THEY are not given much attention by farmers. In fact, some people consider them as wastes and of no value at all.

But at the Mindanao Baptist Rural Life Center (MBRLC) Foundation Inc., azolla, nitrogen-fixing shrubs like kakawate and ipil-ipil, and even earthworms are turning them into something useful: as source of fertilizer and feeds.

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"We found that by growing them in the farm, we can lessen our expenses," said Roy C. Alimoane, who directs the non-government organization based in the southern part of the Philippines. "Also, in a way, we are helping our environment since we don’t throw anything -- including our garbage."

All the garbage in the farm “excluding non-biodegradable” are gathered and placed in the vermicompost area. The collected garbage is used as feed for earthworm. Earthworm castings or vermicompost is one important form of organic fertilizer, which farmers can readily use in their farms.

"We found out that vermicompost is good for vegetables and even fruit trees," said Ian Ogatis, who manages the area. He also conducts vermicompost experiments and teaches farmers who are interested to learn how to raise earthworms and produce their own vermicompost.

"While low in major plant nutrients compared to chemical fertilizers," pointed out Dr. Rafael D. Guerrero III, who popularized vermicomposting in the country, "vermicompost supports microorganisms, which make nutrients more readily available to plants and produce substances that promote plant growth and health."

Studies on the use of vermicompost for crop production show that application of chemical fertilizers can be reduced up to 100 percent for certain vegetables and corn, and by 50 percent for rice and sugarcane. A field experiment using vermicompost with corn at five tons per hectare increased ear lengths of plants by 114 percent, with the total yield comparable to that of plants fertilized at the recommended rate of inorganic fertilizer.

In a recent pot experiment conducted on eggplant, results showed that a combination of vermicompost at 100 grams per pot (6.2 tons per hectare) and 50 percent of the recommended chemical fertilizer application gave a significantly higher yield (15 percent more) of eggplant fruits, compared to that with 100 percent chemical fertilization, after 120 days from planting.

At the MBRLC farm, vermimeal (biomass processed into meal form as a source of animal protein in the diet of fish, poultry, and livestock) is still not used. On a dry weight basis, vermimeal contains 64 to 70 percent protein, 7 to 10 percent fat, 8 to 20 percent carbohydrate and 2 to 3 percent minerals. It is also rich in long-chain fatty acids and vitamins.

Another natural source of feed is the floating fern called azolla.ÿIt is very rich in proteins, essential amino acids, vitamins (vitamin A, vitamin B12 and Beta- Carotene), growth promoter intermediaries and minerals like calcium, phosphorous, potassium, ferrous, copper, and magnesium, among others.

On a dry weight basis, azolla contains 25-35 percent protein, 10-15 percent minerals, and 7-10 percent of amino acids, bio-active substances and bio-polymers. The carbohydrate and fat content of azolla is very low.

"We raise azolla in our ponds using nets," said Alimoane. "Every afternoon, we collect them and use them as feed for our tilapia. In only a matter of minutes, the azolla are immediately gone. Tilapia loves to eat them."

Azolla can also be used as feed for dairy cattle, pigs, ducks, and chickens. Studies reported of increases in milk production, weight of broiler chickens and egg production of layers when these are fed with azolla as compared to conventional feed.

Azolla is also an excellent source of fertilizer. Studies show that azolla contains 4-5 percent nitrogen, 1-1.5 percent phosphorus, and 2-3 percent potassium. As such, it can be applied as organic fertilizer in fresh, dried, or composted form. If composted alone, decomposition takes about two weeks.

Rice farmers should consider growing azolla in their fields. "Any rice plant, modern or traditional, requires one kilogram of nitrogen to produce 15 to 20 kilograms of grain," said Dr. Iwao Watanabe, former head of the Soil Microbiology Department of the International Rice Research Institute. "Most tropical soils absorb enough nitrogen naturally to grow about one ton or 1.5 tons of rice per year. To increase yields above that, nitrogen must be supplied."

Rice farmers who grow azolla can grow their own fertilizer. For only three hours labor per hectare, a farmer can grow enough azolla to increase yields by 1.5 tons per hectare. "Azolla growth does not interfere with normal rice cultivation," Watanabe said. "In fact, it helps control weeds and improves soil texture."

In the upland areas, the natural source of fertilizer would be ipil-ipil as its foliage rivals manure in nitrogen content. One study showed that ipil-ipil leaves were comparable to ammonium sulfate in supplying the nitrogen requirement of rice plants in flooded and non-flooded soil conditions.

Corn grain yields were equally as high whether fertilized with herbage from intercropped ipil-ipil in single hedgerows or with commercial fertilizer.

But there's more to ipil-ipil than just fertilizer. Its aggressive root system "breaks up impervious subsoil layers, improve ng moisture penetration and decreasing surface runoff," to quote the NAS report. "Nutrients from deep strata are gradually deposited on the surface through decay of the leaves and other plant parts; soil organisms increase, topsoil humus rebuilds."

At the MBRLC, leaves of ipil-ipil are used as green manure for vegetable crops grown in its Food Always In The Home (Faith) gardens. The leaves are placed inside the basket or trench composts. In addition, it is used as a hedgerow species to control erosion in its famous Sloping Agricultural Land Technology (Salt).

But due to psyllid (Heterophsylla cubana) infestation, the MBRLC recommends other species. These are Desmodium rensonii, Flemingia macrophylla, Indigofera anil, and Gliricidia sepium. All these species are introduced, excluding the latter which is locally known as kakawate.

"We recommend that farmers plant these four species in their farm. If one species is attacked by pests, there are three other species left," said Alimoane.

All the species are also utilized as feed for their dairy goats. On the other hand, the goat manure are collected and used as fertilizer for the hedgerow species and other crops in the farm.

(Readers who want to know more about what have featured in the article can reach the MBRLC by sending an e-mail to mbrlc@mozcom.com. You can also call them at this number: (064) 533-2378.)