IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...

17 th International Congress on Nitrogen Fixation
Fremantle, Western Australia
27 November – 1 December 2011
Session Details: Wednesday 30 November 2011
Authors:
Concurrent Session 13 - Inoculant Quality & Application
1600 - 1740
Didier Lesueur 1,2 , Laetitia Herrmann 2 , Moses Thuita 2, 3 , Mary Atieno 2, 3 , Edwin Mutegi 2, ,
Keziah Ndung‟u 2, 3 4 , Aliou Faye 2, 5 , Mary Kamaa 2 , Pieter Pypers 2 & Robert Okalebo 3
1 CIRAD, UMR Eco&Sols - Ecologie Fonctionnelle & Biogéochimie des Sols &
Agroécosystèmes (SupAgro-CIRAD-INRA-IRD), 2 Place Viala, F34060 Montpellier,
France.
2 Tropical Soil Biology and Fertility Institute (TSBF) / CIAT - World Agroforestry Centre
(ICRAF), P.O. Box 30677, Nairobi, Kenya.
3 Moi University, Department of Soil Science, PO Box 1125, Eldoret, Kenya.
4 Kenya Agricultural Research Institute (KARI – Kitale), P.O. Box 450 - 30200, Kitale,
Kenya.
5 Institut Sénégalais de Recherche Agricole, Route des hydrocarbures, Dakar, Sénégal
Presentation Title: How commercial rhizobial inoculants can contribute to improved livelihoods of resource
poor African farmers.
Presentation Time: 1640 – 1700
There is a proliferation of commercial bioinoculant products appearing on the market that claim major impact in
increasing crop productivity without any scientific assessments about their effectiveness in the field. TSBF-CIAT
has been mandated by Bill and Melinda Gate Foundation to scientifically evaluate and select effective
commercial products for improving and sustaining crop yields in selected agro ecological zones in 3 African
countries.
Our results on about 120 products showed that many private companies commercialize a mix of non-defined
microorganisms and thus do not ensure the quality of their inoculants. This may explain their lack of impact on
the plant growth even under controlled greenhouse conditions. Generally, high level of contamination was
observed as pure products represented only 33% of the products, 41% of the products contained all the
expected strains and 52% of the products contain none or part of the expected contaminants. We assessed
under greenhouse conditions the possible effect of the formulation of effective rhizobial inoculants on both
soybean growth and nodulation. Our results showed that there was no effect and the association of the rhizobia
with a Bacillus strain didn‟t induce any significant stimulation of soybean growth. However, through field
demonstration trials combining rhizobia with mycorrhiza and P solubilizing bacteria, our results suggested some
relevant positive interactions on soybean yield. In Kenya, we tested one rhizobial inoculant in 3 mandates areas
(about 50 farms in each) and our results demonstrated a significant effect of the inoculation on soybean yield.
The next step will consist of making such effective inoculants cheap and available on the local markets.
Administrative issues shall be sorted out for each country as the national regulations are not similar and of
course the quality control issue shall be taken into account to ensure the viability of the inoculants to farmers who
purchase them.
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2011