Table 7. Analysis of variance of the effects of slag-based silicon fertilizer (slag) and application rate of Si (Si-R) on rice brown spot development at the anthesis stage (%).

		F values
Sources of variation	Df	Incidence of disease	Disease index
Slag	1	0.0145 ns	13.20*
Si-R	3	47.05**	3545**
Slag×Si-R	3	0.00727 ns	5.85 ns

Levels of probability: ns  =  non significant, significantly different *p≤0.05 and **p≤0.01.