RESUMO
Examining the effects of silicon fertilizer on the yield of double-cropping rice and the leaching loss of soil nitrogen (N) and phosphorus (P) could provide a basis for the optimization of formula fertilizer and the comprehensive control technique of agricultural surface source pollution in typical double cropping paddy field. A field experiment was conducted to investigate the effects of silicon fertilizer of 0, 750, 1500, 2250 and 3000 kg·hm-2(T0, T1, T2, T3, T4) on yield and N and P absorption of double-cropping rice, dynamics of N and P in the field surface water, soil available silicon, organic matter, alkali nitrogen and available phosphorus under the fixed nitrogen and phosphorus fertilizers. The results showed that compared with control (T0), the silicon fertilizer increased the yield of early and late rice by 2.2%-30.4% and 3.9%-9.2%, respectively, enhanced rice N accumulation increased by 2.4%-47.3%, rice P accumulation by 2.2%-41.3%, straw N accumulation by 0.4%-28.3%, and straw P accumulation by 5.1%-31.0%. On the first day after fertilization, the total nitrogen (TN) content in the surface water was decreased by 3.4%-28.8% in silicon treatments compared with T0, the ammonium nitrogen (NH4+-N), total phosphorus (TP) and total soluble phosphorus (TDP) was decreased by 10.4%-25.6%, 25.5%-29.2%, 30.8%-38.0%, respectively. 45 days later, TP and TDP contents in the field surface water were significantly higher than T0. The silicon fertilizer treatment was beneficial to increase soil silicon level, contents of organic matter and alkali nitrogen of the double cropping rice, among which the T1 treatment performed the best. Soil available phosphorus showed a decreasing trend with the increasing silicon fertilizer.
