Response of Philippine released rice varieties to different water-saving irrigation schemes

De Dios, J.L.; Quilang, E.J.P.; Corpuz, A.A.; Espiritu, A.J.; Malabayabas, M.D. . Arocena, A.C.; Ramos, L.F.; Ignacio, J.G.; Esteban, L.D.; Liwanag, M.I.

Response of Philippine released rice varieties to different water-saving irrigation schemes

2000

On-farm studies were conducted for specific water management techniques in the 1999 DS [dry season] at Narvacan Guimba, Nueva Ecija [Philippines], with clay-loam soils and in San Rafael Guimba, Nueva Ecija, with silt loam soils. The treatments were: continuous flooding, a farmers' practice (T1); 5 days of no floodwater (T2); 7 days of no floodwater (T3); 9 days of no floodwater (T4); irrigation of 5 cm floodwater every 14 days (T5); continuous soil saturation (T6); and soil saturation until panicle initiation (PI), then flooding at flowering (T7). Treatments were imposed from 7 days after transplanting (DAT) to 2 weeks after flowering. PSB Rc14, PSB Rc28, PSB Rc34, PSB Rc52, and IR60 (farmers' choice) were used. Nitrogen (N), Phosphorus (P), Potassium (K) fertilizers were 120-40-40 kg/ha. Water applied in each plot was measured using a cut-throat flume. Studies on Maligaya clay soils comparing intermittent irrigation with control at 0, 90 and 180 kg N/ha using PBS Rc14 were also conducted during the 1997 and 1998 dry seasons at PhilRice Central Experimental Station (CES) Munoz, Nueva Ecija. The on-farm trials in 1999 showed that IR60, PSB Rc14 and PSB Rc52 easily adapted all the water saving schemes (T2-T7) on clay loam soils. Using these schemes, around 10-25% of the water used during the crop growing period was saved. On silt-loam soils, only T4 was not adapted by all rice cultivars. However, T2, T3, T5, T6, and T7 reduced water use by 25 to 50% without reducing yields in all rice cultivars. Average yields from clay soils ranged from 5.0 to 7.0 tons/ha while yields on silt-loam soils ranged from 3.8 to 5.4 tons/ha. Water saving schemes did not influence tillering and other yield components. Earlier result from trial using Maligaya clay soils showed that yield from T5 was comparable with control regardless of N level. This reduced water used by 47 to 60% against the control without yield loss. Average yield from two seasons ranged from 4 to 8 tons/ha in 1997 and 4 to 6 tons/ha in 1998. Yield difference was shown only among the N levels

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