It depends on the plants you are using, and how you are using them: I grew beans here just this year, and last year there were just 20-year-old clumps of daylilies that I have moved. Between the bean plants this year hid my three young grape vines, and below them, a whole bunch of carrots and strawberries.
This sort of high-intensity intercropping / polyculture gardening, plus using biodynamic fertilisers like compost tea, mitigates a lot of fungal problems. I’m planting two consecutive legume crops, but they are different genera, and flourish in different seasons (the beans like warm midsummer, and the peas like the cool of early spring and autumn).
My beans were also free of any pests: fungal or insect, and I left the root systems of the beans in the ground (only clipping the plant down and covering the stumps of the plants with their own leaf mulch), while planting the peas about 20 cm away.
The environment is also rich in mycelium from the bark mulch and decomposing wood that makes the raised beds and paths, which also suppresses fungal disease. It sounds weird, but I also poured a diluted urine solution, and a very diluted bit of spoiled milk over the leaf mulch. The urine kills most of the fungal pathogens on the leaves, and the microorganisms in the spoiled milk kick-start microbial activity in the area: which is a sort of microbial innoculant (like the aforementioned compost tea). This is not over the new planting, but rather over the mulch area where the beans were.
Generally it is a higher risk, and you have to watch legumes aren’t planted in a soil that is already too nitrogen-rich, but there are a lot of things you can do with your soil and composting practices to make sure that any one pathogen can’t get much of a foothold.
Next year, this certainly won’t be a place for beans and peas: the trellis is designed for grapes, and passionfruits. Planting beans and peas this year is just a mode of enriching the soil so those permanent forest garden features can flourish.