This article is from ECHO Asia Note #24
[Editors’ Note: Over the past several years, ECHO Asia has coordinated research, conducted trainings, and promoted the use of biocontrol fungi known as Trichoderma and Beauveria. This article briefly shares findings by Mennonite Central Committee (MCC) Bangladesh and the Bangladesh Agricultural Research Institute (BARI) about the benefits and techniques of using tricho-compost.]
What is Tricho-Compost?
Tricho-compost is the material that results when spores of a beneficial fungus, Trichoderma sp. are used in the composting process. Trichoderma sp. are natural competitors against a wide range of harmful fungi; when it is added to compost, the latter can then work as an anti-fungal agent to protect crops in the field.
From Where is the Trichoderma Obtained?
Trichoderma is a genus of beneficial fungus present in nature. It needs to be isolated from the soil in order to obtain a pure culture of Trichoderma. Soil samples from the root zone of plants are diluted up to 106 times in distilled water and then used as inoculum in a sterilized Potato Dextrose Agar (PDA) medium to allow the fungi to grow. From the fungi colonies in PDA growth medium, Trichoderma is isolated (by observing the spores/ conidia) and then put for pure culture in the same growth medium. A higher dilution of the soil sample will lead bacterial colonies to grow in the growth medium, rather than fungi, which is not desirable. Trichoderma inoculum is a fresh and pure culture of Trichoderma sp. used in Trichoderma compost preparation. It is usually produced in a lab, where a specific Trichoderma species can be isolated and multiplied on a growth medium without contamination from other species of fungus.
What is Trichoderma Leachate?
Trichoderma leachate is the liquid soup/ syrup that comes out of the compost heap, as a result of the Tricho-composting process (Nahar et al., 2012). This leachate often has a higher content of Trichoderma spores per unit than the same amount of the compost itself. The leachate has a nutritive value for plants, and can be used as a foliar spray (in diluted form) for plants. Alternatively, it can be used as a Trichoderma inoculum for the next batch of compost preparation (Deepthi and Reddy, 2013). Details use of Trichoderma leachate is described later in this document.
In 2008, MCC was approached by BARI to do research on tricho-compost. BARI had developed a method for producing this compost, but wanted help in finding ways to adapt it for use by organizations and farmers in Bangladesh, as their current system was not efficient for these purposes. In turn, MCC approached one of its partners, Grameen Krishok Shahayok Sangstha (GKSS), a group that was already doing vermi-composting, and they agreed to assist with this research. Through research and field testing, a consistent mixture was developed as follows:
• 25% cow dung (rich in nitrogen, with a carbon-to-nitrogen ratio (C:N) of 8)
• 5% sawdust (as a source of carbon)
• 36% poultry refuse (to provide calcium and nitrogen, and to reduce incidence of soilborne disease)
• 33% water hyacinth (to provide potassium)
• 0.5% ash (to provide potassium)
• 0.5% maize bran (as a feed for the inoculum)
Benefits of the Ingredients
This mixture was decided upon for several reasons. Cow dung and water hyacinth are readily available in Bangladesh, and are a good source of nutrients and organic matter.
Poultry refuse is added for its nutrient content as well as anti-nematode and bactericidal effect. In MCC’s experiments here in Bangladesh, we have found that application of poultry refuse around plants results in successful control of bacterial wilt in tomato and eggplant (MCC research Report). When using poultry refuse in tricho-compost, the compost retains this quality. Poultry refuse has some phenolic substances which work as anti-bacterial agents against bacterial wilt. Poultry refuse is also rich in nitrogen and in calcium, which makes the plant cells strong and enable plants to resist diseases like root knot from nematode infestation (Faruk et al., 2011), thus preventing secondary infection by bacteria and fungi that might cause bacterial wilt, and damping off respectively.
Water hyacinth provides a great deal of organic matter, but its C:N ratio is high; it contains 29 times more carbon than nitrogen (Mathew et al., 2014). Poultry refuse and cow dung, by contrast, have lots of nitrogen that can be released quickly in the composting process and can potentially be lost to the atmosphere as ammonia. This means mixing water hyacinth with poultry refuse can increase the C:N ratio of the whole composting mix and thus minimize the nitrogen loss in the compost (Compost Fundamentals, 2015). Including water hyacinth in the tricho-compost allows the nitrogen to be trapped by microorganisms during the decomposition process. Although urine from animals has not been used in the tricho-compost mixture in Bangladesh, it is an alternative nitrogen source. As with poultry refuse, the presence of water hyacinth can help in trapping the nitrogen in the compost. Green water hyacinth also serves as source of carbohydrate (Luu and Getsinger, 1990) in the composting mix; as a carbohydrate source it can be replaced with other green material, but may not contain as much carbon as water hyacinth does.
Ash adds minerals to the compost, especially potassium. Maize bran is added as a growth medium (carbohydrate/energy source) for the Trichoderma to grow and multiply vigorously in the compost mix, especially in the early days of composting.
Apart from being a source of carbon, both sawdust and water hyacinth make the compost mix fluffy and help with aeration. Sawdust also prevents the final product (compost) from being compact and solid, thus making it friable.
All of these ingredients are readily available in Bangladesh at a reasonable price compared to alternatives. However, continued monitoring of market prices is needed, as prices and availability of these and materials may change over time.
Mixing in the Trichoderma Inoculum
The inoculant mix used in Bangladesh is one liter of Trichoderma inoculum mixed with 0.5 kg of molasses and 20-25 liters of water, per ton of compost. These ingredients are mixed together and added to the compost recipe listed above. The compost and inoculum mixture are combined thoroughly before being placed in the compost bin. At first, MCC Bangladesh tried putting the compost mixture in the bin by using a layering method, sprinkling the inoculant mixture over each layer. However, layering was found to be a poor method for several reasons: it was very labor intensive, it subsequently required agitation of the compost to facilitate Trichoderma mycelium to mix with the composting material homogeneously for better decomposition of materials inside layers (a very smelly job that no laborer liked), and the agitation consequently disturbed the natural warm thermal environment that the fungus likes. The current method of composting using latrine rings, described in next paragraph, works great (provided that the compost is mixed well, the moisture level is appropriately maintained, and the compost is not compressed).
Size of the Compost Bin and Use of Latrine Rings
The height of the bin used for composting is important because of the compression issue. Because the composting mixture contains 33% fluffy water hyacinth, as the decomposition process progresses, it gets reduced in volume significantly. Therefore, if the composting pile is not high enough, in few days it will be reduced into a thin layer, and may not be providing the natural warm thermal environment that Trichoderma likes. In their resarch, our staff have found that a 10’ x 5’ x 4.5’ bin is the optimal size for composting. This size is small enough to allow proper aeration but large enough that the Trichoderma can produce some residual heat, which speeds up the process. If the bin is too large, lack of aeration becomes a concern. If the bin is too small, the compost loses its residual heat and the Trichoderma works more slowly.
Given these requirements, currently MCC Bangladesh is mostly using concrete pit latrine rings for our bins. These rings are stacked three high and filled with about 400 kg of compost materials including 240 liters of water, resulting in about 120 to 140 kg of final product from each set of three rings. These rings are used because of their widespread availability to farmers in Bangladesh, and are appropriate because they are scaled to the size of what a farmer would need if they have one cow. Typically in a 10’ x 5’ x 4.5’ design, the bin would have a concrete floor with a drainage system that leads to a trap to catch the leachate that runs off the compost. In MCC Bangladesh’s latrine ring bins, this is not economically feasible. So instead, a sheet of polythene plastic is used under the bin, which works pretty well as a makeshift waterproof floor, as long as it does not get punctured. The leachate should be collected and poured back onto the compost for the first 10 days. The leachate that comes out in first 10 days is not really the result of the decomposition process, but more from the seepage of the excess water (with Trichoderma spores) from the composting mix. Putting it back in the composting bin keeps the composting mixture moist and helps out with the decomposition process. From 15 days after setting up the composting process onward, the leachate may be collected and bottled, as it has multiple beneficial uses described later. Be sure to use caution in bottling, as the liquid still releases gas that can blow the bottle up (Deepthi and Reddy, 2013).
Monitoring of the Bin and Routine Maintenance
After the compost has been placed in the bin, some monitoring is necessary. MCC Bangladesh’s staff recommends checking the temperature of each batch by poking a thermometer (tied onto a stick) or a needle thermometer down into the center every 7-15 days. Once the Trichoderma begins to grow and produce, the temperature of the compost should rise to as much as 50-60o C, depending on the outside temperature and the size of the bin. A decrease in temperature is a sign that there is too little moisture for the Trichoderma, or that the process is near completion. Another form of monitoring is to poke a stick down into the middle of the compost to the bottom and pulled it out to check the colour differences in the stick, the decomposed material will make the stick dark in colour, but the undecomposed segment of the compost mix will make the stick not so dark (natural colour of cow dung). The decomposition process begins from the surface and moves downwards due to higher availability of oxygen in the surface region, which allows Trichoderma to grow faster. Smell is another indicator of the nearness to completion; finished compost smells somewhat sweet, compared to the initial smell of manure and rot. In MCC Bangladesh’s experience, during the summer, when temperatures average 35o C in Bangladesh, the composting process takes roughly 45 days. During the winter, when temperatures may drop as low as 10o C, the process can take up to 70 days.
Tricho-compost is primarily used as a soil amendment. Like traditional compost, it improves soil structure, improves water holding capacity, can help regulate soil pH, and can assist with soil temperature maintenance. It should be applied at a rate of 2 to 2.5 tons/hectare to the crop field. It can be used in the land preparation stage, and/ or as a secondary dose or overhead dose for the farmer’s plants.
Tricho-compost has additional benefits compared to traditional compost:
• Tricho-compost works as a natural antifungal agent against harmful fungi (Pythium sp, Sclerotium sp, Phytophthora sp, Rhizoctonia sp, Fusarium sp, Botrytis sp, Sclerotonia sp ), which are mostly responsible for soil born disease and fungal wilt;
• Because of the inclusion of poultry refuse, Tricho-compost provides resistance against bacterial wilt and nematode infestation (Gapasin, 2007; Nahar et al., 2012);
• Tricho-compost may work as growth promoter in plants (Celar and Valic, 2005; Rabeerdran et al.,2000; Inbar et al.,1994; Lynch et al.,1991; Hoyos-Carvajal et al.,2009).
As previously mentioned, Trichoderma leachate, a by-product of the Tricho-compost process, has many uses. One challenge in Bangladesh is that Trichoderma inoculum is a bit too complex for farmers to produce, and requires laboratory production. This makes Trichoderma inoculum difficult for farmers to obtain. To address this issue, MCC Bangladesh researched with our partners and found that Trichoderma leachate contains enough spores to be used as a substitute for the inoculum for up to six generations of compost production before a fresh inoculum is required again. Additional research is currently being done to see whether this process produces compost with all the same benefits as that made by fresh inoculum.
Trichoderma leachate’s other primary use in Bangladesh is as a foliar spray. For its use, it needs to be sieved (because solid particles present in leachate may block the sprayer) before putting it into the sprayer, and diluted in water at 20ml/liter water. This spray is primarily used for (but not restricted to) fruit trees during flowering, as it provides both nutritional and hormonal boosts to trees during a key stage of production. MCC Bangladesh has also found very good results by spraying it in seedling and growing stages of vegetables. Since the leachate contains micronutrients as well, the user needs to be aware that the overuse of it in the growing stage of plants might result in much vegetative growth which may lead to less fruiting (over-fertilization effect). Spraying of leachate on fruits and vegetables a few days before harvesting might result in fruits and vegetables retaining some foul smell from the leachate.
Story of Md. Abdul Mannan
[Note: Below is a story of how a farmer near Bogra has benefitted greatly from using Tricho compost.]
Md. Abdul Mannan is a Bangladeshi farmer from the Bogra district of Bangladesh. His main source of income is vegetable cultivation. He has one daughter and two sons; all of them are currently studying at the college level. Md. Mannan lives with his elderly mother. In total, five family members live in his household.
Md. Mannan has 0.485 hectares of land, where he has been cultivating vegetables and rice for many years. Every year, Md. Mannan found he needed to spray a huge amount of pesticides to control pests in his vegetable and rice plots. He also had to apply a lot of fertilizer in his field. Because of these expensive inputs, he wasn’t receiving a high amount of profit from his crops. It was difficult for him to bear the cost of his family’s living expenses, as well as the cost of his children’s study expenses.
One day, Md. Mannan was selected as a beneficiary of Grameen Unnayan Prokolpo (GUP), a partner NGO of the MCC Bangladesh food security project. GUP implements integrated pest management (IPM) techniques in vegetable cultivation. Md. Mannan received information about IPM at the GUP yard meetings. Yard meetings are short training sessions with group of farmers gathered in someone’s court yard, like a farmer field school. He also noticed information on billboards and posters that GUP and MCC had displayed in the area where the GUP project was implemented.
After receiving training support from GUP, Md. Mannan started to make tricho-compost and vermicompost (compost prepared by using earth worms) in his homestead. He also learned about the use of pheromones to control harmful insects. Sex pheromone is the chemical usually emitted by female insects to attract males of the same species for mating (Knodel, Petzoldt, and Hoffmann, 1995). Synthetic pheromones are used as bait in a trap to attract the male insect to trap it to death, thus leaving only the females which cannot mate or reproduce. After producing these composts and pheromones, he used the compost in his vegetable field.
By using Tricho-compost, vermicompost, and pheromones, Md. Mannan has been able to greatly reduce his costs for fertilizer and pesticides. In addition, he produced a good quality vegetable crop from his field. Most recently, he cultivated eggplant, country bean (Lablab purpureus), yard-long bean, pointed gourd, and chili on his land. Using the organic farming methods that he learned through GUP, Md. Mannan had higher crop production, as well as good color and vigorous vegetable growth. Last year, Md. Mannan earned US$ 865 from selling vegetables, compared to approximately US$ 288 by any average farmers with similar landholding. He was very happy to see the beneficial effect of the IPM techniques; it was because of these IPM techniques that he earned more money than in past years. Now, he and his family members are very happy, because their income has improved. Due to this success, Md. Mannan isstill practicing IPM techniques in his field and says that he will continue to practice these techniques in future.
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