Browsing by Author "Bahddou, Sophia"
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Item Open Access Changes in soil surface properties under simulated rainfall and the effect of surface roughness on runoff, infiltration and soil loss(Elsevier, 2023-02-03) Bahddou, Sophia; Otten, Wilfred; Whalley, W. Richard; Shin, Ho-Chul; El Gharous, Mohamed; Rickson, R. JaneSoil erosion by water is a result of detachment of particles or small aggregates from the soil surface followed by transport of the detached material. One of the elements that affects surface runoff and soil erosion is the soil surface roughness (SSR). Prior research reports that increasing SSR reduces generation of runoff and soil loss. In addition to that, it is widely reported that across-slope oriented roughness is better at controlling soil and water losses. However, to date there have been few studies into the effect of both magnitude and orientation of SSR on runoff, infiltration and soil erosion at the sub process level (i.e. by raindrop splash and overland flow), occurring simultaneously. In this study, the effects of up-down-slope oriented SSR (Treatment A), across-slope oriented SSR (Treatment B) and random SSR (Treatment C) were compared, along with a smooth surface (Treatment D). A moderate slope gradient of 10 %, a simulated rainfall intensity of 90 mm hr−1 and storm durations of 15 or 30 min were considered. The SSR was measured using the chain method, before and after the rainfall event. Images of the soil surface were taken using a hand-held laser scanner to monitor the effect of rainfall on the surface morphology. The outcome of this study shows that rainfall erosivity increases the SSR of the initially smooth surface, but decreases that of the initially rough surface, particularly in the random SSR treatment, where the decrease in SSR was 64 % of the pre-rainfall condition. This was due to the effects of raindrop impacts and overland flow. The random SSR treatment generated significantly more runoff and soil loss, and less infiltration than all other treatments (p < 0.001), but for raindrop splash erosion, there was no significant difference between random SSR and the other treatments. Contrary to expectations, the across-slope oriented SSR did not always reduce runoff and soil erosion compared to the up-down-slope orientation. This can be explained by degradation of surface microtopography by rainfall and runoff, as confirmed by the post-rainfall SSR measurements.Item Open Access Effect of surface roughness on runoff, infiltration and soil loss(Cranfield University, 2023-02-06 12:12) Bahddou, Sophia; Otten, Wilfred; Rickson, Jane; Whalley, Richard; Shin, Ho-Chul; El Gharous, MohamedThe excel spreadsheet presents the raw data generated from the experiments quantifying soil erosion that are described in the paper by Bahddou et al., 2023, published in Geoderma (Bahddou et al., 2023. Changes in soil surface properties under simulated rainfall and the effect of surface roughness on runoff, infiltration and soil loss). The experimental design and the statistical method are mentioned in the methodology section of the paper. The soil surface roughness data is expressed in two columns (E-F) presenting the measurements before and after the rainfall event (Table 3 and Figure 4 of the paper by Bahddou et al). The variables of the runoff, infiltrate, soil loss and sediment concentration are expressed in the columns G-R, where each variable is expressed in three columns presenting the 1st fifteen minutes of the rainfall event, the 2nd fifteen minutes of the rainfall event and the total 30 minutes of the rainfall event (Table 4 and Figures 6 and 7 in the paper by Bahddou et al., 2023). The columns S-U present the splash erosion after 30 minutes of rainfall, including the measurements on the ridges and in the furrows of Treatment B. More details are in the Materials and Methods section and the Results sections of the publication.Item Open Access A simulation tool to optimize the management of modernized infrastructures in collective and on-farm irrigation systems(Elsevier, 2023-05-02) Zapata, N.; Bahddou, Sophia; Latorre, B.; Playán, E.Irrigated areas face new, pressing challenges due to escalating energy costs for pumping, increasing cost of seeds, fertilizers and agrochemicals, volatility of agricultural commodities, pressure of environmental regulations, water scarcity and mounting cost of irrigation infrastructure investments. At the same time, from the technical standpoint, farmers can chose from a wide array of irrigation design and operation alternatives for collective and on-farm systems, with variable effects on crop yield and profitability. These factors are often subjected to quick changes, complicating decision making. Simulation models have proven useful to support decision making in irrigation infrastructure, water / energy use, crop agronomy and soil management. In this research, new capacities of the Ador-Simulation software are reported, targeting comprehensive analyses of irrigation modernization. The model implements additional on-farm irrigation methods (low-pressure solid-set, center-pivot and drip irrigation); crop intensification (double cropping in the same season); and crop response to different on-farm irrigation management options (timing and frequency). Model performance was verified using a set of theoretical case studies. Finally, the model was applied to the optimization of irrigation design and management (water and energy) in the Bardenas XI project of northeastern Spain. Water application in center-pivot and drip irrigation were simulated using a normal distribution characterized by a user-defined Distribution Uniformity. In center-pivot, the application depth was randomized in every irrigation event, reproducing the random nature of wind disturbances. In drip irrigation, the application depth followed the same random distribution in all irrigation events, reproducing the deterministic effect of manufacturing and hydraulic variability. According to the literature, the effect of irrigation timing was treated differently for two key sprinkler irrigated crops: corn and alfalfa. Differences in water application and crop yield between on-farm methods resulted in different gross and net income. In the Bardenas XI project, irrigation performance indicators showed different patterns of inter-annual variability. Deep percolation was strongly affected by the amount of seasonal precipitation and by Distribution Uniformity. Indicators at the plot level were strongly determined by the on-farm irrigation method, the soil type, and the crop. In the conditions of Bardenas XI, the design option without pumping station was the most adequate. Natural pressure proved sufficient for a combination of low-pressure sprinkler irrigation, pivot and drip irrigation methods, distributed throughout the irrigated area. Escalating energy costs emphasize the need for careful assessment of pumping requirements at the design phase of irrigation projects.