废水灌溉下有机物料对重度盐渍土养分及芦苇生长的影响

Effects of organic amendments on severe saline soil nutrient content and reed growth under wastewater irrigation

  • 摘要: 在山东滨州含盐量为16.7 g·kg-1的重度退化滨海盐碱湿地, 研究了造纸废水灌溉条件下添加有机物料对盐渍土养分和芦苇生长的影响, 以期为重度退化滨海盐碱湿地的生物修复提供依据。试验从春季开始进行, 共设4种处理: 翻耕对照(CK)、翻耕+废水灌溉(FF)、翻耕+废水灌溉+秸秆(FFJ)以及翻耕+废水灌溉+污泥(FFW), 测定了不同处理下土壤养分、呼吸强度、含盐量及芦苇株高和生物量的变化。结果表明, 与对照相比, 各处理土壤有机质显著提高, 10月末时FFJ、FFW和FF处理土壤有机质含量分别是对照的1.34倍、1.29倍和1.22倍; 碱解氮和有效磷含量也高于对照, 依次为FFW>FFJ>FF>CK; 各处理土壤呼吸强度高于对照, 其中FFJ处理显著高于对照, 比试验初期提高96%; 各处理表层土壤含盐量均出现不同程度降低, 以FFJ和FFW降低幅度最大, 分别比对照降低22.6%和16.3%; FFW、FFJ和FF处理的芦苇株高显著高于对照, 8月末分别是对照的3.1倍、2.7倍和2.2倍; FFJ和FFW处理的芦苇生物量、根冠比和平均叶面积都显著高于对照, 而FF处理与对照没有显著差异; FF处理芦苇株高、生物量与土壤有效氮含量相关最为显著, FFJ和FFW处理与土壤有机质含量相关性最为显著。结果表明, 废水灌溉为重度盐渍化土壤提供了充足的水分, 有机物料能有效提高土壤养分含量, 解决了重度盐碱化土壤水分胁迫和养分胁迫的问题, 促进芦苇生长, 但秸秆和污泥两种有机物料之间没有显著差异。

     

    Abstract: The effects of organic amendments on the nutrient state of severe saline soil and reed growth under wastewater irrigation were investigated in this study. The results obtained were critical for bioremediation of degraded saline-alkali wetlands in coastal regions. Experiments were performed in a severely degraded coastal saline-alkali wetland (with salinity level of 16.7 g·kg-1) in the Binzhou County of Shandong Province, China. The experiments were started in the spring and four treatments were tested - tillage (CK) as the control; tillage + wastewater irrigation (FF), tillage + wastewater irrigation + grass straw application (FFJ) and tillage + wastewater irrigation + sludge application (FFW). For each treatment, soil organic matter increased significantly compared with CK. At the end of October, organic matter contents of FFJ, FFW and FF were 1.34, 1.29 and 1.22 times that of CK. Compared with CK, soil available nitrogen and phosphorus also increased with the order of FFW > FFJ > FF. The salinity of the top soil layer (0~20 cm) decreased in all the treatments, and especially in FFJ and FFW which decreased by 22.6% and 16.3%, respectively, compared with that of CK. At the end of August, reed height under FFW, FFJ and FF were 3.1, 2.7 and 2.2 times that of CK. Total biomass, root mass/crown mass and average leaf area under FFW and FFJ increased significantly (P < 0.05) compared with CK. Reed heights under FF, FFJ and FFW treatments significantly correlated with soil organic matter/available nitrogen with respective correlation coefficients (R2) of 0.897/0.963, 0.999/0.837 and 0.998/0.778. Total biomass under FF, FFJ and FFW treatments significantly correlated with soil organic matter/available nitrogen with respective R2 of 0.863/0.937, 0.971/0.876 and 0.996/0.799. Plant height and biomass significantly correlated with soil organic matter under FFJ and FFW, but only significantly correlated with soil available nitrogen under FF. The results showed that wastewater irrigation provided ample water in severe saline soil systems and organic amendments supplied massive amounts of soil nutrient. This relieved water and nutrient stress in severe saline soil and promoted reed growth, which combined effect was beneficial to the restoration of severe saline soils. No significant differences were found between soils amended with grass straw and those with sludge. This study showed that combined treatment of wastewater irrigation and organic amendment sufficiently reduced soil salinity in severe saline soils. Furthermore, the combined treatment of wastewater irrigation and organic amendments improved soil nutrient (organic matter and available nitrogen and phosphorus) content and soil microbial biomass (respiration intensity). The above-noted improvements were ultimately reflected in the improvements in reed plants - reed height, biomass and allocation, etc.

     

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