How to mulch in tropical Tanzania

Dear Forum,
I am a new but enthusiastic veggie gardener and I have recently moved to Tanzania to set up a domestic biogas company. I've had a go at growing some veg with mixed results and I don't think I have figured mulch out as a concept yet although I've read a bit about it. The soil is very sandy with little organic material, the weather is HOT all year with two rainy seasons lasting about 4 months in total when it pours down and the rest of the year is very dry and the sun is intense.
I want to improve the organic content of the soil and it ability to hold water and keep weeds down, so mulch seems to be the way forward.
Firstly I'd like to know the difference between compost and mulch. I have lots of dried bamboo leaves as there is a big bamboo grove on my farm so I was planning on collecting these together, putting them in a big pile, putting some wet cow slurry from my biodigester on top, then maybe some drier cow manure and keep piling on top the layers. Is this mulch or compost? Now I'm thinking this will result in a kind of brown mulch but very rich in nitrogen. Will this be okay to put over all the place and grow veg from? There are also lots of mango and cashew trees, should I add their leaves to my mulch pile or are they toxic in any way?
The rainy season is on its way (hopefully), should I mulch before, during or after these heavy rains??
That's probably too long a post. Oh well, I hope someone can help me with my dreams of a tropical garden full of tasty veg all year round.
Thanks, Oliver.

 

Olly - welcome to the forum. So nice to see someone from somewhere exotic. I do hope that, in due time, we might see some pictures of plants that grow out there.

I think a mulch is something placed on top of the soil to help to reduce the loss of moisture from the soil by evaporation. It can be inorganic - ie plastic sheet, old carpet, stones, gravel etc. They have even used ping-pong balls on a resevoir to reduce evaporation. Or it can be organic like compost, bamboo leaves etc. Dried leaves, I would think, would do very well. The best time to apply a mulch is after a rainy period, when the soil is nice and moist. if you apply it before it could stop the rain getting into the soil, and hence have the oposite effect.

Once you put wet cow slurry on - you are doing something very different, you are putting a fertiliser on. which may well be too strong for the plants. However I don't grow veg, and hope that someone with more knowledge can help.