The low available silica content in the soils of various treatments indicates that silica application in rice production is necessary.

盆栽试验各处理土壤有效硅含量较低这一结果表明，水稻生产中施用硅肥已是必需措施。

youdao

Singlet and multielement lenses are available in a wide variety of configurations and materials, including glass, fused silica, sapphire, and calcium fluoride.

单谱线多元件透镜可以有不同的外形和材料，有玻璃的，二氧化硅的，蓝宝石的和钙氟化合物的。

youdao