CORN -PLANTER CALIBRATION FOR HIGHEST YIELDS

Transcription

1 I I JA~ UNiVERSITY OF R. I. LIBRARY CORN -PLANTER CALIBRATION FOR HIGHEST YIELDS By H. P. Bateman and Wendell Bowers UNIVERSITY OF ILLINOIS COLLEGE OF AGRICULTURE EXTENSION SERVICE IN AGRICULTURE AND HOME ECONOMICS

2 ... This circular will tell you how to calibrate your corn planter for highest yields by following these 8 steps: 1 Check planter parts. 2 Select proper population for fertility level. 3 Read the owner's manual carefully. 4 Match seed to seed plate. S Adiust planter for desired planting rate. 6 Calibrate in a barnlot or roadway before planting. 7 Make a field check. S Count emerged plants and final harvest population. This circular was prepared by H. P. Bateman, Assistant Professor, and Wendell Bowers, Associate Professor of Agricultural Engineering. Urbana, Il li nois November, 1961 Cooperative Exte nsion Work in Agriculture and Ho me Economics : University of Illinois, Colle g e of Agric ulture, and the United States Department of Agriculture cooperating. louis B. HOWARD, Director. Acts approved by Congress May 8 and June 30, 1914.

3 To OBTAIN THE MAXIMUM YIELD OF CORN for a specific fertility level and soil type, it is important to plant the proper number of kernels per acre. The population at harvest is often less than the number of kernels planted (or assumed to have been planted). This reduced population may result from anyone or a combination of several of the following factors: 1. Reduction of stand by germination, weeds, insects, and cultivation. Total population loss from these sources is usually 15 to 20 percent. 2. Selection of improper seed plate. 3. Rust in seed-plate cells. 4. Poorly graded seed. 5. Slippage of planter drive wheels and different size from that used to determine rates in owner's manual. 6. Improper inflation of tires. 7. Calibrating at a much slower speed than normal planting speed. 8. Planting faster than recommended by owner's manual. 9. Planter parts not functioning properly. The eight steps outlined in this circular will help you plant the proper number of kernels for maximum yields. Step 1: Check Planter Parts Carefully check the power train from the ground drive wheels to the seed plate. Loose or worn sprockets, gears, and chains can affect metering accuracy, particularly on the seed-plate drive and the power train from the drill shaft to the hopper. Replace worn cut-off pawls, knockout pawls, and hopper bottom rings. When replacing worn pawls, check for weak spnngs. If cut-off pawl (AI or knockout pawl (BI shows any evidence of wear or damage, replace immediately. This cut-off pawl should be replaced. Be sure both pawls move freely. Step 2: Select Proper Population for Fertility Level For any field with the proper fertility level, there is a population of stalks at harvest that will give the maximum yield of corn. The following table shows the number of kernels to plant for the desired number of stalks per acre at harvest. Expected yield Kernels planted Stalks at harvest per acre per acre per acre 75 bushels 13,300 kernels 12,000 stalks 100 bushels 16,500 kernels 14,000 stalks 125 bushels 20,000 kernels 17,000 stalks 150 bushels 25,000 kernels 20,000 stalks Step 3: Read the Owner's Manual Carefully The owner's manual tells you how to adjust your corn planter to obtain the correct population. I t is also an excellent guide for determining the speed of your planter for a given planting rate. D o not exceed the maximum planting speed recommended in the manual. If you exceed this speed, the seed plate will turn too fast for accurate planting and uniform kernel spacing. Notice g roove worn in hopper bottom ring. Deep grooves like Read the owner's manual to find proper adjustment for desired this can ca use cracked kernels and a ffect planting rate. planting rate. 3

4 In laboratory tests, a seed-corn test stand adjusted to drop 15,200 kernels per acre at 3 miles per hour dropped 14,300 kernels at 5 miles per hour, and only 13,200 kernels at 7 miles per hour. Increasing the population resulted in an even greater reduction in the planting rate. When the test stand was adjusted to drop 18,800 kernels per acre at 3 miles per hour, it dropped 17,400 kernels at 5 miles per hour. At 7 miles per hour, the planting rate was only 15,000 kernels per acre. By using seed plates with more cells than the standard 16-cell plate, you can drive faster at the same planting rate. You can find out from your manual whether plates with more than 16 cells can be obtained for your planter. Step 4: Match Seed to Seed Plate Plan to have an average of 100-percent or slightly higher cell fill. A 100-percent cell fill means that, on the average, one kernel is dropped from each cell. If, for example, 16 kernels are dropped in one turn of a 16-cell seed plate, the cell fill is 1 00 percent. If 12 kernels are dropped, the cell fill is 75 percent. If 20 kernels are dropped, the cell fill is 125 percent. For best results and to avoid damage to the seed as it passes through the hopper mechanism, the cell fill should be 100 percent or slightly higher up to a maximum of 105 percent. To be certain that the cell fill is accurate, match the seed corn and seed plate. These can be matched either on a seed-corn test stand or by a calibration run on the open ground in a lane or barnlot where all the kernels can be counted. Whichever method you use, check rate at field speed and desired planting rate. In selecting the correct seed plate, begin with the seed plate recommended on your bag of seed corn. Be sure to use your own seed plates and seed corn in calibrating your planter. Even small variations between seed plates of the same size and seed corn of the same grade can result in serious planting errors. Remove any rust, seed treatment, or rust preventative from cells before making the test. Step 5: Adiust Planter for Desired Planting Rate Using the owner's manual and the table below, set your planter to plant the number of kernels desired. Spacing of kernels for planting rates of Row 12,000 14,000 16,000 18,000 20,000 24,000 28,000 spacing pera. pera. pera. per A. per A. per A. per A. 36 inches inches inches inches Using the owner's manual as a guide, adjust your planter for desired planting rate. Select the proper plate for accurate calibration at planting speed. Start with the seed plate recommended on your bag of seed corn. Step 6: Calibrate in a Barnlot or Roadway Before Planting Planting speed can cause a wide variation in planting rates. For this reason, final calibration must be made at planting speed on a roadway or barnlot where all of the kernels can be counted over a short distance.. Leave the planter in a raised position and use a wire 4

5 or string to engage the seed-plate drive. The following table shows how far to drive for various row spacings. Each row is 1/ 200 of an acre. To obtain the planting rate per acre, count the kernels from each row and multiply by 200. Kernels to count for planting rates of Row Distance 12,000 14,000 16,000 18,000 20,000 22,000 spacing to d rive per A. per A. per A. per A. per A. per A. 36 inches 72 feet inches 69 feet inches 66 feet inches 63 feet Determine the planting rate for each of the planter rows and list these rates separately. In this way, you can determine if one of the hoppers is giving a poor drop of the seed. If all of the planter parts Drive at planting speed for accurate calibration. Set stakes for cal ib ration run. Check kernels dropped to obtain calibration rate and average hill spacings. Engage seed-plate drive. seem to be functioning properly and the seeding rate is higher than the rate for which the planter is adjusted, then a smaller seed plate should be used. If the planting rate is not high enough to match the adjusted rate on the planter, a larger seed plate should be used. To get an accurate measure of the planting rate, make all of the calibration runs at planting speed. The planting rate in these calibration runs will probably be slightly higher than the field rate, even when the seed is perfectly matched to the seed plate. This is due primarily to the reduced slippage of the drive wheels on the smooth surface. 5

6 In making the calibration run, allow a few hundred extra kernels to compensate for the difference between the calibration rate and the field rate. Suppose that you want to calibrate your planter at 5 miles per hour to drop 18,000 kernels, and you find after making a few calibration runs that you are averaging 18,500 kernels. When you go to the field, the planting rate will be reduced to 18,000 or slightly less, and should be satisfactory. Step 7: Make a Field Check When you have calibrated your planter for planting a given number of kernels per acre on a roadway or barnlot, you can be fairly confident that the planter will give you approximately the desired planting rate. As a final check, however, dig out several kernels along the row and make an estimate of the average kernel spacing. By checking this spacing with the desired rate, you can determine the accuracy of your calibration and make whatever adjustments are necessary on your planter. Step 8: Count Emerged Plants and Final Harvest Population To plant corn accurately, you must know how many kernels have been planted, how many plants have emerged, and how many stalks remain at harvest. (See table on page 5. ) Making these population counts every year will help you determine whether you are planting the correct population for maximum yields. You may even want to experiment with different populations on a few rows to find out which population gives the highest yield. Dig out kernels to check field planting rate. Count emerged plants to determine early population. 6

7 HOW TO DETERMINE FIELD SPEED In planting corn, it is important to know how fast you are driving, especially if you are applying granular or liquid chemicals at the same time. You can determine your field speed as follows: 1. Carefully mark off a distance of 176 feet in the field. 2. As you plant, check the number of seconds required to drive between the markers with a stop watch or watch with a sweep second hand. 3. Divide the time in seconds into 120 for speed in miles per hour. The chart below lists the time in seconds for speeds up to 7 miles per hour. TIME TO DRIVE J 76 feet SPEED 120 seconds mile per hour -. ->- 60 seconds 2 miles per hour 40 seconds 3 miles per hour 30 seconds 4 miles per hour 24 seconds 5 miles per hour ~~- 20 seconds 6 miles per hour 17 seconds 7 miles per hour

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