A field study of the influence of land management and soil properties on runoff and soil loss in central Spain

Soil surface sealing is one of the main causes for low infiltration rate (IR) and high runoff and soil loss under raindrop impact conditions in arid and semiarid regions. Many studies have focused on the effects of soil properties on seal formation under fast wetting conditions. However, in the field, soils can be exposed to different wetting conditions, before an intense rainfall event, which can affect the role of the soil properties on seal formation. The present paper reviews the effects of different initial wetting conditions and their interactions with soil properties on seal formation, IR, runoff, and soil loss in smectitic soils. Fast wetting of soil causes aggregate slaking, which enhances seal formation, runoff, and soil loss under rainfall, mainly in soils with > 40% clay content. An increase in clay content of the soil increases aggregate strength, but at the same time increases the slaking forces. Hence, in soils with low clay content (<40%) and low aggregate stability, raindrop impact alone was sufficient to break down the aggregates and to develop a seal. In contrast, in soils with > 40% clay content and high aggregate stability, slaking plays an important role in aggregate breakdown and seal formation. An increase of raindrop kinetic energy, from 8 to 15.9 kJ/m3, decreased the effect of the slaking forces on seal formation and runoff. It was suggested that the effects of raindrop kinetic energy and of the slaking forces on aggregate disintegration and seal formation are complementary. An increase in soil exchangeable sodium percentage (ESP), from 0.9 to 20.4%, decreased the effect of slaking forces on seal formation and runoff production under rainfall with 15.9 kJ/m3 kinetic energy. Probably, increasing the ESP increased the soil dispersivity, and therefore diminished the effect of the slaking forces on aggregate disintegration and seal formation. Aging (the time since wetting) of soil increased the stability of soil structure, decreased the seal formation, maintained high IR, and diminished soil loss amounts. These effects of soil aging depend on both the prewetting rate of the soil and soil texture.

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A validation test of WEPP to predict runoff and soil loss from a pineapple farm on a sandy soil in subtropical Queensland, Australia

Soil Research ◽

10.1071/sr99104 ◽

2000 ◽

Vol 38 (3) ◽

pp. 537 ◽

Cited By ~ 20

Author(s):

B. Yu ◽

C. A. A. Ciesiolka ◽

C. W. Rose ◽

K. J. Coughlan

Keyword(s):

Soil Properties ◽

Soil Loss ◽

Slope Length ◽

Erosion Prediction ◽

Water Erosion Prediction Project ◽

Loss Prediction ◽

Sandy Slope ◽

Monthly Runoff ◽

Parameter Values ◽

Runoff And Soil Loss

Monthly runoff and soil loss simulated by WEPP (Water Erosion Prediction Project) were compared with field observations on a pineapple farm in south-east Queensland for a 3-year period. The soil at the site is sandy. Slope length and steepness are 36m and 5.5%, respectively. Three treatments, namely bare, farmers’ conventional practice, and mulching of the furrows, were used. Infiltration and erodibility parameters were determined using WEPP-recommended equations and measurable soil properties. These parameters were also calibrated using the runoff and soil loss data for the bare plot only. Apart from the soil loss prediction for the mulching treatment, for which WEPP did not perform well, the average coefficient of efficiency in runoff and soil loss predictions was –0.02 using soil property-based parameter values and 0.66 using calibrated parameter values. The corresponding r 2 values are 0.57 and 0.81, respectively. On the whole, WEPP is able to reproduce the trend and variations in runoff and soil loss among different treatments for the site. Parameter values based on measurable soil properties would greatly under-estimate the runoff and soil loss for the site. Thus, use of WEPP outside its US database requires calibration with locally obtained data. It was also found that WEPP does not seem to model effectively the situation where there is considerable flow impediment with the furrows covered with mulch. We are unable to reject WEPP because the statistical performance indicators are reasonable for the site, and because the model is so complex that it is nearly impossible to pinpoint the source of discrepancy and articulate the model deficiency on physical grounds.

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ASSESSMENT OF SOIL EROSION IN VINH LINH, QUANG TRI USING RMMF MODEL (REVISED MORGAN - MORGAN - FINNEY)

HUE UNIVERSITY JOURNAL OF SCIENCE AGRICULTURE AND RURAL DEVELOPMENT ◽

10.26459/jard.v83i5.3083 ◽

2013 ◽

Vol 83 (5) ◽

Author(s):

Nguyễn Quang Việt ◽

Trương Đình Trọng ◽

Hồ Thị Nga

Keyword(s):

Soil Erosion ◽

Land Cover ◽

Soil Loss ◽

Soil Particle ◽

Transport Capacity ◽

Gis Technology ◽

Particle Detachment ◽

Sediment Transport Capacity ◽

Northern District ◽

Runoff And Soil Loss

Vinh Linh, the northern district of Quang Tri province is characterized by a diversified topography with a large variety of elevations, high rainfall, and decreasing land cover due to forest exploiting for cultivation land. Thus, there is a high risk of erosion, soil fertility washout. With the support of GIS technology, the authors used the rMMF model to measure soil erosion. The input data of model including 15 coefficients related to topography, soil properties, climate and land cover. The simulations of rMMF include estimates of rainfall energy, runoff, soil particle detachment by raindrop, soil particle detachment by runoff, sediment transport capacity of runoff and soil loss. The result showed that amount of soil loss in year is estimated to vary between 0 kg/m2 minimum and 149 kg/m2 maximum and is divided into 4-classes of erosion. Light class almost covers the region researched (75.9% of total area), while moderate class occupies 8.1% of total area, strong classes only hold small area (16% of total area). Therefore, protection of the forest floor in sloping areas is one of the most effective methods to reduce soil erosion.

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