scholarly journals A comparative study on the role of electro-conductive plastics electrode in direct current electroosmosis

2020 ◽  
Vol 198 ◽  
pp. 01047
Author(s):  
Wei Bai ◽  
Tao Jian ◽  
Rongbing Lin ◽  
Xiaoqian Luo ◽  
Lingwei Kong

The electrode material is one of the critical factors affecting the electroosmosis efficiency. The electroosmotic test was conducted to compare the current, volume moisture content, and energy consumption of Electro-Conductive Plastics Electrode (ECPE) and metal electrode in the dispose of sludge. The results show that: the current decreases of ECPE is smaller than the metal electrode before 20h, and the difference value of moisture content between cathode and anode of ECPE is smaller when electroosmosis is stable. The energy consumption of ECPE is lower in the range of soil moisture content of 35% - 60%. The ECPE has a particular advantage in energy consumption and uniformity of soil moisture content, but has a disadvantage in residual moisture content as compared with the metal electrode.

1983 ◽  
Vol 29 (8) ◽  
pp. 1063-1069 ◽  
Author(s):  
S. P. Wani ◽  
P. J. Dart ◽  
M. N. Upadhyaya

Factors affecting nitrogenase activity associated with sorghum and millet roots have been studied. Plants grown in iron cores in the field and then assayed had significantly higher activity than plants cored at the time of assay. Mechanical disturbance during transportation of the cores reduced the activity significantly. Any delay between cutting off the plant top and injecting C2H2 gas led to a reduction in the level of nitrogenase activity determined. Diurnal variation in nitrogenase activity was noted but was not correlated with soil temperature. Most activity occurred at the end of the photoperiod. Seasonal variation in nitrogenase activity of plants was observed and was correlated with the ontogenetic development of the host plant, being most at flowering. A low but significant correlation existed between soil moisture content and nitrogenase activity associated with the plant.


2020 ◽  
Vol 15 (2) ◽  
pp. 68-74
Author(s):  
Paardensha Ivy Chinir ◽  
Manoj Dutta ◽  
Rizongba Kichu ◽  
Sewak Ram

A field experiment was conducted to evaluate the effect of forest litter and its time of incorporation on soil physical properties. The study showed that plots with forest litter incorporated at 45 DBS (Days Before Sowing) had significantly higher soil moisture content as compared to those incorporated at 30 DBS after 30 and 60 DAS. However, the difference in the time of incorporation had no significant effect on soil moisture content at 90 DAS. At 30 DAS, application of forest litter @ 6 t ha-1 and 9 t ha-1 significantly increased the soil moisture content at a rate of 4.11 and 11.42 per cent, respectively over control. At 60 DAS, application of forest litter @ 3 t ha-1, 6 t ha-1 and 9 t ha-1 significantly increased the soil moisture content at the rate of 15.05, 17.26 and 25.65 per cent, respectively over control. At 90 DAS, a trend was noticed which showed that soil moisture content significantly increased at a progressive rate with each increase in the dose of forest litter application. At 90 DAS, the addition of forest litter @ 3 t ha-1, 6 t ha-1and 9 t ha-1 increased the soil moisture content @ 10.16, 17.84 and 22.20 per cent, respectively over control. The plots with forest litter incorporated at 45 DBS had significantly higher hydraulic conductivity, per cent aggregates and mean weight diameter as compared to those incorporated at 30 DBS. However, the difference in the time of incorporation i.e., at 30 and 45 DBS had no significant effect on bulk density, particle density and water holding capacity. Incorporation of forest litter @ 3 t ha-1, 6 t ha-1 and 9 t ha-1 significantly decreased the bulk density at the rate of 3.67, 8.65 and 14.14 per cent; while particle density increased at the rate of 2.59, 3.42 and 6.61 per cent, respectively when compared to control. The addition of forest litter @ 3 t ha-1, 6 t ha-1 and 9 t ha-1 resulted in a significant increase in water holding capacity and hydraulic conductivity at a rate of 3.72, 4.65 and 6.77 per cent and 24.13, 32.30 and 41.73 per cent, respectively over control. Further, the application of forest litter @ 3t ha-1, 6 t ha-1 and 9 t ha-1 significantly increased the per cent aggregate and mean weight diameter of the soil @ 1.77, 3.49 and 6.58 per cent 17.31, 26.28 and 41.35 per cent, respectively over control. The study revealed that incorporating 9 t ha-1 of forest litter at 45 DBS had the most beneficial effect on soil physical properties.


2007 ◽  
Vol 8 (2) ◽  
pp. 207-220 ◽  
Author(s):  
Joseph G. Alfieri ◽  
Peter D. Blanken ◽  
David N. Yates ◽  
Konrad Steffen

Abstract Nearly one-half of the earth’s terrestrial surface is susceptible to drought, which can have significant social, economic, and environmental impacts. Therefore, it is important to develop better descriptions and models of the processes linking the land surface and atmosphere during drought. Using data collected during the International H2O Project, the study presented here investigates the effects of variations in the environmental factors driving the latent heat flux (λE) during drought conditions at a rangeland site located in the panhandle of Oklahoma. Specifically, this study focuses on the relationships of λE with vapor pressure deficit, wind speed, net radiation, soil moisture content, and greenness fraction. While each of these environmental factors has an influence, soil moisture content is the key control on λE. The role of soil moisture in regulating λE is explained in terms of the surface resistance to water vapor transfer. The results show that λE transitioned between being water or energy limited during the course of the drought. The implications of this on the ability to understand and model drought conditions and transitions into or out of droughts are discussed.


2021 ◽  
Author(s):  
Thuanne Braúlio Hennig ◽  
Paulo Roger Lopes Alves ◽  
Felipe Ogliari Bandeira ◽  
Liziara da Costa Cabrera ◽  
Jonas Simon Dugatto ◽  
...  

Abstract The aim of this study was to assess the effect of temperature on the toxicity of fipronil toward earthworms (Eisenia andrei) in two Brazilian soils (Entisol and Oxisol) with contrasting textures. In the case of Entisol, the influence of the soil moisture content on the toxicity was also investigated. Earthworms were exposed for 56 days to soils spiked with increasing concentrations of fipronil under scenarios with different combinations of temperature (20, 25 and 27 ºC) and soil moisture content (60 and 30% of water holding capacity (WHC) for Entisol and 60% WHC for Oxisol). The number of juveniles produced was taken as the endpoint and a risk assessment was performed based on the hazard quotient (HQ). In Entisol, at 60% WHC the fipronil toxicity decreased at 27 ºC compared with the other temperatures tested (EC50 = 52.58, 48.48 and 110 mg kg-1 for 20, 25 and 27 ºC, respectively). In the case of Oxisol at 60% WHC, the fipronil toxicity increased at 27 ºC compared with other temperatures (EC50 = 277.57, 312.87 and 39.89 mg kg-1 at 20, 25 and 27 ºC, respectively). An increase in fipronil toxicity was also observed with a decrease in soil moisture content in Entisol at 27 ºC (EC50 = 27.95 and 110 mg kg-1 for 30% and 60% WHC, respectively). The risk of fipronil was only significant at 27 ºC in Entisol and Oxisol with water contents of 30% and 60% WHC, respectively, revealing that higher temperatures can increase the risk of fipronil toxicity toward earthworms. The results reported herein show that soil properties associated with climatic shifts could enhance the ecotoxicological effects and risk of fipronil for earthworms, depending on the type of soil.


2021 ◽  
Vol 13 (SI) ◽  
pp. 73-79
Author(s):  
G. Manikandan ◽  
B. Shridar ◽  
D. Manohar Jesudas

In the present study, the draft requirement of five tyne duck foot plough was studied on clay soil for different soil moisture content, depth of operation and forward speed of tractor using a specially designed three-point hitch dynamometer.  The designed dynamometer was matched with the tractors having category II or III hitch systems. The data acquisition system adopted for the dynamometer had NI WSN-3214 Strain Nodes, NI 9792 WSN real-time Gateway and NI LAB View 2013 software. A data logger program was developed for the three-point hitch dynamometer. The investigation was carried out at that three levels soil moisture content (10-13%, 14-16% and 17-20%), at three different depth of operation (15, 20 and 25 cm) and three levels of the forward speed of tractor (3, 5 and 7 km h-1). The designed dynamometer performed well in all the levels of the experiment. The results showed that draft force required for five tyne duck foot plough was increased (408 kg) with an increase in soil moisture content (17-20%), whereas it was increased (408 kg) with an increase in depth of operation (25 cm) and forward speed of tractor (7 km h-1). The suitable sweep, the forward speed of operation, depth of operation and soil moisture content that influenced the draft force and energy consumption for tillage operation of duck foot type plough were identified and developed duck foot plough was better coverage with better soil operation.               


Author(s):  
Gabor Milics ◽  
Viliam Nagy ◽  
Tomas Orfanus ◽  
Lubomir Lichner ◽  
Peter Surda

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2251
Author(s):  
Mingcheng Du ◽  
Jianyun Zhang ◽  
Amgad Elmahdi ◽  
Zhenlong Wang ◽  
Qinli Yang ◽  
...  

Soil moisture content (SMC) is an important factor affecting crop growth. Based on the field SMC data measured at the Wudaogou experimental station from 1989 to 2019, two typical crop types, wheat and maize, were selected. By combining the groundwater depth, crop growth period, and meteorological factors in the same period, and using classical statistics and redundant analysis (RDA) methods, the characteristics and influencing factors of SMC changes in vertical profiles of different crops were compared and analyzed. The results showed that the SMC and average daily water storage of wheat were greater than that of maize. The crop growth mainly consumed 0–60 cm SMC. The SMC in this area was moderately variable; the SMC of 0–30 cm belongs to the active layer, and the SMC of 30–100 cm belongs to the sub-active layer. The RDA method identified ground temperature, groundwater depth, relative humidity, and the wheat growing period as the main factors affecting soil moisture variation in wheat fields; groundwater depth, relative humidity, and water vapor pressure differences were the main factors affecting soil moisture variation in maize fields. The results can provide a basis for accurate prediction of soil water dynamics and thus provide a reference for irrigation decision-makers.


2003 ◽  
pp. 15-20
Author(s):  
Csaba Varga

The purpose of our experiments is to discover the effect of different soil cover matter (agroszövet and black polyethylene) on actual (under field circumstances) and potential (under laboratory circumstances) cellulose decomposition activity. In our field research, the Unger-test was used, and in laboratory research, the Petkov-Markova method was applied. In the first year of the experiment (2000) actual cellulose decomposition activity was significantly higher in covered than in the uncovered soil both in spring and autumn. The difference between the two treatments was significant only in spring. In the spring of 2001 black polyethylene showed significantly the lowest, activity, while in autumn the agroszövet (a porous black polyethylene) showed significantly the highest activity. In the autumn of 2001 the soil covered by black polyethylene gave non-significant,and the soil covered by agroszövet gave a significant higher activity value than the control. Averaging the two experimental years (2000-2001), the actual cellulose decomposition activity was significantly higher in covered soils both in spring (with 30-39%) and in autumn (with 34-69%). Moreover, in autumn a significantly higher value was detected under agroszövet than in any other treatment. The difference between the effect of treatments was not significant. In 2000, the potential cellulose decomposition activity was the highest in soil covered by agroszövet in spring, but in autumn higher activity value was detected in every covered soil than in the control. In the spring of 2001, every covered soil showed a lower, but in autumn a higher, potential cellulose decomposition rate than the control. The activity decreased significantly 27 (agroszövet) and 45 (black polyethylene) percent in spring, and increased no- significantly 8 (agroszövet) and 4 (black polyethylene) percent in autumn. During the two experimental years, we observed on average lower potential cellulose decomposition activity (15-60%) in spring and a higher one (14-43%) in autumn. Neither was significant. The dynamic of potential cellulose decomposition activity averaging 2000 and 2001 showed a slight, the actual cellulose decomposition activity an explicit non-significant upward tendency. There was a strong (r=0,189) correlation obtained between the actual and potential cellulose decomposition activity of soil, and a medium-strong (r=0,673) relationship between the soil moisture content and actual cellulose decomposition activity.


Sign in / Sign up

Export Citation Format

Share Document