Drills vs. Planters for No-till Double-Crop Soybean: Agronomics, Economics, and Equipment Setup

Transcription

1 Drills vs. Planters for No-till Double-Crop Soybean: Agronomics, Economics, and Equipment Setup A Preliminary Report of Research Conducted at the Eastern Virginia Agricultural Research & Extension Center Bobby Grisso, Virginia Tech Extension Agricultural Engineer David Holshouser, Virginia Tech Extension Soybean Specialist J.D. Hutcheson, Virginia Cooperative Extension Farm Management Agent Bob Pitman, Eastern Virginia AREC Superintendent

2 Drills vs. Planters for No-till Double-Crop Soybean Agronomics, Economics, and Equipment Setup A Preliminary Report Dr. Bobby Grisso, Virginia Tech Extension Agricultural Engineer Dr. David Holshouser, Virginia Tech Extension Soybean Specialist Mr. J.D. Hutcheson, Virginia Cooperative Extension Farm Management Agent Mr. Bob Pitman, Eastern Virginia AREC Superintendent Choosing the right piece of equipment to do the job is not always easy. Soybean, small grain, and corn growers can share many pieces of equipment between enterprises. For instance, the combine (with header modifications) can harvest all three crops. Seeding equipment is similar in that respect, but not quite as versatile. A corn planter or small grain drill can be used for soybean planting, but the drill cannot be used for corn or the planter for wheat. Therefore, the grain and soybean producer must own at least two pieces of planting equipment a drill and a planter. But, which piece of equipment should be used to plant the soybeans? It is known that reducing the row width of soybean from 30 or greater inches to less than 20 inches will increase yield. Although additional yield increases may be realized by further reductions in row width, the data for this is inconsistent. Virginia research (shown below) indicates an additional yield increase of 4 to 10% with double-crop soybean by narrowing row width from 18 to 9 inches over a wide range of populations. Therefore, there may be benefit to using the drill versus a narrow-row or split-row planter for soybeans. 45 Suffolk Suffolk 1998 Soybean yield (bu/a) inch 18 inch inch 18 inch Suffolk Painter 1999 Soybean yield (bu/a) inch 18 inch inch 18 inch Soybean population (x1000) Soybean population (x1000) However, a drill does not uniformly meter out the seed. Versus a planter, the soybean stand from a drill is spotty and non-uniform. The row spacing research show on the previous page was conducted using the same planter and the stands were uniform, regardless of row spacing. Because of the potential 2

3 of more gaps between soybean plants seeded with a drill, the yield increases shown with drill-width rows may not be realized. In many situations, to make up for this spottiness, producers generally plant more seed with a drill versus a planter in order to compensate for the created gaps. This of course increases seed costs. So, the question remains, which is the best combination of planters and drills that will utilize all equipment to its fullest potential and be most profitable? In order to address some of these issues, the Eastern Virginia Agricultural Research and Extension Center (EVAREC) in cooperation with local farmers and equipment dealers instigated an experiment to: 1) compare the percent emergence and uniformity of stand of soybean planted with two drills and one planter; 2) determine the effect of speed of travel on emergence and uniformity of soybean stand; 3) determine any yield differences caused by different seeding systems; and 4) to perform an economic analysis of the cost of purchasing equipment for three equipment combinations that would fit a corn, small-grain, double-crop soybean system. During a Soybean Field Day at the EVAREC, the authors presented information on properly adjusting the planting equipment, soybean emergence results, and an economic comparison of three equipment combinations described above. The presented information is summarized below. Equipment Considerations for No-till Soybean Seeding No-till planters and drills must be able to cut and handle residue, penetrate the soil to the proper seeding depth, and establish good seed-to-soil contact. Many different soil conditions can be present at the time of planting in the Mid-Atlantic region. Moist soils covered with residue, which may also be wet, can dominate during late fall and early spring and occasionally in the summer. Although this provides for an ideal seed germination environment, such conditions can make it difficult to cut through residue. In contrast, hard and dry conditions may also prevail. This is especially common when no-tilling soybean into wheat stubble during the hot dry months of June and July. Although, cutting residue is easier during dry conditions, it is more difficult to penetrate the hard, dry soils. Proper timing, equipment selection and adjustments, and management can overcome these difficult issues. Condition of the Field and Residue Two of the keys for success with no-till equipment are proper handling of the previous crop residue and weed control. If these are issues are not considered, then the ability of the planter or drill to perform its functions is greatly limited. The residue has to be uniformly spread behind the combine if the opening devices are going to cut through the material. It is very difficult for the planter/drill to cut the residue if the combine has left a narrow swath of thick residue and chaff. Ensure that the combine is equipped with a straw chopper and chaff spreader to distribute residue and chaff over the entire cut area. For example, if a 30 foot platform header is cutting high-yielding small grain and dumping the material into a 5-6 foot swath, then this swath contains 6 to 5 times more material than the other cut area. This mat of material is a great place for disease and pest problems to accumulate and increases problems relating to cutting residue and penetrating the soil. This mat can create a lot of variability that makes it difficult to adjust the planter/drill for proper operation and that limits successful emergence and early growth of the desired crop. Experience has shown that the residue is best handled by the planter/drill when the residue remains attached to the soil and standing. When the residue is shredded and chopped, it has a tendency to mat and not dry out as quickly as standing residue and the loose residue may not flow through the planter/drill as well and has potential to plug the opening devices. The other key is weed control. In double-cropped soybeans, one of the reasons to convert to narrow rows is that crop canopy closure is faster which shades the weeds and gives the soybean more of a competitive advantage. Due to the closure time, 7.5-inch rows may have an advantage over 15- or 30- inch rows. However, if the weeds have a head start, this advantage can be lost. If standing weeds exist, you are asking the planter/drill to cut and move this extra material through the system, plus the crop has lost valuable resources of nutrients and water. 3

4 Coulters and Seed Furrow Openers Probably the primary difference between conventional planter/drill systems and those designed for conservation tillage systems is weight. Since the openers and soil engaging devices must penetrate much firmer soils and cut the residue, the conservation planter/drill systems are built heavier and have the ability to carry much more weight than conventional systems. For adequate coulter penetration, weight may have to be added to the carrier. Some planter/drills use a weight transfer linkage to transfer some of the tractor weight to the coulters to ensure penetration. Because coulters are usually mounted several feet in front of the seed opening/placement device (in the case of a coulter caddies even further), many use wide-fluted coulters, a pivoting hitch or a steering mechanism to keep the seed openers tracking in the coulter slots. Wide-fluted coulters (2-3 inches wide) perform the most tillage and open a wide slot in the residue. They allow faster soil warm-up (which maybe a disadvantage in some double-cropping situations) and may prepare an area for good soil-to-seed contact. However, because of the close spacing, fluted coulters require more weight for penetration, disturb more soil surface, and bury more residues. In wet soil conditions, fluted coulters may loosen too much soil, which could prohibit good seed-to-soil contact. The loose wet soil may stick to the seed openers and press wheels resulting in non-uniform depth control and clogging. Narrow-fluted coulters (1/2 to 1 inch wide) or narrow bubble coulters, ripple coulters and turborippled coulters do not require as much weight for penetration and do not throw as much soil out of the seed furrow as the wide-fluted coulters. Ripple coulters with a smooth edge or smooth coulters are preferred for residue cutting and they can be sharpened to maintain the cutting surface. Operate all coulters close to seeding depth to avoid excessive soil throwing at high operating speed and limit the formation of air pockets below the seeding depth. Use the largest diameter coulters available because when operated properly they have the best angle for cutting residue and require less weight for penetration. Most no-till planters/drill are equipped with independent seeding units that should allow at least 6 inches of vertical movement. This will allow transit over non-uniform surfaces and adjust for root stubs and other obstacles. These units are sometime staggered which helps with the unit functions (more sideto-side space) as well as more space for the residue to flow through the system. These units should be equipped with heavy down-pressure springs and sufficient weight to ensure penetration of both the coulters and seed furrow openers into untilled soil. Usually these springs are adjustable and multiple springs can be added if insufficient pressure is achieved. Some no-till planters/drills are not equipped with coulters. These planters/drills use the seed furrow openers to cut and place the seed. Several planter/drill systems have a staggered double disk seed furrow opener without a coulter. The leading disk (usually ½ to 1 inch in front) cuts the residue and the second aids in opening the seed furrow. Some manufacturers use a single, large disk set a slight angle. These units require less weight for penetration and provide minimal soil disturbance. Some no-till drills use offset double-disk openers and the leading edge of the double disks is subject to significant wear. Single disk openers are also subject to similar wear. Essentially, the leading edge of one disk takes the abrasion and wear of cutting straw or stalks and penetration into the soil. The leading and trailing disk are typically two different parts and cannot be interchanged. As the double disk openers wear, check the gap between them. If a gap opens between the double disks they will push residue into the furrow and have less ability to cut the residue. Adjustment washers are found in the double disk opener assembly, which allow some adjustment to compensate for wear. More on Weight and Down Pressure Individual openers should have sufficient down pressure and independent depth control so as to allow enough movement up and down to ensure that all rows are operating at the same depth. Depending on 4

5 coulter width, opener design and field conditions, up to 500 pounds per row may be necessary for adequate penetration. Down-pressure springs on independent row units must transfer enough weight from the drill frame so that all meter wheels, seed openers, and all depth control devices and seed pressure wheels are making firm contact with the soil. Drills, depending on the opener spacing, have four times the number of row units for a given width of operation compared to similar width of a row-crop planter (30-inch spacing). Thus, the total weight of a no-till drill or narrow-row planter needs almost 2-4 times the weight of a conventional planter. In some case when insufficient drill weight is lacking, the springs may physically lift the meter drive mechanism off the ground. Some manufacturers use a spring-loaded drive mechanism to keep the drive firmly in contact with the soil, but this still requires adequate total drill weight for proper operation. Seed Meter Devices One of the reasons for comparing these planter/drill systems was to evaluate the differences they may have in germination and plant stand consistency. The conventional seed meter devices for drills often result poorly spaced stands with many gaps. To compensate for this stand variability, many operators will over-seed their stands by percent. The interest in the drills with singulation devices similar to row-crop meter devices is due to the possibility to improve stands, reduce seed cost (from not overseeding), and reduce variability seen in conventional flute-meter devices. About 10 years ago, some research was conducted on conventional fluted-meter devices to evaluate them for variable rate seeding. The device performed very poorly for this test and showed that changing shaft speed or forward speed or gate opening greatly hindered the accuracy of population and spacing of the seed. As the seeds increased in size, the variability was even greater. The drill meter devices were usually not considered for the singulation accuracy because the small grains can usually compensate for the inconsistency but this may not be the case for soybeans. Fluted-meters have a cup on a rotating shaft and then an opening gate. Some accuracy and spacing uniformity can be gained with a very specific travel speeds and fixed population but this degrade quickly if travel speed is not consistent. Another problem that contributes to the lack of spacing uniformity was the distance from the meter to the seed furrow. The seed bounce and travel in the seed delivery tube greatly influenced the spacing uniformity. With these inherit problems of conventional fluted-meter devices, manufacturers have designed a spiral cup, and meter devices that singulate out the individual seeds (potential to plant corn) and have moved the meter device to reduce the travel distance to the seed placement. The new meter device on the Precision Seeding System has these singulation features and has a narrow profile that allows a 7.5-inch spacing. Its success in plant stand and spacing uniformity is covered in another section. The unit does have the potential to plant corn and hopeful some demonstration areas will be established to review this potential. Manufacturers have also adapted row-crop planters for narrow row (15 inch spacing) to give producers the seed singulation and spacing accuracy as well as a machine that could be used for both drilled and row-crops in one machine. Several manufacturers have configured row-crop planters so that they are easy to convert from 15 to 30 inch row spacing. Since the meter device in the Kinze and Precision Seeding Systems are very close to the ground, they are difficult to calibrate and check the seed population. Most recommend a static test and rotating the meter drive wheel. While this can be a reflection of the accuracy and uniformity of the individual units, it may not give accurate measurements for field conditions. Be prepared to spend some time in the field observing the seed spacing and calculating seeding population by digging into several seed furrows. 5

6 Metering Device Press Wheels and Depth Control Depth control of most no-till planter/drill systems comes in two methods: 1) gauging the depth from a gauge wheel adjacent to the seed furrow device, or 2) press wheel behind the seed furrow openers. In either case, keep adequate pressure on the gauge or press wheel to force the openers into the soil to proper depth. A harrow behind a drill ensures seed coverage and redistributes residue for effective conservation measures. Regardless of the depth control, wide-flat press wheels are unacceptable for no-till since they will ride on the firm soil adjacent to the seed furrow and do not firm the seed into soil. A wide press wheel equipped with a rib that runs on the sides of the seed furrow or a rib that runs directly over the furrow to press the seed is adequate for good seed-to-soil contact. Another option is to use a pair of angled press wheels behind the opener to gauge planting depth and close the seed furrow at the same time. When using angled press wheels, ensure that pressure is not placed on the seed furrow to the point that a ribbon of soil moves the seed up. Adjust the angle such that the angle of the press wheels meet at the seed depth. The disadvantage of any system using the press wheel for depth control is its distance from the seed opener. As the distance increases there a greater possibility that irregular terrain will influence both depth control and the press wheel s ability to provide good seed-to-soil contact. General Operation Since the planter/drill system must handle and cut the residue, allow the residue to dry and become crisp before planting. These conditions aid in the cutting and handling of the residue. The weight of the drill and pressure from the down-pressure springs are essential for cutting residue, penetrating the soil and preventing seed openers from bouncing over residue. Most manufacturers suggest operating speeds of 6 6

7 to 10 mph. While this hinders accurate metering from fluted-meter devices, a higher operating speed assists in residue flow, especially for planter/drill equipped with a coulter caddie and/or a harrow. Check seed depth. Drill depth control surveys from the mid-west indicated a strong tendency to plant much deeper than intended. Only 20% of the producers were at or near the intended depth, and 68% of the fields were planted too deep. Excessive depth delayed germination and reduced stands. These same surveys found that producers are much more accurate with population rate than with planting depth. Check for seeds on the ground. The closure and seed-to-soil contact device should be adjusted if seeds are found on the soil surface. Varying soil and residue conditions across the field. If depth control is insufficient due to soft soil conditions (sandy soils) or residue amounts are changing, check to see of the manufacturer offers some additional down-pressure spring kits that activate more spring pressure as conditions dictate and less when the down pressure is not needed. Check for hairpinning. When operating a planter/drill system in heavy residue, straw may be pushed in the seed furrow (hairpinning), reducing seed-to-soil contact, and slowing or reducing germination. Make sure the cutting angle on the coulter is correct and the cutting edge is sharp. Depending on the conditions, a smooth coulter may provide more needed cutting of residue than the tillage from a fluted coulter. The hairpin effect is minimized when seeding units operate on a firm soil, and when residue is dry and crisp. Simply waiting a little later in the day, when residue is drier, may greatly improve the operation of the planter/drill system. Successful planting/drilling with no-till equipment depends on specially designed systems that can uniformly place seed through heavy residue and into firm, moist soil. No-till equipment is available to achieve these results for good yields. Soybean Emergence Results from 2001 EVAREC Experiment The EVAREC Field day compared the use of three planter/drill systems. UniSouth Genetics brand 7528RR soybean was planted on July 3, 2001using either a 23/12-row planter, Great Plains Solid Stand 1200 no-till drill, or the newly introduced Precision Seeding System. The systems were operated at 5 or 7 mph. Seeding rate for the and ranged from 192 to 202 thousand seed per acre. Seeding rate for the Great Plains 1200 ranged from 198 to 250 thousand seed per acre. This variability with the standard drill is common and the increased average seeding rate reflects a common practice among users of drills in Virginia. However, the Great Plains 1520P drill showed no greater variability than the Kinze planter. Plot size was the width of the planter/drill by approximately 440 feet. A detailed plot plan is shown on the following page. No burndown herbicide was applied; instead, a Roundup application was planned within 1 week of planting. However, windy conditions prevented Roundup application until 3 weeks after planting. Due to late herbicide application, ragweed competition in areas of the field reduced soybean stands and growth. These areas were noted taken into account when analyzing stand data. Stand counts were taken on July 27 using a 34-inch diameter hula-hoop. Sixteen measurements were made within each plot. Soybean population data is presented in Tables 1 and 2. Areas of severe weed infestation were not included in this analysis. Emergence was generally poor for all equipment treatments, ranging from 55 to 63%. Wheat straw was damp and tough on the day of seeding and considerable hairpinning of the straw was noted. This poor soil-to-seed contact may have reduced percent emergence. Planter speed did not affect final population or percent emergence (Table 1). However, average populations were higher with the Great Plains 1200 drill, followed by the Great Plains 1520P, then by the (Table 2). These differences were due to the higher seeding rates for the Great Plains 1200 and better emergence, as there were no significant differences in percent emergence between seeding systems. 7

8 Plot plan for drill and planter comparison experiment at EVAREC, Warsaw, VA. 5 mph 7 mph 5 mph 7 mph 7 mph 5 mph 7 mph 5 mph Although little difference between average percent emergence between seeding systems were observed, the range in soybean population was much greater with the Great Plains 1200 than the other two systems as shown in Table 2. Many gaps were noted in the Great Plains 1200 plots, but were less evident with the other two seeding systems. These uneven stands are characteristic of standard drills. Table 1. Effect of planting speed on soybean population and percent emergence. Soybean Population (x 1000) Planting Speed Minimum Maximum Average % Emergence 5 mph a 58 a 7 mph a 60 a Table 2. Effect of seeding equipment on soybean population and percent emergence. Avg. Seeding Rate Soybean Population (x 1000) % Planter/Drill (x1000 seed/a) Minimum Maximum Average Emergence Great Plains a 59 a ab 63 a b 55 a From the above data, it is clear that the new precision drill from Great Plains distributes soybean seed more uniformly than a conventional no-till drill, resulting in similar stands as the Kinze planter. Average population for all treatments are lower than that required for maximum yields, therefore it was suspected that the higher population for the Great Plains 1200 drill would give it an advantage. However, the 8

9 uneven stand of this drill was also expected to lower yields; resulting in no net advantage of the standard drill over the split-row planter. Yield Results Yield was not affected by planting speed, but the type of planting equipment used did result in yield differences. The yielded highest, followed by the Great Plains 1200, then the. However, yield averages do not tell the entire story. Due to a lower seeding rate and percent emergence, the Kinze 3600 plots had a lower final plant population than the other two pieces of equipment (Table 2). Average population for all treatments were lower than that required for maximum yields, therefore higher populations would be suspected to result in higher yields. This may explain the lower yields for the, since this planter resulted in the lowest average plant population. However, if yield differences were solely related to plant population, then the Great Plains 1200 should have had the highest yield since that drill gave the highest populations. But yields for this drill were lower than the precision drill. The yield differences between the two drills are likely due to the more uniform stand achieved with the precision drill. Still, yield is definitely related to plant population, as revealed in Figure 1. For the and Great Plains 1200, yield increased with population. At low populations, the yields were actually higher than the Great Plains If higher populations could have been obtained with the Kinze and the population-yield trend continued, then yields with the Kinze planting would have likely been very similar to the Great Plains On the other hand, the yielded higher than the other planters at all populations; the yield of the Great Plains 1200 drill only approached the 1520P yields at the highest populations. Table 3. Effect of planting speed and seeding equipment on soybean yield. Planter/Drill Planting Speed 5 mph 7 mph Average Great Plains ab a b *Means followed by the same letter are not significantly different at P= Soybean Yield (bu/a) R 2 = 0.56 R 2 = 0.73 GP1200 GP 1520P Soybean Population (x1000 plants/a) Figure 1. Effect of planting equipment and soybean population on yield. 9

10 These data relate well to past small-plot research comparing 9-inch versus 18-inch row spacing at difference populations. In that research, 9-inch rows always out-yielded 18-inch rows, regardless of plant population. The same planter was used for both row spacing and the stand was uniform, regardless of row spacing. Likewise, the with 15-inch rows did not yield as high as the with 7.5-inch row spacing, where stands were also uniform for both pieces of equipment. On the other hand, non-uniform stands would likely result in lower yields. As this experiment showed, the Great Plains 1200 drill did not uniformly space the seed. This non-uniform spacing is likely the reason for this drill under-performing the precision drill; at similar populations, the yielded more than the Great Plains Cost Comparisons of Purchasing Equipment for 3 Cropping Systems Many producers are considering the purchase of either a drill, planter, or both. To make an informed decision, the producer will need a detailed economic analysis that includes yield and cost of production numbers. Equipment Cropping System Assumptions The purchase price of equipment necessary to put into practice a corn, wheat, double-crop soybean rotation can be determined from purchase price of new equipment and some assumptions on equipment life. The following is that cost comparison. 1) Equipment Cost a) Standard Drill 12 feet (conventional tillage) - $15,000 b) No-till Drill 15 feet - $30,000 c) Precisio n Drill 15 feet - $38,000 d) No-till Planter 6-row, 30 row spacing - $24,000 e) No-till Split-row planter 6/11-row, 30 /15 row spacing - $27,000 2) 2000 Acres of Crop Land a) 1000 acres of corn b) 1000 acres of wheat, double-crop soybean 3) 10 Years and 10,000 Acres of Useful Life (all five pieces of equipment) 4) Four Cropping System Options Acres Life (yr) a) Standard Drill 1000 acres of conventional-tilled wheat , No-till Split-row Planter 1000 acres of soybean , acres of corn b) No-till Drill 1000 acres of wheat , acres of soybean No-till Planter 1000 acres of corn , c) No-till Drill 1000 acres of wheat , No-till Split-Row Planter 1000 acres of soybean , acres of corn d) Precision Drill 1000 acres of wheat , acres of soybean 1000 acres of corn 10

11 Cost Comparison of Purchasing Cropping System Option Units Purchased over 10-year Period Unit Cost Total Cost over 10-year Period Standard Drill 1 $15,000 15,000 NT Split-row Planter 2 $27,000 54,000 $69,000 No-till Drill 2 $30,000 60,000 No-till Planter 1 $24,000 24,000 $84,000 No-till Drill 1 $30,000 30,000 NT Split-row Planter 2 $27,000 54,000 $84,000 Precision Drill 3 $38,000 $116,700 Although the above analysis is attempted to be fair, one must realize that the first option does not consider the soil, time, and equipment savings from continuous no-till production. Variable and fixed cost of operating and owning tillage equipment is not included and should be added to the final cost of purchasing equipment for the cropping system options. Seed Cost Comparisons and Assumptions Another consideration is the seed savings one will incur with either the split-row planter or precision drill. Approximately 27,000 more seed were used with the Great Plains 1200 drill, therefore increasing seed cost of Roundup-Ready seed by about $4 to $5 per acre (assuming seed/lb and $22-25 per bag of seed). UniSouth Genetics brand USG 7528RR soybean seed were 2700 seed per pound; therefore, we used this seed size in the analysis. 1. Roundup-Ready Soybean Seed: $24.50 per 50 lb. Bag 2. Seeding Rate a. Drill: 224,000 seed per acre b. Planter or Precision Drill: 197, Seed Size: 2700 seed per lb (USG 7528RR) Seed costs using a s tandard no-till drill versus a planter or precision drill. Seeding Rate Seed/acre Lbs/acre Bags/acre $/acre Drill 224, Planter / Precision Drill 197,

12 Yield Assumptions Acres Drill Costs Planter / Precision Drill Cost Planter / Precision Drill Savings 1 $40.65 $35.75 $ $4,065 $3,575 $ $20,325 $17,875 $2, $40,650 $35,750 $4,900 In order to pay for the increased seeding cost of the standard drill, a yield increase of at least 1 bushel per acre would be needed. Although a yield increase did occur with the Great Plains 1200 drill compared to the, this increase was due to lower plant populations and not row spacing. Therefore, we will assume that no yield increase will occur by using a standard no-till drill instead of a 15-inch planter, if planted at equal populations. On the other hand, the Precision Seeding System increased yield by 1.8 and 4.2 bushels per acre over the Great Plains 1200 and, respectively. Since this is consistent with past research conducted in Virginia, we will assume that one would obtain a 2-bushel per acre yield increase with this seeding system. If we assume that one could obtain an average price of $5.25 (after LDP payments), a net per acre benefit of the higher yields would be $ Therefore, total benefits of using the tested pieces of equipment would be as follows: Seeding System Seed Savings Value of Yield Increase Total per acre $ Benefit Total $ Benefit for 1,000 acres Great Plains $ $ 4.90 $ 4,900 $ 4.90 $10.50 $ $ 15,400 Summary One must first realize that we have completed only one year of research comparing the three seeding systems. More research is needed before an accurate assessment of the utility of the new precision drill can be fully assessed. We plan to conduct the above experiment again next year at the same location. Other trials using other pieces of equipment may also be in order. But, until further research is accomplished, the above conclusions should not be the only factor in one s decision to purchase a drill, planter, or precision drill for soybean. Still, this research conducted by the authors seem to validate previous small-plot research; narrowing rows from inches to inches will result in double-crop soybean yield increases if stands are uniform. The same results would not be expected with full-season soybean since more time is available to accumulate needed growth. Soils, seasonal rainfall, and plant populations will also alter results and need evaluation. In summary, although the new drill is rather expensive, the increased soybean yield potential and reduced seed cost makes it more attractive. 12

13 Loading seed into the. The 23/12 Split-Row Planter. The Great Plains Solid Stand The Precision Seeding System