Simulation of salt and water movement and estimation of water productivity of rice crop irrigated with saline water |
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Authors: | V Phogat A K Yadav R S Malik Sanjay Kumar Jim Cox |
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Institution: | (1) Department of Soil Science, CCS Haryana Agricultural University, Hisar, 125004, India;(2) Present address: South Australian Research and Development Institute, Urrbrae, SA, 5064, Australia |
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Abstract: | The HYDRUS-ID model was experimentally tested for water balance and salt build up in soil under rice crop irrigated with different
salinity water (ECiw) of 0.4, 2, 4, 6, 8 and 10 dS m−1 in micro-lysimeters filled with sandy loam soil. Differences of means between measured (M) and HYDRUS-1D predicted (P) values of bottom flux (Q
o) and leachate EC as tested by paired t test were not found significant at P = 0.05 and a close agreement between RMSE values showed the applicability of the HYDRUS-1D to simulate percolation and salt
concentration in the micro-lysimeters under rice crop. Potential ET values of rice as obtained from CROPWAT matched well with
model predicted and measured one at all ECiw treatments. The model predicted root water uptake varied from 66.1 to 652.7 mm
and the maximum daily salt concentration in the root zone was 0.46, 2.3, 4.5, 6.7, 8.4 and 10.2 me cm−3 in 0.4, 2, 4, 6, 8 and 10 dS m−1 ECiw treatments, respectively. The grain production per unit evapotranspiration (
\textWP\textET\texta {\text{WP}}_{{{\text{ET}}_{\text{a}} }} ) value of 2.56 in ECiw of 0.4 dS m−1 treatment declined to 1.31 with ECiw of 2 dS m−1. The
\textWP\textET\texta {\text{WP}}_{{{\text{ET}}_{\text{a}} }} reduced to one-fifth when percolation was included in the productivity determination. Similarly, the water productivity in
respect of total dry matter production (TDM) was also reduced in different treatments. Therefore, the model predicted values
of water balance can be effectively utilized to calculate the water productivity of rice crop. |
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