Business Potential for Agricultural Biotechnology - Asian Productivity ...

4. DEVELOPMENT AND APPLICATION OF
BIOFERTILIZERS IN THE REPUBLIC OF CHINA
Dr. Chiu-Chung Young
Department of Soil and Environmental Sciences
National Chung-Hsing University
Taichung, Republic of China
INTRODUCTION
Taiwan experiences a humid, subtropical climate, with a mean temperature of around 20°C
(November to April) and above 30°C (June to November). Rainfall is over 3,000 mm in the central
region, 1,500–3,000 mm on the east coast, and 1,500–2,000 mm in the western region adjacent
to mountains, with frequent typhoons during summer and autumn impacting agriculture.
Uncontrolled application of chemical fertilizer is a common practice in most areas. The estimated
consumption of chemical fertilizer is about 1,140,000 tons for 844,000 ha. However,
many upland regions and lowland soils are less fertile and need greater fertilizer input to sustain
yields.
Agriculture is oriented towards intensive farming practices, and every effort is being made
to shorten the growth period of each crop so that more crops can be grown during the following
season. Intensive multiple cropping systems have drastically reduced the use of leguminous
plants as green manure, since this requires a longer growth period. Still, legumes such as soybean,
peanut, mungbean, pea, etc. are planted, but only as part of an intensive multiple cropping
system (Young and Chao, 1983).
It is well known that the crop root zone (rhizosphere) provides a unique microsite for the
association of symbiotic and nonsymbiotic microorganisms (Young, 1994). N2-fixing and Psolubilizing
bacteria have been well characterized from various soil types and aquatic environments
(Seshadri et al., 2000; Garg et al., 2001; Berman-Frank et al., 2001; Young et al., 1982;
Young and Cheng, 1998; Young et al., 2003a,b&c), and many isolates have been shown successful
in improving crop yield (Subba Rao, 1982; Young et al., 1988a&b; Young, 1994). Hence,
several beneficial microorganisms can be used effectively as a chemical fertilizer alternative to
minimize the application of inorganic fertilizers.
Biofertilizers, which can be more appropriately called microbial inoculants, can be generally
defined as preparations containing live or latent cells of an efficient microbial strain capable
of nitrogen-fixing, phosphate-solubilizing (bacteria, fungi, or algae), or any other beneficial
activity derived from this process. Biofertilizers may be applied to either seed or soil to accelerate
microbial processes in soil, thereby augmenting the availability of nutrients by making
them easily assimilated by crop plants.
This paper briefly reviews the status of biofertilizers that have been developed in a few Republic
of China laboratories in recent years, with a major emphasis on microorganisms, including
rhizobium, P-solubilizing bacterium, and mycorrhizal fungi that were identified as suitable
candidates able to meet the nutrient requirements of various crop species and known to increase
yields.
SELECTION AND DEVELOPMENT OF BIOFERTILIZERS
Rhizobial Inoculants
In the Republic of China, research on the selection of efficient rhizobial strains for inoculation
started in 1958. Collection, isolation, and subsequent selection of effective rhizobial strains
and their uses in agriculture have yielded fruitful results. Since marked variations were observed
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