Abstract:

The investigation showed that content of soil available silicon in the safe utilization type of polluted paddy fields in Zhejiang Province was between 28-166 mg·kg^-1. Most of the paddy fields had medium or low available silicon, and the problem of soil silicon deficiency in the province was more prominent. Average content of soil available silicon decreased in the order of coastal plain>water network plain>valley plain, which increased with the increase of soil pH value and clay content. The results of nine silicon fertilizer experiments showed that application of basal silicon fertilizer had an obvious effect on increasing rice grain yield by 4.75%-13.71%, and reducing cadmium in brown rice by 6.92%-32.73%. Foliar spraying of silicon fertilizer had no obvious effect on rice yield, but could reduce the content of cadmium in brown rice by 5.19%-18.18%. The effect of silicon fertilizer on increasing rice yield and reducing cadmium in brown rice increased with the decrease of soil available silicon. The results showed that basic silicon fertilizer was a good measure to increase rice yield and reduce cadmium in brown rice on polluted paddy fields with low soil available silicon in Zhejiang Province.

Key words: soil available silicon, safe utilization type of polluted paddy fields, silicon fertilizer, increase of production, reduction of cadmium