UV-B增强下施硅对水稻生长及CH4排放的影响

通过盆栽试验,研究了UV-B增强下不同施硅量和硅肥种类对水稻生长及甲烷(CH₄)排放的影响.UV-B辐射设2个水平,即对照(自然光，A)和增强20%(E);硅肥设4个水平,即Si₀(不施硅,0 kg SiO₂·hm^-2)、Si₁(硅酸钠,100 kg SiO₂·hm^-2)、Si₂(硅酸钠,200 kg SiO₂·hm^-2)和Si₃(钢渣硅肥,200 kg SiO₂·hm^-2).结果表明: 施硅能缓解UV-B增强对水稻生长的抑制作用,使分蘖数、叶绿素含量、地上部和地下部生物量增加.施硅对水稻生长的促进作用随施硅量(硅酸钠)的增加而增加,钢渣硅肥的促进作用大于硅酸钠.UV-B增强可提高稻田CH₄的排放通量和累积排放量,施硅显著降低CH₄的排放通量和累积排放量,且CH₄排放随施硅量的增加而减少.在施硅量相同的情况下,钢渣硅肥的减排效果优于硅酸钠.表明在水稻生产中,施用钢渣硅肥不仅能实现废弃物利用,而且可有效降低UV-B增强下CH₄的排放量.

Effects of silicon supply on rice growth and methane emission from paddy soil under elevated UV-B radiation.

A pot experiment was conducted to investigate the effects of silicon supply on rice growth and methane (CH₄) emission in paddy field under elevated UV-B radiation. The experiment was designed with two UV-B radiation levels, i.e. ambient UV-B (ambient, A) and elevated UV-B radiation (elevated by 20%, E); with four silicon supply levels, i.e., Si₀ (control, without silicon), Si₁ (as sodium silicate, 100 kg SiO₂·hm^-2) ， Si₂ (as sodium silicate, 200 kg SiO₂·hm^-2) and Si₃ (as slag fertilizer, 200 kg SiO₂·hm^-2). The results indicated that, silicon supply obviously alleviated the depressive effect of elevated UV-B radiation on rice growth, and increased the tiller numbers, chlorophyll content, and shoot and root dry masses. Silicon supply promoted rice growth, which increased with the silicon supply level (sodium silicate). Slag fertilizer was better than sodium silicate in promoting rice growth. CH₄ flux and accumulated CH₄ emission were obviously increased by elevated UV-B radiation, but significantly decreased by silicon application. CH₄ emission was reduced with increasing the silicon supply level. Under the same silicon supply level, slag fertilizer was better than sodium silicate in inhibiting CH₄ flux and accumulated CH₄ emission. This research suggested that fertilizing slag in rice production was helpful not only in utilizing industrial wastes, but also in significantly mitigating CH₄ emissions in rice paddy under elevated UV-B radiation.