Abstract

                                Studies conducted to find the effect of drainage on growth and yield of rice revealed that leaf senescence is a physiological process of aging. During the process of senescence the stored reserves are translocated to root system. Leaf senescence is also decided by the soil conditions. In well drained soils the senescence is delayed. Roots under ill-drained situation becomes poorly active and could not accept the reserves from senescing leaves. When the root systems are not active then there is higher residues of stored reserves that are left in the senescing leaves. N fraction in roots in that situation show a low status compared to senescing leaves at maturity. In well drained soils the roots are active till maturity, contain higher N fraction in roots and good root activity but lower N fraction in senescing leaves. Grain yield was more with N fractions low in senescing leaves and high in root

Key words : Leaf senesce. N fraction, Drainage, Root activity, Bio-mass partitioning