Revital Compost Fertilisers
What is compost?
Compost is organic material which has been broken down and oxidised by bacterial and fungal action into simpler compounds and molecules. This break down makes available nutrients for plant growth. Compost makes soil healthier by returning organic matter to the soil in a useable form. The benefits of compost are as follows:
- Provides a slow release fertiliser of plant available nutrients
- Improves a soil's water holding capacity
- Stimulates the growth of beneficial soil micro-organisms.
- Helps to de-compact heavy soils allowing better root penetration
- Improves sandy soil's capacity to hold water and nutrients as a result of composts higher cation exchange capacity
- Modifies temperature extremes in the soil
- Provides a buffering capacity i.e. resists change in the pH of the soil
- Helps suppress weeds when applied in a layer at least 5cm thick
- It is a natural way of returning to the soil, nutrients and organic elements that have been extracted from it.
- Compost can give crops immunity to a number of diseases
Commercial Composting
Traditional Composting is an accelerated biological method of stabilizing and remediating organic residues into plant available nutrients and humus. A good compost is dark in colour, friable in nature, and odourless in smell.
Mature composts offer many benefits as they continue to break down once they are applied to the soil releasing essential plant nutrients such as nitrogen, phosphorous, potassium and micro nutrients in forms that are readily available to plants. This slow breakdown is beneficial as it continually feeds nutrients to the soil and to plants.
Composts contain a high percentage of organic matter which improves soil structure allowing greater water and air penetration, improving a soil's ability to retain moisture in the root zone. An important product of the composting process is humus, which is produced by the oxidation of organic matter. It assists the soil to hold nutrients and promotes healthy plants which are less susceptible to diseases and insect pests.
Humus is important as it assists the soil to retain nutrients both inorganic as supplied by normal fertiliser and those released by the compost.
An important part of Humus is humic acids. Humic acids are negatively charged complex organic molecules. There negative charge attracts plant nutrients such as calcium and magnesium, in a form that is non leachable but plant available.
Humus also helps improve soil structure by decompacting the soil. This is done in two ways, by replacing elements such as Iron and Aluminium in between clay particles and improving the microbial life in the soil. Soil microbes are responsible for nutrient cycling and aggregating soil particles together. There overall effect is to improve soil structure allowing better drainage, and soil aeration, which enhances root growth. Increasing the organic matter in soils also reduces erosion by water and wind.
How do we produce compost?
Revital Fertilisers produces compost commercially in two sites in the central part of the North Island. Tauranga and New Plymouth.
Organic material is sorted to remove contaminants and then shredded and blended to ensure the optimum carbon nitrogen ratio of 33:1 for composting is reached. The material is shredded to reduce the size and increase the surface area of the material to be composted. This increases the speed at which micro-organisms can break the organic matter. The shredded blend is then placed into a windrow approximately 1.5m high 3m wide by 100m long. Over the next four to five months the material is broken down by micro organisms, bacteria and fungi.
To make high grade compost three variables need to be monitored: temperature, oxygen, and moisture.
These variables are controlled through regular turning of the compost piles to add air and control temperature, and sprinkling with water to maintain a consistent moisture content. In the compost process, micro-organisms break down organic matter producing carbon dioxide, water, heat and humus.
Composting proceeds through three phases, the moderate temperature phase which lasts for a few days, the high temperature phase which can last from a couple of weeks to a couple of months and the cooling maturation phase which also takes a couple of months. The reason the temperature changes greatly during composting is a result of different communities of micro-organisms dominating the composting process. It is important to get a compost pile over 55°C as at this temperature many micro-organisms that are human or plant pathogens are destroyed.
The higher temperatures accelerate the breakdown of proteins, fats, and complex carbohydrates like cellulose and hemicellulose, which are the major structural molecules in plants. However you do not want the pile to reach temperatures over 65°C as many micro-organisms can not survive at temperatures greater than this and the rate of decomposition will decrease if the pile exceeds this temperature.
As the supply of these high energy compounds becomes exhausted, the compost temperature gradually decreases and the lower temperature microbes re colonise the compost as it matures. Once the compost has matured it is then screened to remove oversized material and any other contaminants which may have been missed during the initial sorting. The screened mature compost is then ready for application to land or to be used in blends.
REVITAL® Fertiliser
The compost / mulch material is placed into windrows at Tauranga, turned & watered weekly (sufficient to optimise the composting process).
Vermicast - cold composting
The process takes between four to six months to produce REVITAL® Vermicast.
The vermicast is then combined with specially formulated additives to produce balanced organic crop & soil fertilisers for agricultural, horticultural and garden use.
