Impact of Variation in Monsoonal Rainfall and Temperature on Paddy Production and its Adaptive Strategies: A Case Study from Bhaktapur District of Nepal

Abstract

This study was carried out to assess the impact of climate change on paddy yield in Bhaktapur, Nepal. The study compared the summer rainfall variability, summer temperature variability, and farmers' perception of rainfall and temperature changes over a 30-year period. A household survey of 420 houses was conducted to collect information supplemented by meteorological data from the Department of Hydrology and Meteorology (DoHM). Following this, significant increases and decreases in temperature and rainfall were observed on annual and seasonal time scales, respectively. The obtained result shows the annual precipitation trend of the study area is increasing at a rate of 0.24 mm yr-1. The linear trend analysis of the pre-monsoon indicates that the rainfall is increasing at the rate of 0.18 mm yr-1 and the monsoon shows the rainfall is increasing at the rate of 0.57 mm yr-1,whereas the post-monsoon rainfall is decreasing at the rate of 0.02 mm yr-1. The biggest changes in precipitation were observed during the monsoon season. The monsoon precipitation trend in the time series was found to be increasing at a rate of 0.57 mm yr-1. This variation in monsoon rainfall is clearly unfavorable for the agriculture system of the study area. When these recent changes in the temperature and precipitation were compared over 30-year time series data from the weather station, it is apparent that the climate of the study area exhibits fluctuation over time, many of the changes being very erratic. As per the data, all kinds of temperatures are being increased annually. According to the linear trend shown below, average annual temperature, minimum temperature, and maximum temperature are increasing at rates of 0.038°C yr-1, 0.054°C yr-1, and 0.021°C yr-1, respectively. The results show that future climate change in Nepal, including higher temperatures and erratic rainfall, might have a negative impact on paddy productivity and yield in the study area.