Effect of sources of sulphur on yield and disease incidence in crops in Jiangxi Province, China

The Jiangxi Academy of Agricultural Sciences (JAAS) has conducted five experiments to compare elemental S and sulphate S containing fertilizers. The elemental S containing fertilizer used was a sulphur enhanced diammonium phosphate (SEF12) and the sulphate S was supplied from single superphosphate (SSP). A diammonium phosphate (DAP) control was used. In a cabbage experiment conducted in 2003 there was a significant response to S and a lower incidence of soft rot where SEF12 was applied (18-19% reduction compared to DAP, c.f. 5% with SSP) and leaf disease (20-31% reduction, c.f. 19% with SSP) where elemental S was applied. In two rice experiments there was a greater response to SEF12 compared to SSP and this was associated with a lower incidence of disease and insects (rice leaf roller and brown plant hopper) where SEF12 was applied. Incidences of rice leaf blight and rice blast were also observed on the DAP and SSP treatments. Two plot trials with rapeseed were established in 2006 in which the fertilizers were applied either at rates to deliver the same rate of P as applied in DAP at Maying Shishan or with the same rate of S as applied in SSP at Maying Sequ. At the Maying Shishan site there was a significant response to S in SSP and SEF12 when applied at the same P application rate. At the Maying Sequ site SEF12 out yielded SSP when applied at the same S rate. These trials are the first to report soil applied elemental S having an effect on protecting crops against insects and disease and indicate that the mechanism involved requires further investigation in both upland and flooded crops.