The multiple cropping index refers to the ratio of the total sown area of crops to the area of arable land within a year, and is generally expressed as a percentage. The level of the multiple cropping index is restricted by the local sunshine, soil, water conservancy, fertilizer, labor, and scientific and technological conditions. Good sunshine conditions, Long frost-free period, sufficient moisture, reasonable interplanting, etc. are the basis for improving the multiple cropping index.
The multiple cropping index is closely related to the longitude of the area is correct according to the above definition.