As you advance through the reputation with Farmer Fung you unlock several other kites to use instead of the standard kite. There are a total of four types of kites you can get.
When you are "buddies" with Farmer Fung, Wing Nga will offer you a "high-altitude kite": this kite gives you a higher vantage point. This means you can see alot more of the zone and therefor can water plenty more patches from one location.
If you are "good friends" with Farmer Fung, you can use the "swift yellow kite": this kite will dramatically increase the kites speed allowing you to cover more ground faster however the altitude does not change.
If you are "best friends" with Farmer Fung, you can use the "dancing green kite": this kite will make your character dance the whole time while you are on the kite however this kite provides no benefits over the standard kite except of course the dancing!.