This material was reprinted from Farm Machinery and Equipment by Harris Pearson Smith, copyright 1937.
Various methods are used to drop the kernels of corn into the soil, but the specially designed corn planters are used most for this purpose. Such planters are: the hand, the one-row, the two-row drill, and the two- and four-row check-row.
The Hand Corn Planter.- Very little needs to be said of this type of planter because of the small demand for it. However, it does come in handy if replanting happens to be necessary. It is constructed with a wedge-like shoe (Fig. 197) which is easily forced into the soil. One side of this shoe is hinged and is connected to the foot-like lever which, when pressed on the ground as the planter is rocked forward, will open this shoe, pressing the soil apart to allow the kernels of corn to drop from the hopper above through a valve that is opened into the soil.
One-row Walking Corn Planter.- The principal difference in the walking corn planter and the walking cotton planter is in the size of the hopper and plate equipment.
Two-row Check-row Corn Planter.- This type of planter, as shown in Fig. 198, may be used to plant corn in hills or to drill it in rows. When used as a hill planter, a wire, with buttons on it, makes it possible to plant the hills at equal distances apart in each direction. The distance between hills along the row is the same as the distance between the rows. This arrangement allows cultivation to be made in two directions, which aids in the control of weeds and reduces hoeing to a minimum.
The only difference between a check-row planter and a drill planter is that the latter does not have the checking apparatus. There are no valves in the boot, no checking head or wire.
Wheels.- The type of wheel used on check-row planters may be either the open-center tire wheel, the closed tire wheel, or the double wheel. (Fig. 199). The open-center tire wheel, as shown in Fig. 198, is the most popular and can be converted into a closed-tire full-concave wheel by the addition of steel wheel bands. The open-center tire wheel not only carries the planter but serves as both a covering device and a press wheel. Only one wheel furnishes power for operating the dropping devices.
The Back Frame.- The frame consists of two units which may be termed front frame and back frame. The back frame is made of a single piece of flat or channel steel. Holes are provided for attaching the axle and its bearings, the front frame, and other parts (Fig. 200).
Sprockets of different sizes are placed on the axle as one of the methods of changing the speed of the feed shaft. A sprocket and clutch for winding up the check wire are also placed on the axle. If a fertilizer or special planting attachments are used, they are driven from the main axle.
The Front Frame.- The front frame (Fig. 200) is made of the same type of steel as used in the back frame. Incorporated in the front frame are the various parts of the dropping mechanism. The boots attached to the front frame are sometimes known as shanks, or seed tubes. These are bolted to the front on each side, and can be spaced from 28 to 48 inches apart. A drop shaft to operate the valves in the boot and a feed shaft to drive the plates are mounted on the front frame. On these shafts are found the clutch, the variable drop, the gears for driving the plates, and the check forks. On each side of the frame a check head is mounted to control the check wire.
The Feed Shaft.- The feed shaft shown in Fig. 200 is mounted on top of the front frame and is driven by a chain from the main axle. The speed of the shaft is changed by using the different size sprockets on the main axle (Fig. 199). A variable drop mounted on the feed shaft will also change its speed. When drilling corn, the distance between kernels can be varied by changing the speed of the feed shaft. Gears on each end of the shaft drive the seed plates.
The Clutch.- The clutch (Figs. 198 and 200) is mounted on the feed shaft. The sprocket runs loose on the feed shaft but when the clutch units (Figs. 201 and 202), which are keyed to the feed shaft, are engaged, the shaft is revolved. When drilling corn, the clutch remains engaged and keeps the feed shaft turning steadily. When corn is being check rowed the clutch is engaged before and disengaged after each hill is planted. The clutch is operated automatically by the buttons on the wire, which also causes the feed shaft to turn intermittently.
Corn Seed Plates.- There are four types of seed plates used for planting corn, namely, the edge-drop and the flat-drop, which have the cells around the outer edge of the seed plate; the flat-drop round-hole cells; and the full-hill plate. The edge-drop (Fig. 203) carries the kernel of corn on edge in the cell of the plate. The flat-drop (Fig. 204) carries the kernel flat in the cell of the plate. Only one kernel of corn is selected in each cell at a time. As the plate revolves, the kernels are dropped upon the top valve until the desired number of kernels have been accumulated; then, the valve is opened and they are dropped upon the lower valve, and next, into the soil. Figure 209 shows kernels of corn being dropped by the valves.
The full-hill plate (Fig. 205) has cells around the outer edge large enough to admit several kernels at the same time. Kernels enough for one complete hill are dropped upon the valve without having to be accumulated.
The flat-drop round-hole type of plate (Fig. 206) is not used on checkrow planters but is used on many drill planters.
Kernels of corn do not vary greatly in thickness. They do, however, vary considerably in width. It is essential to carefully select a plate having cells of sufficient thickness to prevent cracking of the kernels as they pass under the cut-off cover plate. Where the kernels are selected to lie flat in the cell, several plates are furnished, having cells adapted to small, medium, and large kernels. Both the edge-drop and the flat-drop plates do satisfactory work provided the size of the cell suits the size of the kernel. In each type the corn should be graded to a uniform size. This is more important in the edge drop than in the flat drop.
Selecting and Dropping of Seed.- The accuracy of a planter depends upon the uniformity of kernels, shape of hopper, speed of the plate, shape and size of the cells, and fullness of the hopper.
A crowned hopper bottom (Fig. 207) acting under spring pressure pushes the extra kernels back as the cell passes under the plate cover or it cuts them off from the cell and, at the same time, presses the kernel firmly into the cell.
As the plate revolves to where the cell is over the seed tube a yielding knock-out pawl under spring pressure comes in contact with the kernel, knocking it through the cell into the seed tube, where it is allowed to fall either upon the valve, if checking, or directly into the soil, if drilling.
Drive for Seed Plate.- On each end of the feed shaft is a bevel-gear pinion which meshes with the plate gear and drives the plate by means of a lug in contact with a lug on the plate (Fig. 208).
The Variable Drop.- All check-row planters are provided with devices to vary the speed of the plate and change the number of kernels in the hills. One part of the field may be fertile land and four kernels would be desired while another part may be poor land and two or three kernels would be sufficient.
The most common method consists of a set of three gear changes mounted upon the feed shaft. The gears are enclosed in an oil-tight case and the change in the number of kernels is made by shifting a conveniently located foot lever. To plant two kernels, the feed shaft makes only a half revolution which causes two cells to pass over the valve. When three kernels are desired, the feed shaft makes three-quarters of a revolution. To plant four kernels, the feed shaft makes a complete revolution.
Other variable drops may consist of three rows of teeth on the seed-plate gear. A pinion gear shifted to either row of teeth will change the numbers of kernels. Another method is to have a pinion with three rows of teeth on each end of the feed shaft.
Valves.- Most check-row planters have two valves (Fig. 209) in the boot or shank – a few of them have three. One of these is located at the top of the boot just under the seed plate, while the other is at the bottom of the boot and in the rear part of the furrow opener. The two valves open and close at the same time. Kernels of corn accumulated on the top valve, while closed, are dropped and caught by the lower valve when the buttons on the wire trip the check fork and open both valves. Springs close the valves so quickly that the kernels do not have time to pass from the top valve into the soil before the lower valve closes.
The lower valve is necessary to prevent the hills being staggered and the kernels scattered. When drilling is desired, the valves can be locked open, allowing the seed to drop from the seed plate directly into the soil.
Check Wire.- The check wire is usually furnished in 80-rod lengths, having buttons anywhere from 30 to 48 inches apart. Special wire with shorter spacing can be secured. At intervals of 5 or 6 rods special spreading links are provided so that the wire can be disconnected and passed around obstructions such as trees.
When the planter is not being used, the wire is rolled up on a reel which may be suspended beneath the seat (Fig. 210) or carried to one side of the planter (Fig. 211).
Operation of Check-row Planter in Field.- It is often difficult for the student to fully understand the relation of the various steps in the operation of a check-row planter. Hence, they are given here:
- Laying out and handling wire.
The first step in the field is to lay out the wire. Drive the planter to edge of field and place it in first position shown in fig. 212. Hook wire on anchor stake; then, set stake to rear of planter about four times the distance between rows toward the edge of the field.
Drive carefully straight across the field unreeling the wire. Upon reaching opposite side of field detach wire and turn planter in second position (Fig. 212) for planting the first two rows. Hook the other anchor stake to wire drawing wire fairly tight, and set stake directly behind the center of the planter. Place wire in checking head.
The required tension on the wire can be determined by using spring balances or special registers.
For rows 30 rods or less, pull to 30 pounds.
For rows 40 rods, pull to 40 pounds.
For rows 50 rods or more, pull to 50 pounds.
The planter is again driven across the fields, this time planting. Upon reaching opposite side of the field, the wire is released from the checking head by means of the wire doffer. Turn the planter to third position (Fig 212), change row marker to opposite side of planter; move the anchor stake to directly behind center of planter, drawing wire to same tension as before; then, place wire in checking head and drive to opposite side and repeat operations there.
- The wire being stretched across the field is now placed in the checking head, through the roller guides and the check fork (Figs. 199 and 200).
- Lower the row marker toward the field.
- Now the planter is driven across the field with the buttons striking the checking fork, bending it down.
- As the buttons bend the check fork down the valves are opened and the clutch engaged. When the button slips over the bent down check fork, the fork returns to an upright position, allowing the valves to close and the clutch to disengage.
This action in turn brings about the following operations:
a. Kernels on the lower valves drop into the soil.
b. Kernels on the upper valve drop to the lower valve.
c. The clutch engages which causes the seed plates to turn and accumulate seed on the upper valve for another hill. This action occurs between the times the buttons act on the check fork.
In operating check-row planters it may be difficult to align the hills across the field at right angles to the direction of travel. That is, the hills may be dropped too close or too far from the button. On most horse-drawn planters this can corrected by adjusting the connection under the pole. If the hills are too close to the button, lower the front frame; if too far from the button, raise the front frame. This is true when the wire has been stretched to the proper tautness. Do not try to correct the trouble by shortening or lengthening the neck yoke straps, as this will cause the furrow openers to run shallower or deeper, respectively.
When four-row tractor check-row planters are used, the width of land planted is twice that planted with a two-row planter. Consequently, it will be necessary to leave a wider headland, and the wire will have more “travel.” “Wire travel” is caused by the planter’s pulling the wire tight behind it and pushing the slack ahead of it. With the four-row planter there is greater wire travel than with the two-row, owing to the increased “wire crawl,” or movement of the wire sidewise, and the greater angle at the headlands. To offset this trouble a “cross-over” device should be used on four-row check planters. As shown in Fig. 213, when the crossover mechanism is used, the tractor is first headed toward the center of the field and aligned parallel to the direction of travel, then the stake at the end of the headland is set directly behind the checking head. With this arrangement there is neither wire crawl nor angle of the wire on approaching the headland.
Furrow Openers.- Furrow openers are necessary to open furrow-like trenches in the soil to receive the seed as they are dropped by the dropping mechanism of the planter. On check-row planters four types are used.
The curved runner is shown in Fig. 200; the stub runner in Fig. 215; the single disk in Fig. 216, and the double disk in Fig. 217.
The curved-runner type of opener is used most. The stub runner is suited to rough and stony ground. The double-disk opener is used where a wide furrow is desired.
Attachments for Furrow Openers.- Various types of attachments are shown in Figs. 218 and 219. A furrowing and covering attachment is shown in A Fig. 218. The first blades push away the rocks and clods, permitting the rear covering blades to scrape in a sufficient quantity of earth to cover the seed.
The furrow attachment B Fig. 218, also provides a shallow furrow in which to plant the seed.
The gage shoe shown in C Fig. 218, makes it possible to maintain a uniform depth in loose and mellow soils.
A gage-wheel attachment (Fig. 219) is used in conjunction with the single-disk furrow opener to regulate the depth of the planting.
Row Marker.- Row markers are essential to keep the rows straight, parallel, and of equal distance apart. A reversible-disk type is shown in Fig. 199 while a double-folding type is shown in Fig. 213. Double-disk markers are also used.
Special Attachments.- Several attachments are available for all types of planters. A fertilizer-distributing attachment may be mounted on any of the modern corn planters. Attachments are shown on a two-row planter in Fig. 220. The details of the types of feeds and rate of distribution are discussed under Fertilizer Machinery. Some of the attachments on check-row planters, however, are provided with a valve that is operated by the check fork in unison with the valves of the planting mechanism. Some farmers often use the regular planting mechanism to distribute fertilizer. This cannot be done if the fertilizer is very sticky. When used in this manner, it should always be thoroughly washed to prevent injury to the metal parts.
Figure 222 shows a pea or soybean planting attachment mounted on the front frame and driven by gears clamped on the feed shaft. When this type of planter is sold in the South and Southwest, plates for the planting of cotton and sorghums are furnished as regular equipment. The hopper is made larger to meet the requirements of cotton planting.
Duty of Planters.- An average of 7.1 acres can be planted in a 10-hour day with the one-row one-horse planter when the rows are 3 ½ feet apart. With the same width between rows, a two-row two-horse planter will plant 14.1 acres. (1) The duty of a two- and four-row tractor is practically the same as for a cotton planter.
Draft of Corn Planters.- Very little is known about the draft of a corn planter. However, it is considered a light load for two horses or mules.
(1) U.S. Dept. Agr. Yearbook, p. 1056, 1922.