不同调酸剂对水稻育秧基质调酸效果及对秧苗生长的影响

育秧基质合适酸碱度(pH值)不仅有利于水稻正常生长,同时有利于预防水稻病害。因此,研究不同类型调酸剂对育秧基质的调酸效果,以及育秧过程中对水稻生长的影响很有必要。以我们自己研制的发酵基质作为研究对象,分别添加不同浓度的柠檬酸、稀硫酸、硫磺、磷酸二氢铵,测定基质的pH值和电导率(EC值)。播种后12 d取样,结果发现:(1)磷酸二氢铵的调酸效果较好,并且EC值较低;柠檬酸、稀硫酸和硫磺也具有较好的调酸效果,但在高浓度下会显著增加育秧基质的EC值。(2)磷酸二氢铵处理后育出的秧苗株高、根长、百株地上部干物质量、地上部总氮、总磷含量均显著高于其他调酸剂处理的秧苗;硫酸和硫磺处理组的秧苗生长指标次于磷酸二氢铵,并且在高浓度下对水稻生长有抑制作用,但稀硫酸处理组育出的水稻秧苗叶片含有更高的叶绿素含量;柠檬酸处理显著抑制水稻秧苗根系的生长。综上所述,本试验中磷酸二氢铵适宜作为发酵基质的调酸剂,稀硫酸和硫磺次之。

Effects of Different Acid-Regulating Agents on the Acid-Regulating Effect of Rice Seedling Substrate and Seedling Growth

Suitable pH in rice seedling substrate is not only beneficial to the normal growth of rice, but also beneficial to the resistance of rice to disease. Therefore, it is necessary to study the effects of different types of acid-regulating agents on acid-regulating effect of rice seedling substrate and rice growth. The fermentation substrate made by ourselves are used in present study and applied with different concentrations of citric acid, dilute sulfuric acid, sulfur, ammonium dihydrogen phosphate, the pH and electrical conductivity （EC） of the substrate were detected. Samples were collected after 12 days’ growth, and the results showed that:（1） the application of ammonium dihydrogen phosphate showed a better acid-regulating effect and lower EC value than other treatments; the application of citric acid, dilute sulfuric acid and sulfur also displayed well acid-regulating effect, however, EC value of seedling substrate was increased with the increasing of acid-regulating agents concentration.（2） The plant height, root length, aboveground dry weight of 100 plants, aboveground total N and total P contents of the rice seedlings in the ammonium dihydrogen phosphate treated seedling substrate were significantly higher than other treatments. The growth index of rice seedlings which treated with dilute sulfuric acid and sulfur were inferior to the ammonium dihydrogen phosphate treatment, and the rice growth was inhibited under high acid-regulating agents’ concentration conditions. However, the leaves of the rice seedlings in the dilute sulfuric acid treatment contained higher chlorophyll content. The root growth of rice seedlings was significantly inhibited by citric acid. In conclusion, ammonium dihydrogen phosphate can be used as an acid-regulating agent for fermentation substrate in this experiment, followed by sulfuric acid and sulfur, while citric acid is not suitable as an acid-regulating agent for fermentation substrate.