What was the ritual called done in honor of the god of spring and agriculture in early february that was thought to fertilize the soil and ensure a good crop?

Los Voladores

Explanation:

            Los Voladores dance ritual is also known as Dance of the flyers. It is considered to be an ancient meso american ritual. This is dance form ceremony which was previously practiced in parts of Mexico and America to please the God of Spring and agriculture so that crops grow well.

            In this ritual five people climbed a tall pole. One of them stands at the middle of the pole and plays the flute while the others who are tied with a rope to the hips on the pole swing and dance in the air hanging upside down like the birds.

Hence the answer is -- Los Voladores