Effects of plant spacing on evapotranspiration for estimating crop coefficient of Japonica rice

Abstract

A field experiment was conducted to evaluate the evapotranspiration (ET), crop coefficient (Kc), and water use efficiency (WUE) of rice in two unique transplanting systems: Jejer Manten (JM) and Jajar Legowo (JL) under irrigated conditions. Research studies in Indonesia attribute JM and JL with high yields and water productivity compared to the conventional tile (TL) system using Indica rice. There is no scientific research on the effect of JM and JL on ET for estimating Kc in both Indica and Japonica rice. The aim of the study is to evaluate the influence of JM, JL, and TL on ET, Kc, and WUE of Japonica rice at different rice growth stages. Crop ET and water surface evaporation beneath the rice canopy (Ew) were measured by lysimeters installed in each transplanting system. The average of Kc was calculated at the vegetative, reproductive, and ripening stages. The yield was higher in JM and JL compared to TL. In terms of water conservation and efficiency, JL outperforms JM and TL due to lower ET, Kc values, and higher WUE. Selecting an appropriate transplanting system is subject to local conditions and water availability .