scholarly journals Effectiveness of Polyacrylamide in Reducing Runoff and Soil Loss under Consecutive Rainfall Storms

2020 ◽  
Vol 12 (4) ◽  
pp. 1597 ◽  
Author(s):  
Birhanu Kebede ◽  
Atsushi Tsunekawa ◽  
Nigussie Haregeweyn ◽  
Amrakh I. Mamedov ◽  
Mitsuru Tsubo ◽  
...  

The use of anionic polyacrylamide (PAM) as a soil conditioner could help prevent soil loss by water. In this study, we determined the effective granular PAM rate that best reduces runoff and soil loss from Oxisols. Furthermore, the effectiveness of the selected PAM rate was tested by applying it in a mixture with gypsum (G) or lime (L). The study was conducted in two phases: (i) Dry PAM rates of 0 (C), 20 kg ha−1 (P20), 40 kg ha−1 (P40), and 60 kg ha−1 (P60) were applied onto soil surface and run for six consecutive rainfall storms of 70 mm h−1 intensity for 1 h duration, and the effective PAM rate was selected; and (ii) G (4 t ha−1) or L (2 t ha−1) were applied alone or mixed with the selected PAM rate. The P20 was found to be effective in reducing runoff in the beginning while P40 and P60 were more effective starting from the third storm through the end of the consecutive storms, but with no statistically significant difference between P40 and P60. Hence, P40 was selected as the most suitable rate for the given test soil and rainfall pattern. On the other hand, the mixed application of P40 with G or L increased infiltration rate (IR) in the first two storms through improving soil solution viscosity. However, effectiveness of the mixtures had diminished by various degrees as rain progressed, as compared to P40 alone, which could be attributed to the rate and properties of G and L. In conclusion, the variation in effectiveness of PAM rates in reducing runoff with storm duration could indicate that the effective rates shall be selected based on the climatic region in that lower rates for the short rains or higher rates for elongated rains. Moreover, combined application of PAM with L could offer a good option to both fairly reduce soil erosion and improve land productivity especially in acidic soils like Oxisols, which requires further field verification.

Soil Research ◽  
2008 ◽  
Vol 46 (3) ◽  
pp. 191 ◽  
Author(s):  
Meni Ben-Hur ◽  
Marcos Lado

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.


2008 ◽  
Vol 32 (6) ◽  
pp. 654-677 ◽  
Author(s):  
T. Smets ◽  
J. Poesen ◽  
E. Bochet

Covering the soil surface by rock fragments, organic mulches or vegetation is often done to reduce runoff and soil loss by water erosion compared to a bare soil treatment. The runoff or erosion-reducing effectiveness of these soil surface covers has been investigated for a range of plot lengths under different environmental conditions. Recent research indicates that the effectiveness of soil surface covers in reducing runoff and soil loss by water erosion may be affected by the size of the laboratory or field plots (ie, spatial scale). Therefore, the main objective of this review is to explore to what extent the impact of plot length on the effectiveness of different surface covers (ie, rock fragments, organic mulch and vegetation) in reducing runoff and soil loss by water erosion emerges from a worldwide data set. Furthermore, it is investigated whether there is a significant difference in runoff or erosion-reducing effectiveness between rock fragments, organic mulches and vegetation. Data from 65 experimental studies, investigating the impact of surface cover by rock fragments, organic mulch or vegetation on runoff or soil loss, are collected and analysed in this review. The results indicate that for plot lengths <11 m there is a large variation in the runoff and erosion-reducing effectiveness of a soil cover, depending on various factors and on the larger number of studies conducted on these plots compared to longer field plots. However, with an increasing plot length (up to 50 m) this variation is reduced and surface covers by rock fragments, organic mulches and vegetation become on average more effective in reducing runoff or soil loss by water erosion. A vegetation cover is significantly more effective in reducing runoff rate compared to a rock fragment cover. No other significant differences in runoff or in erosion-reducing effectiveness between the studied soil surface covers are observed. Finally, two equations are proposed describing the possible effect of plot length and cover by rock fragments, organic mulches and vegetation on relative runoff and soil loss by water erosion. These findings have important consequences for the design of runoff and erosion plots, for modelling runoff and soil erosion rates and for scaling up plot data.


1995 ◽  
Vol 35 (7) ◽  
pp. 969 ◽  
Author(s):  
DK Malinda

A medium-term (10 years) stubble x tillage field experiment was established in 1984 on a red-brown earth at Tarlee, 70 km north of Adelaide, to develop a suitable system for sustaining the soil resource. Measurements of infiltration capacity, soil detachment rate, and erosion were taken in summer, autumn, winter, and spring 1989-90. The rotation was wheat-barley-grain legume, and treatments included 3 levels of stubble retention (0.5, 3.0, 5.0 t/ha.year) and 4 types of tillage [no-tillage (NT), direct drill (DD), reduced tillage (RT), conventional cultivation (CC)]. NT was seeded with narrow points (30 mm) and the other tillage treatments with wide shares (150 mm). The Northfield rainfall simulator with an erosive rainfall of 100 mm/h and an energy of 28.6 J/ m2.mm was used to measure runoff and soil and nutrient loss. This paper reports on erosion from this experiment. The results show that runoff was reduced through farming practices such as the retention of adequate stubble residue (about 3-5 t/ha.year of cereals), NT, or a combination of these factors. Increasing the average - - - annual stubble retention decreased runoff and soil loss linearly. The greater the amount of stubble retained annually, the less the runoff and soil loss, whether or not the soil surface was protected. The significant sediment release and soil loss from bared soil is inversely related to soil stability measured by a reduction in soil organic matter. Crop type also influenced erosion; for example, soil was more vulnerable to erosion after peas than after cereal. The amount of stubble after harvest was usually greater with cereals than with grain legumes. Runoff as a percentage of applied rain, and soil loss, ranged from 26 to 60% and 0.52 to 1 .I t/ha for 0.5 t/ha. year stubble (means of all treatments) for April 1989 and August 1990, respectively, and from 5 to 35% and 0.03 to 0.8 t/ha for 5.0 t/ha.year stubble for the same simulation period. Runoff rates in the last 3 min of 18 min simulation ranged from 0.4 to 1.1 mm/min for 5.0 t/ha.year stubble and from 0.8 to 1.7 mm/min for 0.5 t/ha.year stubble. The runoff rates recorded at the 18th minute of simulation ranged from 0.5 to 1.2 mm/min for NT and 0.7 to 1.5 mm/min for CC.


2005 ◽  
Vol 9 (5) ◽  
pp. 1-30 ◽  
Author(s):  
A. L. Presbitero ◽  
C. W. Rose ◽  
B. Yu ◽  
C. A. A. Ciesiolka ◽  
K. J. Coughlan ◽  
...  

Abstract At the Visayas State College of Agriculture (ViSCA) on the island of Leyte in the Philippines, hydrologic and soil-loss measurements were recorded for 32 erosion events over 3 yr on three 12-m-long bare soil plots with slopes of approximately 50%, 60%, and 70%. Measurements included rainfall and runoff rates at 1-min intervals, total soil lost per event from the plot, rill details when observed after an erosion event, and soil settling-velocity characteristics. Storm events are characterized by high rainfall rates but quite low rates of runoff, because of the consistently high infiltration rate of the stable clay soil (an Oxic Dystropept). Both observation and modeling indicated that overland flow is commonly so shallow that much of the soil surface is likely to be unsubmerged. For the 70% slope plot, half the events recorded mean sediment concentrations from 100 to 570 kg m−3. A somewhat constant hydrologic lag between rainfall and runoff is used to estimate a Manning’s roughness coefficient n of about 0.1 m−1/3 s, a value used to estimate velocity of overland flow. Possible effects of shallow flows and high sediment concentrations on existing erosion theory are investigated theoretically but are found to have only minor effects for the ViSCA dataset. A soil erodibility parameter β was evaluated for the data whenever rilling was recorded following an erosion event. The values of β indicate that, except for events with higher stream powers, other erosion processes in addition to overland flow could have contributed to soil loss from erosion plots in a significant number of events.


2021 ◽  
Vol 930 (1) ◽  
pp. 012007
Author(s):  
R Haribowo ◽  
R Asmaranto ◽  
L T W N Kusuma ◽  
B G Amrina

Abstract Installation of mulch on agricultural land, besides reducing weed growth, can also protect the soil surface from rain and erosion. This study aims to determine the effectiveness of rice straw mulch in reducing surface runoff and soil loss before entering the river. The experimental soil materials were similar to those in Sumber Brantas village, Bumiaji Sub-District, Batu. Runoff modelling utilized the Armfield S12 Rainfall Simulator - Advanced Environmental Hydrology System, with rainfall of 1 and 1.7 l/min. Land with rice straw mulch was compared to land without mulch. The land slope was adjusted to study area conditions, with mild (9%) and steep (15%) slopes. The three-Way ANOVA method was utilized for statistical analysis. In all the experimental runs, it was found that straw mulch effectively reduced the sediment yields that could enter the river area by more than 50%. The results of ANOVA analysis on sediment yield also showed that the significance value of the interactions between slope, rain intensity, and mulch usage was 0 (p<0.05). These results show that the difference in variations in these three factors determines the sediment yield that occurs. In the future, comparing straw mulch with other materials to cover agricultural land should be conducted.


Soil Research ◽  
1989 ◽  
Vol 27 (4) ◽  
pp. 759 ◽  
Author(s):  
APB Proffitt ◽  
CW Rose ◽  
CJ Lovell

Temporal changes in soil loss rates as a result of rainfall detachment were measured in modified splash-cups (kc) for two contrasting soil types with 5 mm depth of surface water at two constant rainfall rates (56 and 100 mm h-1). Results were compared with those from a flume (kf) for the same rainfall duration, rainfall rates, soil types and water depth. Reasons are given why soil loss rate commonly measured from splash-cups is not a true measure of soil detachment by rainfall when surface water is present. In order to yield the true rate of soil detachment, the measured net rate of soil loss must be augmented by a correction accounting for the rate of deposition. Theory for the net outcome of rainfall detachment and sediment deposition was used to interpret net soil loss data at equilibrium from splash-cups to yield true soil detachment rates (eTc), and compared those from a flume (eTf ). The two soil types were a cracking clay (black earth or Vertisol) and a slightly dispersive sandy clay loam (solonchak or Aridisol). Splash-cup modification allowed the proportion of sediment lost as airsplash (and therefore not deposited within the splash-cup) to be quantified to allow calculation of true soil detachment rates, and hence true soil detachabilities. Under constant rainfall rates and water depth, kc decreased significantly (5% level) with time until an equilibrium detachment rate was reached. This decrease was attributed to the development of a deposited layer on the soil surface, coarser in texture than the original soil. Values of kc were higher for the solonchak than the black earth, and increased with rainfall rate. At equilibrium, eTc and qf were approximately three orders of magnitude greater than kcand kf, illustrating the importance of recognizing the deposition process in determining true rates of soil detachment and soil detachabilities. There was no significant difference (5% level) between kc and kf at equilibrium for the black earth, but values of kc were significantly higher (5% level) than kf for the solonchak. There were no significant differences (5% level) between qc and eTf for both soil types at the low rainfall rate, but eTc were significantly lower than eTf for both the black earth (5% level) and solonchak (0.1% level) at the high rate.


Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2856
Author(s):  
Judit Alexandra Szabó ◽  
Csaba Centeri ◽  
Boglárka Keller ◽  
István Gábor Hatvani ◽  
Zoltán Szalai ◽  
...  

Soil erosion is a complex, destructive process that endangers food security in many parts of the world; thus, its investigation is a key issue. While the measurement of interrill erosion is a necessity, the methods used to carry it out vary greatly, and the comparison of the results is often difficult. The present study aimed to examine the results of two rainfall simulators, testing their sensitivity to different environmental conditions. Plot-scale nozzle type rainfall simulation experiments were conducted on the same regosol under both field and laboratory conditions to compare the dominant driving factors of runoff and soil loss. In the course of the experiments, high-intensity rainfall, various slope gradients, and different soil surface states (moisture content, roughness, and crust state) were chosen as the response parameters, and their driving factors were sought. In terms of the overall erosion process, the runoff, and soil loss properties, we found an agreement between the simulators. However, in the field (a 6 m2 plot), the sediment concentration was related to the soil conditions and therefore its hydrological properties, whereas in the laboratory (a 0.5 m2 plot), slope steepness and rainfall intensity were the main driving factors. This, in turn, indicates that the design of a rainfall simulator may affect the results of the research it is intended for, even if the differences occasioned by various designs may be of a low order.


Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2327 ◽  
Author(s):  
Layheang Song ◽  
Laurie Boithias ◽  
Oloth Sengtaheuanghoung ◽  
Chantha Oeurng ◽  
Christian Valentin ◽  
...  

Many mountainous regions of the humid tropics experience serious soil erosion following rapid changes in land use. In northern Lao People’s Democratic Republic (PDR), the replacement of traditional crops by tree plantations, such as teak trees, has led to a dramatic increase in floods and soil loss and to the degradation of basic soil ecosystem services such as water filtration by soil, fertility maintenance, etc. In this study, we hypothesized that conserving understory under teak trees would protect soil, limit surface runoff, and help reduce soil erosion. Using 1 m2 microplots installed in four teak tree plantations in northern Lao PDR over the rainy season of 2017, this study aimed to: (1) assess the effects on surface runoff and soil loss of four understory management practices, namely teak with no understory (TNU; control treatment), teak with low density of understory (TLU), teak with high density of understory (THU), and teak with broom grass, Thysanolaena latifolia (TBG); (2) suggest soil erosion mitigation management practices; and (3) identify a field visual indicator allowing a rapid appraisal of soil erosion intensity. We monitored surface runoff and soil loss, and measured teak tree and understory characteristics (height and percentage of cover) and soil surface features. We estimated the relationships among these variables through statistics and regression analyses. THU and TBG had the smallest runoff coefficient (23% for both) and soil loss (465 and 381 g·m−2, respectively). The runoff coefficient and soil loss in TLU were 35% and 1115 g·m−2, respectively. TNU had the highest runoff coefficient and soil loss (60%, 5455 g·m−2) associated to the highest crusting rate (82%). Hence, the soil loss in TBG was 14-times less than in TNU and teak tree plantation owners could divide soil loss by 14 by keeping understory, such as broom grass, within teak tree plantations. Indeed, a high runoff coefficient and soil loss in TNU was explained by the kinetic energy of rain drops falling from the broad leaves of the tall teak trees down to bare soil, devoid of plant residues, thus leading to severe soil surface crusting and soil detachment. The areal percentage of pedestal features was a reliable indicator of soil erosion intensity. Overall, promoting understory, such as broom grass, in teak tree plantations would: (1) limit surface runoff and improve soil infiltrability, thus increase soil water stock available for both root absorption and groundwater recharge; and (2) mitigate soil loss while favoring soil fertility conservation.


1985 ◽  
Vol 25 (3) ◽  
pp. 628 ◽  
Author(s):  
JW Cooke

The effect on runoff and soil loss of four methods of preparation of fallow was investigated at each of three sites in north-central Victoria. There was a chemical fallow treatment (uncultivated) and three scarified treatments (smooth, medium and rough cultivation). When the results from the three sites were combined, there was 10.7 mm runoff from the uncultivated treatment, 5.1 mm from the smooth, 0.8 mm from the medium and 0.3 mm from the rough scarified treatments. Soil loss from the uncultivated treatment was 103 g/m2 compared with 87 g/m2 from the smooth, 22 g/m2 from the medium and 13 g/m2 from the rough treatment. The concentration of sediment in the runoff was negatively correlated (R2 = -0.56 to -0.98) with runoff. It ranged from 1.21% (w/w) for the uncultivated to 5.06% (w/w) for the rough scarified treatment. The results show that a regimen of minimum scarification to produce a rough surface, and then use of herbicides to control weeds, reduces soil loss compared with either an uncultivated or a smoothly cultivated soil surface.


Soil Research ◽  
1995 ◽  
Vol 33 (5) ◽  
pp. 833 ◽  
Author(s):  
C Carroll ◽  
M Halpin ◽  
K Bell ◽  
J Mollison

Runoff and sediment movement were measured from irrigated furrows of different lengths on a Vertisol in central Queensland. Two farm properties (Denaro's and Roberts') were used to compare a short furrow length (SFL) and a long furrow length (LFL). At Denaro's farm, furrows were 241 and 482 m long, and at Roberts' farm they were 151 and 298 m long, with gradients of 1.0% and 1.3% respectively. Runoff and soil loss were measured from six furrows. At Denaro's farm, soil movement off the farm was measured at a taildrain outlet. Sediment concentration from both rainfall and irrigation declined when cultivation had ceased, soil in the furrows had consolidated and when the cotton canopy provided surface cover. Total soil loss from rainfall and irrigation was approximately 4-5 t ha-1. Rainstorms caused most of the seasonal soil loss, typically 3-4 t ha-1. The critical soil erosion period was between pre-plant irrigation and canopy closure. Soil surface cover, peak runoff rate and furrow length explained 97% of variance in soil loss caused by rainfall. Furrow length was not significant in the soil loss model for irrigation (r2 0.59).


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