Let's say I had purchased a piece of land in 2005. At the time of purchase, I had one of the following two intentions without any importance attached to either one of them:

1) My first intention was to build an apartment complex in the future if I ever have sufficient funds and therefore I may one day get rent out of an apartment complex.

2) My second intention was to sell the land at a higher price if there is ever a very good appreciation of the land.

The land has just been sitting there for last three years and I have not done anything with it. There is, however, a very small appreciation of the land and I don't wish to sell it yet. I have four questions for you:

1) Is zakat due on this land?

2) If zakat is due, do I have to pay the zakat on the entire amount every year or just full the 2.5% in the first year and then on the appreciated difference in subsequent years?

3) I read somewhere that land kept for years before re-sale, which was always intended to be sold at the right price, is not liable to zakat until it has been sold. On receipt of the price, zakat is payable on the whole amount received, and only once. Is this true, and is there any evidence for this?

4) If zakat is due on the entire value of the land after one year of holding, and if I don't have enough cash at hand to meet the obligation of zakat, do I have to sell the land to pay the zakat? For example, after one year, the value of the land is - let's say - $500,000, but I have only $3,000 in cash with me. Do I have to sell this land to pay zakat on it?

I will be very thankful if you would answer, if possible, with evidence.