THE PELTIER EFFECT AND ITS USE FOR DETERMINING RELATIVE ACTIVITY OF SOIL WATER

1959 ◽  
Vol 39 (1) ◽  
pp. 76-85 ◽  
Author(s):  
H. C. Korven ◽  
S. A. Taylor
Keyword(s):  
Relative Activity ◽  
Dew Point ◽  
Peltier Effect ◽  
Silty Clay ◽  
Constant Temperature Bath ◽  
Clay Loam Soil ◽  
Silty Clay Loam ◽  
Laboratory Procedure ◽  
Loam Soil ◽  
Membrane Methods

An apparatus is described which involves the use of a small thermocouple, cooled to the dew point by the Peltier effect, as a means of determining the relative activity of water in soils.Thermocouples were calibrated over a series of sulphuric acid solutions immersed in a constant temperature bath controlled to within 0.003 °C. The temperature of the bath for all readings was 25 °C. Readings were taken over Benjamin silty clay loam soil samples that had been brought to desired soil moisture relative activities by the pressure plate and pressure membrane methods. The following conclusions were reached:1. The thermocouple technique shows promise as a laboratory procedure for determining the relative activity of water in soils.2. The majority of the results showed a gradual lowering of the readings with time. This was overcome at the expense of speed by treating the thermocouple with a plastic spray paint.3. More study and testing are required before the technique can be considered a completely satisfactory procedure.

Effect The Treatments of Biofertilizer and Mineral Fertilizer on Content of N P K of Soil Cultivated With Crop Corn (Zea Mays L).

2019 ◽  
Vol 9 (2) ◽  
pp. 247-256
Author(s):  
Mohammed Aajmi Salman ◽  
Jawad A. Kamal Al-Shibani
Keyword(s):  
Zea Mays ◽  
Zea Mays L ◽  
Mineral Fertilizer ◽  
Silty Clay ◽  
Clay Loam ◽  
Potassium Fertilizer ◽  
Clay Loam Soil ◽  
Silty Clay Loam ◽  
Fall Season ◽  
Loam Soil

Beneficial microorganisms play a key role in the availability of ions minerals in the soil and use Randomized Complete Block Desing ( R.C.B.D ). The objective of this paper to the study effect of the of biofertilizer and miniral treatments on availability of NPK for crop corn zea mays L.Two types of biofertilizer are Bacterial Bacillus subtilis and Fungal Trichoderma harianum. Three levels of potassium fertilizer are (2.9533, 0.4000 and 2.9533). A field experiment in fall season of 2018 Has been conducted in silty clay loam soil. The experimental Results indicated that Bacillus and Trichoderma inoculation separately or together Have made a significant effect to increase in the availability of N P K in the soil compare to other treatments. The grain yield is where (2.9533, 0.4000 and 2.9533) of bacterial and fungal bio-fertilizer and potassium fertilizers respectively as compared to the control.

Aggregate slaking during rapid wetting: Hydrophobicity and pore occlusion

2008 ◽  
Vol 88 (1) ◽  
pp. 85-97 ◽  
Author(s):  
Hafida Zaher ◽  
Jean Caron
Keyword(s):  
Organic Matter ◽  
Management Strategies ◽  
Water Entry ◽  
Paper Sludge ◽  
Silty Clay ◽  
Clay Loam ◽  
Wetting Front ◽  
Clay Loam Soil ◽  
Silty Clay Loam ◽  
Loam Soil

The slaking process after rapid wetting is a key factor controlling soil structural stability in dry soil, and an understanding of the relative importance of the different mechanisms involved in slaking may help in the design of management strategies aimed at maintaining a stable surface soil structure. Slaking has been linked to, among other factors, rapid pressure build-up in aggregate, and previous work has emphasized the role of organic matter to hamper that pressure build-up, possibly due to hydrophobicity, reducing rapid water entry within aggregates and hence the build-up. This study emphasizes this latter aspect linked to slaking. The evolution of the intra-aggregate pressure, the matter lost by slaking and the expelled air after rapid wetting of two soils of different textures (clay loam soil and silty-clay loam soil) amended with different types of paper sludge were studied. Hydrophobicity effects were also studied using a tensio-active solution. The results of these experiments showed that when aggregates were submitted to sudden wetting, those treated with paper sludge had an improved resistance to the destructive action of rapid wetting. The lower pressures measured in the aggregates from the amended soils and having less slaking resulted most likely from slow water entry and reduced swelling. Detailed investigation on the link between hydrophobicity and water entry revealed that the true hydrophobic effect (modification of contact angle) was non-existent for the silty-clay loam and minor for the clay loam. This study, rather, suggests that changes in the water potential at the wetting front following organic matter addition and aggregate immersion most likely depend on pore occlusion and on changes in pore surface roughness. Key words: Aggregate stability, organic matter, slaking, pressure, swelling, wettability

scholarly journals Annual White Grub Control on a Golf Course Fairway Using Subsurface and Conventional Application Methods, 1994

1995 ◽  
Vol 20 (1) ◽  
pp. 287-287
Author(s):  
F. P. Baxendale ◽  
A. P. Weinhold ◽  
K. Von Bargen ◽  
R. D. Grisso
Keyword(s):  
Kentucky Bluegrass ◽  
Golf Course ◽  
Silty Clay ◽  
Soil Cores ◽  
White Grub ◽  
Clay Loam Soil ◽  
Silty Clay Loam ◽  
Water Ph ◽  
Plot Area ◽  
Loam Soil

Abstract This study was conducted in Lincoln, NE on a golf course fairway. The turf (100% Kentucky bluegrass) was maintained at a mowing height of 5/s inches. Thatch accumulation (finger compressed) in the plot area was 0.5 to 0.75 inches. Field conditions at the study site were: soil type, silty clay loam; soil organic matter, 3-5%; soil pH, 6.7; water pH, 7.0. Soil moisture was maintained at approximately 17% by weight, throughout the study. Plots were 40 inches × 15 ft and the experimental design was a RCB with 3 replications. Insecticide treatments were applied on 23 Aug 1994 using either a Cushman prototype subsurface applicator designed to place insecticide granular treatments at the soil-thatch interface (avg depth 0.75 inches), or a Gandy 24H12 drop spreader. Following applications, plots were irrigated with 0.5 inches of water. Posttreatment precipitation totaled 0.42 inches. Treatments were evaluated 21 DAT on 13 Sep by removing from each plot three, 8-inch diam turf-soil cores (1.05 ft2 total area) to a depth of 3 inches and counting the number of surviving grubs. Pretreatment counts indicated 10-40 SMC/ft2 with 80-90% in the third instar stage in the test area.

Common Cocklebur Competition in Soybeans

Weed Science ◽  
1974 ◽  
Vol 22 (6) ◽  
pp. 600-603 ◽  
Author(s):  
W. L. Barrentine
Keyword(s):  
Soybean Seed ◽  
Soybean Plant ◽  
Silty Clay ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Silty Clay Loam ◽  
Competitive Effects ◽  
Loam Soil ◽  
Seed Yields ◽  
Over The Top

The competitive effects of common cocklebur (Xanthium pensylvanicumWallr.) on soybeans[Glycine max(L.) Merr. ‘Lee 68′] were studied on Dundee silty clay loam soil from 1970 to 1972. Full-season competition by common cocklebur at 3,300, 6,600, 13,000, and 26,000 plants/ha reduced the 2-year average soybean seed yields 10, 28, 43, and 52%, respectively. Competition from common cocklebur at 100,000 plants/ha for 4, 6, 8, 10, 12, and 16 weeks after soybean emergence reduced soybean seed yields 10, 36, 40, 60, 80, and 80%, respectively. A reduction in soybean stand occurred after 12 or more weeks competition, and an increase in soybean plant height occurred after 10 or more weeks competition. When common cockleburs were removed during the first 4 weeks after soybean emergence, no further removal was required to obtain maximum soybean yield. Bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-(4)3H-one 2,2-dioxide] at 1.1 to 2.2 kg/ha applied over-the-top of common cockleburs and soybeans was as effective as hand removal in terminating competition provided common cocklebur plants were not flowering.

scholarly journals Effect of biochar amendment on nitrate retention in a silty clay loam soil

2016 ◽  
Vol 11 ◽  
Author(s):  
Angela Libutti ◽  
Massimo Mucci ◽  
Matteo Francavilla ◽  
Massimo Monteleone
Keyword(s):  
Agricultural Soils ◽  
Water Solution ◽  
Application Rate ◽  
Silty Clay ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Silty Clay Loam ◽  
Nitrate Retention ◽  
Addition Rate ◽  
Loam Soil

Biochar incorporation into agricultural soils has been proposed as a strategy to decrease nutrient leaching. The present study was designed to assess the effect of biochar on nitrate retention in a silty clay loam soil. Biochar obtained from the pyrogasification of fir wood chips was applied to soil and tested in a range of laboratory sorption experiments. Four soil treatments were considered: soil only (control), soil with 2, 4 and 8% of biochar by mass. The Freundlich sorption isotherm model was used to fit the adsorbed amount of nitrate in the soil-biochar mixtures. The model performed very well in interpreting the experimental data according to a general linear regression (ANCOVA) statistical approach. Nitrate retention in the soil-biochar mixtures was always higher than control, regardless the NO<sub>3</sub><sup>-</sup> concentration in the range of 0-400 mg l<sup>-1</sup>. Different sorption capacities and intensities were detected depending on the biochar application rate. The highest adsorption capacity was observed in the soils added with 2 and 4% of biochar, respectively. From the results obtained is possible to infer that nitrate retention is higher at lower biochar addition rate to soil (2 and 4%) and at lower nitrate concentration in the soil water solution. These preliminary laboratory results suggest that biochar addition to a typical Mediterranean agricultural soil could be an effective management option to mitigate nitrate leaching.

scholarly journals Influence of Post-Application Irrigation on Control of Annual White Grubs on a Golf Course Fair-Way, 1996

1997 ◽  
Vol 22 (1) ◽  
pp. 355-355
Author(s):  
F.P. Baxendale ◽  
A.P. Weinhold ◽  
K.A. Weinhold
Keyword(s):  
Kentucky Bluegrass ◽  
Golf Course ◽  
Silty Clay ◽  
Clay Loam Soil ◽  
Silty Clay Loam ◽  
White Grubs ◽  
Time Of Application ◽  
Water Ph ◽  
Plot Area ◽  
Loam Soil

Abstract This study was conducted in Lincoln, NE on a golf course fairway. The turf (20% Kentucky bluegrass and 80% perennial rye) was maintained at a mowing height of 11/16 inch. Thatch accumulation (finger compressed) in the plot area was 0.375 to 0.50 inch. Field conditions at the study site were: soil type, silty clay loam; soil organic matter, 4%; soil pH, 6.2; water pH, 7.0. Environmental conditions at the time of application were as follows: soil moisture 12% by wt.; air temperature 72°F; soil temperature 72°F; relative humidity 43%; wind direction and velocity 6° at 7 mph. Plots were 6 X 10 ft and the experimental design was a RCB with 3 replications. Insecticides were applied once on 9 Jul and twice on 11 Jul. Liquids were applied using a CO2 sprayer with a TeeJet® 8002 nozzle at 30 psi and delivering 2 gal/1000 square feet. A pre-calibrated Gandy 24H12 drop spreader was used to apply granular insecticides. Post-application irrigations were applied as follows: 09 Jul application, none; 11 Jul, first application, 0.35 inch; 11 Jul, second application with syringe, approximately 0.125 inch. Normal irrigation was resumed after 48 h. Precipitation between application and evaluation totaled 11.3 inches. Treatments were evaluated 57 DAT on 4 SEP by removing from each plot three, 8-inch diam turf-soil cores (1.05 ft2 total area) to a depth of 3 inches and counting the number of surviving grubs. Insecticides were applied prior to the onset of masked chafer oviposition.

Aggregation of a Silty Clay Loam Soil by Mycorrhizal Onion Roots

1986 ◽  
Vol 50 (6) ◽  
pp. 1494-1499 ◽  
Author(s):  
R. S. Thomas ◽  
S. Dakessian ◽  
R. N. Ames ◽  
M. S. Brown ◽  
G. J. Bethlenfalvay
Keyword(s):  
Silty Clay ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Silty Clay Loam ◽  
Loam Soil

Effect of soil, machine, and working state parameters on the required draft force of a subsoiler using a theoretical draft-calculating model

Soil Research ◽  
2017 ◽  
Vol 55 (4) ◽  
pp. 389 ◽  
Author(s):  
Iman Ahmadi
Keyword(s):  
Adverse Effect ◽  
Soil Degradation ◽  
Silty Clay ◽  
Clay Loam ◽  
Reasonable Accuracy ◽  
Clay Loam Soil ◽  
Silty Clay Loam ◽  
Draft Force ◽  
Loam Soil ◽  
American Society

One of the most important soil degradation agents in agriculture is compaction. To rehabilitate compacted fields, farmers usually use subsoilers to break compacted layers. Moreover, the required draft force of a subsoiler dictates the amount of energy needed to operate it. Therefore, measurement, calculation or prediction of the draft force of this machine is vital for designing an efficient subsoiler. In the present study, an analytical model was developed to calculate the subsoiler draft force. To verify the model developed herein, model outputs regarding the draft force of a subsoiler were compared with corresponding results from the American Society of Agricultural Engineers (ASAE) standard, as well as the results of literature studies. Moreover, the output of the model was compared with the measured draft force of subsoiling a silty clay loam soil. Furthermore, the results obtained regarding the quantitative effect of model inputs on the draft force of a subsoiler were checked from the viewpoint of compatibility with the expected trends or observed results in other studies. The data obtained from the developed model were compatible with those of the ASAE standard. Moreover, the draft force of a single-shank subsoiler was almost 10 kN, which is approximately 14% higher than the result obtained by the model (8.73 kN). Therefore, the model developed herein can be used to calculate the subsoiler draft force with reasonable accuracy. Of the machine parameters, subsoiler wingspan had an adverse effect on the specific draft of this machine. Moreover, for the range of working depths between 30 and 50cm, the minimum values of specific draft took place.

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