Nakshatra based rainfall variability, trends and its influence on rice-wheat production - A case study over two sites in Bihar, India

Abstract

An attempt has been made to study the variability and trends of rainfall during nakshatra periods for two sites, Patna and Samastipur of Bihar and verified the relation of four traditional knowledge/ proverbs/ beliefs of nakshatra based rainfall pattern, which are popular in this part of the region with rice-wheat productivity. Maximum rainfall and highest rainy days occurred during punarvasu nakshatra (July 6 – July 19) over both sites followed by pushya (July 20- Aug 2). The coefficient of variation of rainfall shows below 100 % from aridhra (June 22 – July 5) to uttara (Sept 13-26) at Patna and from rohini to purbha (Aug 31- Sept 12) for Samastipur. A significant increasing trend of 0.965 mm y-1 and decreasing trend of -0.857 mm y-1, respectively have been noticed during pubbha and hasta at Patna. However, a significant increasing trend of 1.536 mm y-1 and decreasing trend of -0.774 mm y-1, respectively have been noticed during aridhra and hasta at Samastipur.

Keywords

• Nakshatra
• Rainfall variability
• Mann-Kendall non-parametric test
• Productivity index
• Rainfall anomaly index
• Correlation