Soil erosion processes and nutrient loss. 1. The interpretation of enrichment ratio and nitrogen loss in runoff sediment

Soil Research ◽  
1990 ◽  
Vol 28 (4) ◽  
pp. 623 ◽  
Author(s):  
RG Palis ◽  
G Okwach ◽  
CW Rose ◽  
PG Saffigna

The ratio of nutrient concentration in eroded sediment to that in the original soil (the enrichment ratio, ER) commonly varies with the accumulated soil loss. The objective of this study was to investigate possible factors contributing to this change in ER when erosion was accompanied by a significant depth of water. The enrichment ratio was directly measured on sediment from a sandy clay loam soil. ER was followed as a function of time for eight erosion experiments in which the mix of erosion processes and the fractional surface cover was varied. By using a simulated rainfall tilting flume facility, experiments covered low slope (0.1%), when rainfall detachment was the only erosion process, and 3% soil surface slope, where the processes of rainfall detachment and entrainment occurred. The type and extent of fractional surface cover was varied for the experiments with the 3% slope. In all cases, the rainfall rate was 100 mm h-1and the drop size was 2.2 mm. A new analytical framework is described, showing that ER can be interpreted from the product of two component distributions. The first component distribution is the concentration of sediment as a function of sediment size (a distribution found to vary with time and mix of erosion processes). The second distribution is nitrogen concentration (largely organic) as a function of size (found to be much less time-variable than sediment size). The conclusions reached, after analysis of these experimental data by using this framework, were: (i) time variation in ER was largely due to time variation in the first component distribution; (ii) values of ER different from unity require some variation with sediment size (or settling velocity) in the concentration of the nutrient sorbed to the soil or closely associated with the soil organic matter; (iii) the more that rainfall detachment dominates runoff erosion as the major erosion process, the more likely it is that ER is greater than unity.

Soil Research ◽  
1990 ◽  
Vol 28 (4) ◽  
pp. 641 ◽  
Author(s):  
RG Palis ◽  
G Okwach ◽  
CW Rose ◽  
PG Saffigna

Thirty-five erosion experiments, involving four levels of surface contact cover by corn stalks and corn leaves (the latter represented by flat metal sheets) on three slopes, were carried out under simulated rainfall to investigate the effect of fractional surface contact cover and type on the loss and enrichment ratio (ER) of nitrogen in eroded sediment. All experiments were in a tilting flume of the simulated rainfall facility with a sandy clay loam soil. Experiments with rainfall detachment as the only erosion process were conducted on a low slope of 0.1%, to prevent entrainment occurring. The simulated rainfall rate was 100 mm h-1, and sediment samples were collected at the flume exit for up to 40 min. In experiments with entrainment as the only erosion process, clear water was applied as runon at the top of the flume. A stream power of 0 33 W m-2 was used and maintained with entrainment alone and in experiments with rainfall and runon combined for both 3 and 6% slopes. Sediment samples were fractionated through a series of sieves and total nitrogen was analysed for each size range to give the enrichment ratio (ER). The aggregate size or settling velocity characteristics, enrichment ratio (ER), and total nitrogen loss of the eroded sediment varied considerably with slope and cover types for the different erosion experiments. As cover by corn stalks increased, the settling velocity characteristics of eroded sediment became finer; the degree of this fineness was greater than when simulated leaves provided the same cover. For the rainfall detachment alone experiments, values of ER were greater than unity for both cover types and slopes, and greater than values for all other experiments. For the combined rainfall and runon experiments, ER was higher for corn stalks than simulated leaves. For experiments with entrainment alone, values of ER were close to unity for both cover types and slope, even by the early sampling time of 0.6 min. It may be concluded that the effectiveness of cover in reducing nutrient loss lies in reducing sediment loss, not in reducing ER. When rainfall detachment and entrainment were applied together, sediment concentration and total nitrogen loss were substantially increased over the sum of the contribution of rainfall detachment and entrainment acting alone. This finding indicates synergism in nutrient loss between these two erosion processes.


Author(s):  
Juan An ◽  
Jibiao Geng ◽  
Huiling Yang ◽  
Hongli Song ◽  
Bin Wang

Seepage plays a key role in nutrient loss and easily occurs in widely-used contour ridge systems due to the ponding process. However, the characteristics of nutrient loss and its influential factors under seepage with rainfall condition in contour ridge systems are still unclear. In this study, 23 seepage and rainfall simulation experiments are arranged in an orthogonal rotatable central composite design to investigate the role of ridge height, row grade, and field slope on Nitrate (NO3−–N) and Orthophosphate (PO4+3–P) losses resulting from seepage in contour ridge systems. In total, three types of NO3−–N and PO4+3–P loss were observed according to erosion processes of inter-rill–headward, inter-rill–headward–contour failure, and inter-rill–headward–contour failure–rill. Our results demonstrated that second-order polynomial regression models were obtained to predict NO3−–N and PO4+3–P loss with the independent variables of ridge height, row grade, and field slope. Ridge height was the most important factor for nutrient loss, with a significantly positive effect and the greatest contribution (52.35–53.47%). The secondary factor of row grade exerted a significant and negative effect, and was with a contribution of 19.86–24.11% to nutrient loss. The interaction between ridge height and row grade revealed a significantly negative effect on NO3−–N loss, whereas interactions among the three factors did not significantly affect PO4+3–P loss. Field slope only significantly affected NO3−–N loss. The optimal design of a contour ridge system to control nutrient loss was obtained at ridge height of 8 cm, row grade of 2°, and field slope of 6.5°. This study provides a method to assess and model nutrient loss, and improves guidance to implement contour ridge systems in terms of nutrient loss control.


Author(s):  
L. A. Novikova ◽  
◽  
S. N. Artemova ◽  
V. K. Makuev ◽  
E. Y. Yakovlev ◽  
...  

The research is devoted to the study of poorly preserved psammophytic variants of meadow steppes in the forest-steppe zone of the Middle Volga Region. It has allowed to define the main stages of re-establishment of vegetational cover and estimate the conservation prospects on the river Ardym in different ecological conditions (geomorphological and edaphyc). It has been established that the re-establishment of psammophytic steppes vegetation occurs in a similar way both on the slopes of the predominantly southern exposition and on watershed surfaces. However, in the absence of anthropogenic effects on watershed surfaces, there is a sylvatization of the vegetation cover resulting in displacement of psammophytic steppes. Only the constantly occurring weak natural erosion processes on the slopes of the predominantly southern exposition contribute to the preservation of these rare communities here. Under intense anthropogenic influence, as well as in the conditions of a significant erosion process, the psammophytic steppes fail to be preserved or replaced by steppe meadows.


2021 ◽  
Vol 51 (2) ◽  
pp. 102-112
Author(s):  
Cornélio Alberto ZOLIN ◽  
Eduardo da Silva MATOS ◽  
Ciro Augusto de Souza MAGALHÃES ◽  
Janaína PAULINO ◽  
Rattan LAL ◽  
...  

ABSTRACT Soil, water, and nutrient loss by water erosion are among the main factors leading to land degradation, decreasing soil productivity and the provision of ecosystem services. The Cerrado-Amazon ecotone in western Brazil has suffered rapid land-use cover changes with impacts on soil erosion and land degradation. Despite the importance of the region for Brazilian agriculture and environmental conservation, studies on soil, water, and nutrient loss are still scarce. We tested integrated crop-livestock-forestry (ICLF) as a sustainable agriculture management system for the Cerrado-Amazon ecotone region. A field experiment was established in the north of Mato Grosso state to quantify total soil, water, carbon and nitrogen loss during the rainy season in 2012-2013 in plots of integrated crop-forestry (ICF), pasture (PAST), eucalyptus plantation (EUC), no-tillage crop succession (CS) and bare soil (BS). Total soil, water, carbon and nitrogen losses in BS were, on average, 96.7% higher than in ICF, EUC, PAST, and CS. ICF had significantly lower water loss than CS, EUC and PAST. Total loss of carbon (4.3 - 428.2 kg ha-1) and nitrogen (0.3 - 29.2 kg ha-1) differed significantly among treatments. The production systems with tree components (EUC and ICF) and PAST showed reduced soil and nutrients loss compared to CS. Our results demonstrated that ICLF can avoid soil quality loss and thus improve agriculture sustainability in the Cerrado-Amazon ecotone.


1997 ◽  
Vol 20 ◽  
pp. 9-26
Author(s):  
Antonio José Teixeira Guerra

The present paper concerns rill initiation and evolution, taking into account its role on the erosion process. Therefore, several aspects of the process are developed, such as: the process itself, evidences of the process, through field and laboratory experiments, the importance of the models, the consequences to agricultural soils and the conectivity with other soil erosion processes.


2022 ◽  
pp. 92-111
Author(s):  
Bhavya Kavitha Dwarapureddi ◽  
Swathi Dash ◽  
Aman Raj ◽  
Nihanth Soury Garika ◽  
Ankit Kumar ◽  
...  

Climatic conditions, precise relief features, variations of soil, flora cover, socio-economic conditions together lead to torrential flood waves as a result of current soil erosion processes. Erosion and torrential floods are aggravated due to over exploitation of agricultural and forest land along with urbanization. Effects of soil erosion include nutrient loss, land use changes, reduced productivity, siltation of water bodies, among other effects like affecting livelihood of marginal communities dependent on agriculture globally and public health. Nearly 11 million km2 of soil is impacted by erosion precisely by water. Other factors like intensified agriculture and climate change contribute to and aggravate the erosion rate. Contemporary torrential floods are characterized by their increased destruction and frequency unlike the pre-development periods when their occurrence was rare. The focus of this review is to compile and aid as a data base for understanding methods of preventing erosion of soil and torrential floods as put forth by various researchers.


2016 ◽  
Vol 78 (5-5) ◽  
Author(s):  
Azlinda Saadon ◽  
Junaidah Ariffin ◽  
Jazuri Abdullah ◽  
Norhidayati Mat Daud

Bank erosion is commonly associated with river meandering initiation and development, through width adjustment and planform evolution. It consists of two types of erosion processes; basal erosion due to fluvial hydraulic force and bank failure under the influence of gravity. Most of the studies only focused on one factor rather than integrating both factors. Evidences of previous works have shown integration between both processes of fluvial hydraulic force and bank failure. Bank failure seldom treated as a probabilistic phenomenon without assessing the physical characteristics and the geotechnical aspects of the bank. Thus, the objective of this paper is to investigate factors governing streambank erosion process and to perform a dimensional analysis considering the physical characteristics of both processes namely fluvial erosion and mass failure and their interaction.


2013 ◽  
Vol 8 (No. 4) ◽  
pp. 172-177 ◽  
Author(s):  
H. Noor ◽  
S. Fazli ◽  
S.M. Alibakhshi

Suspended sediment (SS) resulted from distributed soil erosions facilitates soil organic matter and phosphorus (P) transportation and influences soil depletion and water quality. Organic matter (OM) in soil is the most important indicator of soil quality and productivity. P is one of the major nutrients controlling eutrophication of surface water. Irregular contaminant load pulsed by heavy rainfall may damage the ecological quality of downstream waters. Evaluation of OM and P, depleted by erosion processes in watershed scale, is necessary for better understanding the watershed system and should lead to appropriate management approaches. On the other hand, different behaviours of soil erosion as well as the necessity of regional studies have been proved. The present study was conducted in the Kojour watershed, Iran in order to (1) get some ideas about the storm-wise OM and P load in river, (2) evaluate the relationship between the peak of OM and P concentration and discharge during individual rainfall events, and (3) assess the applicability of rainfall and runoff variables of ten storm events in the prediction of storm-wise OM and P loss. The results showed that most of the OM and P peaks preceded the peak discharge, following a clockwise hysteretic loop that exhibited hysteresis with a greater OM and P concentration for a given discharge occurring on the rising limb rather than on the falling limb. The results also showed that regression models had good efficiency in estimation of storm-wise OM and P loss with coefficient of determination of 0.96 and 0.93, respectively.


1989 ◽  
Vol 69 (3) ◽  
pp. 639-647 ◽  
Author(s):  
G. J. BEKE ◽  
C. W. LINDWALL ◽  
T. ENTZ ◽  
T. C. CHANNAPPA

Rainfall simulation by sprinkler irrigation was used to evaluate the characteristics of sediment and runoff water from erosion plots on a Dark Brown Chernozemic soil near Lethbridge, Alberta. Replicated land treatments consisted of bare fallow, perennial alfalfa/wheat grass forage (Medicago sativa L./Agropyron riparium Scribn. & Smith) planted in rows parallel to the slope, barley (Hordeum vulgare L.) planted in rows parallel to the slope (barley-S) and barley on contour (barley-C). The eroded sediment from all four treatments was generally enriched in organic matter (OM), NH4-N, total N (TN), and PO4-P, but not in NO3-N or total P (TP). The sediment from the bare fallow treatment was enriched in silt-size particles and had the highest OM enrichment. Maximum NH4-N and TN enrichment occurred in the sediment from the barley-S treatment, and maximum PO4-P in that from the forage treatment. This selective removal of plant nutrients was attributed mainly to erosion processes and to cropping-induced differences in C:N:P ratios of organic complexes. The runoff water from all four treatments was enriched in NO3-N, TN, and PO4-P. For the three cropping treatments in this experiment, nutrient enrichment of the runoff water decreased from forage > barley-S > barley-C treatment. In general, more NO3-N was lost in the runoff water than in the sediment. Key words: Erosion, sediment quality, water quality, nutrient loss, nitrogen forms, phosphorus forms.


2020 ◽  
Vol 17 (1) ◽  
pp. 67
Author(s):  
Oteng Haridjaja

Soil consevation management system is an activity for diminishing sediment enrichment ratio and nutrient leacheds by water run off and soil erosion processes. The research was aimed to study sediment enrichment ratio and nutrient leached by run off and soil erosion on cacao plantations. Arachis pintoi with strips parallel contour and multiple strip cropping of upland rice or soybean (Glycine max) were planted to improve soil physical characterictic on cacao plantation as a main plant. The expriment were conducted with treatments as 10-15% and 40-45% slopes, 5-7 months and 25-27 months cacao ages (as main plants). As sub plots are T1 as a monoculture which to be cleaning under the plant canopy, T2 as a multiple strip cropping of upland rice or soybean, T3 as a combination of T2 and A. Pintoi strip. The results showed that  total N, P2O5, and K2O and organic-C contents in water run off and soil sediments indicated that T3 >T2 >T1 treatment, with the contents of each nutrient: T3 (total N 0.18%; 24.87 mg 100 g-1 P2O5: K2O 15.16 mg 100 g-1), T1 (total N 0.16%, 22.39 mg 100g-1 P2O5, K2O 11.50 mg 100g-1).  The total N, P2O5, K2O and organic-C soil contents < accumulation nutrient contents of total water run off and soil sediment transport. All of treathments have sediment enrichment ratios > 1.


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