I am farming and offering help to a friend on her farm north of Cairo Egypt. Her farm is struggling financially and i would like to help her out...
There are mango and citrus trees with no under crop. My thought is to design a rotational grazing system under the trees, with sheep feeding on alfalfa. The alfalfa needs a sprinkling system for irrigation.
The problem is that the sprinklers will wet the tree trunks to about a meter high (maybe more), and i feel it might create an environment for fungi to grow on the mango trees.
Does anyone have any ideas of how to solve this in a clean way?
Thanks a million!
Citrus trees won't like an under-crop. Look at the tree in its natural state; it forms a dense canopy all the way down to the ground to exclude anything else from growing under it. It doesn't want an undercrop, it wants to be alone. Where citrus trees have been paired with other plants, like date trees, they are the undercrop. If there is some extra space in between the citrus trees, you might want to consider adding some date palms.
Mangoes are a different thing entirely. They can be huge trees, 30-40m in height. There is lots that can go on under a mango tree, including putting a house under one. Being tropical trees, they have evolved in conditions of high temperature and humidity and are used to being exposed to lots of fungi. Unless you have your mulch a meter high, the mango tree is probably not going to notice some fungal activity going on at the base of the trunk. However, sprinklers have a tendency to bleach the trunk of a tree, and while that can look alarming, it's not doing the tree much harm. In your climate, the dry desert air is not going to let much in the way of fungi grow on the trunk of the tree. I would be more worried about the amount of salts in the irrigation water. Over time, the evaporation of water from the sprinklers may leave salts on the tree trunk, and that could potentially harm them.
Mulch under the trees, to 1-2" of the trunk of the tree. Mulch more if younger trees. Fungi is helpful to the trees to grow and will exchange nutrients in exchange for a little sugar. Just keep the mulch/plants away from the trunk of the tree and you won't have an issue.