Unveiling rice (Oryza sativa L.) root dynamics and yield architectures under divergent establishment methods and irrigation regimes

The present investigation was conducted for two consecutive kharif seasons
(2021 and 2022) at the Agricultural Research Station, Kampasagar, Nalgonda district,
on sandy clay loam soils using a split-plot design with three main plots and three sub-
plots, replicated thrice. Root parameters such as root volume and root-to-shoot ratio
showed significant variation among establishment methods, with dry direct seeded
rice (M 1 ) recording numerically higher values. However, yield-attributing traits like
number of panicles m⁻² (285.5), panicle length (27.3 cm), panicle weight (4.69 g),
number of spikelets panicle⁻¹ (196.7), filled grains panicle⁻¹ (189.8) and test weight
(26.6 g) were significantly influenced by establishment methods, with wet direct
seeded rice (M 2 ) performing better, on par with manual transplanting (M 3 ) and
superior to dry seeding. Irrigation treatments and interactions had no significant
effect on root traits and yield parameters, although alternate wetting and drying
(AWDI) and continuous submergence performed better than saturation irrigation. A
key challenge in the study was managing uniform field conditions across varying
methods and seasons. Despite this, the study contributed valuable insights into the suitability of different crop establishment methods and irrigation strategies under
semi-arid conditions, highlighting the potential of wet direct seeding and AWDI to
improve rice productivity while optimizing water use.