What benefit do the leaves from the trees provide in alley-cropping?

The leaves from trees in an alley-cropping system offer significant benefits by acting as a natural fertilizer. As the leaves decompose, they release essential nutrients back into the soil, enriching it and promoting better growth for the crops planted in the alleys between the rows of trees. This organic matter not only enriches the soil but also improves its structure, making it more conducive to plant health and growth. This natural process reduces the need for synthetic fertilizers, making alley-cropping an environmentally friendly agricultural practice while also maintaining soil fertility and productivity over time.

While the other choices represent potential ecological benefits associated with diverse agricultural systems, they do not capture the primary benefit of leaf litter in an alley-cropping context, which focuses specifically on nutrient enrichment through decomposition.