| dc.description.abstract | This report was compiled by the Tropical Soil Biology and Fertility Institute of the
International Center for Tropical Agriculture (CIAT-TSBF) at the request of the Food and Agriculture
Organization of the United Nations (FAO) Commission on Genetic Resources for Food and
Agriculture. It is focusing on the state of knowledge and trends in the conservation and use of microorganisms and invertebrates in cropping systems based on roots and tubers -, including cassava,
potatoes, sweet potatoes, yams, cocoyam and aroids. The main emphasis is to understand the status
and trends of micro-organism and invertebrate diversity in root crop-based production systems and to
review the current and potential contribution of such organisms to these systems. Areas for future
research and gaps in knowledge are also identified and highlighted.
The soil is “alive”, harboring organisms whose diversity and abundance is largely unknown.
Specific information is still lacking on the importance of species that are key to specific functions and
their role in maintaining below and above-ground biodiversity. It is this information gap that this
report addresses. Most of what is presented deals with the integration of the root and tuber crops with
soil organisms and their functions.
When soil organisms eat, grow, and move, they contribute to the delivery of ecosystem
services that are essential for human society. Among the key ecosystem services mediated by soil
biota are: the transport, storage, and provision of clean ground water; the storage of carbon and the
prevention of trace gas emissions crucial for climate control; the provision of nutrients; pest and
pathogen regulation; and supporting plant growth and above-ground biodiversity. Most of the
structure and functioning of the above-ground individuals and communities are regulated directly or
indirectly by altering the dynamics of nutrients that are available to plants.
As production of the root and tuber crops expands, it is important to use production
technologies which secure a safe and clean environment that minimizes use of synthetic chemicals.
Research is needed on how best to integrate soil organisms in the production of the crops both as biofertilizers as well as use as bio-control agents (BCAs). Mechanisms of co-existence of soil organisms
in mutualistic, proto-cooperation, commensalism, neutralism, antagonism, predation and parasitic
relationships can be used to explore further how best to integrate these associations with the root and
tuber crops. Biological control methods have provided alternative safer methods to pesticides and
herbicides for pathogen, insect pest and weed control. However developing BCAs is labor intensive
but this may lead to localized niche businesses that provide jobs and create wealth. Benefits might
also accrue to the growers who use BCAs because of the premium price for pesticide-free and organic
produce. This may not yet be happening but the major benefit from BCAs may be in preserving root
and tuber crops from postharvest breakdown because of the perishable nature of root and tuber crops
that can inhibit large scale exports apart from cassava which are first dried before chips are exported.
Emerging technologies in biological sciences allow the study of these soil microorganisms
beyond the microscope. Gene marking, DNA finger printing, PCR amplification, genomics,
proteomics and metabolomics and associated microarray technologies have enhanced opportunities for
throughput in bio-prospecting and understanding mechanisms of soil organism action that can lead to
discovery of novel properties and products especially from microorganisms. More research is needed
to ensure food security and to increase food production levels in developing countries in part by a
better understanding of how to manage soil biological processes. In order for this to be realized, there
will be need for budgets, reference databases, North-South collaborations as well as championing | en |
