Effect of N-P-K fertilization on severity of "|stem rot"| (Sclerotium hydrophilum Sacc.) in rice

Rodrigo Ortega B.1, Roberto Alvarado A.1 y Ciro Belmar N.1

In a Vertisol soil, where severe damage had been caused by the disease known as pudrición del tallo ("stem rot") a trial was carried out during the 1989/90 crop season. The objectives were to evaluate the effect of different combination leveis of N-P-K, in the yield and other agronomic charaeteristics of the rice and in the severity of the disease. A factorial experimental desígn was used in a randomized complete block. Natural infestation of "stem rot" caused a decrease in the growth and yield of rice. Potash fertilization increased the yield, dry malter production and K content of rice tissues and produced a drastic decrease in "stem rot" severity. N and P fertilization did not influence the disease severity, although high N content in the rice tissues, associated with high leveis of N fertilization and K deficiency, could increased rice suceptibillty to "stem rot". P fertilization increased the rice yield and dry malter production. The effect of N fertilization was observed only in presence of K fertilization. In soils infested with "stem rot", a balanced N-P-K fertilization will be the recommended practice.

Keywords: rice, stem rot, fertilization, nitrogen, phosphorus, potassium.
1 Estación Experimental Quilamapu (INlA). Casilla 426, Chlllán, Chile.