Solute Transport Simulated With the Fractional Advective-Dispersive Equation

2005 ◽  
Author(s):  
F. San Jose Martinez ◽  
Y. A. Pachepsky ◽  
W. J. Rawls
Keyword(s):  
Solute Transport ◽  
Numerical Method ◽  
Field Experiments ◽  
Dispersion Coefficient ◽  
Scale Effects ◽  
Chloride Transport ◽  
Sandy Loam ◽  
Dispersive Equation ◽  
Flux Boundary Condition ◽  
Soils And Sediments

Solute transport in soils and sediments is commonly simulated with the parabolic advective-dispersive equation, or ADE. Although the solute dispersivity in this equation is regarded as a constant, it has been found to increase with the distance from the solute source. This can be explained assuming the movement of solute particles belongs to the family of Le´vy motions. A one-dimensional solute transport equation was derived for Le´vy motions using fractional derivatives to describe the dispersion. This fractional advective-dispersive equation, or FADE, has two parameters — the fractional dispersion coefficient and the order of fractional differentiation α, 0<α≤2. Scale effects are reflected by the value of α, and the fractional dispersion coefficient is independent of scale. The ADE is a special case of the FADE. Our objectives were (a) to test applicability of the FADE to field data on solute transport in soils, and (b) to develop a numerical method to solve FADE that would assure the solute mass conservation. Analytical solutions of the FADE and the ADE were successfully fitted to the data from field experiments on chloride transport in sandy loam and bromide transport in clay loam soils. A numerical method to solve the boundary problem for FADE was proposed and tested, that uses the mass-conserving flux boundary condition. The FADE is a promising model to address the scale-dependence in solute dispersion in soils and sediments.

Yields of Sub-humid Rainfed Crops in Relation to Soil Water Retention and Cropping Sequence

1978 ◽  
Vol 14 (3) ◽  
pp. 253-259 ◽  
Author(s):  
H. N. Verma ◽  
S. S. Prihar ◽  
Ranjodh Singh ◽  
Nathu Singh
Keyword(s):  
Water Retention ◽  
Field Experiments ◽  
Sandy Loam ◽  
Sandy Loam Soil ◽  
Yield Response ◽  
Soil Water Retention ◽  
Cropping Sequence ◽  
Loam Soil ◽  
Rabi Crops ◽  
Water Holding

SUMMARYField experiments were conducted for 4 years to study the yield of ‘kharif’ and ‘rabi’ crops grown in sequence on two soils differing in water-holding capacity. The results indicated that drought caused greater reduction in yield of rainy-season crops on loamy sand than on sandy loam soil. In low retentivity soil it was more profitable to raise a single crop of wheat on soil-stored water. In sandy loam soil of higher retentivity, two crops a year gave much higher yields than a single crop. Of the sequences tried, maize followed by wheat gave the highest and most stable yields. For ‘rabi’ crops, stored water showed a better yield response than an equivalent amount of rain during the growing season.

Effect of nitrogen, phosphorus and potassium application on yield of potato tubers (Solatium tuberosum L.)

1987 ◽  
Vol 108 (2) ◽  
pp. 321-329 ◽  
Author(s):  
U. C. Sharma ◽  
B. R. Arora
Keyword(s):  
Field Experiments ◽  
Sandy Loam ◽  
Farmyard Manure ◽  
Potato Tubers ◽  
Solatium Tuberosum ◽  
Loam Soil ◽  
Potassium Application ◽  
Phosphorus And Potassium ◽  
Grade Increase ◽  
Nitrogen Phosphorus

SummarySix field experiments, three each during 1982–3 and 1983–4, were conducted on a sandy loam soil to study the effect of varying levels of nitrogen, phosphorus and potassium, in the absence and presence of farmyard manure (FYM) (30 t/ha), on the number of tubers and yield of potato in three grades. Increase in nitrogen, phosphorus and potassium application, in the absence or presence of FYM, did not significantly affect the total number of tubers/m2 but did affect the number of tubers in different grades. An increase in nitrogen and potassium significantly decreased the number of tubers/m2 in small (< 25 g) and increased in medium (25–75 g) and large (> 75 g) grades at 45, 60, 75 and 90 days after planting. Increase in the application of phosphorus increased the number of tubers/m2 in the small grade and decreased it in the large grade but did not affect the number in the medium grade. Increase in nitrogen and potassium application decreased the tuber yield in the small grade and increased it in the medium and large grades. Applied phosphorus increased the yield in the small and medium grades and decreased it in the large grade. The increase in the yield of tubers with increase in nitrogen and potassium application was found to be caused by an increase in the number of tubers in the medium and large grades at the expense of the small grade; however, with applied phosphorus the increase in yield was due to increase in the weight of individual tubers within the small and medium grades. FYM application decreased the number of tubers in the small grade and increased it in the medium and large grades. The response of potato to nitrogen increased and to phosphorus and potassium decreased with the application of FYM.

Weed control in sugar beet with single and split applications of herbicides

1971 ◽  
Vol 77 (2) ◽  
pp. 247-252 ◽  
Author(s):  
Maurice Eddowes
Keyword(s):  
Sugar Beet ◽  
Weed Control ◽  
Field Experiments ◽  
Sandy Loam ◽  
Soil Conditions ◽  
The West ◽  
West Midlands ◽  
Free Environment ◽  
Annual Weeds ◽  
Residual Herbicide

SummaryRecent developments in chemical weed control in sugar beet have been reviewed. Two main approaches to the problem of providing reliable season-long control of annual weeds in sugar beet are, (a) the use of mixtures of herbicides applied pre-planting and incorporated into the soil during seed bed preparation, and (b) the use of split applications with a residual herbicide applied pre-emergence followed by a contact herbicide applied post-emergence.The second approach (b) was examined in a series of field experiments from 1967 to 1969, on light to medium sandy loam soils in the West Midlands. Comparisons were made between pre-emergence application of lenacil and pyrazon, pre-emergence application of lenacil and pyrazon followed by post-emergence application of phenmedipham, and post-emergence application of phenmedipham for weed control in sugar beet.Under dry soil conditions in April 1967, lenacil and pyrazon controlled only about 40% of the annual weeds, but in 1968 and 1969, when moist soil conditions predominated in April and May, lenacil and pyrazon controlled 80–95% of the annual weeds.Phenmedipham applied post-emergence gave about 90% control of annual broadleaved weeds initially, but it seemed unlikely that a single application of this herbicide would provide satisfactory weed control in sugar beet.In each of the 3 years 1967–9, a split application of a soil-acting residual herbicide (pro-emergence) followed by phenmedipham (post-emergence) gave outstanding weed control and enabled sugar beet to be established and grown until mid-June at least, in a near weed-free environment. It was concluded that this technique was the most effective for weed control in sugar beet on light to medium sandy loam soils in the West Midlands.

scholarly journals New protectants for potato protection

2020 ◽  
pp. 4-7
Author(s):  
Grigoriy Leonidovich Belov ◽  
Vladimir Nikolaevich Zeyruk ◽  
Vladimir Anatolyevich Barkov ◽  
Marina Konstantinovna Derevyagina ◽  
Svetlana Viktorovna Vasilieva
Keyword(s):  
Growth And Development ◽  
First Generation ◽  
Field Experiments ◽  
Negative Impact ◽  
Sandy Loam ◽  
Control Treatment ◽  
Potato Tubers ◽  
Complete Protection ◽  
Potato Beetle ◽  
Two Component

In field experiments in the conditions of sod-podzolic sandy loam soils of the Moscow region, protectants were tested. Before planting potatoes, tubers were treated with a new two-component insectofungicide AVG – 0190 (Idikum, SC, iprodion, 133 g/l + Imidacloprid, 100 g/l + diphenoconazole, 6.7 g/l)-1.0 – 1.5 l/t and a mixture of the fungicide Syncler, SC (75 g/l fludioxonyl) and the insecticide Tabu Super, SC (Imidacloprid, 400 g/l and fipronil, 100 g/l)-0.2-0.3 l/t. According to the results of three-year tests, it was found that the etching of potato tubers before planting does not have a negative impact on the germination and biometric indicators of growth and development of potatoes. Their use helped to reduce the development and spread of rhizoctoniosis and provided almost complete protection of potatoes from the first generation of the Colorado beetle – during the mass appearance of older larvae and during the beginning of the departure of larvae for pupation. Biological efficacy against Rhizoctonia amounted to 58.8-66,3%, the Colorado potato beetle – 93,7 95.5 per cent. The use of new potato tuber protectants allowed to increase the gross yield by 6.2-7.1 t / ha or 30.9-35.3% compared to the control. Treatment of seed tubers with protectants helped to obtain a crop free from rhizoctoniosis and increase the yield of standard healthy potatoes by 57.7

scholarly journals Evaluation of MACRO model by short-term water and solute transport simulation in Maury silt loam soil

2011 ◽  
Vol 51 (No. 3) ◽  
pp. 110-123 ◽  
Author(s):  
H. Merdun ◽  
V.L. Quisenberry
Keyword(s):  
Solute Transport ◽  
Water Flow ◽  
Chloride Transport ◽  
Effective Diffusion ◽  
Diffusion Path ◽  
Silt Loam ◽  
Short Term ◽  
Silt Loam Soil ◽  
Diffusion Path Length ◽  
Loam Soil

Modeling preferential flow has been a concern of many academic fields in the past 30 years all over the world and helps to prevent groundwater contamination. A dual-porosity model, MACRO, was evaluated for short-term (less than 2 days) simulation of water flow and non-reactive solute (chloride) transport through the profile of six plots in well-structured Maury silt loam soil. Water flow in micropores is calculated by the Richards&rsquo; equation while simple gravity flow is assumed in the macropores. Solute transport in the micropores is calculated by the convection-dispersion equation (CDE) while the dispersion and diffusion in the CDE is neglected for the solute transport in the macropores. The applied water and chloride reached the bottom of the profile during the 2 and 1-hour(s) application periods in studies 2 and 3, respectively. There is a strong indication of macropore flow in this soil. Based on the statistical criteria, the model accurately simulated water flow and solute transport with depth and time in all plots. The mean values of three statistical parameters (coefficient of residual mass, model efficiency, and correlation coefficient) for water and chloride transport were &ndash;0.0014, 0.791, 0.903 and 0.0333, 0.923, 0.956, respectively. Preliminary studies showed that the model could not simulate flow and transport well enough with the one-domain flow concept. In the two-domain flow, effective diffusion path-length, boundary hydraulic conductivity, and boundary soil water pressure were the three most important parameters that control flow and transport between the two domains. The effective diffusion path-length represented the structural development with depth in the Maury silt loam soil.

Weed Management in Minimum-Tillage Peanuts (Arachis hypogaea) as Influenced by Cultivar, Row Spacing, and Herbicides

Weed Science ◽  
1985 ◽  
Vol 33 (2) ◽  
pp. 233-237 ◽  
Author(s):  
Daniel L. Colvin ◽  
Glenn R. Wehtje ◽  
Mike Patterson ◽  
Robert H. Walker
Keyword(s):  
Arachis Hypogaea ◽  
Weed Management ◽  
Field Experiments ◽  
Sandy Loam ◽  
Management Systems ◽  
Row Spacing ◽  
Seeding Rate ◽  
Minimum Tillage ◽  
Naphthylphthalamic Acid ◽  
Peanut Production

Field experiments were conducted in 1982 and 1983 on a Dothan sandy loam (Plinthic Paleudult) at Headland, AL, to investigate minimum-tillage production of peanuts (Arachis hypogaeaL.). The experiments included two peanut varieties: a) ‘Pronto’ (an earlier maturing Spanish type), and b) ‘Florunner’ (a later maturing runner type). Two row-spacing patterns were used: a) conventional 91-cm rows, and b) a modified twin 18-cm row pattern. A constant seeding rate (140 kg/ha) was used regardless of row spacing. Six herbicide systems were evaluated within each combination of variety and row spacing. The Florunner variety outyielded the Pronto variety across both years and weed management systems. Modified twin 18-cm rows outyielded conventional 91-cm rows across years and peanut varieties. Two of the six weed management systems were successful: 1) paraquat (1,1’-dimethyl-4,4’-bipyridinium ion) + oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide) (preemergence), paraquat (ground cracking), naptalam (N-1-naphthylphthalamic acid) + dinoseb (2-sec-butyl-4,6-dinitrophenol) (postemergence); and 2) paraquat + pendimethalin [N-(1-ethylpropyl-3,4-dimethyl-2,6-dinitrobenzenamine] (preemergence), acetochlor [2-chloro-N(ethoxymethyl)-6’-ethyl-o-acetotoluidide] + dinoseb (ground cracking), and cyanazine {2-[[4-chloro-6-(ethylamino)-s-triazine-2-yl]amino]-2-methylpropionitrile} (early postdirected spray). Both systems provided the best overall control of Texas panicum (Panicum texanumBuckl. ♯ PANTE), Florida beggarweed [Desmodium tortuosum(Sw.) DC. ♯ DEDTO], and sicklepod (Cassia obtusifoliaL. ♯ CASOB) and were acceptable for use in minimum-tillage peanut production.

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