Yes, you can modify the initial spatial distribution of the sugar.
It is currently generated based on sugar-map.txt so you either need to alter that file, create a new file or initialise the distribution based on some code in netlogo itself.
You have to look in your program files to find the original file (for example: "C:\Program Files\NetLogo 6.2.2\app\models\Sample Models\Social Science\Economics\Sugarscape/sugar-map.txt")