Well a little information here might help us to help you! If this is a valid request, give us your approximate location (country, area, etc.), a picture of the tree would be nice, or a good description, plus what kind of mix it's planted in, whether you keep it indoors or out, how often you water and how you do that, and anything else you can think of.

It is one year old. Water by hand, dirt, ouside. Water by touch. When dirt does not stick to finger. Liquid fertilizer and plan water

"Water by hand" - if you mean vs a hose, I guess that's good, but I meant rather that if it is in a pot, that you water from above vs submerged in a sink. "Dirt" also tells me that it isn't in the fast draining grit that bonsai and certainly maples in pots need. Most 'regular' soil holds water too long in the pots. There are various types of fast draining grit you can buy, and mix with a very small amount of an organic component, that are generally used for maples that aren't directly in the ground. You can learn more about those at www.bonsaisite.com in their Soil subforum. I have a feeling your tree either got watered too often, especially for what it's growing in, or else you forgot all about it in too much heat and didn't water at all to speak of, or enough to run out the bottom. With (still) not enough information, only you can say. It's also possible it was left out in that sun all day with no 'filter' such as a larger tree nearby, to help protect it a bit. Maples do like the soil in their pots to almost dry out between waterings and sometimes just testing the top inch or so isn't enough to be sure it isn't too wet lower down in the pot, especially if it's in store bought "Potting" soil which is usually mostly peat moss and holds onto water much too long.

A better way to test for water is keeping a chopstick halfway between the pot rim and the tree (until you're very sure of how much is enough) and using it like a dipstick daily. Also, once it's potted (only in early spring though!) in the proper mix it won't matter as much if you give it 'too much' water sometimes because it will run right through the pot and out the (hopefully) large drain hole(s). Bonsai cannot be treated like either house plants or 'just' garden trees, and it takes time to get things right.