Analyzing the Relationship between Climatic Variability and Vegetables Yield: A Study in Syangja District, Nepal

Vegetable production is highly dependent on climatic variability. Several studies have concluded that Syangja district (latitude 28°4'60 North and longitude 83°52'0 East) of Nepal is more vulnerable to climate change; thus, a changing climate should have a significant impact on vegetable crop yields. In this paper, the relationship between climate variation and vegetable output in Syangja district for the period 2005 to 2014 was analyzed. This work aims to explore the impact of climate change on major vegetable crop yields and to determine their relationships based on a regression model between historical climatic data and yield data for vegetable crops. Tomato (Solanum lycopersicum) was ranked as the most affected vegetable crop in the study area. An analytical analysis of the last 20 years of climatic data from meteorological stations of Syangja district was done. Microsoft excels and STATA12 have been used for the trend analysis and quantification of climatic data. Trend analysis of area under vegetable and productivity shows increasing trend over last 10 years in the study district. Both maximum and minimum temperature shows the increasing trends over the last 15years. The mean maximum temperature was increasing significantly (P<0.1) at the rate of 0.029°C per year, while the average minimum temperature was increasing significantly (P<0.01) at the rate of 0.044°C per year. Rainfall shows decreasing trend by 11 mm per year and relative humidity in the morning and evening shows increasing trend by 0.009 and 0.27% per year respectively. Logistic regression analysis was used to determine the role of climatic variables in productivity of Vegetable crops. The logit regression analysis of vegetable production with climatic variables revealed a coefficient of determination of 0.94 indicating 94% of vegetable production variance is explained by climatic variables. Results showed positive significant relationship with area under vegetable cultivation (P<0.1) and negative significant relationship with average minimum temperature (P<0.5).