Investigating the effect of vetiver and polyacrylamide on runoff, sediment load and cumulative water infiltration

Abstract

Soil erosion is one of the most critical environmental problems currently facing Iran, and soil conservation is crucial for managing natural resources. The objective of this study was to investigate the effect of a vetiver cultivation system, known to be a valuable bioengineering technique, and polyacrylamide (PAM) addition on runoff, sediment load (SL) and cumulative water infiltration under field conditions in a loamy soil. The experimental treatments were vetiver cultivation, PAM (applied at 20 and 40kgha–1) and a mixture of vetiver and different PAM application rates. Three simulated rainfall intensities of 15, 30 and 45mmh–1 were applied on the treated soils. Runoff and SL were collected at different time steps. The results showed that vetiver significantly decreased runoff and SL and increased cumulative water infiltration at different rainfall intensities, whereas the effect of PAM on runoff, SL and cumulative water infiltration depended on the PAM level. At the 15mmh–1 rainfall intensity, PAM application increased the runoff, but decreased SL and cumulative water infiltration. At the 30mmh–1 rainfall intensity, the 20kgha–1 PAM level decreased the runoff and SL. At the 45mmh–1 rainfall intensity, the higher PAM level was more effective to enhance the cumulative water infiltration and to reduce the runoff and SL. In general, although simultaneous application of vetiver and PAM significantly decreased the runoff volume and SL and increased water infiltration compared with the control, vetiver considerably decreased the runoff and SL. This suggests that vetiver may sufficiently decrease soil erosion and PAM is therefore unnecessary in controlling runoff and soil erosion where vetiver is applied.

Dual benefits of polyacrylamide and other soil amendments: Mitigation of soil nutrient depletion and improvement of use‐efficiency in midland agro‐ecology, Ethiopia

“…Additionally, the better vegetative cover of the crops in PAM + L plots (Table S3), which might protect the soil against raindrop impacts and reduced soil erosion and nutrient losses (Table 1 & Table S4). Also effect of PAM and vegetation significantly decreases soil erosion and runoff reported by Amiri et al (2017). On the contrary, as the N and P content of biochar is significantly higher than that of other amendments (Table S1), resulting in higher nutrient losses from water erosion (OUT5) was greater than in those treated with other amendments.…”

Reinforcement losses in soil stabilisation due to decomposing roots of Chrysopogon zizanioides and Chrysopogon nemoralis

“…In this study, we measured the variations of the biomechanical properties of decomposing roots of two contrasting vetiver species, including C. nemoralis and C. zizanioides , following herbicide application, and the changes of their ability to provide mechanical reinforcement to the soil. Both C. nemoralis and C. zizanioides species are widely distributed in Southeast Asian countries and have been extensively studied and recognised to be used for eco‐friendly slope stabilisation (Amiri et al, 2017; Donjadee et al, 2010; Eab et al, 2015; Fahlen, 2002; Gao et al, 2020; Kavian et al, 2018; Leknoi & Likitlersuang, 2020; Mahannopkul & Jotisankasa, 2019b; Phan et al, 2021; Wasino et al, 2019). The objectives were: to (i) quantify the evolution of the root biomechanical properties (in terms of tensile strength, Young's modulus, secant modulus, breakage strain) of the two species with increasing duration of decomposition by using uniaxial tensile strength combined with an image processing; and (ii) measured the variations of root reinforcement (in terms of cohesion increment) and maximum dilatancy due to decomposition by using direct shear tests.…”

New polymer composites improve silty clay soil microstructure: an evaluation using NMR

“…Large‐scale engineering activities by human beings cause a series of ecological and environmental problems, such as soil erosion, fugitive dust, and desertification (N. Li et al, 2019; Sun et al, 2019). Improving the cohesion between soil particles and pore structure can effectively improve the stability of the soil, thereby reducing the amount of soil erosion caused by potential environmental hazards (e.g., wind, rainfall, and freeze–thaw) and human activities (Amiri et al, 2017; Roshanizarmehri et al, 2018). Soil improvement enhances soil strength and water retention capacity by changing the soil composition and structure.…”