Hydrus-1D for Simulating Potassium Transport in Flooded Paddy Soils
Shashank Shekhar, Damodhara Rao Mailapalli, Bhabani S. Das, Ashok Mishra, Narendra Singh Raghuwanshi
Abstract
Understanding the transport of potassium (K) in flooded rice fields is important for the efficient management of K fertilizers. In this study, the data from lysimeter experiments were used for simulating the water flow and K transport using Hydrus-1D and the influence of split doses of recommended K fertilizer on its availability to paddy crop was investigated. Paddy crop was grown in non-weighing-type lysimeters. The depth of ponding water, soil matric potential heads, K concentration of ponding water and soil solution were measured during three paddy growing seasons. The Hydrus-1D model was calibrated and validated using the lysimeter data and simulated the water flow and K concentrations well. The deep percolation was 51–56% of the applied water and the K load in deep percolation was 0.3–0.7% of the total available K. About 56–62% of K is utilized by rice crop. The applied K was observed to be remained mostly within the top 20 cm soil depth and did not transport to deeper layers. The recommended dose of K fertilizer with four equal splits applied at four crop growth stages could increase the K availability to paddy throughout its growing period, and it may be the best K management practice for paddy.