Composting Bioculture

Composting is the natural process of ‘rotting’ or decomposition of organic matter by microorganisms under controlled conditions. Raw organic materials such as crop residues, animal wastes, food garbage, some municipal wastes and suitable industrial wastes, enhance their suitability for application to the soil as a fertilizing resource, after having undergone composting.

A mass of rotted organic matter made from waste is called compost. The compost made from farm waste like sugarcane trash, paddy straw, weeds and other plants and other waste is called farm compost. The average nutrient contents of farm compost are 0.5 per cent N, 0.15 per cent P2O5and 0.5 per cent K2O. The nutrient value of farm compost can be increased by application of superphosphate or rock phosphate at 10 to 15 kg/t of raw material at the initial stage of filling the compost pit. The compost made from town refuses like night soil, street sweepings and dustbin refuse is called town compost. It contains 1.4 per cent N, 1.00 per cent P2O5 and 1.4 per cent K2O.

Farm compost is made by placing farm wastes in trenches of suitable size, say, 4.5 m to 5.0 m long, 1.5m to 2.0 m wide and 1.0 m to 2.0 m deep. Farm waste is placed in the trenches layer by layer. Each layer is well moistened by sprinkling cow dung slurry or water. Trenches are filled up to a height of 0.5 m above the ground. The compost is ready for application within five to six months.

Composting is essentially a microbiological decomposition of organic residues collected from rural area (rural compost) or urban area (urban compost).

WHY COMPOSTING IS NECESSARY?

• The rejected biological materials contain complex chemical compounds such as lignin, cellulose, hemi cellulose, polysaccharides, proteins, lipids etc.
• These complex materials cannot be used as such as resource materials.
• The complex materials should be converted into simple inorganic element as available nutrient.
• The material put into soil without conversion will undergo conversion inside the soil.
• This conversion process take away all energy and available nutrients from the soil affecting the crop.
• Hence conversion period is mandatory.

ADVANTAGES OF COMPOSTING

• Odor control.
• Volume reduction of waste.
• Final weight of compost is very less.
• Composting temperature kill pathogen, weed seeds and seeds.
• Matured compost comes into equilibrium with the soil.
• During composting number of wastes from several sources are blended together.
• Excellent soil conditioner.

THE ECONOMIC AND SOCIAL BENEFITS OF COMPOSTING INCLUDE THE FOLLOWING:

• Brings higher prices for organically grown crops.
• Composting can offer several potential economic benefits to communities.
• Extends current landfill longevity and delays the construction of a more expensive replacement landfill or incinerator.
• Reduces or avoids landfill or combustor tipping fees, and reduces waste disposal fees and long-distance transportation costs.
• Offers environmental benefits from reduced landfill and combustion use.
• Creates new jobs for citizens.
• Produces marketable products and a less-cost alternative to standard landfill cover, artificial soil amendments, and conventional bioremediation techniques.
• Provides a source of plant nutrients and improves soil fertility; results in significant cost savings by reducing the need for water, pesticides, fungicides, herbicides, and nematodes.
• Used as an alternative to natural topsoil in new construction, landscape renovations, and container gardens. Using composts in these types of applications is not only less expensive than purchasing topsoil, but it can also often produce better results when establishing a healthy vegetative cover.
• Used as mulch for trees, orchards, landscapes, lawns, gardens, and makes an excellent potting mix. Placed over the roots of plants, compost mulch conserves water and stabilizes soil temperatures. In addition, it keeps plants healthy by controlling weeds, providing a slow release of nutrients, and preventing soil loss through erosion.

DRAWBACKS OF USING COMPOSTS

Agricultural use of composts remains low for several reasons:

• The product is weighty and bulky, making it expensive to transport.
• The nutrient value of compost is low compared with that of chemical fertilizers, and the rate of nutrient release is slow so that it cannot usually meet the nutrient requirement of crops in a short time, thus resulting in some nutrient deficiency
• The nutrient composition of compost is highly variable compared to chemical fertilizers.
• Agricultural users might have concerns regarding potential levels of heavy metals and other possible contaminants in compost, particularly mixed municipal solid wastes. The potential for contamination becomes an important issue when compost is used on food crops.
• Long-term and/or heavy application of composts to agricultural soils has been found to result in salt, nutrient, or heavy metal accumulation and may adversely affect plant growth, soil organisms, water quality, and animal and human health.

TYPES OF COMPOSTING

Composting may be divided into two categories by the nature of the decomposition process.

ANAEROBIC COMPOSTING:

In anaerobic composting, decomposition occurs where oxygen (O) is absent or in limited supply. Under this method, anaerobic micro-organisms dominate and develop intermediate compounds including methane, organic acids, hydrogen sulphide and other substances. In the absence of O, these compounds accumulate and are not metabolized further. Many of these compounds have strong odours and some present phytotoxicity. As anaerobic composting is a low-temperature process, it leaves weed seeds and pathogens intact. Moreover, the process usually takes longer than aerobic composting. These drawbacks often offset the merits of this process, viz. little work involved and fewer nutrients lost during the process.

AEROBIC COMPOSTING:

Aerobic composting takes place in the presence of ample O. In this process, aerobic microorganisms break down organic matter and produce carbon dioxide (CO2), ammonia, water, heat and humus, the relatively stable organic end product. Although aerobic composting may produce intermediate compounds such as organic acids, aerobic micro-organisms decompose them further. The resultant compost, with its relatively unstable form of organic matter, has little risk of phytotoxicity.

The heat generated accelerates the breakdown of proteins, fats and complex carbohydrates such as cellulose and hemi-cellulose. Hence, the processing time is shorter. Moreover, this process destroys many micro-organisms that are human or plant pathogens, as well as weed seeds, provided it undergoes sufficiently high temperature. Although more nutrients are lost from the materials by aerobic composting, it is considered more efficient and useful than anaerobic composting for agricultural production. Most of this publication focuses on aerobic composting.

Composting objectives may also be achieved through the enzymatic degradation of organic materials as they pass through the digestive system of earthworms. This process is termed vermin composting.

THE AEROBIC COMPOSTING PROCESS

The aerobic composting process starts with the formation of the pile. In many cases, the temperature rises rapidly to 70-80 °C within the first couple of days. First, mesophilic organisms (optimum growth temperature range = 20-45 °C) multiply rapidly on the readily available sugars and amino acids (Figure 1). They generate heat by their own metabolism and raise the temperature to a point where their own activities become suppressed. Then a few thermophilic fungi and several thermophilic bacteria (optimum growth temperature range = 50-70 °C or more) continue the process, raising the temperature of the material to 65 °C or higher. This peak heating phase is important for the quality of the compost as the heat kills pathogens and weed seeds.

The active composting stage is followed by a curing stage, and the pile temperature decreases gradually. The start of this phase is identified when turning no longer reheats the pile. At this stage, another group of thermophilic fungi starts to grow. These fungi bring about a major phase of decomposition of plant cell-wall materials such as cellulose and hemi-cellulose. Curing of the compost provides a safety net against the risks of using immature compost such as nitrogen (N) hunger, O deficiency, and toxic effects of organic acids on plants.

Eventually, the temperature declines to ambient temperature. By the time composting is completed, the pile becomes more uniform and less active biologically although mesophilic organisms recolonize the compost. The material becomes dark brown to black in colour. The particles reduce in size and become consistent and soil-like in texture. In the process, the amount of humus increases, the ratio of carbon to nitrogen (C:N) decreases, pH neutralizes, and the exchange capacity of the material increases.

FACTORS AFFECTING AEROBIC COMPOSTING

AERATION

Aerobic composting requires large amounts of O, particularly at the initial stage. Aeration is the source of O, and, thus, indispensable for aerobic composting. Where the supply of O is not sufficient, the growth of aerobic micro-organisms is limited, resulting in slower decomposition. Moreover, aeration removes excessive heat, water vapour and other gases trapped in the pile. Heat removal is particularly important in warm climates as the risk of overheating and fire is higher. Therefore, good aeration is indispensable for efficient composting. It may be achieved by controlling the physical quality of the materials (particle size and moisture content), pile size and ventilation and by ensuring adequate frequency of turning.

MOISTURE

Moisture is necessary to support the metabolic activity of the micro-organisms. Composting materials should maintain a moisture content of 40-65 percent. Where the pile is too dry, composting occurs more slowly, while a moisture content in excess of 65 percent develops anaerobic conditions. In practice, it is advisable to start the pile with a moisture content of 50-60 percent, finishing at about 30 percent.

NUTRIENTS

Micro-organisms require C, N, phosphorus (P) and potassium (K) as the primary nutrients. Of particular importance is the C:N ratio of raw materials. The optimal C:N ratio of raw materials is between 25:1 and 30:1 although ratios between 20:1 and 40:1 are also acceptable. Where the ratio is higher than 40:1, the growth of micro-organisms is limited, resulting in a longer composting time. A C:N ratio of less than 20:1 leads to underutilization of N and the excess may be lost to the atmosphere as ammonia or nitrous oxide, and odour can be a problem. The C:N ratio of the final product should be between about 10:1 and 15:1.

TEMPERATURE

The process of composting involves two temperature ranges:While the ideal temperature for the initial composting stage is 20-45 °C, at subsequent stages with the thermophilic organisms taking over, a temperature range of 50-70 °C may be ideal. High temperatures characterize the aerobic composting process and serve as signs of vigorous microbial activities. Pathogens are normally destroyed at 55 °C and above, while the critical point for elimination of weed seeds is 62 °C. Turnings and aeration can be used to regulate temperature.

LIGNIN CONTENT

Lignin is one of the main constituents of plant cell walls, and its complex chemical structure makes it highly resistant to microbial degradation (Richard, 1996). This nature of lignin has two implications. One is that lignin reduces the bioavailability of the other cell-wall constituents, making the actual C:N ratio (viz. ratio of biodegradable C to N) lower than the one normally cited. The other is that lignin serves as a porosity enhancer, which creates favourable conditions for aerobic composting. Therefore, while the addition of lignin-decomposing fungi may in some cases increase available C, accelerate composting and reduce N loss, in other cases it may result in a higher actual C:N ratio and poor porosity, both of which prolong composting time.

POLYPHENOLS

Polyphenols include hydrolysable and condensed tannins (Schorth, 2003). Insoluble condensed tannins bind the cell walls and proteins and make them physically or chemically less accessible to decomposers. Soluble condensed and hydrolysable tannins react with proteins and reduce their microbial degradation and thus N release. Polyphenols and lignin are attracting more attention as inhibiting factors. Palm et al. (2001) suggest that the contents of these two substances be used to classify organic materials for more efficient on-farm natural resource utilization, including composting.

pH value

Although the natural buffering effect of the composting process lends itself to accepting material with a wide range of pH, the pH level should not exceed eight. At higher pH levels, more ammonia gas is generated and may be lost to the atmosphere.

TECHNIQUES FOR EFFECTIVE AEROBIC COMPOSTING

Simple replication of composting practices does not always give the right answer to potential composters. This is because composting takes place at various locations and under diverse climates, using different materials with dissimilar physical, chemical and biological properties. An understanding of the principles and technical options and their appropriate application may be helpful in providing the optimal environment to the compost pile.

IMPROVED AERATION

In order to obtain the end product of uniform quality, the whole of the pile should receive a sufficient amount of O so that aerobic micro-organisms flourish uniformly. The methodologies deliberated in this publication made use of the techniques as presented below.

PILE SIZE AND POROSITY OF THE MATERIAL

The size of the pile is of great significance and finds mention in the sections on passive composting of manure piles and turned wind-rows. Where the pile or wind-row is too large, anaerobic zones occur near its centre, which slows the process in these zones. On the other hand, piles or wind-rows that are too small lose heat quickly and may not achieve a temperature high enough to evaporate moisture and kill pathogens and weed seeds. The optimal size of the piles and wind-rows should also consider such parameters as the physical property (porosity) of the materials and the way of forming the pile. While more porous materials allow bigger piles, heavy weights should not be put on top and materials should be kept as loose as possible. Climate is also a factor. With a view to minimizing heat loss, larger piles are suitable for cold weather. However, in a warmer climate, the same piles may overheat and in some extreme cases (75 °C and above) catch fire.

VENTILATION

Provision of ventilation complements efforts to optimize pile size. Ventilation methods are varied. The simplest method is to punch holes in the pile at several points. The high temperature compost method of Chinese rural composting involves inserting a number of bamboo poles deep into the pile and withdrawing them a day later, leaving the pile with ventilation holes. Aeration is improved by supplying more air to the base of the pile where O deficiency occurs most often. In addition to the above-mentioned vertical poles, Ecuador on-farm composting  uses a lattice of old branches at the base to allow more pile surface to come into contact with the air, and the composting period is reduced to two to three months in warm seasons. This technique is also practised in the rapid composting method developed by the Institute of Biological Sciences (IBS) in the Philippines , where the platform should be 30 cm above the ground. The passively aerated wind-rows method uses a more sophisticated technique. It entails embedding perforated pipes throughout the pile. As the pipe ends are open, air flow is induced and O is supplied to the pile continuously. The aerated static pile method  takes this aeration system a step further; a blower generates air flow to create negative pressure (suction) in the pile and fresh air is supplied from outside.

TURNING

Once the pile is formed and decomposition starts, the only technique for improving aeration is turning. The frequency of turning is crucial for composting time. In some cases, turning not only distributes air throughout the pile, it also prevents overheating as it kills all the microbes in the pile and terminates decomposition. However, turning too frequently might result in a lower temperature.

INOCULATION

While some composters find improved aeration enough for enhanced microbial activities, others may need inoculation of micro-organisms. Inoculum organisms utilized for composting are mainly fungi such as Trichoderma sp. (IBS rapid composting and composting weeds and Pleurotus sp. (composting Coir Pith ) and composting weeds). This publication also features ‘effective micro-organisms’ (EMs) (EM-based quick compost production process . The inoculums are an affordable choice for those with access to the market and also for resource-poor farmers.

COMPOSTING PURPOSE:

Composting of sugar mill press mud along with partially treated or completely treated distillery spent wash; activated through proper procedure along with microbial culture, produce valuable compost for sustainable agriculture. The spent wash based compost is beneficial to soil and crop and also provides the benefit of utilization of waste as a resource and proper management of the environment. Under aerobic conditions, the main products from composting of organic substrates are carbon dioxide, water and heat and under anaerobic conditions metabolic products of the decompositions are methane, carbon dioxide and intermediates of low-molecular weight organic acids.

STAGES OF COMPOSTING

Composting is a biochemical process through which organic matter is decomposed and you get a humus called compost. The stages of composting are very particular and have to be frequently controlled to ensure that the temperature, humidity, the oxygen, and other factors are developed correctly. As a general rule it requires specific facilities in order to carry out the composting, precisely to secure greater control on how the organic raw material that must be converted into compost evolves step by step.

STAGES OF COMPOSTING PROCESS:

1. 1. Mesophilic Stage: the mixture of raw materials is still at environmental temperature and without moisturizing. The “mesophilic” microorganisms (microorganisms that grow between 20-45 °C) begin to reproduce by breaking down carbon and nitrogen. The metabolic activity of the microorganisms raises the temperature to 40-45 °C between two to eight days. It also lowers the pH of the mixture due to the production of organic acids.
2. Thermophilic Stage: also known as the “sanitation” phase, in this stage the temperature rises over 45 °C and the mesophilic microorganisms are replaced by the “thermophiles” (microorganisms that proliferate at temperatures between 45 °C and 70 °C). Thermophiles break down more complex carbon sources, such as cellulose and lignin. Another important change is that the nitrogen is transformed into ammonia and the Ph of the mixture becomes alkaline. Starting at 60 ºC sporagenic (spore-producing) bacteria and actinobacteria appear. These two bacteria are responsible for breaking down waxes, hemicelluloses and more complex proteins. Afterwards and for several days, even months (depending on the used raw material), it keeps a high temperature and reduces biological activity of the microorganisms. Then a pasteurization process is produced where bacteria dies and harmful microorganisms (such as Salmonella or Escherichia coli). This process allows us to sanitize the product. During this phase the mixture must be frequently ventilated with the objective to supply oxygen to the microorganisms so they can continue the decomposition process.
3. Cooling Stage: when carbon and nitrogen have been consumed, the temperature is lowered down to 40-45 ºC. The mesophilic appears again and decomposes the remaining material of cellulose and lignin. Also, the pH drops again slightly.
4. 4. Maturation Stage: in this stage of the process it is required that the mixture stays at room temperature. During this time a series of secondary reactions are produced that triggers condensation and polymerization of the humus. At the end of this period we obtain a product that you can now call compost. `The composting process contributes great benefits to natural manure, it offers sanitation, a reduction of bad odors and that it will be 100% natural. Without a doubt, compost is one of the most complete and beneficial fertilizers for plant life NANOZYME COMPOST MODULE NANOZYME are fast decomposers. NANOZYME function optimally within a pH range of 6–7.5 and are less tolerant of low moisture conditions than other types of microorganisms. Some bacteria form endospores that enable them to withstand unfavorable environmental conditions, such as high temperature or low moisture. When the environment becomes more favorable for survival, the endospores germinate and the NANOZYME become active again. This feature of certain Nanzoyme helps to continue the composting process during the cooling phase that follows peak thermophilic temperatures.

NANOZYME attack more complex materials, or may exploit substances released from the less degradable materials due to the extracellular enzyme activities of other organisms. Many thermophilic species of Thermus have been isolated from compost at temperatures as high as 65°C and even 82°C. Nitrosomonas spp. and Nitrobacter spp. are the ammonium oxidizing and nitrite oxidizing NANOZYME, respectively, present in the compost heap. Establishment of a large population of denitrifying NANOZYME suggests that some anaerobic microhabitat exists within the compost piles.

These microhabitats could have been developed within the piles partially due to the initial high water content (65%) of the piles and partially because of the rich contents of organic matter and nitrogen present in the sub-strate, which promote microbial activity to the extent of causing depletion in the O2 content in isolated pockets within the piles.

Mesophilic microorganisms are partially killed or poorly active during the thermogenic stage (40– 60°C). The diversity decreased as tempera-ture increased, with a shift from Pseudomonas,Achromobacter, Flavo bacterium, Micrococcus, and Bacillus to being dominated by Bacillus. NANOZYME related to B. schlegelii, Hydrogenobacter spp. and particularly to the genus Thermus (Th. thermophilus, Th. aquaticus) appear to be the main active microbes in hot compost (65–80°C).

NANOZYME survival in high temperature composting material is possible through the formation of microcolonies. Mesophiles are likely to contribute little to compost degradation at these temperatures. Microbial fermentation of carbohydrates generally results in an increase in acidity. Clostridium species com-monly ferment glucose to yield butyl and ethyl alcohols and certain acids. Lactobacillus lactis yields almost entirely lactic acid, while Lactobacillus bevis yields lactic and acetic acids, ethyl alcohol and carbon dioxide

FACTOR INFLUENCING THE COMPOSTING

A given nutrient in waste can be utilized only if it is available to active microbes. Availability may be chemical and physical. A nutrient is chemically available to microbes if it is a part of a molecule that is vulnerable to attack by the microbes. Usually, breakdown of compounds or nutrients is accomplished enzymatically by microbes that either possess the necessary enzyme or can synthesize it. Physical availability is interpreted in terms of accessibility tomicrobes. Accessibility is a function of the ratio of mass or volume to surface area of a waste particle, which in turn is determined by particle size. Factors which influencing composting are divided into two major group that is, nutrient factors and environmental factors.

CARBON-TO-NITROGEN RATIO (C:N)

The carbon-to-nitrogen ratio (C:N) is a major nutrient factor. Based on the relative demands for carbon and nitrogen in cellular processes, the theoretical ratio is 25:1. The ratio is weighted in favor of carbon, because the uses for carbon outnumber those for nitrogen in microbial metabolism and the synthesis of cellular materials.

Thus, not only is carbon utilized in cell wall or membrane formation, protoplasm and storage products synthe-sis, an appreciable amount is oxidized to CO2 in metabolic activities. On the other hand, nitrogen has only one major use as a nutrient, an essential constituent of protoplasm.

In compost practice, it is in the order of 20:1 to 25:1. The general experience is that the rate of decomposition declines when the C:N exceeds that range. On the other hand, nitrogen probably will be lost at ratios lower than 20:1. The loss could be due to the conversion of the surplus nitrogen into ammonia-N.

The high temperatures and pH levels characteristic of composting during the active stage could induce the volatilization of the ammonia. In a developing country, an unfavorably high C:N can be lowered by adding nitrogenous waste to the compost feedstock. If economics permit, it also can be lowered by adding a chemical nitrogen fertilizer, such as urea or ammonium sulfate.

Conversely, a carbonaceous waste can be used to elevate a low C:N.The relative proportion of carbon and nitrogen is a major controlling factor in the com-posting process. Carbon serves primarily as an energy source for the microorganisms, while a small fraction of the carbon is incorporated to the microbial cells.

Nitrogen is critical for microbial population growth, as it is a constituent of protein that forms over 50% of dry Nanzoyme l cell mass. If nitrogen is limited, microbial populations will remain small and it will take longer to decompose the available carbon.

Excess nitrogen, beyond the microbial requirements, is often lost from the system as ammonia gas. In the composting process, the substrate should achieve a C:N ratio of 30:1 for stimulating degradation and immobilization of nitrogen. A balanced carbon to nitrogen (C:N) ratio of 25:1–30:1 is ideal for an active compost pile. C:N ratios of as low as 20:1 or as high as 40:1 also produce good quality finished compost.

If C:N< 20:1Excess nitrogen will let off gas into the atmosphere as NH3 or N2O, resulting in anundesirable odor If C:N > 40:1Nitrogen mineralization generally occurs in two phases, a rapid exponential immobilization or mineralization phase, followed by a slow linear mineralization phase. Nitrogen mineralization is the process by which organic nitrogen is converted to the plant available inorganic form such as ammonium and nitrate.

The C:N ratio of the substrate determines whether immobilization or mineralization will dominate in the early stages of compost-ing. The rate of inorganic N release to the soil from composted manure depends on the rate of decomposition of the organic matter and on subsequent turnover of the decomposed C and N in the soil. Release of plant available N from manure in the soil is controlled by the balance of N immobilization and mineralization, which in turn is controlled, to a large extent, by the C:N ratio of the decomposing organic material. The decomposition rate (i.e., composting process) slows down.

ENVIRONMENTAL FACTOR INFLUENCING THE COMPOSTING

The principal environmental factors that affect the compost process are temperature, pH, moisture, and aeration. The rate and the extent of decomposition are proportional to the degree that each nutritional and environmental factor approaches optimum. A deficiency in any one factor would limit the rate and extent of composting, in other words, the deficient factor is a limiting factor.

METHODS OF COMPOSTING

In Coimbatore method, composting is done in pits of different sizes depending on the waste material available. A layer of waste materials is first laid in the pit. It is moistened with a suspension of 5-10 kg cow dung in 2.5 to 5.0 I of water and 0.5 to 1.0 kg fine bone meal sprinkled over it uniformly. Similar layers are laid one over the other till the material rises 0.75m above the ground level. It is finally plastered with wet mud and left undisturbed for 8 to 10 weeks. Plaster is then removed, material moistened with water, given a turning and made into a rectangular heap under a shade. It is left undisturbed till its use.

In the Indore method of composting, organic wastes are spread in the cattle shed to serve as bedding. Urine soaked material along with dung is removed every day and formed into a layer of about 15 cm thick at suitable sites. Urine soaked earth, scraped from cattle sheds is mixed with water and sprinkled over the layer of wastes twice or thrice a day. Layering process continued for about a fortnight. A thin layer of well decomposed compost is sprinkled over top and the heap given a turning and reformed. Old compost acts as inoculum for decomposing the material.The heap is left undisturbed for about a month. Then it is thoroughly moistened and given a turning. The compost is ready for application in another month.

In the Bangalore method of composting, dry waste material of 25 cm thick is spread in a pit and a thick suspension of cow dung in water is sprinkled over for moistening. A thin layer of dry waste is laid over the moistened layer. The pit is filled alternately with dry layers of material and cow dung suspension till it rises 0.5 m above ground level. It is left exposed without covering for 15 days. It is given a turning, plastered with wet mud and left undisturbed for about 5 months or till required.

In Coimbatore method, there is anaerobic decomposition to start with, following by aerobic fermentation. It is the reverse in Bangalore method. The Bangalore compost is not so thoroughly decomposed as the Indore compost or even as much as the Coimbatore compost, but it is bulkiest.

Compost is a rich source of organic matter. Soil organic matter plays an important role in sustaining soil fertility, and hence in sustainable agricultural production. In addition to being a source of plant nutrient, it improves the physico-chemical and biological properties of the soil.

As a result of these improvements, the soil:

(i) becomes more resistant to stresses such as drought, diseases and toxicity;

(ii) helps the crop in improved uptake of plant nutrients; and

(iii) possesses an active nutrient cycling capacity because of vigorous microbial activity. These advantages manifest themselves in reduced cropping risks, higher yields and lower outlays on inorganic fertilizers for farmers.

COMPOSTING MANGOES

Over 2,500 varieties of Mango are grown throughout the tropics and these give us  a delicious tropical fruit. Mangos once eaten provide the composter with the peel and seed to add to the compost bin.  Any  Mango flesh not eaten will breakdown  quickly when added to the  bin,  or wormery. Peel will be decomposed more slowly but will rot more quickly if  cut it into thin strips before adding to the bin or the complete skin can be added along with other kitchen waste.

However, if significant quantities of mango peel are to be composted  a hot composting system is recommended using fresh cow dung (3:1 ratio) and 2.5% Urea dissolved in water. The compost bin is every three or four days and should be ready in about a month. The compost may need soaking when turned to  moisture level of about 50%.

The mango seed can be composted but this will take a longer to compost and, like eggshells, will   not be decomposed the first time it passes through  a cold composting system.  These seeds can take years to decompose in the compost bin,  it is just a case of putting them back  into the bin for another year or two when harvesting the compost.  However, you might find that they germinate in a cold compost heap and can be transplanted to provide you own tree (or orchard). Soaking  the seeds in boiling water is recommended as this will  speed up the decomposition process and prevent germination in the bin.

Leaves from Mango trees can be composted in the normal way and are suitable for vermiculture. The dried leaves can also been ground with a pestle and mortar or a shredder and used as an organic fertiliser/mulch.

COMPOSTING ORGANIC MATERIALS WITH HIGH LIGNIN CONTENT – LIME TREATMENT

• By adding organic wastes such as sawdust, wood shavings, coir pith, pine needles, and dry fallen leaves, while preparing organic waste mixtures for composting, one can ensure that the compost produced contains sufficient and long-lasting humus. However gardeners often find that where they use lignin-rich plant materials, the compost does not ripen rapidly. A technique for making good compost from hard plant materials Involve es mixing lime in a ratio of 5 kg per 1000 kg of waste material. Lime can be applied as dry powder or after mixing with a sufficient quantity of water. Treatment with lime enhances the process of decomposition of hard materials.
• Liming can enhance the humification process in plant residues by enhancing microbial population and activity and by weakening lignin structure. It also improves the humus quality by changing the ratio of humic to fulvic acids and decreases the amount of bitumen, which interferes with the decomposition process. Instead of lime, powdered phosphate rock can be used in a ratio of 20 kg per 1 000 kg of organic waste. Phosphate rock contains a lot of lime. The phosphates and micronutrients contained in phosphate rock make composts rich in plant nutrients.

COMPOST ENRICHMENT

Farm compost is poor in P content (0.4-0.8 percent). Addition of P makes the compost more balanced, and supplies nutrient to micro-organisms for their multiplication and faster decomposition. The addition of P also reduces N losses. Compost can be enriched by:

• Application of superphosphate, bone meal or phosphate rock: 1 kg of superphosphate or bone meal is applied over each layer of animal dung. Low-grade phosphate rock can also be used for this purpose.
• Use of animal bones: these can be broken into small pieces, boiled with wood ash leachate or lime water and drained, and the residue applied to the pits. This procedure of boiling bones facilitates their disintegration. Even the addition of raw bones, broken into small pieces and added to the pit, improves the nutrient value of compost significantly.
• Wood ash waste can also be added to increase the K content of compost.

THE BENEFITS OF USING COMPOSTS TO AGRICULTURE

Compost has been considered as a valuable soil amendment for centuries. Most people are aware that using composts is an effective way to increase healthy plant production, help save money, reduce the use of chemical fertilizers, and conserve natural resources. Compost provides a stable organic matter that improves the physical, chemical, and biological properties of soils, thereby enhancing soil quality and crop production. When correctly applied, compost has the following beneficial effects on soil properties, thus creating suitable conditions for root development and consequently promoting higher yield and higher quality of crops.

IMPROVES THE PHYSICAL PROPERTIES OF SOILS

• Reduces the soil bulk density and improves the soil structure directly by loosening heavy soils with organic matter, and indirectly by means of aggregate-stabilizing humus contained in composts. Incorporating composts into compacted soils improves root penetration and turf establishment.
• Increases the water-holding capacity of the soil directly by binding water to organic matter, and indirectly by improving the soil structure, thus improving the absorption and movement of water into the soil. Therefore, water requirement and irrigation will be reduced.
• Protects the surface soil from water and wind erosion by reducing the soil-dispersion action of beating raindrops, increasing infiltration, reducing water runoff, and increasing surface wetness. Preventing erosion is essential for protecting waterways and maintaining the quality and productivity of the soil.
• Helps bind the soil particles into crumbs by the fungi or action mycetes mycelia contained in the compost and stimulated in the soil by its application, generally increasing the stability of the soil against wind and water erosion.
• Improves soil aeration and thus supplies enough oxygen to the roots and escapes excess carbon dioxide from the root space.
• Increases the soil temperature directly by its dark color, which increases heat absorption by the soil, and indirectly by the improved soil structure.
• Helps moderate soil temperature and prevents rapid fluctuations of soil temperature, hence, providing a better environment for root growth. This is especially true of compost used as a surface mulch.

ENHANCES THE CHEMICAL PROPERTIES OF SOILS

• Enables soils to hold more plant nutrients and increases the cation exchange capacity (CEC), anion exchange capacity (AEC), and buffering capacity of soils for longer periods of time after composts are applied to soils. This is important mainly for soils containing little clay and organic matter.
• Builds up nutrients in the soil. Composts contain the major nutrients required by all plants [N,P,K, calcium (Ca), magnesium(Mg), and S] plus essential micronutrients or trace elements, such as copper (Cu), zinc (Zn), iron (Fe), manganese (Mn), boron (B), and molybdenum (Mb).
• The nutrients from mature composts are released to the plants slowly and steadily. The benefits will last for more than one season.
• Stabilizes the volatile nitrogen of raw materials into large protein particles during composting, thereby reducing N losses.
• Provides active agents, such as growth substances, which may be beneficial mainly to germinating plants.
• Adds organic matter and humus to regenerate poor soils.
• Buffers the soil against rapid changes due to acidity, alkalinity, salinity, pesticides, and toxic heavy metals.

IMPROVES THE BIOLOGICAL PROPERTIES OF SOILS

• Supplies food and encourages the growth of beneficial microorganisms and earthworms.
• Helps suppress certain plant diseases, soil borne diseases, and parasites.
• Research has shown that composts can help control plant diseases (e.g. Pythium root rot, Rhizoctonia root rot, chili wilt, and parasitic nematode) and reduce crop losses. A major California fruit and vegetable grower was able to cut pesticide use by 80% after three years of compost applications as part of an organic matter management system. Research has also indicated that some composts, particularly those prepared from tree barks, release chemicals that inhibit some plant pathogens. Disease control with

compost has been attributed to four possible mechanisms:

1) successful competition for nutrients by beneficial microorganisms;

2) antibiotic production by beneficial microorganisms;

3)successful predation against pathogens by beneficial microorganisms;

4)activation of disease-resistant genes in plants by composts;and

5) high temperatures that result from composting kill pathogens.

• Reduces and kills weed seeds by a combination of factors including the heat of the compost pile, rotting, and premature germination.

ECONOMIC AND SOCIAL BENEFITS OF COMPOSTING

The economic and social benefits of composting include the following:

• Brings higher prices for organically grown crops.
• Composting can offer several potential economic benefits to communities:
• Extends current landfill longevity and delays the construction of a more expensive replacement landfill or incinerator.
• Reduces or avoids landfill or combustor tipping fees, and reduces waste disposal fees and long-distance transportation costs.
• Offers environmental benefits from reduced landfill and combustion use.
• Creates new jobs for citizens.
• Produces marketable products and a less-cost alternative to standard landfill cover, artificial soil amendments, and conventional bioremediation techniques.
• Provides a source of plant nutrients and improves soil fertility; results in significant cost savings by reducing the need for water, pesticides, fungicides, herbicides, and nematodes.
• Used as an alternative to natural topsoil in new construction, landscape renovations, and container gardens. Using composts in these types of applications is not only less expensive than purchasing topsoil, but it can also often produce better results when establishing a healthy vegetative cover.
• Used as mulch for trees, orchards, landscapes, lawns, gardens, and makes an excellent potting mix. Placed over the roots of plants, compost mulch conserves water and stabilizes soil temperatures. In addition, it keeps plants healthy by controlling weeds, providing a slow release of nutrients, and preventing soil loss through erosion. Herewith we have submitted the required method of preparation of culture and implementation to your plants.