Tillage, physical properties of Coto clay and the yields of plantain and sweet potato

1969 ◽  
Vol 71 (3) ◽  
pp. 307-311
Author(s):  
Winston Martínez-Rivera ◽  
Héctor M. Lugo-Mercado ◽  
José Badillo-Feliciano ◽  
James S. Beaver
Keyword(s):  
Physical Properties ◽  
Sweet Potato ◽  
Physical Property ◽  
The Other ◽  
Soil Resistance ◽  
Minimum Tillage ◽  
No Till ◽  
Potato Yields ◽  
Tillage Method ◽  
Tillage Methods

The only physical property of Coto clay found to be affected by the tillage method was soil resistance, which was greater for the no-till than for the other tillage treatments. The upper 10 cm were the most affected. Tillage methods did not affect plantain yields; thus, minimum tillage can be recommended for this crop.  On the other hand, significantly higher sweet potato yields were obtained when the soil was plowed and disced twice.

scholarly journals The effect of integrated tillage of light soil on potato yields

2017 ◽  
Vol 54 (2) ◽  
pp. 187-201
Author(s):  
Ryszard Walkowiak ◽  
Stanisław Podsiadłowski ◽  
Michał Czajka
Keyword(s):  
Negative Impact ◽  
Life Sciences ◽  
Sandy Soils ◽  
Potato Yield ◽  
Tuber Growth ◽  
Light Soil ◽  
Potato Yields ◽  
Tillage Method ◽  
Tillage Methods

Summary Excessive compaction of soil has an adverse effect on its aggregate structure, and as a result also on the yields of various crops. To prevent this negative impact, diverse methods of limited tillage are applied. However, these methods are not effective when cultivating sandy soils of very low natural porosity. An original integrated tillage method for such soils has been developed at the Poznań University of Life Sciences. This paper presents a comparison of yields and quality of three popular potato cultivars following the application of conventional and integrated tillage methods. The experiment shows that integrated tillage contributes to an increase in potato yield by providing better conditions for tuber growth.

EFFECT OF LONG-TERM MINIMUM TILLAGE PRACTICES ON SOME PHYSICAL PROPERTIES OF A CHERNOZEMIC CLAY LOAM

1989 ◽  
Vol 69 (3) ◽  
pp. 443-449 ◽  
Author(s):  
C. CHANG ◽  
C. W. LINDWALL
Keyword(s):  
Hydraulic Conductivity ◽  
Physical Properties ◽  
Bulk Density ◽  
Infiltration Rate ◽  
Conventional Tillage ◽  
Soil Physical Properties ◽  
Clay Loam ◽  
Minimum Tillage ◽  
No Till

This study was conducted to compare the long-term (20 yr) effects of conventional tillage, minimum tillage and no-till on various soil-water related properties within the tilled layer (0–30 and 30–60 mm) and immediately below the tilled layer (90–120 mm) under a spring cereal-summerfallow rotation cropping system. Parameters measured included saturated hydraulic conductivity, saturation percentage, plant-available water-holding capacity, large pore porosity, bulk density, and infiltration rate of the soil. Tillage treatment effects on these soil properties in each of the four sampling periods were not significantly different. The confidence interval test showed some temporal changes in these soil physical properties, of which hydraulic conductivity was the most affected. In the summerfallow field, regardless of the previous cereal crops, the steady infiltration rate was significantly lower in the soil under conventional tillage than with that under no-till. The results indicate that the surface soil structure was most stable under no-till. In the fresh stubble field, the type of cereal crop had an effect on the infiltration rate of the soil. The mean infiltration rate was higher in the summerfallow field than in the fresh stubble field and also was higher in the fresh barley stubble than in the fresh wheat stubble. Except for infiltration rates, there is no significant advantage of one tillage method over the other with respect to the soil physical properties measured in this Brown Chernozemic clay loam soil. Key words: No-till, minimum tillage, hydraulic conductivity, bulk density, infiltration

Abrasion-Reinforcement: Methods of Evaluation

1962 ◽  
Vol 35 (5) ◽  
pp. 1276-1307 ◽  
Author(s):  
A. E. Juve ◽  
A. G. Veith
Keyword(s):  
Physical Properties ◽  
Small Diameter ◽  
Physical Property ◽  
The Other ◽  
Sufficient Evidence ◽  
Particle Removal ◽  
Subsequent Work ◽  
Actual Measurement ◽  
Tear Strength ◽  
Empirical Prediction

Abstract There are basically three methods by which abrasion-reinforcement may be studied (1) conventional laboratory physical property measurement and empirical prediction of reinforcement (2) laboratory abrasion tests for an actual measurement of reinforcement under accelerated conditions and (3) a study of the mechanism of abrasion with a theoretical deduction of the important physical properties relevant to the phenomenon of abrasion. None of the above are without serious difficulties in their execution at the present state of rubber technology. Known reinforcing materials such as fine particle size carbon blacks increase modulus, tensile strength, tear strength and hardness while decreasing breaking elongation. Measurements of these properties can be very helpful in the selection of reinforcing materials but such measurements used alone are not entirely reliable. They must be supplemented however with actual laboratory abrasion measurements. The choice of a laboratory abrasion test that is strongly correlated with service performance is mandatory. Such a laboratory test must be capable of reliably evaluating all rubbers and all types of reinforcing materials without serious ambiguity. Sources of such ambiguity are abrasive contamination, unrealistic severity effects and an altered dependency of abrasion vs conventional physical properties when compared to tire test results. A laboratory abrasion tester, the Pico abrasion machine, is shown to do a much better job at reliably predicting service preformance for a variety of rubber compositions than the other presently used abrasion machines. The earliest serious work in attempting to deduce the mechanism of wear was by Wiegand who decided that discrete particles were removed. Subsequent work by Sohallamach and others using radiotracers agree in principle with the basic concept of Wiegand. Schallamach has demonstrated that during severe wear a wear pattern or set of ridges at right angles to the direction of abrasion develops. From a study of the motion of this system of ridges he has deduced that rubber is removed by a tearing action or some other rupture process from the under side of the ridges. This is accomplished through a bending back of the forward pointing ridges during contact with the abrading surface. Stiehler on the other hand holds that wear occurs on a “molecular” scale due to localized degradation of the surface layer of the rubber with subsequent volatilization of the degraded fragments. The arguments for discrete particle removal seem to be supported by sufficient evidence to discount the “molecular” removal theory. It must be acknowledged however that under mild abrasion conditions the particles removed are microscopic in size. Zapp has shown in a qualitative treatment that, everything else being equal, the lower the dynamic modulus of a rubber formulation the greater the resistance to abrasion. Schallamach has advanced farther than anyone in explaining what factors or mechanical properties govern the resistance to abrasion in his study of the wear of slipping wheels. The wheels which he refers to are solid rubber wheels of small diameter used to carry a load in much the same manner as pneumatic tires. From the intensive study of solid wheels he has shown the following. At constant angle of slip the abrasion of a slipping wheel is proportional to the resilience of the rubber and is also proportional to the stiffness of the wheel. The term stiffness may be thought of as synonymous with dynamic hardness. When, however, abrasion is carried out at constant side force then the abrasion is again directly proportional to the resilience but is inversely proportional to the stiffness. if the composite qualitative picture as outlined above is correct the tearing strength or tearing energy should play an important role. A brief review of the only really quantitative and theoretical work of the tearing of rubber is given. This work has been carried out by Greensmith, Thomas and Mullins at the NRPRA. It can be concluded from their work that no clear cut evidence is on hand that shows that the tear strength of known abrasion resistant formulations is materially greater than for very poor wearing compounds. While there is some evidence indicating that formulations reinforced with HAF do possess higher tear strengths than corresponding gum vulcanizates under some conditions these conditions are not the ones that are present during abrasion. Unfortunately the tear strengths of vulcanizates at high rates of strain have not been determined due to the extreme experimental difficulties involved. Such measurements are needed to determine what role tear strength really plays in the overall abrasion process.

scholarly journals Multivariate Statistical Analysis Applied to Physical Properties of Soybean Cultivars in The Design and Regulation of Post-Harvest Equipment

2021 ◽  
Author(s):  
Paulo Coradi ◽  
Josiane Oliveira ◽  
Larissa Teodoro ◽  
Dágila Rodrigues ◽  
Paulo Teodoro ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Physical Properties ◽  
Manufacturing Industry ◽  
Physical Property ◽  
Principal Component ◽  
Component Analysis ◽  
The Other ◽  
Specific Mass ◽  
Post Harvest ◽  
Soybean Cultivars

Abstract The present work had as aim to evaluate the similar of soybean cultivars according to physical properties as a guiding parameter for decision making in the design and regulation of post-harvest equipment using multivariate analysis. First, Pearson's correlation coefficients were estimated. Posteriorly, principal component analysis was performed to verify the interrelationship between variables and soybean cultivars. A biplot was built with the first two principal components. Finally, a boxplot was built for each variable considering the grouping presented by the analysis of main components. By principal component analysis, we identified the formation of two clusters (G1 and G2) of cultivars. Unit specific mass was the physical property that most contributed to the formation of G1, while the other physical properties contributed to the formation of G2. Soybean cultivars comprising the G1 are more similar to each other only for unit specific mass, and the cultivars allocated in group G2 are more similar for all the other properties evaluated. These results are recommended by the equipment manufacturing industry and the seed processing units to carry out projects and equipment adjustments to efficiently manage the post-harvest of soybean seeds.

scholarly journals Assessment of Growth and Yield of Watermelon and Soil Physical Properties in Response to Different Tillage Methods

2020 ◽  
pp. 79-88
Author(s):  
A. J. Baayim ◽  
H. K. Dapaah ◽  
K. Agyarko ◽  
K. Atakora ◽  
K. Kyere ◽  
...  
Keyword(s):  
Physical Properties ◽  
Yield Components ◽  
Growth Yield ◽  
Soil Physical Properties ◽  
Crop Growth ◽  
Annual Rainfall ◽  
No Tillage ◽  
Minimum Tillage ◽  
Yield And Yield Components ◽  
Tillage Methods

Field experiment was conducted to investigate the response of soil physical properties, crop growth, yield and yield components of watermelon to different tillage methods in the transitional zone of Ghana in a two year period. The tillage treatments used in the study were plough and harrowed (PH), minimum tillage (MT) and no tillage (NT) which was laid out in a Randomized Complete Block design (RCBD) with 3 three replications. The two field experiments were undertaken at the experimental site of the University of Education, College of Agriculture, Mampong-Ashanti, (7°08‘ N, 1°24‘ W )located within the transitional agro-ecological zone between the forest and Guinea Savannah zones characterized with two rainfall regimes with an annual rainfall of 1094.2 mm with 30°C temperature. The soil belongs to the Bediase series with ochrosol type formed from voltain sandstone and a pH between 5.5 to 6. The statistical analysis revealed that, tillage methods significantly affected soil physical properties particularly, total porosity, volumetric water content and bulk density. Also, tillage methods influenced crop growth, (number of leaves and vine length), yield and yield components of watermelon in the order of Plough and harrowed > Minimum tillage > No-Tillage in almost all the treatments.  Accordingly, the ploughed and harrowed (PH) was found to be more appropriate and profitable tillage method to improving  soil physical properties, crop growth, yield and yield components of watermelon in the forest-transitional of Ghana.

HAYNES STELLITE ALLOY No. 98M2

Alloy Digest ◽  
1960 ◽  
Vol 9 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Physical Properties ◽  
Room Temperature ◽  
Base Alloy ◽  
Heat Treating ◽  
The Other ◽  
Stellite Alloy ◽  
Cobalt Base Alloy ◽  
Cobalt Base

Abstract HAYNES STELLITE 98M2 Alloy is a cobalt-base alloy having higher compressive strength and higher hardness than all the other cobalt-base alloys at room temperature and in the red heat range. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness. It also includes information on heat treating, machining, and joining. Filing Code: Co-22. Producer or source: Haynes Stellite Company.

scholarly journals IX. The electric conductivity of nitric acid

1898 ◽  
Vol 191 ◽  
pp. 365-398 ◽  
Keyword(s):  
Nitric Acid ◽  
Physical Properties ◽  
Nitrous Acid ◽  
Internal Resistance ◽  
The Other ◽  
Reasonable Degree ◽  
Mineral Acids ◽  
Artificial Illumination ◽  
The Subject ◽  
Deep Green

Of the commoner mineral acids the chemical changes of Nitric Acid, from their evident complexity, have formed the subject of numerous memoirs, while those of sulphuric acid, from their assumed simplicity, have been to some degree neglected; on the other hand, the physical properties of the latter have been studied with considerable elaboration, while those of the former have been passed over, doubtless on account of the corrosive nature of the acid and the difficulty of preparing and preserving it in a reasonable degree of purity. Further, with certain exceptions, the alterations in physical properties induced by the products of reduction, be they nitrogen peroxide or nitrous acid, either singly or conjointly, have attracted but little attention, though it is a common matter of observation that the current intensity of a Grove’s or other cell containing nitric acid remains constant, even though the fuming acid, originally colourless or red, has become of a deep green tint. It is more than probable that of the factors of Ohm’s law, both the E. M. F. and internal resistance are continually varying. At the earliest stages of the enquiry it was found that the passage of a few bubbles of nitric oxide gas into a considerable volume of nitric acid produced an alteration of one percent, in the resistance, and the same result could be effected to a less degree by exposure to sunlight, and to a still less degree by exposure to artificial illumination. Therefore, we determined to investigate the alterations of conductivity produced by changes of concentration and temperature in samples of acid purified with necessary precautions, more especially as former workers upon the subject have either used samples of acid confessedly impure, or have been silent as to any method of purification, or have adopted no special care in dealing with a substance so susceptible of polarisation.

scholarly journals Some Preliminary Notes on the Physical Properties of the Soils of the Ganges Valley, more especially in their relation to Soil Moisture

1906 ◽  
Vol 1 (4) ◽  
pp. 454-469 ◽  
Author(s):  
H. M. Leake
Keyword(s):  
Soil Moisture ◽  
Physical Properties ◽  
Short Duration ◽  
Irrigation Water ◽  
The Other ◽  
Indian Agriculture ◽  
Northern India ◽  
The One ◽  
The Ganges

In a stretch of arable lands like those of the Ganges Valley, although damage may be caused by occasional floods, which are sudden and of short duration, the more general, and by far the most serious loss is due to deficiency of moisture of the soil: thus the relation of the soil to soil moisture becomes of more than ordinary importance. Dr Voelcker, in his Report on Indian Agriculture, remarks: “In India the relation of soils to moisture acquires a greater significance than almost anywhere else.......” This relation is fundamental, for on it depends the methods for the conservation of soil moisture, for the economical application of irrigation water, and for the treatment of barren and salt lands—all problems of direct interest to agriculturists in the plains of Northern India. The methods for dealing with these problems must be largely—if not entirely—empirical until such time as the behaviour of the soil in its relation to moisture is investigated. The problem in all its various branches is enormous, and in a country in which the seasons follow each other with such rapidity, and vary the one from the other in so marked a manner, it frequently happens that a particular point, if not determined within a period of a few days, must await solution until the following year.

Clinical Performance and Physical Properties of Twelve Amalgam Alloys

1978 ◽  
Vol 57 (11-12) ◽  
pp. 983-988 ◽  
Author(s):  
J.W. Osborne ◽  
E.N. Gale ◽  
C.L. Chew ◽  
B.F. Rhodes ◽  
R.W. Phillips
Keyword(s):  
Compressive Strength ◽  
Physical Properties ◽  
Failure Rate ◽  
Clinical Performance ◽  
Physical Property ◽  
One Year

An assessment of the marginal failure rate of 1,041 restorations of twelve alloys was made at one year. In addition, physical property tests were conducted. A correlation was found between the clinical performance and creep (.79), flow (.62) and 24-hour compressive strength (.60).

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