A comparison between modified splash-cup and flume techniques in differentiating between soil loss and detachability as a result of rainfall detachment and deposition

Soil Research ◽  
1989 ◽  
Vol 27 (4) ◽  
pp. 759 ◽  
Author(s):  
APB Proffitt ◽  
CW Rose ◽  
CJ Lovell
Keyword(s):  
Surface Water ◽  
Water Depth ◽  
Soil Loss ◽  
Soil Surface ◽  
Deposition Process ◽  
Rainfall Rate ◽  
High Rate ◽  
Soil Types ◽  
True Rate ◽  
Significant Difference

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.

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 ◽  
...  
Keyword(s):  
Soil Loss ◽  
Soil Surface ◽  
Infiltration Rate ◽  
Solution Viscosity ◽  
Combined Application ◽  
Significant Difference ◽  
Short Rains ◽  
Two Phases ◽  
In The Beginning ◽  
Runoff And Soil Loss

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.

Impact of plot length on the effectiveness of different soil-surface covers in reducing runoff and soil loss by water

2008 ◽  
Vol 32 (6) ◽  
pp. 654-677 ◽  
Author(s):  
T. Smets ◽  
J. Poesen ◽  
E. Bochet
Keyword(s):  
Soil Loss ◽  
Soil Surface ◽  
Water Erosion ◽  
Rock Fragment ◽  
Organic Mulch ◽  
Rock Fragments ◽  
Significant Difference ◽  
Runoff And Soil Loss ◽  
The Impact ◽  
Field Plots

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.

Clinical evaluation of a new thyroglobulin immunoradiometric assay in the follow-up of differentiated thyroid carcinoma

2003 ◽  
Vol 42 (02) ◽  
pp. 71-77 ◽  
Author(s):  
I. Schreivogel ◽  
C. Angerstein ◽  
U. Siefker ◽  
K. Lehmann ◽  
G. Altenvoerde ◽  
...  
Keyword(s):  
Thyroid Carcinoma ◽  
Residual Disease ◽  
False Negative ◽  
Differentiated Thyroid Carcinoma ◽  
Threshold Concentration ◽  
High Rate ◽  
Functional Assay ◽  
Hypothyroid Patient ◽  
Assay Sensitivity ◽  
Significant Difference

SummaryAim: Formal and clinical comparison of a new 3rd-gene-ration-Tg-IRMA (3-G-IRMA; Dynotest®Tg-plus) with a conventional Tg-IRMA (3-G-IRMA; SELco®Tg-assay) for patients with differentiated thyroid carcinoma. In addition we evaluated, if thyroglobulin (Tg) levels above a specific threshold concentration indicate the need for further investigations for residual disease. Patients, methods: Tg concentration of 105 sera of 93 consecutive patients with a differentiated thyroid cancer was determined with both assays and compared at different cut-off values (Dynotest®Tg-plus: 0.2, 1, 2 ng/ml; SELco®Tg-assay: 0.5, 1, 2 ng/ml) with the clinical results in respect to the corresponding TSH concentration. Results: Tg concentration did not show any significant difference (SELco®Tg-assay 0.5 ng/ml, Dynotest® Tg-plus 0.2 ng/ml). The Tg-values of both assays correlated with 97%. However, correlation of recovery in both assays was small (40%). The sensitivities and specificities of both assays at different cut-offs and TSH values did not reveal significant differences. In patients with TSH concentration >30 µU/ml the functional assay sensitivity was superior to arbitrary cut-offs in the decision to start further evaluations. Conclusions: In our study neither formal nor clinical significant differences between two Tg-assays were found. In a hypothyroid patient (TSH >30 µU/ml, Tg concentration exceeding the functional assay sensitivity) further investigations for residual disease are warranted. Higher thresholds are of limited value, due to a inacceptable high rate of false negative results.

scholarly journals Cross Validation of Rainfall Characteristics Estimated from the TRMM PR, a Combined PR–TMI Algorithm, and a C-POL Ground Radar during the Passage of Tropical Cyclone and Nontropical Cyclone Events over Darwin, Australia

2018 ◽  
Vol 35 (12) ◽  
pp. 2339-2358 ◽  
Author(s):  
Anil Deo ◽  
S. Joseph Munchak ◽  
Kevin J. E. Walsh
Keyword(s):  
Tropical Cyclone ◽  
Tropical Rainfall Measuring Mission ◽  
Rainfall Rate ◽  
Rainfall Characteristics ◽  
Significant Difference ◽  
Median Volume ◽  
Precipitation Type ◽  
Correct Direction ◽  
Microwave Imager ◽  
Trmm Microwave Imager

AbstractThis study cross validates the radar reflectivity Z; the rainfall drop size distribution parameter (median volume diameter Do); and the rainfall rate R estimated from the Tropical Rainfall Measuring Mission (TRMM) satellite Precipitation Radar (PR), a combined PR and TRMM Microwave Imager (TMI) algorithm (COM), and a C-band dual-polarized ground radar (GR) for TRMM overpasses during the passage of tropical cyclone (TC) and non-TC events over Darwin, Australia. Two overpass events during the passage of TC Carlos and 11 non-TC overpass events are used in this study, and the GR is taken as the reference. It is shown that the correspondence is dependent on the precipitation type whereby events with more (less) stratiform rainfall usually have a positive (negative) bias in the reflectivity and the rainfall rate, whereas in the Do the bias is generally positive but small (large). The COM reflectivity estimates are similar to the PR, but it has a smaller bias in the Do for most of the greater stratiform events. This suggests that combining the TMI with the PR adjusts the Do toward the “correct” direction if the GR is taken as the reference. Moreover, the association between the TRMM estimates and the GR for the two TC events, which are highly stratiform in nature, is similar to that observed for the highly stratiform non-TC events (there is no significant difference), but it differs considerably from that observed for the majority of the highly convective non-TC events.

scholarly journals Effect of Digestate and Straw Combined Application on Maintaining Rice Production and Paddy Environment

2021 ◽  
Vol 18 (11) ◽  
pp. 5714
Author(s):  
Xue Hu ◽  
Hongyi Liu ◽  
Chengyu Xu ◽  
Xiaomin Huang ◽  
Min Jiang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Surface Water ◽  
Soil Organic Matter ◽  
Paddy Soil ◽  
Rice Yield ◽  
Soil Surface ◽  
Rice Production ◽  
Straw Decomposition ◽  
Rice Grains ◽  
Combined Application

Few studies have focused on the combined application of digestate and straw and its feasibility in rice production. Therefore, we conducted a two-year field experiment, including six treatments: without nutrients and straw (Control), digestate (D), digestate + fertilizer (DF), digestate + straw (DS), digestate + fertilizer + straw (DFS) and conventional fertilizer + straw (CS), to clarify the responses of rice growth and paddy soil nutrients to different straw and fertilizer combinations. Our results showed that digestate and straw combined application (i.e., treatment DFS) increased rice yield by 2.71 t ha−1 compared with the Control, and digestate combined with straw addition could distribute more nitrogen (N) to rice grains. Our results also showed that the straw decomposition rate at 0 cm depth under DS was 5% to 102% higher than that under CS. Activities of catalase, urease, sucrase and phosphatase at maturity under DS were all higher than that under both Control and CS. In addition, soil organic matter (SOM) and total nitrogen (TN) under DS and DFS were 20~26% and 11~12% higher than that under B and DF respectively, suggesting straw addition could benefit paddy soil quality. Moreover, coupling straw and digestate would contribute to decrease the N content in soil surface water. Overall, our results demonstrated that digestate and straw combined application could maintain rice production and have potential positive paddy environmental effects.

scholarly journals Effect of Mosses on physical and chemical properties of soil in temperate forests of Garhwal Himalayas

2021 ◽  
pp. 1-10
Author(s):  
Anshu Siwach ◽  
Siddhartha Kaushal ◽  
Ratul Baishya
Keyword(s):  
Physical Properties ◽  
Chemical Properties ◽  
Nutrient Status ◽  
High Rate ◽  
Physical And Chemical Properties ◽  
Garhwal Himalayas ◽  
Forest Sites ◽  
Significant Difference ◽  
Physical And Chemical ◽  
And Chemical Properties

Abstract Mosses are one of the most important and dominant plant communities, especially in the temperate biome, and play a significant role in ecosystem function and dynamics. They influence the water, energy and element cycle due to their unique ecology and physiology. The present study was undertaken in three different temperate forest sites in the Garhwal Himalayas, viz., Triyuginarayan (Kedarnath Wildlife Sanctuary (KWLS)), Chakrata, and Kanasar forest range. The study was focused on understanding the influence of mosses on soil physical properties and nutrient availability. Different physico-chemical properties were analysed under two different substrata, that is, with and without moss cover in two different seasons, viz., monsoon and winter. We observed mosses to influence and alter the physical properties and nutrient status of soil in both seasons. All soil physical and chemical properties, except magnesium, showed significant difference within the substrates, among all the sites and across the two seasons. Besides the soil characteristics underneath the moss vegetation, the study also highlights the diversity of mosses found in the area. Mosses appear to create high nutrient microsites via a high rate of organic matter accumulation and retain nutrients for longer periods thus, maintaining ecosystem stability.

scholarly journals A Strip-Till One-Pass System as a Component of Conservation Agriculture

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2015
Author(s):  
Iwona Jaskulska ◽  
Kestutis Romaneckas ◽  
Dariusz Jaskulski ◽  
Piotr Wojewódzki
Keyword(s):  
Co2 Emissions ◽  
Soil Loss ◽  
Soil Surface ◽  
Conservation Agriculture ◽  
Plant Residues ◽  
Pass System ◽  
Previous Crop ◽  
Bacteria And Fungi ◽  
The Stability ◽  
The Impact

Conservation agriculture has three main pillars, i.e., minimum tillage, permanent soil cover, and crop rotation. Covering the soil surface with plant residues and minimum mechanical soil disturbance can all result from introducing a strip-till one-pass (ST-OP) system. The aim of this study was to determine the impact of the ST-OP technology on the management of plant residues, soil properties, inputs, and emissions related to crop cultivation. We compared the effect of a ST-OP system against conventional tillage (CT) using a plough, and against reduced, non-ploughing tillage (RT). Four field experiments were conducted for evaluating the covering of soil with plant residues of the previous crop, soil loss on a slope exposed to surface soil runoff, soil structure and aggregate stability, occurrence of soil organisms and glomalin content, soil moisture and soil water reserve during plant sowing, labour and fuel inputs, and CO2 emissions. After sowing plants using ST-OP, 62.7–82.0% of plant residues remained on the soil surface, depending on the previous crop and row spacing. As compared with CT, the ST-OP system increased the stability of soil aggregates of 0.25–2.0 mm diameter by 12.7%, glomalin content by 0.08 g·kg−1, weight of earthworms five-fold, bacteria and fungi counts, and moisture content in the soil; meanwhile, it decreased soil loss by 2.57–6.36 t·ha−1 year−1, labour input by 114–152 min·ha−1, fuel consumption by 35.9–45.8 l·ha−1, and CO2 emissions by 98.7–125.9 kg·ha−1. Significant favourable changes, as compared with reduced tillage (RT), were also found with respect to the stability index of aggregates of 2.0–10.0 mm diameter, the number and weight of earthworms, as well as bacteria and fungi counts.

scholarly journals Possible tics diagnosed as stereotypies in patients with severe autism spectrum disorder: a video-based evaluation

2020 ◽  
Author(s):  
Cristiano Termine ◽  
Enzo Grossi ◽  
Valentina Anelli ◽  
Ledina Derhemi ◽  
Andrea E. Cavanna
Keyword(s):  
Autism Spectrum Disorder ◽  
Rating Scale ◽  
Young Patients ◽  
Autism Spectrum ◽  
Repetitive Behaviors ◽  
Spectrum Disorder ◽  
High Rate ◽  
Video Recordings ◽  
Significant Difference ◽  
Severe Autism

Abstract Background The association of stereotypies and tics is not rare in children with severe autism spectrum disorder (ASD). The differential diagnosis between stereotypies and tics in this patient population can be difficult; however, it could be clinically relevant because of treatment implications. Methods A total of 108 video recordings of repetitive behaviors in young patients with stereotypies in the context of ASD were reviewed by a movement disorders expert and a trainee, in order to assess the prevalence of possible co-morbid tics. The Modified Rush Videotape Rating Scale (MRVS) was used to rate tic frequency and severity. Results Out of 27 patients with stereotypies (24 males; mean age 14 years), 18 (67%) reported possible tics. The most frequently observed tics were eye blinking, shoulder shrugging, neck bending, staring, and throat clearing. The mean MRVS score was 5, indicating mild tic severity. The only significant difference between patients with tics and patients without tics was the total number of stereotypies, which was higher in the subgroup of patients without tics (p = 0.01). Conclusions Expert review of video-recordings of repetitive behaviors in young patients with ASD and stereotypies suggests the possibility of a relatively high rate of co-morbid tics. These findings need to be integrated with a comprehensive clinical assessment focusing on the diagnostic re-evaluation of heterogeneous motor manifestations.

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