ASSESSMENT OF PLANT DENSITY AND INTERACTIONS WITH SOIL TYPES AND TRANSPLANTING METHODS IN RICE CULTIVATION

Resumen

Soil properties play a critical role in determining rice yield by influencing both belowground and aboveground parts of the plant, while also affecting optimal plant density. This study aimed to evaluate the effects of plant density and its interactions with two distinct soil types under manual and mechanical transplanting across two growing seasons of rice cultivation. A split-split plot arrangement was employed within a randomized complete block design with four replications. Two soil types with distinct properties (first soil type and second soil type) were considered as the main factor, planting methods (manual and mechanical transplanting) as the sub-factor, and plant densities (15.9, 20.8, and 27.8 plants m-2) as the sub-sub-factor. Phenological traits, root characteristics, yield, and yield components were assessed. In 2022, at panicle initiation, the longest root length (23.93 cm) was observed at a density of 27.8 plants m-2, while the highest root fresh weight (66.23 g) was recorded in the second soil type. At maturity, the second soil type at a density of 15.9 plants m-2 with manual transplanting recorded the longest root length (22.43 cm), and the highest root fresh weight (86.40 g). Regarding number of spikelets per panicle, in 2021, the highest values were observed in the first and second soil types at 27.8 and 15.9 plants m-2, reaching 122.7 and 122.1 spikelets, respectively; in 2022, the second soil type with 27.8 plants m-2 recorded the highest value of 122.4 spikelets. The second soil type with 27.8 plants m-2 achieved the highest number of panicles, with values of 554.6 and 547.4 under mechanical and manual transplanting, respectively. Grain yield was indirectly
influenced by yield components, being 8.7% higher in the second soil type compared to the first soil type (8048 kg ha-1), peaking at 8687 kg ha-1 at a density of 27.8 plants m-2. A density of 27.8 plants m-2 increased the number of spikelets per panicle in the first soil type, while it increased the number of
panicles per m-2 in the second soil type. Accordingly, a density of 27.8 plants m-2 is recommended for both soil types.