Estimation of potential recharge through direct seeded and transplanted rice fields in semi-arid regions of Punjab using HYDRUS-1D

The present study utilizes soil water balance and HYDRUS-1D for estimating and predicting potential recharge in groundwater declining region of central Punjab, respectively. A field experiment was conducted at Punjab Agricultural University, Ludhiana. Two treatments viz direct-seeded (DSR) and transplanted rice (TPR) with three replications, were sown/transplanted during kharif season of 2019. The amount of water applied through rainfall/irrigation was recorded and bottom flux was measured using frequency domain reflectometry (FDR) and then predicted using HYDRUS-1D in order to assess potential groundwater recharge which was further compared with deep percolation determined using soil water balance. The performance of the HYDRUS-1D was evaluated using RMSE, NSE, and R(2) and found to be performing well. The paired t-test (t = 1.28 and t = 1.30 for TPR and DSR, respectively) was found to be non-significant at P = 0.05 which showed the correspondence between predicted and estimated parameters. The percentage change between estimated and predicted potential groundwater recharge was found to be 0.7% and 2.32% in TPR and DSR, respectively. The study revealed that there was 9% water saving and 14.6% more deep percolation (cumulative bottom flux) in DSR as compared to TPR that may potentially contribute to groundwater recharge.