Effect of irrigation practices on root growth and yield of rice

O. Sariam

Abstract

Rice root development, which is essential for growth and yield, is influenced by soil water condition. A planthouse study was conducted to evaluate the effectc of irrigation practice on rice root growth and yield. Three irrigation practices imposed on MR 220 were flooded, non flooded-saturated (NFsat) and non flooded-field capacity (NFfcap). Total root length increased rapidly from maximum tillering to panicle initiation stage irrespective of irrigation practice, and after heading, under flooded and NFsat conditions. At maturity, total root dry weight of rice grown under NFfcap was only 25% of the total root dry weight of rice grown under flooded and NFsat conditions. Root growth and root length density decreased with the increase in soil depth during all growth stages measured under flooded and NFsat conditions. However, root length density under NFfcap conditions was high at the top 10 cm soil layer, decreased in the second 1 0 cm layer and increased again with depth especially during panicle initiation and heading stages. Shoot dry weight and grain yield of rice did not differ significantly between flooded and NFsat, but significantly lower under NFfcap condition. Results suggested that reducing irrigation water and maintaining the soil at NFsat conditions will not affect root as well as shoot growth and yield of irrigated rice.

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