Compost obtained from municipal solid waste stimulates mycorrhization by native arbuscular mycorrhizal fungi and delays foliar senescence in grapevine (Vitis vinifera L.)

Compost application enhances soil structure, fertility, and microbial activity, reducing the need for chemical inputs and supporting agroecosystem resilience, while mycorrhizal sym­biosis improves nutrient and water uptake efficiency, thereby increasing crop tolerance to abiotic stresses. Moreover, both compost and mycorrhizae contribute to soil carbon seques­tration, offering an environmental-friendly solution to miti­gate greenhouse gas emissions while maintaining long-term soil productivity and health. The use of municipal solid waste (MSW)-derived compost in agriculture supports a circular economy by recycling organic waste into valuable soil amend­ments, aligning with zero-waste principles and reducing pres­sure on landfills. In this work, we treated grapevine plants with MSW-compost, arbuscular mycorrhizal fungi (AMF) or the combination of both, in a pot experiment with agricultural soil as growth substrate. Root mycorrhization was evaluated by staining and microscopy, while effects on the aerial parts of the plant were evaluated by measurement of the reflectance spectra of leaves. Results showed that MSW-compost increased the root mycorrhization by native AMF (i.e. in non-AMF inoculated plants), leading to mycorrhization levels comparable to those obtained with the addition of commercial inoculum. At the same time, MSW-compost amended plants showed a delayed leaf senescence. The integration of compost and arbuscular mycorrhizal fungi (AMF) represents a promising strategy to both improve adaptation of agriculture to climate change and reduce our dependence on synthetic fertilizers, fostering virtuous prac­tices in sustainable agricultural systems.