Seeding Rate and Row Spacing Effects on Yield and Yield Components of Ratoon Rice
1987
Jones, D. B. | Snyder, G. H.
Ratoon cropping of rice (Oryza sativa L.) has recently received renewed attention as a means to lower unit production costs. However, little information is available on the effect of main crop cultural practices on ratoon yields of drill-seeded rice. The objective of this study was to determine the effect of main crop seeding rate and row spacing of drill-seeded rice on yield and yield components of the ratoon crop. Two contrasting plant types, tall (cv. Lebonnet) and semi-dwarf (cv. Bellemont and Lemont), were drill-seeded at rates of 50, 100, and 150 kg seed ha⁻¹ in 0.15-, 0.20-, and 0.25-m row spacings in three tests conducted on an organic soil. Ratoon grain yields differed significantly (P6O.O1) among tests for both plant types, and were not significantly (P60.05) correlated to main crop grain yields (r= −0.62). Ratoon grain yields of both cultivars were not significantly (P<0.05) affected by main crop seeding rate, row spacing, or seeding rate X row spacing interaction. Increased seeding rates significantly increased ratoon panicles per square meter (P< 0.01) and decreased ratoon filled grain number per panicle (P<O.O1) in all tests for both plant types. Panicles per square meter and filled grain number per panicle accounted for over 85% of the variation in ratoon grain yield. Compensation between these two yield components stabilized ratoon grain yield at relatively low levels.
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