LeapAgri: Participatory Pathways to Sust. Intensification. Innovation platforms to integrate leguminous crops into small-scale agriculture

Informations

Funding country

Norway

Acronym

-

URL

-

Start date

1/1/2018

End date

12/31/2022

Budget

276,750 EUR

Fundings

Abstract

The overarching goal of PASUSI is to improve productivity, livelihoods, nutrition and household wellbeing in Ghana and Uganda, while counteracting environmental degradation and mineral depletion caused by monocultures. A major contribution of PASUSI should be to promote sustainable production of local legume crops and to increase their fraction of the daily diet. The work packages in which NMBU was particularly involved aimed at identifying nitrogen fixing bacterial strains, so-called rhizobia, suitable as inoculants for locally grown legumes to improve their yield and protein content. Smallholder farming systems in most African countries rely on plant-based proteins for nutrition security and income. Rapidly growing populations require increased plant production, but possibilities to expand cropland are limited and there is a need for intensification of agriculture. Poor soil fertility is an increasing problem, and many areas suffer from severe soil acidification due to excessive use of urea-based fertilizers. Legumes offer solutions to these problems. They have high protein content and general nutritional value and increase soil fertility by providing nitrogen to the soil, which reduces the need for synthetic fertilizers. Legumes fix nitrogen in symbiosis with root-nodulating rhizobia, and this nitrogen is transformed into forms into forms that the plant can use to make proteins. All combinations of rhizobia and plant type do not, however, lead to efficient nitrogen fixation and soils often compatible bacteria, especially when introducing new plant species. To ensure efficient symbiosis it is therefore becoming increasingly common to inoculate legume seeds with the "right" rhizobia before sowing. There are at present only a limited number of inoculant types on the global market, and there is need for development of new and more efficient varieties that are adapted to local agricultural conditions and plant varieties. A dual benefit: Our recent results obtained by the PASUSI and other projects show that many rhizobia can also act as efficient consumers of the greenhouse gas N2O, which is produced in agricultural fields, especially from acidic soils. This is the third most severe greenhouse gas and the main destructor of the ozone layer. Our PASUSI partners have isolated rhizobia from relevant legumes in Ghana and Uganda and classified them taxonomically. Work is ongoing to test them for their efficiency to fix nitrogen. Our focus is on rhizobia (genus Bradyrhizobium) that nodulate soybean and Bambara ground nut, since these often can reduce N2O. Surprisingly, and contrary to other collections, almost all of them turned out to lack the gene for N2O reduction. We therefore initiated, together with our partner in Tamale, Ghana, an investigation of acidic soil from northern Ghana to try to isolate bacteria able to reduce N2O. We incubated soil slurries anoxically at an acidity that always was below pH6 and provided N2O as sole electron acceptor and managed to enrich bacteria able to grow under such conditions. The identity of these bacteria is currently being investigated both by metagenomics and by plate isolation. We foresee that this approach will provide us with interesting candidate bacteria for the development of novel types of inoculants with two beneficial roles: efficient N2-fixation and efficient N2O reduction. The long-term goal of this part of PASUSI is to initiate local production of high-quality and climate smart inoculants, adapted for different varieties of selected legumes and able to thrive in acidified soil.