Testing of Commercial Inoculants to Enhance P Uptake and Grain Yield of Promiscuous Soybean in Kenya

A. Faye, Z.P. Stewart, K. Ndung’u-Magiroi, M. Diouf, I. Ndoye, T. Diop, Y. Dalpé, P.V.V. Prasad and D. Lesueur
Additional contact information
A. Faye: Institut Senegalais de Recherches Agricoles (ISRA)—Regional Centre of Excellence on Dry Cereals and Associated Crops (CERAAS) BP, Thies 3320, Senegal
Z.P. Stewart: Department of Agronomy, Kansas State University, Manhattan, KS 66506, USA
K. Ndung’u-Magiroi: Kenyan Agricultural and Livestock Research Organisation (KALRO), Kitale Research Centre, PO Box 15, Kitale 30200, Kenya
M. Diouf: Direction de l’Horticulture, Route du Front de Terre x avenue Bourguiba, Dakar BP 4005, Senegal
I. Ndoye: Département de Biologie Végétale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop de Dakar (UCAD), Dakar BP 5005, Senegal
T. Diop: Département de Biologie Végétale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop de Dakar (UCAD), Dakar BP 5005, Senegal
Y. Dalpé: Eastern Cereal and Oilseed Research Centre (ECORC), Agriculture and Agri-Food Canada, 960 Carling Ave, Ottawa, ON K1A 0C6, Canada
P.V.V. Prasad: Department of Agronomy, Kansas State University, Manhattan, KS 66506, USA
D. Lesueur: Centre de Cooperation Internationale en Recherche Agronomique pou le Developpement (CIRAD), UMR Eco&Sols, Hanoi, Vietnam

Sustainability, 2020, vol. 12, issue 9, 1-15

Abstract: The aim of this study was to assess the potential of commercial mycorrhizal inoculants and a rhizobial inoculant to improve soybean yield in Kenya. A promiscuous soybean variety was grown in a greenhouse pot study with two representative soils amended with either water-soluble mineral P or rock P to assess product performance. The performance of selected mycorrhizal inoculants combined with a rhizobial inoculant (Legumefix) was then assessed with farmer groups in three agroecological zones using a small-plot, randomized complete block design to assess soybean root colonization by mycorrhiza, nodulation, and plant biomass production in comparison to rhizobial inoculant alone or with water-soluble mineral P. Greenhouse results showed highly significant root colonization by commercial mycorrhizal inoculant alone ( p < 0.001) and in interaction with soil type ( p < 0.0001) and P source ( p < 0.0001). However, no significant effect was shown in plant P uptake, biomass production, or leaf chlorophyll index. In field conditions, the effects of mycorrhizal and rhizobial inoculants in combination or alone were highly context-specific and may induce either a significant increase or decrease in root mycorrhizal colonization and nodule formation. Mycorrhizal and rhizobial inoculants in combination or alone had limited effect on plant P uptake, biomass production, leaf chlorophyll index, and grain yield. Though some mycorrhizal inoculants induced significant root colonization by mycorrhizal inoculants, this did not lead to higher soybean yield, even in soils with limited P content. Our results are further evidence that inoculant type, soil type, and P source are critical factors to evaluate commercial inoculants on a context-specific basis. However, our results highlight the need for the identification of additional targeting criteria, as inoculant type, soil type, and P source alone were not enough to be predictive of the response. Without the identification of predictive criteria for improved targeting, the economic use of such inoculants will remain elusive.

Keywords: mycorrhizal inoculant; rhizobial inoculant; arbuscular mycorrhizal fungi; phosphorus; soil health (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2020
References: View complete reference list from CitEc
Citations: View citations in EconPapers (3)

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