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Plant roots play an important role in reducing soil detachment and increasing soil erosion resistance. Current studies have mainly focused on the quantification of the soil detachment rate (SDR). However, few studies have been conducted to explore the variation in the SDR and root effects during the soil detachment process. In this study, undisturbed soil samples were collected from four shrublands (with the main species Caragana korshinskii, C. korshinskii mixed with Agropyron cristatum, C. korshinskii mixed with Bothriochloa ischaemum, and C. korshinskii mixed with Artemisia gmelinii) and three grasslands (with the main species B. ischaemum, B. ischaemum mixed with A. cristatum, and B. ischaemum mixed with A. gmelinii) on the Loess Plateau, China. The samples were subjected to flow scouring through hydraulic flume experiments under six different shear stresses. The duration of this experiment was 6 min, and the SDR of each minute was estimated. The results showed that the SDR of shrubland was higher than that of grassland in each detachment process. The dominant factors affecting SDR gradually changed from the root–soil composite properties to the hydrodynamic parameters in this process. The effect of roots on the SDR was stronger than that of soil properties in the root–soil composite. In the early detachment stage, the 0–2 mm fine roots had the strongest effect on the SDR, while it was affected by the combined effect of fine roots and coarse roots in the later stage. When the fibrous roots were mixed with the tap roots, the fibrous roots had a significant negative effect on the SDR and mainly affected the early detachment stage. However, the tap roots had a weak effect in all stages. With the detachment process, the soil erosion resistance first increased and then stabilized, and the variations were mainly concentrated from 0 to 3 min. The roots mainly affected the SDR and soil erosion resistance by influencing rill erodibility parameters. [ABSTRACT FROM AUTHOR]

Plant roots can significantly prevent soil erosion and aid in soil conservation and slope protection. With the rapid acceleration and advances in vegetation reconstruction the study of indicators and models of the root system′s resistance to soil erosion is becoming increasingly reasonable and accurate, especially in the context of morphological and spatial characteristics of root systems. However, current characterization indexes cannot accurately capture and correlate the comprehensive effects of root morphological characteristics and spatial linkage characteristics with soil erosion resistance. Therefore, based on the review of morphological characteristics, spatial characteristics, and models of soil erosion resistance of plant root system, a new concept of "root framework" was proposed in this paper. This is expected to provide a new reference for the study of the relationship between soil erosion and vegetation allocation on slope lands. [ABSTRACT FROM AUTHOR]

Plant roots significantly affect soil erosion, while few works have pursued why root-penetrated soil obtained higher soil erosion resistance as compared with plain soil. For the purpose to investigate the relative contribution of root physical enlacing (root net-link and root-soil bond functions) and root biochemistrical exudates to soil erosion resistance. This study selected Purple alfalfa root- and designed root-penetrated Loess soil as study object, and subjected to flow scouring. The results showed that roots could significantly ameliorate soil properties, especially for soil enzymes. Root physical enlacing is the main reason, accounting for 77.7–82.0% of the root total effect in strengthening soil erosion resistance. And of this total, the relative contribution ratio of net-link and soil-root bond functions to soil erosion resistance was 0.71:0.29, averagely. Root surface area density could effectively reflect root physical enlacing effect. This kind of study may provide theoretical explanations for the root reinforcement in the flow-induced erosion regions. [ABSTRACT FROM AUTHOR]

Changes in soil properties caused by artificial vegetation planting is of great interest to both scientists and policy-makers. However, a quantitative understanding of the effects ofCaraganaplanting on soil erodibility is not available. This study selected fiveCaraganaplantations aged 0 (control), 9, 21, 33 and 46 years to assess the erosion resistance ofCaraganasoils using spatio–temporal substitution method in Zhi Fanggou small watershed on the hilly Loess Plateau. Findings showed thatCaraganaplanting significantly reduced soil loss compared with the control. Sediment loss over time was well described by a negative exponential function. On average, about 80% of the soil sediment was lost within the first 3 abrasion minutes. Compared with control, soil bulk density of surface (0–20cm) and middle soil layers (20–40cm) decreased by 8.9% and 18.0%, respectively, but minimal changes occurred in the lower soils (40–60cm). Soil aggregate content and shear strength increased significantly, whereas soil disintegration rate decreased significantly, with a maximal reduction of 357.1% in the middle soil layer. Soil erosion resistance increased 9.3, 4.1 and 4.2 fold in the surface, middle and lower soils, respectively. Linear regression equations could well fit the relationship between soil erosion resistance and soil physical properties, with root biomass. Soil aggregate content and root density were the key factors in the reinforcement of soil erosion resistance forCaraganaplantations on the hilly Loess Plateau. [ABSTRACT FROM PUBLISHER]