Institute of Resource and Environment, Shandong Academy of Forestry, Jinan, China.
College of Ecology, Resources and Environment, Dezhou University, Dezhou, China.
PLoS One. 2024 May 7;19(5):e0303096. doi: 10.1371/journal.pone.0303096. eCollection 2024.
Fast-growing poplar plantations are considered a great benefit to timber production, but water availability is a key factor limiting their growth and development, especially in arid and semi-arid ecosystems. Super-absorbent polymers facilitate more water retention in soil after rain or irrigation, and they are able to release water gradually during plant growth. This study aimed to examine the effects of reduced irrigation (60% and 30% of conventional border irrigation) co-applied with super-absorbent polymers (0, 40 kg/ha) on root exudates, enzyme activities, microbial functional diversity in rhizosphere soil, and volume increments in poplar (Populus euramericana cv. 'Neva'). The results showed that 60% border irrigation co-applied with super-absorbent polymers significantly increased the content of organic acids, amino acids and total sugars in the root exudates, and the activities of invertase, urease, dehydrogenase, and catalase in the rhizosphere soil in comparison to conventional border irrigation without super-absorbent polymers. Meanwhile, this treatment also enhanced the average well-color development, Shannon index, and McIntosh index, but decreased the Simpson index. Additionally, the average volume growth rate and relative water content of leaves reached their maximum using 60% irrigation with super-absorbent polymers, which was significantly higher than other treatments. However, using 30% irrigation with super-absorbent polymers, had a smaller effect on rhizosphere soil and volume growth than 60% irrigation with super-absorbent polymers. Therefore, using an appropriate water-saving irrigation measure (60% conventional border irrigation with super-absorbent polymers) can help to improve enzyme activities and microbial diversity in the rhizosphere soil while promoting the growth of poplar trees.
快速生长的人工杨树林被认为是木材生产的巨大收益，但水分供应是限制其生长和发育的关键因素，特别是在干旱和半干旱生态系统中。高吸水性聚合物有助于在雨后或灌溉后更多地保留土壤中的水分，并且能够在植物生长过程中逐渐释放水分。本研究旨在探讨减少灌溉（常规畦灌的 60%和 30%）与高吸水性聚合物（0、40kg/ha）共施对根分泌物、酶活性、根际土壤微生物功能多样性以及欧美杨（Populus euramericana cv. 'Neva'）体积增量的影响。结果表明，与不施高吸水性聚合物的常规畦灌相比，60%畦灌与高吸水性聚合物共施显著增加了根分泌物中的有机酸、氨基酸和总糖含量，以及根际土壤中的转化酶、脲酶、脱氢酶和过氧化氢酶活性。同时，该处理还提高了平均好氧显色指数、香农指数和麦克因托什指数，但降低了辛普森指数。此外，用高吸水性聚合物进行 60%灌溉时，叶片的平均体积增长率和相对含水量达到最大值，明显高于其他处理。然而，用高吸水性聚合物进行 30%灌溉对根际土壤和体积生长的影响小于 60%灌溉。因此，采用适当的节水灌溉措施（60%常规畦灌与高吸水性聚合物共施）有助于提高根际土壤的酶活性和微生物多样性，同时促进杨树的生长。
