RICE RATOONING - IRRI books - International Rice Research Institute

N FERTILIZER MANAGEMENT FOR MAXIMUM RATOON YIELDS 1891. N fertilizer rates (kg/ha) and application times for main and ratoon crops of varieties Lemont andLabelle in 1984 and 1985 at Beaumont and Ganado, Texas.treatments could have 4 replications of the 3 postharvest or ratoon crop N rates (0,56, or 112 kg N/ha).Preflood main crop N rates were 79 or 117 kg/ha for Labelle and 117 or 157 kgN/ha for Lemont (Fig. 1). The lower main crop preflood N rate was chosen to helpensure response to postflood N application, and the higher rate to establish the Nresponse potential. All N was applied as urea at stages shown in Figure 1. P wasapplied preplant at 20 kg P/ha.Hand harvesting resulted in a uniform stubble height of about 45 cm forLabelle and about 50 cm for Lemont, from which the ratoon crop could develop.After main crop harvest, N applied on dry soil at 56 or 112 kg/ha promotedratoon crop development. Plots were then reflooded to an initial depth of 5 cm, andthe flood increased to 10 cm within 14 d. Floodwater was drained about 10 d beforeratoon crop harvest each year.