半干旱区湖泊湿地土壤养分与盐碱化特征研究以岱海为例

Study on the characteristics of soil nutrients and salinization of lake wetlands in semi-arid region: taking Daihai Lake as an example

  • 摘要: 为探究半干旱区湖泊湖滨带土壤养分与盐碱化特征,以典型盐化湖泊岱海为例,分析其湖滨带的草地、浅滩和盐碱地3种土地类型的土壤剖面4种养分〔有机质(OM)、碱解氮(AN)、有效磷(AP)、速效钾(AK)〕浓度、土壤钙(Ca2+)、镁(Mg2+)、交换性钾(K+)、交换性钠(Na+)、碳酸根(CO3 2−)、重碳酸根(HCO3 )、氯(Cl)和硫酸根(SO4 2−)离子浓度分布,结合主成分分析和冗余分析等统计学方法,研究湖滨带土壤盐碱化特征及其影响因素。结果表明:1)岱海湖滨带不同类型土壤剖面盐分空间分布差异明显,其中草地和浅滩呈明显盐分表聚现象,表层全盐量均值分别达1.99、15.27 g/kg,而盐碱地土壤10~20 cm全盐量最高(17.30 g/kg)。2)湖滨带土壤pH为8.24~8.86,在浅滩和盐碱地深层较高,而在草地的浅层较高。盐碱地与浅滩土壤均属于碱土,而草地表层土壤多属于中度碱化土,其碱化度沿深度方向降低。3种土地类型的主要盐碱化因子为Cl、Mg2+、SO4 2−、Na+、全盐量、HCO3 、pH、CO3 2−。3)3种土地类型的4种养分浓度基本呈随土壤深度增加而减少的趋势,其中浅滩营养元素最丰富。根据冗余分析结果,3种土地类型中大部分离子间都具有很强的相关性,AP、Mg2+与pH均具有负相关性,其他盐分与养分在不同土地类型中相关性差异较大。

     

    Abstract: Influenced by human activities and climate change, the salinization of shallow lake wetlands in semi-arid regions is becoming worse, which threatens the health of riparian ecosystems. Daihai Lake, a typical salinized lake, was selected to analyze the distribution of four nutrients such as organic matter (OM), alkali-hydrolyzable nitrogen (AN), available phosphorus (AP) and available potassium (AK), as well as soil calcium ion (Ca2+), magnesium ion (Mg2+), exchangeable potassium ion (K+), exchangeable sodium ion (Na+), carbonate ion (CO3 2−), bicarbonate ion (HCO3 ), chloride ion (Cl) and sulfate ion (SO4 2−) concentrations in three types of soil profile, including riparian grassland, shoal and saline-alkali land. By statistical methods such as principal component analysis (PCA) and redundancy analysis, the salinization characteristics and influencing factors were investigated. The results showed that the difference in the spatial distribution of salts in different types of soil profile in Daihai lakeside zone was large, and there was obvious salt accumulation in grassland and shoals, with the total salt average of 1.99 g/kg and 15.27 g/kg, respectively, on the soil surface; however, the total salt content was the highest at 10-20 cm in the saline-alkali soil, with a total salt content of 17.30 g/kg. pH in the lakeside zone soil was 8.24-8.86, which was higher in the deep soil of shoal and saline-alkali land, as well as the shallow soil of grassland. According to the classification of alkalization, saline-alkali land and shoal soil belonged to alkali soil, and the surface soil of grassland was mainly moderate alkali soil, with a decline of alkalization as the soil went deeper. The major salinization factors in the three land types of Daihai Lake were Cl, Mg2+, SO4 2−, Na+, total salt, HCO3 , pH, and CO3 2−. The concentrations of the four nutrients showed a trend of decline with the increase of depth in the 3 types of soil. Besides, the nutrients were the most abundant in the shoal. According to redundancy analysis, a strong correlation existed between most ions in the 3 types of soil. AP and Mg2+ were negatively correlated with pH, but other salts and nutrients showed a disparity in different types of soil.

     

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