Trees for the enhancement of mycorrhizal functioning in low-input maize cropping systems.

Arbuscular mycorrhizal fungi (AMF), widely occurring plant-beneficial root-symbionts, have the potential to link plants of the same or different species and improve plant mineral nutrition in the short-term and soil fertility over the longer-term. Arbuscular mycorrhizal fungi develop extensive mycelia (conglomeration of fungal filaments) that help in improving soil structure and exploring soil space for nutrients (e.g. phosphorus (P) and nitrogen (N)). Fungal hyphal linkages of plants (i.e. common mycorrhizal networks, CMN) provide a possible way to exchange nutrients between plants, which can be very important for plant growth, especially seedling establishment. Due to their perennial nature, trees can play an important role in maintaining AMF from one cropping season to the next. Thus, crop seedlings may get a nutritional head start by not having to initially invest into the built-up of new AMF, but rather by tapping into the pre-existing AMF mycelia maintained by the trees and immediately become connected into a functional CMN. The maintenance of this CMN can also further enhance the interactions between soil structure, soil biology, and nutrient cycling and, thereby, contribute to the biocycling of nutrients and hence longer-term soil fertility. Yet, our knowledge about the role of trees in sustaining CMN, enabling a tree-to-crop transfer of P and N, and thus enhancing crop establishment remains limited and confined to few model experiments in the greenhouse. With this project the following questions are being addressed:

1)       Do single standing mango (Mangifera indica) and faidherbia (Faidherbia albida) trees in Malawian smallholder farmers’ maize fields maintain AMF abundance during the dry season and thereby improve soil structure, nutrient availability to maize, and maize performance?

2)       Does a transfer of nutrients (N and P) via CMN from tree to maize occur and enhance nutrient uptake and productivity of maize?

Besides advancing our fundamental knowledge on AMF, and particularly CMN functioning in the field, the project will develop guidelines for soil fertility management strategies capitalizing on AMF mediated soil processes.

For further information please contact Johan Six ().