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Soil solution composition affects microstructure of tropical saline alluvial soils in semi-arid environment
Soil and Tillage Research ( IF 6.1 ) Pub Date : 2020-05-26 , DOI: 10.1016/j.still.2020.104662
Alan Carlos Batistão , Dörthe Holthusen , José Miguel Reichert , Jeane Cruz Portela

The remediation of soils stressed by salinity improves soil quality for food production. However, information on how remediation techniques affect microstructural stability/elasticity and resistance is lacking. Hence, the objective of this study was to characterize the microstructure of saline alluvial soils from a semi-arid environment, and to evaluate how the techniques of leaching soil and Na+ substitution by other cations affect the microstructure strength and elasticity evaluated by rheological techniques. Homogenized soil of sixteen horizons of four salinized soil profiles (an Abruptic Solonetz, a Eutric Gleysol, and two Hypereutric Planosols) were collected in Northeast of Brazil. Each horizon was analyzed separately in a completely randomized design, with three replications. The treatments corresponded to soils saturated with 1 × 10−4 mol m−3 of KCl (+K), CaCl2 (+Ca) or MgCl2 (+Mg), leaching of salts (LS) by successive leaching with alcohol 60%, and untreated soil (control). The soils were submitted to an amplitude sweep test with controlled strain in a compact modular rheometer. The obtained variables were strain and stress at the end of the linear viscoelastic interval (LVR) (γLVR and τLVR, respectively), strain (γYP) and stress (G’YP) at the yield point, shear stress (τmax), and integral Z (Iz). The rheological properties varied greatly between the horizons of the same soil profile. The LS increased γLVR compared to control, while the saturation with cations caused reduction in γLVR, especially in soils of higher clay content. The saturation with saline solution increased γYP and Iz, with greater effect in + K treatment. Both leaching of salts and cation saturation increased soil shear strength at the end of the LVR and at the yield point. Leaching of salts caused destabilization of soil microstructure, which is an important finding that needs to be addressed by measures accompanying remediation of salinized soils to maintain soil physical quality.



中文翻译:

土壤溶液成分影响半干旱环境中热带盐溶冲积土的微观结构

盐分胁迫对土壤的修复改善了食品生产的土壤质量。但是,缺乏有关修复技术如何影响微结构稳定性/弹性和抵抗力的信息。因此,本研究的目的是表征半干旱环境中盐溶冲积土壤的微观结构,并评估如何淋溶土壤和Na +的技术。被其他阳离子取代会影响通过流变技术评估的微结构强度和弹性。在巴西东北部收集了四种盐化土壤剖面(突变索洛涅茨,Eutric Gleysol和两种Hypereutric Planosols)的十六层均质土壤。在完全随机的设计中分别对每个层进行了分析,并进行了三次重复。处理方式对应于用1×10 -4 mol m -3的KCl(+ K),CaCl 2(+ Ca)或MgCl 2饱和的土壤(+ Mg),通过用60%的酒精连续浸出来盐分(LS),以及未处理的土壤(对照)。在紧凑的模块化流变仪中对土壤进行受控应变的振幅扫描测试。将所得到的变量是在的线性粘弹性间隔(LVR)(γ的端部的应变和应力LVR和τ LVR,分别地),应变(γ YP)和应力(G” YP)在屈服点,剪切应力(τ最大)和积分Z(Iz)。在相同土壤剖面的水平之间,流变特性差异很大。与对照相比,LS增加了γLVR,而阳离子的饱和导致γLVR降低,尤其是在粘土含量较高的土壤中。用盐溶液饱和会增加γYP和Iz,在+ K处理中效果更大。在LVR的末端和屈服点,盐分的淋溶和阳离子的饱和都增加了土壤的抗剪强度。盐分的浸出导致土壤微结构的不稳定,这是一个重要的发现,需要通过盐碱化土壤的修复措施来解决,以保持土壤的物理质量。

更新日期:2020-05-26
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