Mushrooms are growing on my lawn, they are edible and now i want to know how do encourage more to grow?

You are lucky! Several times I have thought I'd got edible ones and when i picked them they turned out to be yellow stainers instead. Very disappointing. I don't know how you can encourage them - they do seem to like fields where horses have been but that's not very practical for a garden. I failed to grow them even with a mushroom kit.

keep the area damp and organically fertilized

magic man

Your Agaricus campestrie is known as field mushrooms or more appropretly *Horse Mushrooms. For Mushroom Spores to germinate they need to settle on animal dung - preferably Horse Manure - hence the Horse Mushroom - However, they can an do settle on dog and cattle droppings. Its possible that the mushroom you have grew on some form of animal droppings that hppened to be in your garden as the spores arrived. Therefore, it would be necessary to import manure into your garden in order to encourage the mushrooms. BTW Matthew W`s answer is correct

Don't eat them, you may die, natural selection at work.

most mushrooms like horse manure

Many types of mushrooms look the same. Some are edible, most are not. THEY CAN LOOK THE SAME. Unless you have had an expert in edible mushroom identification positively identify these mushrooms for you, I WOULD NOT EAT THEM. I read an article a number of years ago about a woman whose parents came for a visit from Asia. Mother saw what she thought were straw mushrooms growing in the yard. Mother cooked with them and they ended up killing their livers. They were saved with liver transplants, but a few hours later and they would have died. Never, never, NEVER eat mushrooms that you cannot 100% identify.

First of all, be sure of your identification. It doesn't really look like a Destroying Angel mushroom, but make sure you don't eat one of those- apparently some people confuse them. Mushrooms live most of their life as an invisible web of microscopic filaments in the soil, called the mycellium. The mycellium eats decaying organic matter in the soil, and when conditions are good, it produces mushrooms to spread spores. The decaying organic matter would come from grass roots, and from the manure of grazing animals in a natural setting. Horse manure is ideal, and you will have the best grass in town. The main thing you need to do is avoid poisoning the mycellium with pesticides, herbicides, and salty inorganic fertilizers.

Seems that when I mow over them they multiply. Don't know that you can eat them tho.