Temporal stability and patterns of runoff and runon with different cover crops in an olive orchard (SW Andalusia, Spain)

Abstract

Conventional tillage (CT) and cover crops (CC) trigger different runoff (Q) and runon (Q in) magnitudes and patterns in woody crops. The spatial and temporal stability of these patterns is not well known yet. In this study, we run the uncalibrated DR2-2013 © SAGA v1.1 model (0.5 x 0.5 m of cell size) to simulate time to ponding (Tp), runoff duration (T Q), initial runoff per raster cell (q 0), Q sim and Qin in six olive plots (480 m 2 per plot) during two years (108 rainfall events and 648 simulations). Two plots were managed with a mixture of plant species (CC-I), two with one single plant species (CC-II) and two with CT. Runoff yield from each plot was collected (Q obs) in gaugingstations during 27 time-integrated samples and used for modelling validation (162 control points). On average, Q obs was 9% higher under CT than under CC-I, and 8% higher than under CC-II. Topsoil saturation was simulated for the entire plots during 29 events (test-period), and Q sim appeared in another 51 and 52 events in the plots with CC and CT. Tp with CT was 2.3 times higher (59 s) than the average duration with CC and the topsoil became saturated 3.3 times faster in the inter-rows than below the trees. Values of q 0 with CC were 2.3% lower than with CT and total Q sim with CC was 2% higher than with CT. However, the differences of Q sim between the different treatments were not statistically significant. The mean observed and simulated runoff coefficients were of 11 and 14%, with median values of 7 and 10%. Q sim correlated well with Q obs (Pearson ca. 0.861), and Q sim was overestimated ca. 10%. The model performed better CATENA 147: 125-137 (2016) when rainfall depth and intensity were high, and the range of variability of both Q sim and Q obs was similar. The average, best and worst Nash-Sutcliffe coefficients were 0.665, 0.791 (P6) and 0.512 (P3) and thus model simulations were satisfactory. The four plots with CC presented on average a worse performance (Kling-Gupta coefficient = 0.607) than the two plots with CT (KGE = 0.769). The lowest spatial variability of q 0 , Q obs , Q sim and actual available water (Waa, the sum of Qin and stored water in the soil surface) were found in the plots with CC. CT triggered higher spatial variability of runoff and higher temporal variability of runon than CC.

Soil and Water Conservation in Rainfed Vineyards with Common Sainfoin and Spontaneous Vegetation under Different Ground Conditions

“…The observed differences in the effectiveness of water conservation between the cover crop (CC) of common sainfoin and the plant cover of spontaneous vegetation (SP) may be explained by the differences in plant density, much higher in the CC than in the SP. In olive orchards in southern Spain, López-Vicente et al [28] also found different runoff coefficients in runoff crops with homogeneous and heterogeneous plant covers. The wet and stable soil moisture conditions observed in the corridors may be explained by: (i) the occasional tractor traffic that compacts the topsoil, reducing evaporation; (ii) the lack of grapevines in this compartment that clearly reduces the water consumption; (iii) the presence of SP that favored water infiltration; and (iv) the higher content of silt and the lower content of sand in the soils of this compartment in comparison with the rows and inter-row areas (see Table 1).…”

“…The value of SDRDiT serves as one of the measures of the temporal stability [28,33,51,52] by comparing its magnitude to the spatial variability of MRDiT. The sensitivity analysis was done for the vineyards' compartments (rows, inter-row areas and corridors) of each field and for the whole study area.…”

“…In addition, some techniques usually adopted in vineyards' installation and management (e.g., intense tractor traffic throughout fixed paths) deteriorate soil structure and produce soil surface compaction [26]. In the literature, the benefits of VC in vineyards, fruit-tree orchards and reclaimed soils has been widely evaluated in a variety of soil and climate conditions throughout the world [13,[27][28][29].…”

Spatial Variability and Temporal Persistence of Event Runoff Coefficients for Cropland Hillslopes

“…Rüttimann et al () reached a similar conclusion by analyzing runoff data collected in the Swiss Plateau and the Jura. In contrast, López‐Vicente et al () analyzed runoff data from 80 events over six experimental plots with a constant size of 480 m 2 in southwestern Spain and reported that runoff processes over croplands showed highest temporal stability. The existence of temporal persistence of spatial pattern in runoff responses at small spatial scales remains unclear.…”

Influence of DEM resolution on modelling hydrological connectivity in a complex agricultural catchment with woody crops

“…Permanent features in agricultural lands, such as the trunks of woody crops and grooves and rows following straight lines, mainly control overland flow paths, especially in areas with low and moderate slope (López-Vicente et al, 2016). Woody crops, such as vineyards, almond, olive, orange, coffee, tea, and other fruit groves, as well as forest plantations, are cultivated on a significant percentage of the world's agricultural soil.…”