不同pH值土壤及其浸提液对羊草种子萌发和幼苗生长的影响

研究了不同pH值土壤以及重度盐碱土和非盐碱土浸提液对羊草(Leymus chinensis)种子萌发及幼苗生长的影响。不同pH值土壤由配土和调酸两种方式取得,前者由重度盐碱土(pH=10．24)与非盐碱土(pH=7．49)按不同比例配制,后者是由重度苏打盐碱土经硫酸调酸处理得到。配土发芽的实验结果表明,当pH值在7．49-9．14时,种子的发芽率均在50％以上,且幼苗能够正常生长;pH=9．53时,羊草种子的发芽率低于50％,仅部分幼苗个体能够成活;当pH>9．86时,幼苗在萌发后50天左右全部枯死。说明羊草种子个体萌发期最大耐受pH值在9．14-9．53之间。重度苏打盐碱土调酸发芽实验结果表明,当调酸后的土壤pH值降至7．0-10．0时,均能显著促进羊草种子的萌发,且幼苗生长正常。确定了羊草种子萌发的最适pH值为8．0-8．5。土／水比为1:1的非盐碱土浸提液能够显著提高羊草种子发芽率,而重度苏打盐碱土浸提液对羊草种子萌发没有产生显著抑制。

Effects of Different Soil pH and Soil Extracts on the Germination and Seedling Growth of Leymus chinensis

We investigated the effect of soils with different pH and soil extracts of nonsaline-alkali soil and saline-alkali soil on the germination and seedling growth of Leymus chinensis. Soils with different pH values were obtained by mixing the nonsaline-alkali soil and saline-alkali soil at different ratios and adjusting the saline-alkali soil with sulfuric acid. For the mixed soil, the proportion germination in the substrate with pH values from 7.49 to 9.14 was higher than 50%, and the seedlings could grow normally. When the pH value was higher than 9.53, the proportion germination was lower than 50% and only some of the seedlings could grow normally; when the pH value was higher than 9.86, all the seedlings died within 50 d after sowing. After adjustment with sulfuric acid, seed germination rates were significantly improved; seedlings grew well in the saline-alkali soil and better with pH values between 7.5 and 9.5. Seeds of L. chinensis germinated best with pH between 8.0 and 8.5. Different concentrations of the extracts of the nonsaline-alkali soil could improve the germination to some extent, and a ratio of soil to water of 1:1 resulted in a significantly higher germination rate as compared with the control. However, treatments of the saline-alkali soil extracts and the control did not produce different germination rates.