Trends in Climatic Variables and Their Impact on Crop Water Requirement and Crop Production (Published)
Climate change have innumerable potential effects on agricultural production which is a key economic sector in Bangladesh. Bogra, Rangpur and Rajshahi in the north-west region have been selected as the study area. This paper aims to investigate the combined effects of climatic variables on ETo and NIR and to estimate the yield of the crop Boro and Aman in these study area. For testing the statistical significance of trends in different agro-climatic variables both parametric and non-parametric methods are used. The results of the analysis reveal that maximum temperature has decreasing trends of 0.20c, 0.10c and 0.30c per decade at Bogra, Rajshahi and Rangpur station and relative humidity has increasing trends in most 10-day periods. Sunshine hour and solar radiation show decreasing trends and minimum temperature and wind speed show increasing trends. It is found that ETo has decreasing trends at Bogra, Rangpur and Rajshahi station which are 0.41, 0.35 and 0.15 mm/day respectively per decade. NIR shows decreasing trend of 0.0428, 0.021 and 0.0434 mm/day per decade at those stations respectively. Sensitivity analysis was done in terms of percentage change in temperature, wind speed, relative humidity and radiation to identify the relative importance of climatic variables on Eto. Though the temperature is increasing due to global warming and it has a positive effect on ETo and NIR, the changes in other climatic variables are more prominent than the changes in temperature which result in a decrease in ETo and NIR. Aqua Crop version 4.0 software was used to estimate the crop yield Boro and Aman at the three stations. At Rajshahi station yield of Boro and Aman is found to be 6.407 and 4.732 tons per hectare respectively. At Bogra station, yield of Boro and Aman is 6.407 and 3.66 tons per hectare. The yield of Boro is found to be 6.42ton per hectare at Rangpur station. These values are found to be relatively close to the values obtained from the Agricultural Statistics Report, 2011of BBS.
Keywords: Amon, Aquacrop, Boro, Crop Water Requirement, Evapotranspiration