Dep shud be charged on oofice building in accordance with sec 32 of income tax Act at the rate of 10% on WDV. Even if u dont charge dep on building it will deemed to have been allowed and WDV will be reduced by the amt of dep. There is no provioon in Income tax Act to charge dep on land and u cannot charge dep on land in income tax Act. Even if u charge the same it will be disallowed while calculating income under head business/profession.
The above provisions of IT Act has nothing to do with how u charge dep in accounts.