Agriculture Reference
In-Depth Information
agroecosystems in the Tropical Andean highlands, agriculture is also limited by a
familiar set of environmental constraints throughout the region, with climate
playing the most important role at high altitudes (Stadel 1991 ). On the other
hand, with a few exceptions, soils in the high Andes are generally thin, fragile,
and highly nutrient limited. For example, non-allophanic Andosols, which domi-
nate the Ecuadorean highlands (Poulenard et al. 2001 ), can have severe problems of
P deficiency, acidity, and aluminum toxicity (Dahlgren et al. 2004 ).
5.4 The Need to Develop Biofertilizers for Mountainous
Regions
The land quality in the mountain regions of the developing world is deteriorating,
leading to a declining in soil fertility and productivity. That is why many mountain
families are facing food shortages which contribute to the chain reaction process of
poverty-resource deterioration-scarcity-poverty (Jodha and Shrestha 1993 ). It is,
therefore, imperative to explore new options for increasing the productivity and
carrying capacity of farms, in order to improve the livelihoods of marginal moun-
tain households (Partap 1999 ). This will also allow the mountain people to compete
favorably in the modern world. One of these options is the cultivation of high value
cash crops, such as fruits and vegetables, a tendency which is slowly increasing in
the IHR (FAO Report 2003 ). Adoption of organic farming practices largely exclud-
ing the use of synthetic agro-chemicals and fertilizers and rescue of native species,
varieties, and breeds which have played an important role in the human diet and
traditional cultures and which are threatened by extinction are other promising
alternatives. A complementary and very promising approach for improving the
agricultural productivity of farmers without serious economic or environmental
impacts is the development and correct use of biofertilizers, well suited to perform
efficiently under the particular conditions of mountainous agroecosystems. A
biofertilizer can be defined as a product containing live or latent cells of agricul-
turally beneficial strains of microorganisms that are applied to seeds or soils to build
up the numbers of such microorganisms and accelerate certain microbial processes
to augment nutrient acquisition by plants (Motsara and Roy 2008 ). Biofertilizers
consist of nitrogen fixers (N-fixers) ( Rhizobium , Azotobacter , Azospirillum ,
cyanobacteria/blue-green algae, Azolla ), phosphate-solubilizing bacteria (PSB),
and mycorrhizal fungi. In the contemporary world, the use of biofertilizers to
enhance crop yield particularly of N-fixers and PSB is widespread and well
documented (Banerjee et al. 2006 ). However, use of commercially available
biofertilizers in colder climates like the ones prevailing in mountainous ecosystems
has proven ineffective (Pandey et al. 1998 ). Indeed, low temperatures impose a
serious threat to the metabolic activities of microorganisms. For instance, it has
been estimated that lowering the temperature by 10 C induces a two- to fourfold
decrease in enzyme activity (Feller and Gerday 2003 ). Therefore, it has become
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