Journal article

Publication year: 1992

Pages: 384-389

Journal: Plant Disease

Volume number: 76

Issue number: 4

ISSN: 0191-2917

Publisher: American Phytopathological Society

Abstract: 
Nitrogen is essential for increased upland rice productivity, but the severity of blast disease increases with N application. The potential to suppress blast disease through timing and splitting of N application was tested during the 1987 and 1988 wet seasons in the Philippines on a strongly acidic soil. We studied the effects of 90 kg of N per hectare applied as two early-split applications, two late splits, three equal splits, and five equal splits on disease progress, crop growth, and yield. A no-N check was included. Leaf blast was suppressed when N was applied late (30 and 60 days after seeding) compared with early- and equal-split applications. Panicle blast was less in the no-N check but was not consistently reduced by any of the other treatments. Leaf and panicle blast correlated with total dry matter (ra = 0.60-0.70), Si/N ratio (ra = -0.50 to -0.80), and with the concentrations of Si (ra = -0.40 to -0.70) and N (ra = 0.50-0.80). Increased leaf blast was attributable to both increased tissue susceptibility and increased canopy density. In inoculated plots, total dry matter (5.6 t/ ha) and grain yields (1.1 t ha) were reduced compared with fungicide-treated plots (6.3 and 1.8 t/ha), and the yield loss was correlated with the incidence of severe panicle infection (ra = 0.86). Nitrogen treatments had no significant effect on grain yields. None of the treatments controlled both leaf and panicle blast and increased yields.

Harvard Citation style: KURSCHNER, E., BONMAN, J., GARRITY, D., TAMISIN, M., PABALE, D. and ESTRADA, B. (1992) EFFECTS OF NITROGEN TIMING AND SPLIT APPLICATION ON BLAST DISEASE IN UPLAND RICE, Plant Disease, 76(4), pp. 384-389

APA Citation style: KURSCHNER, E., BONMAN, J., GARRITY, D., TAMISIN, M., PABALE, D., & ESTRADA, B. (1992). EFFECTS OF NITROGEN TIMING AND SPLIT APPLICATION ON BLAST DISEASE IN UPLAND RICE. Plant Disease. 76(4), 384-389.