Climate Variability and Its Influence on Maize (Zea mays L.) Production Decline in Eastern Bhutan

Kinzang Thinley, Thinley Gyeltshen, Dorji Wangchuk, Kinley Sithup, Tenzin Rabgay, Tshering Choden, Tshering Pem & Sonam Deki

Maize is a staple food crop in eastern Bhutan, but its production has significantly declined in recent years, potentially due to the effects of climate change. Despite this, there has been limited research on the impact of climate variability on maize yield in the region. This study aims to assess climate variability trends and their effects on maize yields from 2006 to 2023. Using the Mann–Kendall trend test and Sen’s slope estimation, the temperature and rainfall trends were analysed, while Pearson correlation and multiple linear regression were applied to examine the relationship between climate variables and maize yields. Minimum and maximum temperatures showed an upward trend increasing by 0.03°C and 0.06°C, respectively. In contrast, rainfall exhibited no clear trend but displayed significant year-to-year variability. While rainfall and minimum temperature had a weak influence on maize production and yield, maximum temperature had a significant positive impact, explaining 29% of the variation in production and 37% of the variation in yield. The remaining unexplained (71% for production and 63% for yield) suggest the importance of non-climatic factors and localized microclimatic conditions. This research emphasis the focus on non-climatic and microclimatic factors to fully understand the causes behind the declining maize production in the region. To enhance climate monitoring and develop more effective adaptation strategies for agricultural crops, it is recommended to establish additional weather stations beyond those currently operated by the National Centre for Hydrology and Meteorology (NCHM).

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