Ecology and Environment ›› 2024, Vol. 33 ›› Issue (11): 1727-1736.DOI: 10.16258/j.cnki.1674-5906.2024.11.007

• Research Article [Ecology] • Previous Articles     Next Articles

Influence of Plant Configuration on Sediment Size and the Removal of Carbon, Nitrogen and Phosphorus in Agricultural Drainage Ditches

HE Ziqi1(), FANG Xi1,2,*(), HONG Yu1,3   

  1. 1. College of Life and Environmental Science, Central South University of Forestry and Technology, Changsha 410004, P. R. China
    2. Huitong National Field Station for Scientific Observation and Research of Chinese Fir Plantation Ecosystem in Hunan Province, Huitong, 438107, P. R. China
    3. Institute of Agricultural Resources and Environment, Ningxia Academy of Agriculture and Forestry Sciences, Yinchuan 750002, P. R. China
  • Received:2024-05-16 Online:2024-11-18 Published:2024-12-06
  • Contact: FANG Xi

农田排水沟植物配置对底泥粒度特征及碳氮磷去除效果的影响

何紫琪1(), 方晰1,2,*(), 洪瑜1,3   

  1. 1.中南林业科技大学生命与环境科学学院,湖南 长沙 410004
    2.湖南会同杉木林生态系统国家野外科学观测研究站,湖南 会同 438107
    3.宁夏农林科学院农业资源与环境研究所,宁夏 银川 750002
  • 通讯作者: 方晰
  • 作者简介:何紫琪(1997年生),硕士研究生,研究方向为农业面源污染阻控研究。E-mail: 522617067@qq.com
  • 基金资助:
    宁夏回族自治区重点研发计划项目(2022BEG02007);宁夏自然科学基金项目(2022AAC03447)

Abstract:

Controlling and reducing pollutant concentrations in agricultural runoff is crucial for preventing and mitigating eutrophication in irrigated areas and water bodies. The farmland drainage ditch serves as the primary watercourse for farmland runoff. In order to reveal the validity and efficiency of plant species in purifying water quality in farmland drainage ditches, three plant configuration patterns, including the Phragmites australis pattern (Ditch-1), the Phragmites australis+Typha orientalis pattern (Ditch-2), and the Phragmites australis+Typha orientalis+Nymphaea tetragona, Myriophyllum verticillatum, Scirpus validus pattern (Ditch-3) were set up in three independent farmland drainage ditches in Ningxia Yellow River Diversion Irrigation District of China. The effects of these plant configuration patterns on sediment particle composition, particle size parameters, and carbon (C), nitrogen (N), and phosphorus (P) contents were investigated. The results showed that the sediments in the studied farmland drainage ditches were classified as silt loam, characterized by a high silt content and the lowest proportion of clay particles. The average particle size ranged from 5.20Φ to 6.07Φ, indicating poor sorting performance characterized by nearly symmetrical and positively skewed skewness, moderate and narrow kurtosis, a fractal dimension of 2.19-2.63, and coarse texture. The plant configuration significantly altered the particle composition and size parameters of the sediments. With an increase in the number of plant species and coverage, the volume ratios of silt and clay significantly increased, but the volume ratio of sand significantly decreased. In addition, there was a significant increase in the particle size parameters and fractal dimension with an increase in plant species and coverage. The frequency curve of sediment particle size showed a unimodal pattern in Ditch-1 and Ditch-2, and bimodal pattern in Ditch-3. The grain size probability accumulation curve was predominantly influenced by saltation components, and the cumulative volume proportion of suspended components was significantly higher in Ditch-3 than in Ditch-1 and Ditch-2. The composition of the sediment particles exerted a significant influence on the contents of C, N and P in sediment. Among these factors, fractal dimension and clay were identified as pivotal drivers of variations in C, N, and P contents in the sediment. Plant configuration significantly influenced the adsorption, fixation, and decomposition of C, N, and P in sediments by affecting their particle composition and size parameters. Ditch-2 exhibited the highest levels of C, N, and P adsorption and fixation in the sediment, whereas Ditch-3 showed the most pronounced decomposition and reduction of these elements. This study suggested that multiple-species plant configurations could be employed in farmland drainage ditches to effectively mitigate hydrodynamic conditions, optimize sediment particle composition and size parameters, and bolster the purification capacity of agricultural runoff and sediments.

Key words: Ningxia Yellow River diversion irrigation area, farmland drainage ditch, sediment particle size, planting configuration, coverage, carbon, nitrogen, and phosphorus

摘要:

控制和降低农田退水污染物浓度是防治灌区及水体富营养化的关键。农田排水沟是农田退水流经的首个场所,为了探究植物配置对农田排水沟底泥粒度特征及碳氮磷去除效果的影响,在宁夏引黄灌区3条独立的农田排水沟:芦苇(Phragmites australis)模式(沟-1),芦苇+香蒲(Typha orientalis)模式(沟-2),芦苇+香蒲+睡莲(Nymphaea tetragona)、狐尾藻(Myriophyllum verticillatum)、水葱(Scirpus validus)模式(沟-3)采集0-20 cm底泥,测定底泥颗粒组成、粒度参数及碳氮磷含量。结果表明:3条排水沟底泥属于粉砂壤土,以粉粒为主,黏粒占比最低,平均粒级为5.20-6.07Φ;分选性较差,偏度为近对称和正偏,峰度为中等和尖窄,分形维数为2.19-2.63,质地偏粗;随植物种类和覆盖度增加,底泥粉粒、黏粒体积分数显著增加,砂粒体积分数显著下降,粒度参数显著增大;沟-1、沟-2底泥粒度频率曲线呈单峰分布,沟-3呈双峰分布,粒度概率累积曲线以跃移组分为主,沟-3悬移组分累积体积分数显著高于沟-1、沟-2,植物配置显著改变底泥颗粒组成和粒度参数;底泥颗粒组成和粒度参数对碳氮磷含量影响显著,其中,分形维数、黏粒体积分数是关键影响因素,表明排水沟植物配置通过影响底泥颗粒组成、粒度参数而显著影响底泥对碳氮磷吸附、固定和分解消减能力,沟-2底泥对碳氮磷吸附固定能力最强,沟-3底泥对碳氮磷分解消减能力最强。因此,农田排水沟混种多种植物,适当提高植被覆盖度,可减弱水动力条件,提高底泥粉粒、黏粒占比,优化底泥粒度参数,增强底泥对有机污染物和氮磷的净化能力。

关键词: 宁夏引黄灌区, 农田排水沟, 底泥粒度, 植物组成, 覆盖度, 碳氮磷

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