Key words: Composting, compost fungus activator, inorganic fertilizers, technology transfer
Fertilizer Production and Utilization in the Philippines
The Philippines is basically an agricultural country. Most of the population live in rural areas, and agriculture employs about 50% of the total work force. A large amount of chemical fertilizers are used: 1.4 million mt in 1995. Of this, 37% was urea, half of which was imported. In 1995, the Philippines exported around 700,000 mt of chemical fertilizer and imported about 1,237 thousand mt, about half of which was urea. More than half the chemical fertilizer applied in the Philippines (52%) is used for rice and corn.
Organic fertilizer production began in 1974, but in 1978 organic fertilizers were less than 1% of total fertilizer sales, rising to 1.34% in 1992. As of 1993, there were 26 licensed manufacturers of organic fertilizers, and 15 processors of guano phosphate, phosphate rock, and soil conditioners (PCARRD info sheet 1996). These figures may have increased by 1996, since a number of producers of compost who use the Rapid Composting Technology have obtained licenses from the Fertilizer and Pesticide Authority (FPA).
Major Concerns about Soil Fertility Status in the Philippines, and Fertilizer Recommendations
Some major problems regarding soil nutrients and soil productivity in the Philippines, and fertilizer use by Filipino farmers, have been identified by the Bureau of Soils and Water Management (BSWM) of the Philippine Department of Agriculture.
Most soils in Central Luzon, a major rice producing area of the country, have been degraded. They are suffering from soil acidity, low organic matter, and a deficiency of zinc and sulfur. In most cases, the sulfur deficiency is because of the continuous use of urea as the main nitrogen carrier.
Zinc deficiency is not confined to Central Luzon, but is also found in other major rice-producing areas of the country. A number of zinc-deficient areas have been identified where lack of zinc is a major limiting factor, and yields are low even with high fertilizer applications. The problem is thought to arise because the soils are derived from limestone, and because of intrusions of tidal sea water.
There is an increasing consumption of fertilizer in the Philippines, but this increase has not been translated into a proportional increase in crop yields. This is probably because of the lack of a good nutrient balance in fertilizer applications. Filipino farmers use 4 - 7 kg nitrogen to every kilogram of phosphorus fertilizer, while the desired ratio should be 3 - 4 kg N for every kilogram of P.
In most situations, small-scale farmers apply much less fertilizer than has been recommended. This can be attributed to the high cost of chemical fertilizers.
Furthermore, most soils in the Philippines require a balanced supply of calcium and magnesium, in addition to N, P, and K.
The Bureau has submitted a series of recommendations for fertilizer use. These include both primary fertilizer recommendations to supply basic soil nutrients, and secondary fertilizer recommendations that supply additional nutrient requirements according to the need of the actual crop location. These nutrients can be supplied by both organic and inorganic sources. Different grades for inorganic fertilizers, or the amount of organic fertilizer needed for each soil type and climatic types in each province and region, are available (BSMW, Dept. Agriculture 1996).
The Fertilizer and Pesticide Authority (FPA) is an agency under the Department of Agriculture that regulates the importation, manufacture, distribution, and sale of fertilizer. It has formulated guidelines on good agricultural practices to optimize fertilizer use. These guidelines advocate an integrated plant nutrition system that involves the combined use of organic and inorganic fertilizers. It is designed to promote sustainable productivity.
The Ibs Rapid Composting Technology
This technology was developed by the author (Dr. V.C. Cuevas), and is named after the Institute of Biological Sciences (IBS) where the author works. It is a development of the windrow type of composting, and the main innovation is inoculation with pure cultures of Trichoderma harzianum Rifai, a cellulolytic fungus. The fungus is cultured in sterile sawdust mixed with leaves of ipil-ipil ( Leucaena leucocephala, a leguminous tree). The whole package — a one-kilogram pack of fungus medium in a plastic bag — is referred to as compost fungus activator (CFA). The activator is broadcast over rice straw or other plant residues when the substrate is made into a pile. It should be applied at a rate of 1% (by fresh weight) of the substrate. Adequate moisture and aeration should be provided throughout the composting period. The initial C:N ratio of the substrate should be kept low, by combining animal manure with plant materials with a high carbon content. The composting time, using this procedure, ranges from 21 to 45 days, depending on the plant substrates used (Cuevas 1988a, b).
The activator increases the population of microbial cellulose decomposers. If the compost pile has an adequate moisture content, enough nitrogenous materials and good aeration, these microorganisms multiply rapidly. The increase in the population of microorganisms raises the temperature inside the compost heap, which in turn hastens the decomposition process. The composting period is shortened to just four weeks.
The technology basically consists of two parts: the production of the compost fungus activator, and the composting process.
Technology Transfer to Filipino Farmers
In 1990, the Philippine government, through the Philippine Council for Agriculture, Forestry and Natural Resources Research and Development (PCARRD), began a national program which introduced to Filipino farmers the rapid composting technology and the use of compost as fertilizer. The compost produced through this technology is now part of fertilization recommendations for rice and other crops.
During the first three years, emphasis was on the establishment of mass production centers for the compost fungus activator throughout the Philippines. Government technicians were trained in the production of the activator, and in the composting process using this activator. These trainees in turn conducted their own training courses in their home provinces. The target of the program then changed to farmers, encouraging them to produce their own compost using raw materials such as rice straw and animal manure available on their farms.
In this second phase of the program, farmers' cooperatives, private enterprises and non-government organizations were assisted to establish compost production units. Mechanization of some of the production steps was included in the program. The compost produced was sold to farmers in 50 kg bags. Assistance was given in terms of:
- Training in the production of the activator;
- Advise on how to use it in proper composting procedures;
- Analysis of the nutrient content of the compost produced;
- Mechanization of the composting process;
- Help in obtaining credit from banks and other institutions;
- Conduct of efficacy trials of the compost produced;
- Registration of the compost at the FPA; and
- Securing a license as a compost manufacturer from the FPA.
Steps in Composting
Preparation of Substrates
Substrates such as rice straw, weeds and grasses should be chopped. Chopping helps speed up decomposition by increasing the surface area available for microbial action, and providing better aeration. If large quantities of substrates are to be used (i.e. several tons), a forage cutter/chopper is needed. Chopping can be dispensed with if the compost is not needed in the near future.
Adjustment of Moisture Content
Substrates should be moistened with water. Plant substrates can be soaked overnight in a pond, which cuts down on the need for water. If a large volume of substrates are to be composted, a sprinkler is more convenient.
The Compost Mixture
Carbonaceous substrates should be mixed with nitrogenous ones at a ratio of 4:1 or less, but never lower than 1:1 (on a dry weight basis). Some possible combinations are:
- 3 parts rice straw - 1 part ipil-ipil
- 4 parts rice straw - 1 part chicken manure
- 4 parts grasses - 1 part legume materials + 1 part manure
- 4 parts grasses - 1 part Chromolaena odorata or Mikania cordata + 1 part animal manure
Note: Chromolaena odorata is a common broad-leaf weed. Mikania cordata is an herbaceous climbing plant, a common weed in the Philippines.
It is important to use grasses and weeds which do not have any flowers or seeds.
The substrates should be piled loosely in a compost pen to provide better aeration within the heap. The material should not be too compact and no heavy weights should be put on top. Compost heaps should be located in shady areas such as under big trees. The platform should be raised about 30 cm from the ground, to provide adequate aeration at the bottom. Alternatively, aeration can be provided by placing perforated bamboo trunks horizontally and vertically at regular intervals, to carry air through the compost heap.
The compost activator, consisting of a cellulolytic fungus, is broadcast onto the substrates during piling. The amount of activator used is usually 1% of the total weight of the substrates (i.e. about 1 kg compost activator per 100 kg substrate). Decomposition is faster if the activator is mixed thoroughly with the substrate. A greater amount of activator can be used if faster decomposition is desired.
The heap should be covered over completely. This maintains the heat of decomposition, and minimizes water evaporation and ammonia volatilization. White plastic sheets, or plastic sacks with their seams opened and sewn together, can serve as a cover.
The compost heap usually heats up in 24 - 48 hours. This heat is very important, especially if manure is used, because it kills disease microorganisms. Some seeds of weeds are also rendered nonviable. Temperature readings should be taken at different parts of the pile at least three times a week.
Heat should be maintained at 50°C or higher, and the heap should be turned over every 5-7 days for the first two weeks, and thereafter once every two weeks. Turning over the pile provides adequate aeration, and evens up the rate of decomposition throughout the pile. It also serves as a means of checking the moisture content of the substrate. After the first week, the volume of the pile should be reduced by one-third. After two weeks, the volume of the pile should be reduced to one half the original.
The compost is ripe if:
- The temperature in all parts of the pile drops to 33-35°C, or approximately air temperature, after the 2nd or 3rd turning.
- The different materials in the substrate are no longer recognizable.
- The compost is dark brown to black, and looks like soil.
- The ripe compost does not emit a foul odor.
If the temperature of the heap drops to 30°C but the compost is not needed immediately, it is best to let decomposition continue further. The mature compost should be removed from the pen, and dried in the sun for two days. It should then be put into sacks and stored in a shaded area. Decomposition will continue until the substrate is finely fragmented, so that the finished product has a powdery texture. Then, once decomposition is complete, the compost should be sun-dried again until the moisture contest is at most 10-20%.
If mature compost is needed at once, it should be sun-dried for one day, as soon as its temperature drops to 30°C. Drying removes excess moisture, and makes the compost much easier to handle. Although the compost still retain some fibers, it can be applied immediately as fertilizer.
In a tropical country like the Philippines, compost can be made throughout the whole year. Mature compost can be stored for at least six months without any appreciable change in nutrient content, especially if the stored compost has a very low moisture content (10-20%).
Commercial Compost Production
In the large-scale commercial production of compost, it is recommended that the following steps be mechanized.
- Chopping of substrates.
- Mixing/Turning. When there are several tons of substrate, a pay loader will make mixing of substrates or turning of heaps much easier.
- A hammer mill should be used to break up big lumps of mature compost before drying.
- During rainy months, it is more economical to dry compost mechanically than try to sun dry it.
Nutrient Content of Compost
Table 1(541) presents the ripening period and chemical composition (% C, N, P, K) and pH of the mature compost produced through this rapid composting technology. The compost has a neutral to alkaline pH. The length of time needed for the compost to mature was dependent on the type of plant substrates used for composting. The more fibrous the plant materials, the longer the period needed for composting. The composting period for rice straw, for example, was almost double that needed for sugarcane bagasse. This difference can be traced to the initial C:N ratio of the substrates used for composting. Usually, fibrous materials have a low nitrogen content but are rich in carbon, giving a high initial C:N ratio. The initial C:N ratio of the substrates used for composting plays a major role in determining the length of the composting period. If substrates have an initial C:N ratio of 25:1, the composting period can be shortened to only three weeks.
The mature compost has a low level of N, P and K, compared to chemical fertilizer. On the other hand, compost also contains a wide range of the plant nutrients that are essential for crop growth. Table 2(557) shows that compost contains C, Ca, Mg, Zn, and B, and probably contains a number of other micronutrients which were not included in the analysis. These micronutrients are not present in the ordinary formulations of inorganic fertilizer sold on the market. The presence of large quantities of organic carbon in compost also helps improve the physical and chemical properties of soils. Common changes which follow continuous compost application are: improved water holding capacity, increased soil aeration and increased soil pH.
Fertilizer Recommendations Using Compost
Compost Produced by Individual Farmers
Farmers are advised to utilize all available materials on the farm as substrates. All the compost produced should be applied as a basal fertilizer just before the last harrowing, and before the transplanting of rice seedlings. The compost should be applied at a rate of at least 1 mt/ha. With regard to chemical fertilizer, half of the recommended rate should be applied 30 - 45 days after transplanting, as a side-dressing or top-dressing.
When commercially-produced compost is used, 500 - 750 kg/ha should be applied (10 - 15 bags, 50 kgs each) as basal fertilizer. As with the farm compost, half of the recommended level of chemical fertilizers should be applied 30 - 45 days after transplanting.
It can be seen that the recommended level of compost to be applied by farmers when they make it themselves is higher than when commercial compost is used. Experience has shown that the compost produced on farms has a very low N, P and K content, because only small amounts of nitrogenous substrates are used for composting. Table 1(541) shows that farmers' compost contained only 1% of N, P and K. Farmers have difficulty in obtaining large amounts of animal manure. Filipino farmers do not usually confine their draft animals in feedlots, but graze them in the open field, which makes it difficult to collect the livestock manure.
Commercially produced compost is regulated by the FPA. For a product to be registered as a commercial organic fertilizer, it must contain a total of at least 7% of the three main elements, N, P and K, and at least 10% carbon. The National Program requires that of this 7%, the N content is not lower than 1.5%, while P and K make up the remainder. Thus, commercial compost has a much higher N, P and K content than the compost produced by most farmers. To compensate for the low nutrient content of compost produced on farms, larger quantities of the fertilizer are therefore recommended.
Constraints Experienced in Technology Transfer
One reason why large number of Filipino farmers were not very enthusiastic in adopting the rapid composting technology was the high labor input involved in making the compost and applying it as fertilizer. The labor demand was about 6% higher than when chemical fertilizer alone was used. The higher labor input involved: the gathering of substrates, piling substrates into heaps, and applying a large volume of compost to the field. Filipino farmers would prefer to buy commercial organic fertilizer (if this is available), rather than make their own compost.
Other major constraints in making compost on farms were the lack of animal manure as a source of nitrogen and phosphorus, and also of plants rich in nitrogen, and water shortage during dry months. In many parts of the Philippines, there is a dry season which lasts 2 - 4 months.
These three major factors — increased labor demand, inadequate nitrogenous materials and lack of water for composting — made transfer of the technology difficult in the first three years of the program. The emphasis at that stage was on convincing farmers to produce their own compost. Mass production centers for the activator were established in almost every province, so the activator would be easily available to farmers.
Despite these drawbacks, a sizeable number of farmers adopted the technology, and followed the recommendations for using the compost as fertilizer. In addition, there were a number of farmers' cooperatives, NGOs, and small enterpreneurs who picked up the idea of commercially producing compost, using the technology. The National Program shifted its emphasis, and over the last three years (1993 - 1996), has been assisting interested organizations to establish compost production units.
The two biggest problems encountered in doing this was firstly, the registration of the compost product as organic fertilizer by the Fertilizer and Pesticide Authority (FPA), and secondly, securing a license for the compost producers from FPA to allow them to produce compost commercially. The rules and regulations regarding efficacy trials for their compost were not immediately clear to the compost producers. This lack of proper information posed great problems in marketing, and was a constraint to further expansion of commercial compost production.
Important lessons noted were the importance of extension staff and demonstration farms in technology adoption.
Positive Impact of the Compost Technology
Crop Yields and Economic Benefits
Pilot testing of the technology in different parts of the Philippines have shown clearly the benefits farmers can get if they follow the program. Table 3(539) presents the cost/benefit analysis of rapid composting during pilot tests in two regions of the country in 1989-90. At that time, the increase in farmers' income ranged from US$78-100 per cropping season (4 months). In terms of crop yields, combined use of compost + 50% inorganic fertilizers resulted in increases in crop yields which were 13% - 16% higher than in fields where chemical fertilizers alone were used.
A socio-economic analysis was conducted in 1996 on the impact of the rapid composting technology. This study confirmed the increased incomes of 68 farmers (from three different provinces) who had adopted the technology. These results are presented in Table 4(587) and Table 5(481). Yield increases were up to 15% higher compared to those of farmers who did not use the technology, but used only chemical fertilizers. In monetary terms, the increase in income per season was up to US$169. Although, the main emphasis in gathering data was on rice, increases in yields were also noted in sugarcane and vegetables where compost was applied as a basal fertilizer and chemical fertilizers were applied as a side or top-dressing.
Improvement in Physical and Chemical Properties of Soil
Other benefits were also mentioned by the farmers. These perceived benefits, and the relative importance given to them by farmers, are presented in Table 6(588). Improvement of soil tilth and texture, increase in soil fertility and reduced fertilizer costs were the most important benefits that farmers got from using compost in rice production. The decrease in nitrogen fertilizer requirements was estimated to be about 19 kg N/ha.
The yield increases in rice and other crops can be traced to the capability of the compost to supply nutrients needed for crop growth. The Bureau of Soils and Water Management of the Philippines has identified an imbalance of nutrients supplied by chemical fertilizers alone, and a deficiency of Ca, Mg and Zinc in soils in different parts of the country. These elements, lack of which may limit crop growth and productivity, are present in compost fertilizer. Fertilizer applications which included compost have a better chance of meeting all the crop's nutrient requirements. The technology therefore has great potential in helping Philippine agriculture attain sustainability, not only in terms of crop yields, but also in terms of protecting and conserving soil fertility.
Compost Production As a Viable Business Enterprise
As farmers became aware of these benefits, a demand for commercial compost arose. The number of compost production units using the rapid composting technology increased. At present, there are 48 Mass Production Centers for the fungus activator, and 23 Mass-Production Compost units in different parts of the Philippines. Most of these are in the large islands of Luzon (northern Philippines) and Mindanao (southern Philippines), with relatively few in the Visayas. Most of the Mass Production Centers have been established by national or local government agencies, and serve individual farmers who want to produce their own compost.
Table 7(500) presents the production and sales of the compost produced by commercial plants using the activator. Compared to the production and sales of the organic fertilizers from 1988 - 1992, the performance of these plants was better. Their sales were higher, reaching about 50% of their production, whereas sales of organic fertilizer before the rapid composting technology (1992) reached only 35% of production. Rola, et al. (1996), in their socio-economic evaluation of the technology, noted the positive growth rate of the compost plants, which suggests that farmers are increasingly buying compost rather than producing it themselves.
High Cost-Benefit Ratio
A cost-benefit analysis of the government investment into the National Program was carried out, using socio-economic data collected by Rola et. al. 1996. The techno-logy transfer of rapid composting to farmers was accompanied by an increase in total rice production in the Philippines of 0.11%. The data are presented in Table 8(546). An incremental value of US$13.3 million was estimated for this increase in rice production for the period 1992 - 1996. The computed cost-benefit ratio for the technology was 7.7 ( Table 9(465)). Using 1996 monetary values, it is estimated that the government's investment of US$2.36 million into technology gave a benefit of US$18.1 million (Librero and Tidon 1997).
Employment Generated by the Production Units
The cost benefit ratio of 7.7 mentioned above was based only on the contribution made by the compost to rice production. Rola et al. (1996) mentioned the employment generation that the establishment of compost production units brings to local communities as an additional benefit derived from the rapid composting technology. Each composting unit employs 2 - 23 laborers. Although employment is often intermittent, these composting units are located in rural areas where employment is very scarce.
Environmental Impact of the Technology
Another benefit from the technology is the efficient recycling of agricultural wastes. A number of compost production units utilize mud-press, a waste product of sugarcane processing, as a substrate. Others use corn cobs, while one farmers' cooperative utilizes banana peels, and still others use market wastes. Animal wastes such as chicken and hog manure are now being collected from farms and sold to compost producers. In this process, environmental pollution due to these wastes is slowly being reduced.
Present Status of the National Program
Additional funds from the Philippine Government are being requested for continuation of the program for another three years, which will constitute its last phase. The emphasis during this last phase will be on completing the technical assistance to the CPUs and to all other organic fertilizer producers. The main goal is to offer to farmers in the Philippines good-quality organic fertilizers at a reasonable price, to the benefit both of farm incomes and Philippine agriculture.
- Bandara, W.M.J. 1991. Effects of Lime and Organic Matter on Soil Acidity, Aluminum, Phosphorus and Growth of Corn and Mungbean on Two Acidic Soils. M.Sc. Thesis, University of the Philippines at Los Baños, College, Laguna, Philippines.
- Bureau of Soils and Water Management, Department of Agriculture. Philippines. 1996. A Primer on Reformulating Fertilizer Recommendations.
- Cuevas, V.C., S.N. Samulde and P.G. Pajaro. 1988a. Trichoderma harzianum Riifai as an activator for rapid composting of agricultural wastes. The Philippine Agriculturist 71,4: 461-469.
- Cuevas, V.C. 1988b. Make Your Own Compost. TLRC-UPLB Techguide Series No. 11. National Book Store, Inc., Manila, Philippines.
- Cuevas, V.C. and M.T. Agarrado. 1987. Technology: Make Composting Easy with Trichoderma. Philippine Council for Agriculture, Forestry and Natural Resources Research and Development, Los Baños, Laguna, Philippines.
- Cuevas, V.C. 1991. Rapid Composting for Intensive Riceland Use. Innovations for Rural Development 1,1: 5-10. SEARCA.
- Fertilizer and Pesticide Authority (FPA), Department of Agriculture, Philippines. 1996. Fertilizer Statistics from CY 1990 to January - June 1996.
- Fertilizer and Pesticide Authority (FPA). 1993. Report. Department of Agri-culture, Philippines.
- Fertilizer and Pesticide Authority (FPA). 1997. Guidelines on Good Agricultural Practices. Department of Agriculture, Diliman, Q.C., Philippines.
- Librero, A.I. and A.G. Tidon. 1997. Socio-Economic Evaluation of the Commercialization of Rapid Composting Technology. Paper presented during the 5th Annual Meeting of the National Program on Rapid Composting held at Marina de Bay, Puerto Princesa City, Palawan, April 16-17, 1997. (Unpublished mimeograph).
- Maglinao, A.R. 1997. The National Program on Rapid Composting and Use of Compost as Fertilizer: Accomplishments and Direction. Paper presented during the 5th Annual Reional Coordinators Meeting of the National Program on Rapid Composting held at Marina de Bay, Puerto Princesa City, Palawan, April 16-18, 1997. (Unpublished mimeograph).
- Philippine Council for Agriculture, Forestry and Natural Resources Research and Development (PCARRD). 1996. Information Sheet: The Fertilizer Industry. May 1996.
- Rola, A.C., A.R. Chupungco, M.G. Umali and S.D.E. Callet. 1996. Socio-Economic Evaluation and Policy Analysis of the Commercialization of the Rapid Composting Technology-Phase II. Terminal Report. University of the Philippines at Los Baños and the Philippine Council for Agriculture, Forestry and Natural Resources Research and Development, College, Laguna, Philippines. (Unpublished mimeograph).
Dr. Cuevas was asked about the origin of the fungal inoculant for compost production. She explained that she had isolated it in soil from Mount Makiling, near the University of the Philippines at Los Baños. This had been part of a survey of fungal flora, particularly of Trichoderma which is a common fungus in the Philippines. The identification had been confirmed by Kew Gardens, United Kingdom. The fungus produces a cellulase and can be cultured very easily in a simple medium such as coconut water. It is a common contaminant of mushroom culture, and Trichoderma culture should not be carried out near mushroom production houses.
It was noted that bags of compost sold in the Philippines must carry a label with the N, P and K content. One participant asked how often the company checks on the nutrients in the compost. Dr. Cuevas explained that the FPA requires the producer to submit an analysis of the nutrient content of the compost before it is registered, and before the producer is granted a license to make commercial compost. She did not know whether the NPK levels are regularly monitored, but thought that levels would probably be variable, since the materials used for compost are variable. Another participant asked whether the compost is tested, and Dr. Cuevas explained that commercial compost must pass an efficacy test in the field, carried out by an approved research institute.
Another participant asked about the cost of compost compared to chemical fertilizer, on a nutrient basis. Dr. Cuevas replied that a 1 kg bag of urea costs about US$20, and contains 23% N. In comparison, a 1 kg bag of compost costs US$5, and contains about 4% N. Chemical fertilizers are therefore much cheaper, on a nutrient basis. It is recommended that farmers use a combination of chemical and organic fertilizers, rather than compost alone. Because of excessive nitrogen use in the past, many soils have an imbalance of nutrients, and show a good response to compost.
The question was asked what the term "maturing period" meant, in Table 1(1). Dr. Cuevas explained that this refers to the length of time it took the compost to reach maturity. There are several criteria of compost maturity, one being color — mature compost is black. Temperature is also a good indication of maturity. If after some time, the temperature of the compost falls to a stable lower level of around 28-30 oC, the compost is probably mature. The main indicator of compost maturity is the C:N ratio, but this is not suitable for use by farmers, who must rely on temperature changes and the appearance of the compost.
Index of Images
Table 1 Maturing Period and Composition of Compost from Different Materials, Using Rapid Composting Technology
Table 2 Composition of Compost Made from Rice Straw + Weeds (Grasses, Broadleaved Weeds), Chicken Manure and Inoculant ( Trichoderma Harzianum)
Table 3 Cost-Benefit Analysis of Rapid Composting Using Rice Straw (1989-90 Data)
Table 4 Comparative Analysis 1) of Rice Yields, Fertilizer Use and Labor, among Users and Non-Users of Rapid Composting Technology, 1993 and 1995 Wet Season
Table 5 Comparative Analysis of Cost and Returns 1) Per Hectare among Users and Non-Users of Rapid Composting Technology, 1993 and 1995 Wet Seasons
Table 6 Farmers' Perceived Benefits from Using the Rapid Composting Technology 1), Wet Season 1995.
Table 7 Compost Production and Distribution Using Rapid Composting Technology
Table 8 Estimated Incremental Rice Production from Rapid Composting Technology (RCT) 1992-1996
Table 9 Estimates of Economic Benefit and Cost from Rapid Composting (Us$ Million at 1996 Prices)
Download the PDF. of this document(434), 327,563 bytes (320 KB).