CA1243882A - Subsoil tillage machine - Google Patents

Abstract

I. ABSTRACT OF THE DISCLOSURE.
A soil tillage machine has a straight pull-type main frame.
Attached to the main frame are standards to which novel deep tillage knives are attached. A pair of wings are attached to the lower part of the narrow knife shaped main blade. The wings slope downwardly at an angle of approximately 10% relative to a line parallel to the soil surface. The front portion of the wing bottom lies in a plane parallel to the soil surface. The back portion of the wing bottom lies in a plane parallel to the top surface of the wing. When the tillage machine is pulled through the soil, The wings on the knives lift and fracture the soil the entire width of the machine, breaking up any hard pan. This lifting action aerates the soil with minimal displacement and mixing of surface soil. The tillage machine can be used both before and after planting of crops.

Description

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PATENT APPLICATION

A SUBSOIL TILLAG MACHINE

B CROSS REFERENCES ~O RELATED APPLICATIONS
.
A division of this patent application was filed on October 20, 1986 as Serial No. 920990.
C. STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY- 10 SPONSORED RESEARCH AND DEVELOPMENT
NOT APPLICABL~
D BACKGROUND OF THE INVENTION
1 Field of Invention This invention relates to an agricultural tillage machine 15 designed to be pulled behind an agricultural tractorr which machine includes novel subsoil tillage knives with wings. Unlike conventional subsoil tillage machines, this invention's unique soil lifting action lifts and fractures the soil the en~ire width of the tillage machine, causing increased aeration of the soil, 20 with minimal soil surface disturbance. This inven~ion may be used both before and after the crop planting.

2. Description of Related Art Including Information Dis-closed Under Sections 1.97-1.99.
The conventional tillage methods used in agriculture today 25 consist mainly of three types of soil workiny tools, i.e., the moldboard plow, disc-like tilling elements, and a variety of chisel plows and one-pass tillage systems~ This inven~ion relates to a subsoil tillage machine designed to aerate the soil with minimal soil surface disturbance. ~ 30

3~2 Perhaps the most commonly used tillage tool for plowing is the conventional moldboard plow. The plow bottom is typically set at a particular depth of plowing, for example, eight or ten inches.
These plows are mounted to a main beam which is inclined relative to the direction of travel of a tractor so that each moldboard is 5 set to take a strip of land, cut it, and roll the ground over into a furrow formed by the next forward moldboard. The leading moldboard turns its strip of ground over into a furrow formed on a previous pass of the plow system. Furthermorel a moldboard plow displaces to one side all of the 50il it has tilled. Eventually, 10 the ground must be plowed in the opposite direction, and when this occurs, a deep side ridge normally is left at the end swath.
Another form of blade used in tillage systems is referred to as a "disc", which takes the shape of a dish or bowl. The edge of the disc blade is used to cut trash, while the concave surface of 15 the blade ia used to throw some of the top soil to the side.
~ypically, a plurality of disc blades are arranged at a relatively close spacing and mounted on a common shaft which extends at an acute angle relative to a line transverse of the direction of travel of the tractor. When a gang of disc blades is pulled across 20 a field, complete coverage is obtained. That is, all of the soil is tilledO the trash is cut up and mixed with top soil, while some trash is buried. The disc is generally used in conjunction with the moldboard plow to prepare an appropriate seedbed for planting.
A major disadvantage of repeated use of the disc and plow is 25 the formation of the hard pan or plow sole, a layer of highly compacted soil formed just beneath the tilled soil. Plant roots ~ ~3~

have difficulty penetrating the hard pan, thereby denying the plant access to extra nutrients and water. In addition, water has a tendency tv drain over the hard pan~ instead of being absorbed into the subsoils, ~hus resultins in increased water saturation of the topsoil. 5 A chisel plow, which is designed to shatter and open hard packed subsoil, consists mainly of a series of parabolic two to three inch wide shanks attached to a main frame. The wider the frontal area of the knife, the more horsepower is needed to pull said knife through the soil. These shanks woxk at depths of ten lO
to twenty inches breaking through the hard pan created by the moldboard plow and disc. The use of chisel plows is generally limited to fall tillage because of their working action of the soil. The ground surface is usually left very uneven due to the churning action caused by the wide frontal area of the knives. The 15 soil mus~ be reworked in the spring with a disc or other complete tillage system to prepare the soil for planting.
A commonly used plow point found in one pass tillage systems is made from a bar of steel approximately four inches wide that is curved to bolt in front of a chisel plow shank. It is twisted on 20 a helix, and right and left hand units are used. Due to the wide curved surface, the point tends to bulldoze the soil, and power requirements become high at deeper depths.
Conventional tillage knives and obviously, knives used on one-pass tillage systems, tend to mix the subsoil with the topsoil. 25 In certain agricul~ural areas, some mixture may not be harmful; but in many other areas, blending is undesireable. For example, in ~3~
many parts of the fertile midwestern agricultural belt, a layer of fertile topsoil, rlch in nutrients and decomposed organic matter, overlies an often highly acidic hard pan subsoil layer. Mixing this subsoil with the fertile topsoil lowers the pH of the topsoil, thereby acidifying or otherwise changing the plant supporting 5 upper layer to the extent that many varieties of crops grow poorly.
Another disadvantage associated with conventional tillage machines is the inability to con'rol erosion. When strips of land are worked by conventional tillage machines, the mixing of the soil leaves very little crop residue on the surface to absorb the impact 10 of rainfall. When the soil, and not the crop.residue, absorbs the great forces generated by rainfall, the soil is loosened and put into a liquid suspension, resulting in great soil erOSiDn.
As a result of the aforementioned disadvantages of conven-tional methods of agricultural tillage, an agricultural tillage 15 system known as no-till planting has evolved. In this method of crop production, crops are planted direc~ly into crop residue without plowing, discing, or other soil tillase. No-till plantir.g was made possible by the revision of existing planters, allowing them to plant seeds directly into the residue left by the previous 20 year~s crop.
The main advantages of no-till planting are reduced expenses and the ability to control soil erosion. With no-till planting, higher levels of residue are left on the soil surface, thereby helping to absorb the force of rainfall, thus decreasing soil 25 erosion. In addition, more water can be absorbed into the subsoils, which water can then be used as reserves in the hot, dr~
growing months of summer.

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The main disadvantage of no-tlll planting is that the crop yields associated therewith are generally less than those yields associated with conventional tillage methods. The main reason for the decreased yields is that the soil transversed by no-till plar.iing is generally less aerated than soil txansversed by 5 conventional tillage methods. The root system of a plant must have oxygen in ordex to utilize fertility nutrients from the soil. As roots need oxygen for maximum growth to occur~ the reduced amount of oxygen in the soil results in reduced yields.
Examples of conventional subsoil tillage machines and knives 10 are described in the following patents:
Patent Number Patent Date Country Patentees 3,912,01910/1975 ~.S. Baughman 184,17111/1876 U.S. Porter 2,906,35309/1959 U.S. Rogers 15

4,415,04211/1983 U.S. Cosson 3,188,98806/1965 U.S. Peck 2,595,353OS/1952 U.S. Graham 4,106,56808/1978 U.S. Cline 4,243,10401/1981 U.S. ~ipos 20 4,245,70601/1981 ~.S. Dietrich, Sr.
4,403,6S209/1983 U.S. Dietrich 2,031,25204/1380 United Kingdom Taylor 1,595,78408/1981 United 25 Kingdom Cant 557~839 1958 Canada Lagemaat E. SUMMARY OF THE INVENTION.
The present invention is directed to an agricultural tillage instrument with a unique subsoil tillage knife designed to aerate 30 the soil with minimal soil surface disturbance, thus reducing soil erosion. While designed mainly for use in a no till farming system, the invention can also be used in conventional tillage systems.

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The invention is a deep tillage knife assembly for liEt-ing and aerating soil through which the kni-Ee assembly is pulled in a forward direction along the soil surface, said knife assembly comprising: ~ vertical kniEe blade having a leading edge, a trail-ing edge, an upper end and a lower end extending from said leading edge to said trailing edge; said leading edge projecting along a generally straight line downward and forward below -the soil surface at a blade angle of approximately 30 degrees relative to a line perpendicular to the soil surface; a-t least a portion of said bottom end of said knife blade sloping rearward and upward relative to the soil surface; a pair of generally symmetrical wings at-tached to opposite sides of said vertical knife blade near said bottom end and extending la-terally from said vertical knife blade; each said wing including upper and lower surfaces and a forward edge defined generally by the intersection of said upper and lower surfaces;
said upper surfaces including generally parallelogram shaped lift-ing surfaces sloping rearward and upward from said forward edge at a lift angle not greater -than approximately 15 degrees for impart-ing a lifting force to fracture the soil above the wings while maintaining the location of the soil; said forward edges of said wings extending latera]ly outward from said kniEe blade substan-tially parallel to the soil surface and sloping rearwardly at awing angle at least approximately as large as said blade angle;
and said lower surfaces each including a landside generally parallel to the soil surface :Eor absorbing downward force resulting from reaction of said upper surfaces against the soil.
The wings preferably are at-tached approximately two inches above the tip of each knife, extend out approximately five inches from the main knife blade, and lie in a plane projecting downward approximately 10 relative to the soil surface.
The knives are attached to an implement frame which is pulled by a tractor at speeds of four to six miles per hour through es-tablished growing corn of two to twelve inches in height (or other crops at suitable heights), with the tillage knives penetra-ting the soil at depths of twelve to fourteen inches. The wings on the knives lift and fracture the soil the entire width of the invention between and under the growing plants. The knives are spaced to run in the middle of the crop rows, -thus causing no damage to the grow-ing crop's root system. The invention can also be used before planting in the fall or springj however.
The main advantage of the invention is that it elimina-tes the disadvantages associated with conventional tillage machines and knives. By penetrating the soil at the aforementioned depths, the invention greatly aids in breaking up soil compaction, thus allow-ing roots to grow deeper to seek needed nutrients and water. Soil compaction is one of the main factors that limit high crop yields because of its effect on root growth, water movement, and air and water holding capacity of -the soil. By reducing soil compaction, plant roots which previously would not penetrate -the -6a-~3~

hard pan are now able to grow deeper into the subsoil which has added reserves of water and nutrients. The plant is ther fore less likely to be stressed in dry weather due to lack of moisture.
Another unique aspect of the invention is that it is designed to be primarily used after the planting of the crop, leaving the 5 soii in the most desirable state for maximum growth and yield potential. In contrast, chisel plows or other one-pass tillage systems can be used only after a crop is harvested in the fall or before the crop is planted in the spring. The rainfall during the fall and winter months causes the soil to silt back together, thus 10 reducing the aeration caused by the subsoil tillage operation. In addition, compaction is also created by the wheel traffic during the pre planting (plowing, discing, etc.) and planting process.
The aeration created by the use of the invention, on the other hand, remains for two to four months after use, the time of maximum 15 plant growth.
The unique angle of the wings and the knife results in an unique lifting action which bends and breaks the soil, creating macropores in the soil structure and leaving the soil in a crurnbly state with minimal disturbance of surface residue. This lifting 20 (but not mixing) action distinguishes the invention from the one pass complete tillage systems and chisel plows, which lack this ability, and from other conventional moldboard plows which result in the turning over of large slabs of soil. The aeration of the soil promotes bacterial proliferation which breaks down organic 25 matter into humus which is rich in nutrients in an exchangeable form to aid in crop growth.

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The invention has the added advantage of reducing soil erosion. The invention lifts the fractured soil approximately one to three inches, settling it back into its original location, without turning or mixing the topsoil. Any crop residue on the surface is left practically undisturbed by the use of the inven- 5 tionO This non-mixing feature also distinguishes the invention from the prior art. By loosening the soil, but not disturbing the crop residue on the surface, the invention keeps erosion within acceptable limits while at the same time allowing the rain water to reach deeper penetration of the soil. The crop residue left on 10 the surface absorbs the shock of rainfall and slows the water runoff, thus keeping the top soil in place.
Other objects and advantages of the invention will become apparent from the following description taken in connection with the accompanying drawings wherein are set forth by way of illus- 15 tration and example, certain embodiments of this invention.
F. BRIEF DESCRIPTION OF THE DRAWINGS.
FIG. 1 is a frontal view of the invention.
FIG. 2 is a top view of the structure of FIG. 1.
FIG. 3 is a sectional view of the invention. 20 FIG. 4 is a frontal view of the tillage knife.
FIG. 5 is a side view of the tillage knife.
FIG. 6 is a sectional view of the bottom half of the tillage knife.
FIG. 7 is a side view of the tillage knife attached to a 25 standard, being pulled through a representative soil profile of a growing crop of corn. It also shows an exaggerated view of the ~3~

result of increased crop root growth over time by the breaking up of the hard pan.
G. DESCRIPTION OF THE PREFERRED EMBODIMENTS.
Referring to Fig. 1 and Fig. 2, the main frame (1) of the invention consists of a square beam having a center line per- 5 pendi~ular to the direction of travel. It is attached to a tractor via a three-point hitch through hitch plates (2) welded per-pendicular to the main frame.
Referring to Fig. 1 and Fig. 3, there are a row of knife standards (3). These knife standards are attaohed to the main 10 frame tl) by weldiny or other means and project backward below the main frame (1) at an approximate angle of 3~ relative to per-pendicular. Gussetts (4) are welded to the main frame (1) and the knife standards (3~.
Referring to Fig. 1, Fig. 3 and Fig. 7, the knives (5) are 15 mounted to the standards (3) via two bolts. The top bolt (6) is a soft shear bolt which will shear in case of hitting an immovable object in the soil thereby preventing any extensive damage to the standards (3) or the main blade (5). The lower bolt t7) acts as a pivot in case of the top bolt (6) shearing, allowins the main 20 blade (5) to swing backward and upward.
Referring to Figs. 4 through 6~ the main knife blade (5) is fashioned from approximately five-eighths inch thick steel. The main blade (5) includes a beveled leading edge t8) to reduce the friction as the blade is pulled through the soil. The bottom edge 25 of the blade (5~ travels through the ground at depths of twelve to fourteen inches during normal usage.

_g_ Referring to Fig. 5 and Fig. 7, the front approximate one-third of the bottom edge (9) of the blade lies in a plane parallel to the soil surface. The back approximate two-thirds sf the bottom edge of the blade (10) slopes upwardly at an approximate angle of 15. The main blade (5) projects forward at an approximate 30 5 angle relative to a line perpendicular of the surface. Thi~ angle reduoes the compression of the soil. The main blade (5) thus requires less horsepower to be pulled through the soil than a knife with a less acute angle of attack.
The mounting arrangements of the wings (11) can be viewed in 10 Figs. 4 through 7. The wings (11~ are mounted on the lower part of the knives (5). Each wing (11) extends approximately five inches outward from the main blade (5).
Referring to Figs. 5, 6 and 7, the wings (11), which have a beveled leading edge (12), point down at an angle of approximately 15 10~ relative to a line parallel to the direction of travel.
Experiments have shown 10 to be the optimal angle of the wings lll) for tillage performed on growing crops. An excessive angle on the wings (11) may cause the tearing of the roots on growing crops, thus resulting in reduced yields. Referring to Fig. 6, the 20 rearward inclination oE the leading edges of said wings (11) is approximately 30 to a line transverse of the direction of travel of said vehicle.
Referring to Fig. 7, the wings (11) travel through the ground at a depth of ten to twelve inches. After the leading edge (12) 25 of the wing lll) shears the soil, it lifts it in a manner to break ~ 3~

~he soil creating air pockets all the way to the surface. The front portion of the wing bottom ~11) is flat and is known as a landside (13). The landside tl3), which lies in a plane parallei to the soil surface, absorbs much of the downward pressure exerted by the wing's (11) lifting action of the soil. The landside (13) 5 eliminates the need to have depth control de~ices on the invention.
The back portion of the wing bottom (14) lies in a plane parallel to the top surface (15) of the wing ~11).
Fig. 7 demonstrates the action of the invention and the difference in the soil structure before and after operation. The 10 soil is highly compacted before aeration. As the invention is pulled through this highly compacted 50il, it lifts and bends the soil over the wings (11), leaving a very porous structure which promotes maximum root growth because of oxygen introduction into the soil profile. Rainfall is also more readily absorbed into the 15 porous structure instead of running off the surface soil and causing erosion. 8y creating this type of environment, maximum crop growth can be achieved, thereby enabling the farmer to realize maximum profit.
Preferred embodiments of the invention having been dis- 20 closed, persons skilled in the art will be able to modify the structure and to substitute equivalent elements for those de-scribed while continuing to practice the principle of the invention. It is, therefore, intended that all such modifications and substitutions be covered, as they are embraced within the 25 spirit and scope of the appended claims.

Claims (15)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A deep tillage knife assembly for lifting and aerating soil through which the knife assembly is pulled in a forward direc-tion along the soil surface, said knife assembly comprising:
a vertical knife blade having a leading edge, a trailing edge, an upper end and a lower end extending from said leading edge to said trailing edge;
said leading edge projecting along a generally straight line downward and forward below the soil surface at a blade angle of approximately 30 degrees relative to a line perpendicular to the soil surface;
at least a portion of said bottom end of said knife blade sloping rearward and upward relative to the soil surface;
a pair of generally symmetrical wings attached to oppo-site sides of said vertical knife blade near said bottom end and extending laterally from said vertical knife blade;
each said wing including upper and lower surfaces and a forward edge defined generally by the intersection of said upper and lower surfaces;
said upper surfaces including generally parallelogram shaped lifting surfaces sloping rearward and upward from said forward edge at a lift angle not greater than approximately 15 degrees for imparting a lifting force to fracture the soil above the wings while maintaining the location of the soil;
said forward edges of said wings extending laterally out-ward from said knife blade substantially parallel to the soil sur-face and sloping rearwardly at a wing angle at least approximately as large as said blade angle; and said lower surfaces each including a landside generally parallel to the soil surface for absorbing downward force resulting from reaction of said upper surfaces against the soil.

2. A deep tillage knife assembly as claimed in claim 1 wherein said blade angle is 30 degrees.

3. A deep tillage knife assembly as claimed in claim 1 wherein said wing angle is approximately equal to said blade angle.

4. A deep tillage knife assembly as claimed in claim 1 wherein said lift angle is approximately 10 degrees.

5. A deep tillage knife assembly as claimed in claim 4 wherein said lift angle is 10 degrees.

6. A deep tillage knife assembly as claimed in claim 1 wherein said lower end of said knife blade extends below said wings.

7. A deep tillage knife assembly as claimed in claim 6 wherein said bottom end of said knife blade includes a forward portion generally parallel to said soil surface and a rearward portion sloping rearward and upward.

8. An agricultural implement for subsoil tillage of soil across which the implement is drawn in a forward direction, said implement comprising in combination:
a frame having a predetermined width across the direction of implement movement;
knife support means connected to said frame;

a plurality of knife assemblies carried by said knife support means at laterally spaced positions along the width of said frame;
each of said knife assemblies including a vertical knife blade having a leading edge, a trailing edge, an upper end and a lower end extending from said leading edge to said trailing edge;
said upper ends of said blades being fixed to said knife support means;
said leading edges of said blades projecting parallel to one another along generally straight lines downward and forward below the soil surface to a blade depth at a blade angle of approxi-mately 30 degrees relative to a line perpendicular to the soil sur-face;
at least a portion of said bottom ends of said knife blades sloping rearward and upward relative to the soil surface;
a pair of generally symmetrical wings attached to oppo-site sides of each knife blade near said bottom end and extending laterally from said knife blade;
each said wing including upper and lower surfaces and a forward edge defined generally by the intersection of said upper and lower surface;
said upper surfaces including generally parallelogram shaped lifting surfaces sloping rearward and upward from said for-ward edge at a lift angle not greater than approximately 15 degrees for imparting a lifting force to fracture the soil above the wings while maintaining the location of the soil;
said forward edges of said wings extending laterally outward from said knife blade substantially parallel to the soil surface and sloping rearwardly at a wing angle at least approxi-mately as large as said blade angle; and said lower surfaces each including a landside generally parallel to the soil surface for absorbing downward force resulting from reaction of said upper surfaces against the soil.

9. An agricultural implement as claimed in claim 8, further comprising coulter support means connected to said frame and a plurality of coulters carried by said coulter support means, one of said coulters being positioned in front of each of said knife assem-blies.

10. An agricultural implement as claimed in claim 9 wherein said coulters extend into the soil to a coulter depth less than said blade depth.

11. An agricultural implement as claimed in claim 10 wherein said coulter depth is approximately between 20 and 50 percent of said blade depth.

12. An agricultural implement as claimed in claim 8, said knife support means comprising a plurality of knife standards pro-jecting downward and rearward from said frame.

13. An agricultural implement as claimed in claim 8 wherein said wing angle is approximately equal to said blade angle.

14. An agricultural implement as claimed in claim 8 wherein said lift angle is approximately 10 degrees.

15. An agricultural implement as claimed in claim 8 wherein said lower ends of said knife blades extend below said wings.