Laboratory of Forest Genetics and Ecophysiology, National University of Mongolia, Ulaanbaatar, Mongolia.
Department of Environment and Forest Resources, College of Agriculture and Life Science, Chungnam National University, Deajeon, South Korea.
PeerJ. 2023 Sep 29;11:e16107. doi: 10.7717/peerj.16107. eCollection 2023.
The impacts of climate change, such as increased soil dryness and nutrient deficiency, highlight the need for environmentally sustainable restoration of forests and groundwater resources. However, it is important to consider that extensive afforestation efforts may lead to a depletion of groundwater supply due to higher evapotranspiration rates, exacerbating water scarcity issues. Consequently, we conducted a study to examine how the fast-growing tree species (Horth ex Tausch) and (L.) respond morpho-physiologically to varying watering regimes and types of fertilizers, aiming to better understand their specific water and nutrient requirements.
We used two-year-old nursery-growth seedlings ( = 512) of and with initial root collar diameter (RCD) and the height of 0.51 ± 0.02 mm and 68 ± 2.94 cm and 0.33 ± 0.01 mm and 51 ± 1.14 cm, respectively. The leaf area (LA), specific leaf area (SLA), chlorophyll concentration, stomatal conductance (g), chlorophyll fluorescence, and predawn and midday leaf water potential were measured across treatments. Four different irrigation regimes and two different fertilizer types were applied: no irrigation (control, 0 L h), 2 L h = 0.25 mm m, 4 L h = 0.5 mm m, 8 L h = 1.0 mm m and 120 g and 500 g tree of NPK and compost (COMP). Twelve plots (600 m) were established in the study site for each species and treatments.
During the first growing season (2021), the LA of was larger in the 4-8 L h without fertilizer, but it was smaller in the 4 L h+ COMP during the second growing season (2022). The 2 L h without fertilizer and 2 L h + NPK had larger LA compared with the control (CONT) for the first and second growing seasons, respectively, for seedlings at 4 L h without fertilizer had the highest SLA for 2021 and at 2 L h + NPK for 2022, whereas CONT and 4 L h had the highest SLA than the other treatments for 2021 and 2022 growing seasons, respectively, for The chlorophyll concentration of seedlings in the first year was generally higher in CONT, while the 2 L h without any fertilizer yielded a significantly higher chlorophyll concentration of Chlorophyll fluorescence parameters (PI and F) were generally lower in CONT with/without NPK or COMP for both species. The CONT with NPK/COMP generally had a higher g compared with the other treatments in both experimental periods for whereas CONT and 2 L h+ NPK-treated seedlings had a significantly greater g during the first year and second year, respectively. The predawn and midday leaf water potentials of both species were generally the lowest in CONT, followed by 2 L h+ NPK/COMP during the first growing season, but a different pattern was observed during the second growing season. Overall, the morpho-physiological traits of the two species were affected by watering and fertilizer treatments, and the magnitude of the effects varied depending on growing season, amount of irrigation, and fertilizer type, and their interactions.
气候变化的影响，如土壤干燥和养分缺乏的增加，凸显了环境可持续地恢复森林和地下水资源的必要性。然而，需要考虑的是，由于较高的蒸散速率，广泛的造林工作可能会导致地下水资源的消耗，从而加剧水资源短缺问题。因此，我们进行了一项研究，以检验速生树种（Horth ex Tausch）和（L.）如何在不同的浇水制度和肥料类型下在形态和生理上做出响应，旨在更好地了解它们特定的水和养分需求。
我们使用了两年生苗圃生长的幼苗（n = 512），初始根颈直径（RCD）和高度分别为 0.51 ± 0.02 毫米和 68 ± 2.94 厘米，0.33 ± 0.01 毫米和 51 ± 1.14 厘米。测量了叶片面积（LA）、比叶面积（SLA）、叶绿素浓度、气孔导度（g）、叶绿素荧光、以及预晨和中午叶片水势。应用了四种不同的灌溉制度和两种不同的肥料类型：无灌溉（对照，0 L h）、2 L h = 0.25 mm m、4 L h = 0.5 mm m、8 L h = 1.0 mm m 和 120 g 和 500 g 树的 NPK 和堆肥（COMP）。在每个物种和处理的研究地点建立了 12 个（600 m）的试验区。
在第一个生长季（2021 年），没有肥料的 4-8 L h 处理下的 叶片面积较大，但在第二个生长季（2022 年）的 4 L h + COMP 处理下则较小。在第一个生长季，没有肥料的 2 L h 和 2 L h + NPK 与对照（CONT）相比，叶片面积更大，而在第二个生长季，4 L h 没有肥料的处理的叶片面积最大。对于 2021 年，没有肥料的 2 L h 处理的 SLA 最高，而对于 2022 年，2 L h + NPK 处理的 SLA 最高，而对于 2021 年和 2022 年的生长季，CONT 和 4 L h 的 SLA 均高于其他处理。2021 年，所有处理中对照的叶绿素浓度普遍较高，而无任何肥料的 2 L h 处理的叶绿素浓度显著较高。叶绿素荧光参数（PI 和 F）在两个物种的对照中普遍较低，而对照与 NPK 或 COMP 一起处理的叶绿素荧光参数则较低。在两个实验期内，对于 来说，CONT 一般具有较高的 g，而 CONT 和 2 L h + NPK 处理的 幼苗在第一年和第二年分别具有更高的 g。两个物种的预晨和中午叶片水势在对照中普遍较低，其次是第一个生长季的 2 L h + NPK/COMP，但在第二个生长季观察到不同的模式。总体而言，两个物种的形态生理特征受到浇水和施肥处理的影响，其影响的幅度取决于生长季、灌溉量和肥料类型及其相互作用。
