Simplify the following text for a Grade 6 native English-speaking person.
Original: The Chinese calendar year has nine main festivals , seven determined by the lunisolar calendar , and two derived from the solar agricultural calendar . ( Farmers actually used a solar calendar , and its twenty-four terms , to determine when to plant crops , due to the inaccuracy of the lunisolar traditional calendar .
Simplified: The Chinese calendar is a lunisolar calendar .