氮肥与硅肥配施对杂交稻冈优725干物质和镉积累的影响

以杂交籼稻冈优725为材料,设置不同施氮量(0、90、180 kg/hm~2)和施硅量(0、150、300 kg/hm~2),研究氮硅配施对冈优725干物质积累和镉吸收的影响。结果表明:各施氮水平下,施硅均能够显著促进水稻根系干物质的积累和地上部氮的积累,施氮量为0、90 kg/hm~2时,施硅均能够显著促进地上部干物质的积累;施氮量相同的条件下,与不施硅相比,施硅量为150 kg/hm~2处理可显著增加有效穗数,显著降低水稻千粒质量;施氮为0时,与不施硅相比,施硅可显著增加每穗粒数;各施氮水平下,水稻产量均随施硅量的增加而提高,但在施氮量为180 kg/hm~2时,施硅的增产效果不明显;各施氮水平下,施硅能显著降低根、茎、穗、精米中镉的含量及地上部镉的积累量,但叶片中镉含量升高,施氮量为180 kg/hm~2时,施硅量为150 kg/hm~2和300 kg/hm~2处理精米中镉的含量差异不明显。综合本研究结果,施氮量180 kg/hm~2+施硅量150 kg/hm~2对冈优725的增产降镉的效果较好。

Effects of combined application of nitrogen and silicon on dry matter and cadmium accumulation in hybrid rice (Oryza sativaL.) Gangyou725

A field experiment was conducted in cadmium contaminated paddy rice field to investigate the effects of combined application of nitrogen and silicon on growth and cadmium accumulation in hybrid rice cultivar Gangyou725. In the present study, three nitrogen (0, 90, 180 kg/hm2) and/or silicon (0, 150, 300 kg/hm2) levels were applied, dry matter weight, nitrogen accumulation in rice shoot, rice yield and its component factors, cadmium content and accumulation amount in rice root and shoot and cadmium content in polished rice were investigated. The results showed that under 3 nitrogen application levels, silicon could improve the root dry matter weight significantly. But it only improved the shoot dry matter weight at 0 and 90 kg/hm2 nitrogen treatments. Under the three nitrogen treatments, the nitrogen accumulation in shoot of the rice was increasing with the silicon levels applying in the field. The yield component factors were significantly affected by combined application of nitrogen and silicon. Treatment with 150 kg/hm2 silicon could increase the effective panicle numbers under the same nitrogen levels, but decrease the 1000-grain weight compared to the treatments with 0 kg/hm2 silicon treatment. Under 0 kg/hm2 nitrogen treatment, applying 150 and 300 kg/hm2 silicon improved the spikelets per panicle significantly compared to the 0 kg/hm2 silicon treatment. Under each nitrogen level, rice yield was higher in 150 and 300 kg/hm2 silicon treatments compared with 0 kg/hm2 silicon treatment, but the effect was not significant under 180 kg/hm2 nitrogen treatment. The cadmium contents in root, stem, panicle and the cadmium accumulation amount were lower in treatment with 150 and 300 kg/hm2 silicon treatments than those in 0 kg/hm2 silicon treatment under each nitrogen level, but the cadmium content in 150 and 300 kg/hm2 silicon treatments was higher than in 0 kg/hm2 silicon treatment. The cadmium contents in polished rice were decreased significantly by the silicon under the three nitrogen levels, there was no difference between the two silicon treatments under 180 kg/hm2 nitrogen treatment. Based on the rice yield and cadmium content in panicle, combined application of 180 kg/hm2 with 150 kg/hm2 silicon could both improve rice yield and decrease cadmium in polished rice.