Scheduling of Irrigation Based on IW/CPE for Aerobic Rice – A Review

Abstract

The scheduling of irrigation according to the ratio between irrigation water depth (IW) and cumulative pan evaporation (CPE) rate for aerobic rice. During these days, the shortage of water resources is increasing continually due to climate change. It has led to the adaptation of rice farming under aerobic conditions. This saves irrigation water, labour, eliminates puddling, reduces seepage, percolation losses, and methane emissions. Aerobic rice cultivars produce higher plant growth, physiological, root growth, yield, water use efficiency, productivity, and soil nutrient uptake under different (0.6, 0.8, 1.0, 1.2, 1.4, 1.5, 2, and 2.5) IW/ CPE ratios. Under these irrigation schedules, the yield of rice in aerobic soil is recorded at between 4.5 and 7.1 t ha-1 and the water use efficiency is from 25 to 70 kg ha-1. However, the decline in yield or even crop failure under continuous monocropping, weeds, nematode problems, and aerobic rice micronutrient deficiency Our important findings in aerobic rice are: (1) Scheduling of irrigation based on various IW/ CPE ratios recorded the higher rice plant height, number of tillers hill-1, dry matter production, leaf area index, crop growth rate, relative growth rate, root length, productive tillers, number of grains panicle-1, number of filled grain panicle-1, total number of grains panicle-1, test weight and yield; (2) The last 15 years of aerobic rice research findings focused on irrigation scheduling by IW/CPE ratio for driving economic water use; and (3) nutrient uptake increased with irrigation at more than 1.0 IW/CPE ratio with depth of 5 cm irrigation water. Declining water availability due to climate change makes it necessary to conduct more research on irrigation scheduling in rice crops in order to increase yield and water use efficiency.