Biofertilizers
The national goal of increasing production of agroforestry
products is heavily dependent on the use of chemical fertilizers. This goal is
difficult to attain because the country cannot produce all its chemical
fertilizer requirements. Production of chemical fertilizers requires high inputs
of energy. As an agrobased economy. agricultural productivity is dependent on
chemical fertilizers which are mostly imported. If not for government subsidies,
the use of chemical fertilizers to produce agricultural and forestry products
would have been very expensive and out of reach to most farmers. The fertility
of most uplands is usually poor because of nutrient losses due to high erosion
rates. Nitrogen and phosphorus are two essential nutrients that are severely
deficient in most uplands. These elements along with other essential nutrients
can limit growth and productivity in the uplands.
In the early 80's, the country experienced the paralyzing effect
of the energy crisis. The cost of fertilizers increased. This had a tremendous
impact in reducing agricultural productivity. It was during that time that the
country had to search for alternative technologies to replace chemical
fertilizers. This search led to the use of biofertilizers.
Biofertilizers are defined as microbially-based fertilizers
which are effective in promoting growth/yield of plants. Two common
biofertilizers are: nitrogen-fixers and mycorrhiza. The atmosphere contains 78
percent nitrogen by volume but this is not readily available to all plants.
Nitrogen gas has to be fixed by microorganisms such as bacteria, algae, etc. The
fixed nitrogen is converted to organic forms, which can be utilized by plants.
Thus, plants like legumes which form symbiotic associations with nitrogen-fixers
(rhizobia) can derive most of their nitrogen requirements from this system.
Mycorrhiza is a symbiotic association between the roots of
plants and a fungus. The mycorrhizal fungus can improve the absorption of
unavailable nutrients (e.g., fixed phosphate) which are then donated to the host
plant. In addition, mycorrhiza can promote the absorption of water even under
water-stressed conditions. Mycorrhiza may also produce growth hormones and
control some biologically pathogenic organisms. Together, nitrogenfixers and
mycorrhiza can provide the nitrogen and phosphorus requirements of plants. In
addition, mycorrhiza can facilitate the absorption of other essential nutrients.
TYPES OF BIOFERTILIZERS
Two groups of commercial biofertilizers are available locally in
the Philippines. The first group is made up of nitrogen-fixers fixers which are
bacterial-based. These are NitroPlus containing Rhizobium effective for mung
beans, peanut and soybeans; and, BIO-N which contains Azospirillum effective for
rice and corn
The second group of biofertilizer is made up of mycorrhizal
fungi which infect roots of the host plant where they proliferate. The fungus
increases the absorption of nutr ents and water, produce growth hormones and
serve as biocontrol for pathogenic soil borne organisms. The mycorrhizal
technologies are divided into five groups: MYCOGROE, MYCOBEADS, MYKOVAM-1,
MYKOVAM-2 and Direct seeding Blocks (DSB). MYCOGROE and MYCOBEADS are effective
for reforestation using pines, eucalyptus and agoho. MYKOVAM-1, MYKOVAM-2 and
DSB are effective for agricultural crops, fruit trees and reforestation species.
These products are commercially available from BIOTECH, UP Los
Bathos, College, Laguna. For more information, inquire directly from
BIOTECH.
