Long-Term Perspective Changes in Crop Irrigation Requirement Caused by Climate and Agriculture Land Use Changes in Rechna Doab, Pakistan

Abstract

Climate change and agriculture land use changes in the form of cropping patterns are closely linked with crop water use. In this study the SDSM (statistical downscaling model) was used to downscale and simulate changes in meteorological parameters from 1961 to 2099 using HadCM3 General Circulation Model (GCM) data under two selected scenarios i.e., H3A2 and H3B2. Results indicated that Tmax, Tmin, and wind speed may increase while relative humidity and precipitation may decrease in the future under both H3A2 and H3B2 scenarios. Downscaled meteorological parameters were used as input in the CROPWAT model to simulate crop irrigation requirement (CIR) in the baseline (1961–1990) and the future (2020s, 2050s and 2080s). Data related to agriculture crop sown area of five major crops were collected from Punjab statistical reports for the period of 1981–2015 and forecasted using linear exponential smoothing based on the historical rate. Results indicated that the cropping patterns in the study area will vary with time and proportion of area of which sugarcane, wheat, and rice, may exhibit increasing trend, while decreasing trend with respect to the baseline scenario was found in maize and cotton. Crop sown area is then multiplied with CIR of individual crops derived from CROPWAT to simulate Net-CIR (m3) in three sub-scenarios S1, S2, and S3. Under the H3A2 scenario, total CIR in S1, S2, and S3 may increase by 3.26 BCM, 12.13 BCM, and 17.20 BCM in the 2080s compared to the baseline, while under the H3B2 scenario, Net-CIR in S1, S2, and S3 may increase by 2.98 BCM, 12.04 BCM, and 16.62 BCM in the 2080s with respect to the baseline. It was observed that under the S2 sub-scenario (with changing agriculture land-use), total CIR may increase by 12.13 BCM (H3A2) and 12.04 BCM (H3B2) in the 2080s with respect to the baseline (1961–1990) which is greater as compared to S1 (with changing climate). This study might be valuable in describing the negative effects of climate and agriculture land use changes on annual crop water supply in Rechna Doab.

Investigation into the Effects of Climate Change on Reference Evapotranspiration Using the HadCM3 and LARS-WG

“…Thus, applying suitable downscaling models can improve the results of climate change studies [5][6][7][8]. LARS-WG, as one of the downscaling models, is used for the simulation of climate information under current and future circumstances.…”

Impact of Climate Change on Groundwater Recharge in Cotton Irrigated Fields under Agronomical Practices

“…Reinecke et al (2020) reported that the uncertainty range in climate change is large, and predictions with confidence with groundwater recharge can only be made for a specific region. Climate change decreases cotton yield from 699 to 534 kg.ha -1 and elevates cotton irrigation requirement from 960.1 to 1048.9 mm in Pakistan (Arshad et al 2019;Abbas 2020;Rehman 2021). However, from T1 to T6, cotton yield per hectare increased (Fig.…”

Remote Sensing and Modelling Based Framework for Valuing Irrigation System Efficiency and Steering Indicators of Consumptive Water Use in an Irrigated Region

“…From the historical data analyses, it is clear that canal water supply is on the decline in Rechna Doab, along with significantly decreasing rainfall, especially in the middle and lower regions. On the other hand, according to [75], crop irrigation requirements would significantly increase in the coming years. The major reasons are elevated temperatures and decreasing air humidity.…”