Influence of Three Soil‐water Regimes on Root Porosity and Growth of Four Rice Varieties1

Abstract

AbstractA better understanding of the growth response of rice (Oryza sativa L.) to waterlogged soil conditions is desirable. The objective of this study was to measure the influence of soil water regime on root porosity, growth, and nutrient content of four varieties of rice at various dates after transplanting.Four rice varieties (‘IR8’, ‘Padma’, ‘BC6’, and ‘IR22’) were grown under three soil water regimes (continuous flooding, alternate flooding, and no flooding) in a greenhouse on a clay loam soil. Root porosity, growth of plants and nutrient (N, P, K, Ca, and Mg) content of shoots were determined at four different plant ages (30, 60, 85, and 110 days after transplanting).Root porosity was greatest in plants grown with continuous flooding. Porosity of roots in all four varieties reached maximum values between 30 and 60 days and then started to decline. Padma and BC6 had higher root porosities than IR8 and IR22. High root porosity was associated with greater root length, increased dry weight of roots and shoots, and higher nutrient content in shoots.