scholarly journals Spatial Variability of Preferential Flow and Infiltration Redistribution along a Rocky-Mountain Hillslope, Northern China

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1102
Author(s):  
Si-yuan Zhao ◽  
Yang-wen Jia ◽  
Jia-guo Gong ◽  
Cun-wen Niu ◽  
Hui-dong Su ◽  
...  

Rock fragments in soil strongly increase the complexity of hydrological processes. Spatial variability of preferential flow and infiltration characteristics, especially along a rocky-mountain hillslope are poorly understood. In this study, five rainfall–dye tracer experiments were performed in the rocky Taihang Mountains, northern China, to investigate the spatial variability of preferential flow and infiltration redistribution on different hillslope positions. Tracers were used to distinguish macropore flow and actual water flow patterns, and preferential flow indices and spatial non–uniformity of the infiltration redistribution were calculated using image analysis. Results showed increasing trends in the dye coverage, maximum infiltration depth, and steady infiltration rate with increased hillslope position, with a preferential flow fraction of 0.10, 0.11, 0.15, 0.29, and 0.26 for the bottom–, down–, mid–, upper–, and top–slope positions, respectively. With increased hillslope position, the spatial non–uniformity of the infiltration redistribution gradually increased in orthogonal and parallel directions to the stained section, and was supported by the fractal dimensions. Positive (gravel mass ratio, saturated water content, altitude, hydraulic conductivity and roots) and negative (bulk density and clay content) impacts on preferential flow and infiltration redistribution were quantitatively emphasized. The characteristic and mechanism of infiltration process were further identified along a rocky-mountain hillslope.

Water SA ◽  
2019 ◽  
Vol 45 (3 July) ◽  
Author(s):  
Ahmed Z Dewidar ◽  
Hussein Al-Ghobari ◽  
Abed Alataway

The prediction of the soil infiltration rate is advantageous in hydrological design, watershed management, irrigation, and other agricultural studies. Various techniques have been widely used for this with the aim of developing more accurate models; however, the improvement of the prediction accuracy is still an acute problem faced by decision makers in many areas. In this paper, an intelligent model based on a fuzzy logic system (FLS) was developed to obtain a more accurate predictive model for the soil infiltration rate than that generated by conventional methods. The input variables that were considered in the fuzzy model included the silt and clay contents. The developed fuzzy model was tested against both the observed data and multiple linear regression (MLR). The comparison of the developed fuzzy model and MLR model indicated that the fuzzy model can simulate the infiltration process quite well. The coefficient of determination, root mean square error, mean absolute error, model efficiency, and overall index of the fuzzy model were 0.953, 1.53, 1.28, 0.953, and 0.954, respectively. The corresponding MLR model values were 0.913, 2.37, 1.92, 0.913, and 0.914, respectively. The sensitivity results indicated that the clay content is the most influential factor when the FLS-based modelling approach is used for predicting the soil infiltration rate.


2006 ◽  
Vol 78 (5) ◽  
pp. 1081-1090 ◽  
Author(s):  
Werner Kördel ◽  
Michael Klein

Herein, we describe how pesticide leaching is assessed in Europe in order to fulfill EU Directive 91/414. The assessment schemes were developed to protect groundwater from unacceptable effects caused by pesticide use. They presently focus on chromatographic flow processes, which are dominant in sandy soils. Nevertheless, important regions in Europe are characterized by structured soils where transport through macropores is most relevant.Comparison of parallel field studies with isoproturon performed in sandy and silty soils showed that maximum concentration in the structured soil at a soil depth of 1 m may exceed respective concentrations in sandy soils by a factor of 60. Similar results were obtained by lysimeter studies using silty soil cores with maximum concentration of 40 μg/l at the soil bottom. These results demonstrate that preferential flow is more the rule than the exception in well-structured fine-textured soils, and pesticide losses via macropore flow may exceed losses via matrix transport considerably. All present information available for macropore flow suggest the need for greater regional assessments. Other recommendations include analysis of the influence of different soil management practices on the formation of macropores.


2015 ◽  
Vol 12 (16) ◽  
pp. 13215-13240 ◽  
Author(s):  
W. Luo ◽  
P. N. Nelson ◽  
M.-H. Li ◽  
J. Cai ◽  
Y. Zhang ◽  
...  

Abstract. Soil pH buffering capacity (pHBC) plays a crucial role in predicting acidification rates, yet its large-scale patterns and controls are poorly understood, especially for neutral-alkaline soils. Here, we evaluated the spatial patterns and drivers of pHBC along a 3600 km long transect (1900 km sub-transect with carbonate containing soils and 1700 km sub-transect with non-carbonate containing soils) across northern China. Soil pHBC was greater in the carbonate containing soils than in the non-carbonate containing soils. Acid addition decreased soil pH in the non-carbonate containing soils more markedly than in the carbonate containing soils. Within the carbonate soil sub-transect, soil pHBC was positively correlated with cation exchange capacity (CEC), carbonate content and exchangeable sodium (Na) concentration, but negatively correlated with initial pH and clay content, and not correlated with soil organic carbon (SOC) content. Within the non-carbonate sub-transect, soil pHBC was positively related to initial pH, clay content, CEC and exchangeable Na concentration, but not related to SOC content. Carbonate content was the primary determinant of pHBC in the carbonate containing soils and CEC was the main determinant of buffering capacity in the non-carbonate containing soils. Soil pHBC was positively related to aridity index and carbonate content across the carbonate containing soil sub-transect. Our results indicated that mechanisms controlling pHBC differ among neutral-alkaline soils of northern China, especially between carbonate and non-carbonate containing soils, leading to different rates, risks, and impacts of acidification. This understanding should be incorporated into the acidification risk assessment and landscape management in a changing world.


2021 ◽  
Vol 930 (1) ◽  
pp. 012054
Author(s):  
I K Hidayati ◽  
Suhardjono ◽  
D Harisuseno ◽  
A Suharyanto

Abstract Ponding time is the period from the beginning of rainfall/infiltration until the occurrence of ponding. This paper aims to determine the infiltration rate and ponding time on different land uses, such as open fields, residential, agriculture, and vegetation. This research was conducted in one of the watersheds in the Brantas River Basin, namely the Lesti River Basin, which is administratively included in the Malang Regency, East Java. The Lesti River is one of the tributaries of the Brantas River, which originates around Mount Semeru, a very intensive area for planting rice, sugar cane, and coffee. Infiltration data were collected at 35 points using a double-ring infiltrometer spread across the Lesti watershed with Andosol, Mediterranean, and Regosol soil types. At the same time, ponding time was obtained from infiltration measurements in the field using the flooding method. The physical properties of the soils were tested in the laboratory to obtain water content, porosity, and bulk density values. This study resulted in the infiltration rate and ponding time for each land use and shows how the physical properties of the soil affect the ponding time.


Agronomy ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 286 ◽  
Author(s):  
Guillaume Létourneau ◽  
Jean Caron

Improvements in water productivity are of primary importance for maintaining agricultural productivity and sustainability. Water potential-based irrigation management has proven effective for this purpose with many different crops, including strawberries. However, problems related to spatial variability of soil properties and irrigation efficiency were reported when applying this management method to strawberries in soils with rock fragments. In this study, a field-scale experiment was performed to evaluate the impacts of three irrigation management scales and a pulsed water application method on strawberry yield and water productivity. An analytical solution to Richards’ equation was also used to establish critical soil water potentials for this crop and evaluate the effects of the variability in the soil properties. Results showed that spatial variability of soil properties at the experimental site was important but not enough to influence crop response to irrigation practices. The studied properties did not present any spatial structure that could allow establishing specific management zones. A four-fold reduction in the size of the irrigation management zones had no effect on yield and increased the water applications. Pulsed application led to significant yield (22%) and water productivity (36%) increases compared with the standard water application method used by the producer at the experimental site.


2014 ◽  
Vol 988 ◽  
pp. 498-501
Author(s):  
Fang Shao ◽  
Dong Wen Liu ◽  
Shu Jiang ◽  
Zhi Yong Qiao ◽  
Shan Lin

Infiltration is an important indicator of water and nutrient holding capacity of soil. Lap infiltration apparatus was used to measure vertical water infiltration process in the third year of Yellow River sediment filling reclamation. Five infiltration models were selected to fit the infiltration characteristic curves, analyzed the infiltration experimental results during 3 years of reclamation. The results showed that, the mean initial infiltration rate and mean stable infiltration rate of filling farmland in the third year were 17.06mm/min and 2.38mm/min, and were 8.81mm/min and 0.99 mm/min higher than that of the first year, 3.58mm/min and 0.39mm/min higher than that of the second year. It indicated that, infiltration rate of filling farmland increased significantly after cultivation due to the farming practices and roots development, and the role of soil microorganisms and small animals. Filling farmland has some self-recovery capabilities. In addition, Kostiakov model has better fitting effect than Mezencev model for both filling farmland and control farmland.


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