Influence of Silicon Application Timing on the Performance of Rice Under Limited Water Supply

The beneficial impact of Silicon (Si) in mitigating diverse abiotic stresses, such as drought stress, has been extensively recorded across various crops. A pot experiment was conducted at the Asian Institute of Technology, Thailand, to evaluate the performance of a popular Thai rice variety (RD57) commonly cultivated in Thailand's central plains under three soil moisture levels as affected by five Si application timings. Si was added to the soil at 300 kg Si ha–1. Reduced water supply (75% field capacity [FC] and 50% FC) caused lengthening of the growth period with reduced yield and its components. Si application resulted in an enhanced root and shoot growth irrespective of application timings, compared with the control. However, Si application with split doses of 25% at basal, 50% at panicle initiation (PI), and 25% at the heading stage was found to be the most effective. Even under severe water stress, more root growth and panicle numbers were found during this application timing. Si absorption was also found more for all application timings than the control; however, the same application timing resulted in the highest absorption (8.62%). A strong positive correlation was observed between Si uptake and grain and straw yield under all moisture-deficient conditions. Si application can be recommended in split doses for rice cultivation under a limited water supply.