Seedling characteristics and the early growth of transplanted rice under different water regimes

A series of experiments was conducted oil rice seedlings in a nursery seedbed and after transplanting in order to understand root and shoot characteristics, and their contribution to the production of tillers and dry matter. At the nursery stage, the seedlings' were studied at varying densities (high and low) and fertilizer treatments (with and without nitrogen) at 12 and 24 days after sowing (DAS) in wet or (It), seedbeds. After transplanting, the effects of seedling age at the time of transplanting (12 and 30 days), method of raising seedlings (dry or wet seedbed) and water regimes (flooded or non-flooded) were studied. The overall aim was to understand the benefits, if any of this system of rice intensification (SRI) management practices over conventional methods. The study revealed that in a nursery at 12 DAS, rice seedlings raised in a city seedbed, irrespective of seeding density and fertilizer application, showed accelerated growth with better shoot and root characteristics in terms of greater leaf number, plant height, lateral root formation and elongation, and dry mass compared to seedlings grown in it wet seedbed. At 24 DAS, a significant interaction between seeding density and fertilizer application was found for dry-seedbed plants compared to those grown in a wet seedbed. Poor shoot and root growth was seen in older seedlings grown without fertilizer. Seedling age was found to be the most important factor affecting both shoot characteristics after transplanting (number of tillers, plant height, dry matter production) and root characteristics (root length density, root weight density). Younger seedlings performed better than older seedlings transplanted into either flooded or non-flooded soils with greater uptake of nitrogen and manganese than older seedlings. These results indicate that many of the constraints previously associated with non-flooded rice Cultivation may be alleviated by transplanting younger seedlings that have been raised by SRI methods.