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University of Basel (2019)

Common mycorrhizal network as facilitator of bioirrigation for rainfed agriculture tested in legume – millet intercropping system

Singh, Devesh

Titre : Common mycorrhizal network as facilitator of bioirrigation for rainfed agriculture tested in legume – millet intercropping system

Auteur : Singh, Devesh

Université de soutenance : University of Basel

Grade : Doctor of Philosophy (PhD) 2019

Résumé partiel
Food security for growing population and achieving the zero hunger target by 2050 is a major challenge for mankind. Sustainable intensification of agriculture, i.e. increased food production without causing environmental damage has been foreseen as the way forward to address this challenge. In this study we tested a sustainable legume – millet intercropping model based on “bioirrigation” and biofertilization to mitigate drought induced yield loss in rainfed areas of arid and semiarid tropics. “Bioirrigation” is based on the principle of hydraulic lift (HL) where transfer of water occurs through roots from wet deep soil layers to dry top soil layers as a consequence of a soil water potential gradient. Specifically, the process of bioirrigation describes the transfer of hydraulically lifted water from a deeprooted plant to a neighbouring shallow-rooted plant. The main challenge for bioirrigation derives from distance between rhizospheres of the two plants, water released into the rhizosphere of bioirrigator is not available to neighbouring plant since it is tightly held up in to the rhizosphere. In this study, we tested a potential solution to facilitate bioirrigation between rhizosphere of deep-rooted pigeon pea and shallow-rooted finger millet by connecting the rhizosphere through a common mycorrhizal network (CMN) using arbuscular mycorrhizal fungi (AMF). In this study, we conducted several pot experiments under controlled conditions inside the greenhouse at University of Basel to test the hypothesis of CMN mediated bioirrigation between pigeon pea and finger millet. The results of pot experiments clearly showed that pigeon pea does perform HL, and when roots of pigeon pea and finger millet are connected through AMF network water relations of finger millet are supported by pigeon pea through bioirrigation. In our experimental set up, after testing the role of CMN in pot experiments, we scaled up (approx. 3 times) the pot size to mimic the field like conditions and test if bioirrigation facilitated through CMN can help shallow-rooted to survive a long drought period of 10 to 11 weeks. The results from scaled up pot experiment did not show significant effect of CMN on water-relations (stomatal conductance) of finger millet in intercropping treatments, but finger millet in treatments with CMN had significantly lower foliar damage percentage and mortality than treatments without CMN. The results from pot experiments show the importance of bioirrigation for rainfed agriculture i.e. if bioirrigation based intercropping is practiced, shallow-rooted plants would be able to tolerate the drought period.

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Page publiée le 28 mai 2021