Diagnosis of Sulfur Deficiency and the Effect of Sulfur on Rice Grain Yield

The field and hydroponic experiments were conducted to confirm the effect of sulfur on rice grain yield and diagnostic index of sulfur deficiency,the results showed as follows: ①Fertilization of sulfur enhanced the number of effective panicles,percentage of filled grain and 1000 grain weight,significantly increased the grain yield.In sandy soils,which contained medium available sulfur,the proper doses of sulfur fertilizer was 15 kg per hectare. ②The effect of sulfur deficiency on rice grain yield was more serious at tillering stage than that at seedling and ear developing stage.Sulfur fertilizer should be applied as basic fertilizer. ③The proper organ for sulfur diagnosis was rice leaves.Total sulfur,sulfate sulfur and N/S ratio could be used for sulfur diagnosis and the critical levels were 0.11%,190 μg/g and 31 respectively at tillering stage.