use in agriculture. Coir pith is composted to reduce the wider C:N ratio, reduce the lignin and cellulose content and also to increase the manorial value of pith. Composting of coir pith reduces its bulkiness and converts plant nutrients to the available form.
2. Coir pith composting technology
Collection of raw material
Coir pith heap
Coir pith is collected from the coir industry without any fiber. If fibrous materials are present, it is removed by sieving at the source it self. Otherwise, it has to be removed at the end of composting at the compost yard. These fibrous materials will not get composted and it will hinder with composting process. It is advisable to bring fibre free coir pith for composting.
Site selection for composting
A separate area should be earmarked for composting. It is better to have an elevated place for composting. In between coconut trees, shade under any tree is good for composting. The shady area conserve the moisture in the composting material. The floor of the compost making area should be levelled. If earthen floor is available the floor can be made to hard by hard pressing and also by applying cow dung slurry. Presence of roof over the composting material is advantageous, since it protects the material from rain and severe sunshine.
Coir pith is an aerobic composting. So it should be heaped above the soil. There is no need for pit or cement tub to make the compost. Coir pith should be spread to the length of 4 feet and breadth of 3 feet. Initially coir pith should be put up for 3 inch height and thoroughly moistened. After moistening, nitrogenous source material should be added. The nitrogenous source may be in the form of urea or fresh poultry litter. If urea is applied, it is recommended that 5 kg urea is required for one ton of coir pith. This 5 kg equally divided into five portions and in alternative layer of coir pith one kg of urea should be applied. If fresh poultry litter is applied, it is recommended @ 200 kg for one ton of coir pith.
One has to proportionally divide and put the required amount of poultry litter over the coir pith. For example if one ton coir pith is divided into 10 portion, in the first layer, 100 kg poultry litter is added. After adding, the nitrogen source, the microbial inoculums Pleurotus and TNAU biomineralizer (2%) are added over the material. Over this one portion of coir pith is added and the same input mentioned above should be added. It is advisable to make a heap up to minimum of 4 feet height. But beyond 5 feet, it requires machinery to handle the materials. The increase in height retains the temperature generated in the coir pith compost process. If the height is low, what ever the heat generated will be dissipated easily.
Turing of material
The compost heap should be turned once in 10 days to allow the stale air trapped inside the compost material to go out and fresh air will get in. The composting process is an aerobic one, the organism performing the composting require oxygen for its metabolic activity. This turning of material indirectly aerate the substrate. The other way of giving aeration is inserting perforated unused PVC or iron pipe in the composting material both vertically and horizontally.
Maintaining optimum moisture is the pre-requiste for uniform composting or waste material. Sixty percent moisture is to be maintained 60 % moisture is, the compost material should be always wet. But excess water should not be drained form the waste material is to take a handful of composting material and put in between the palms and squeeze it. If no water is coming out of the material, that moisture status is ideal for composting.
The period of composting vary from substrate to substrate. If all the above said conditions are maintained in the composting, it will take sixty days (60 days) for some of the physical parameters to be observed in the compost. First observation is volume reduction of waste material. When the waste material is composted, the compost heap height will be reduced by 30 %. The second observation is waste materials are turned to black in colour and the waste particle size is reduced. The third observation is that composted material emits earthy odour. The chemical observation for compost maturity is to be analysed in the laboratory. The chemical observations are narrower C:N ratio (20:1), less oxygen uptake, less number of microorganism, more amount of available nutrients and highly cation exchange capacity.
The composted material which is obtained from sieving is ready for use. If the composition is not used immediately, it should be stored in a open, cool place, to retain the moisture, so that the beneficial micro organism present in the compost will not die. Once in a month, water is sprinkled over the compost material to maintain the moisture.
3. Nutritive value of raw and composted coir pith compost
|Parameters||Raw coir pith (%)||Composted coir pith (%)|
4. Benefits of composted coir pith
- The addition of composted coir dust improves soil texture, structure and tilth, sandy soil become more compact and clayey soil become more arable.
- It improves the soil aggregation
- It improves the water holding capacity (more than 5 times its dry weight) contributing towards increased soil moisture.
- The bulk density of both the sub surface (15-30 cm) sioil is reduced to considerable extent with the application composted coir pith.
- Composted coir dust contains all plant nutrient elements and it can provide a supplemental effect along with inorganic fertilizers.
- There is improvement in cation exchange capacity of soils, where composted coir pith is applied.
- Coir pith compost application increased the soil native microflora because of addition of humic materials.
- Ammonification, nitrification and nitrogen fixation are increased due to improved microbiological activity.
5. Application of coir pith compost
- It is recommended that 5 tons of composted coir ppith per hectare of land irrespective of the raised.
- Is is advised that composted coir pith should be applied basally before take up the sowing.
- For nursery development in poly bags and in mud pots, while preparing the potting mixture 20 % of composted coir pith can be mixed with the soil and sand before filing it in the poly bag or mud pot
- For applying to the established trees like coconut, mango, banana and other fruit bearing trees, minimum 5 kg composted coir pith is required.
6. Limitation in using composted coir pith
- It is not economical to buy composted coir pith and put in the farm for large areas. It is better to prepare compost in the own farm.
- Beforebuying composted coir dust, it should be ensured that the material is composted completely and quality analysis certificate is available with the material.
- If immature compost is applied to the soil, even after entering into the soil, it will undergo decomposition inside the soil, by taking nutrients from the soil. Because of this, standing crop will get affected.