Field Guide of Discovery-based Exercises for - Aseanipm ...

Section 3 • Living Soil, Integrated Soil Nutrient and Crop Managements
Exercise No. 3.11
MICROBIAL-BASED FERTILIZERS AS SUPPLEMENT
FOR ORGANIC SOLID FERTILIZERS IN ORGANIC
VEGETABLE PRODUCTION
BaCKGroUND aND raTIoNalE
Microbial-based fertilizers are preparation of live cells
of microorganism strains. Some of these microbes could
fix air nitrogen, render phosphate soluble, or degrade
cellulose. Others would infect root systems to assist plant
roots in absorbing more water and nutrients and increasing
plant resistance against root pathogens. Microbialbased
fertilizers are also called microbial inoculants or
biofertilizers. 71 These biofertilizers, which can supplement
organic solid fertilizers in organic vegetable production,
may consist of: (a) spores, infected roots, and propagules of beneficial vesicular-arbuscular
mycorrhiza [VAM] fungi belonging to genus Glomus [G. mosseae or G. fasciculatum]; or (b)
powdered inoculants of nitrogen-fixing bacteria [NFB] belonging to genus Azospirillum, isolated
from roots of ‘talahib’ [Saccharum spontaneum] grass.
Microbial-based fertilizers consisting of VAM fungi are cheap and easy to use since a kilogram of
these microbial inoculants can fertilize 200-400 plants. The application is done only once throughout
entire life of a plant. These biofertilizers can be stored for 6 months in room temperature and one
year at 4 ºC. They can replace 60-85 % of plant’s chemical fertilizer requirement thus; farmers can
have substantial savings and more income. They can also increase resistance and tolerance of plants
to drought, heavy metals, and prevent root pathogen infections, by secreting growth-promoting
substances to improve soil texture and soil aggregation.
On the other hand, a microbial-based fertilizer consisting of nitrogen-fixing bacterium (NFB) of
genus Azospirillum has capability to convert atmospheric nitrogen (N 2 ) into a form usable by plants.
As microbial inoculants, it enhances root development, growth, and yields of rice, corn, and a number
of vegetable crops such as tomato, eggplant, okra, lettuce, and ampalaya. It also maintains soil
natural properties and fertility as well as keeps plant healthy and green even during droughts and pest
infestations. It can restore 30-50 % of total nitrogen requirement of plants. 72
71 PCARRD. 2006. Philippine Recommends for Organic Fertilizer Production and Utilization, Series No. 92, Philippine Council for Agriculture, Forestry,
and Natural Resources Research and Development (PCARRD), Los Baños, Laguna, Philippines. pp78.
72 PCARRD. 2007. Appropriate Use of Bio-fertilizers and Bio-pesticides for Small-scale Farmers in Asian and Pacific Region. Philippine Council for
Agriculture, Forestry, and Natural Resources Research and Development (PCARRD), Los Baños, Laguna, Philippines pp105.
97
when is this exercise most
appropriate?
ɶ In FFS, TOT, and VST
sessions, as follow-up
or integral part of topic
on ‘Integrated Soil and
Nutrient Management’; and
ɶ When farmers want to
learn from facilitators
and other farmers some
innovative microbial-based
fertilizers as plant nutrient
supplement for organic
solid fertilizers.