Putting Planters to the Test
The question caused Tom Jensen to grimace a bit as he steered his combine down the sunflower rows. Jensen’s 2007 irrigated confection field was yielding well; but his chagrin sprang from the question about consistency of plant stands. The western Nebraska producer readily agreed that his stand wasn’t as uniform as he’d like it to be — and that the problem ultimately traced back to the planting seeds’ being so large and irregularly shaped, compared to the other crops for which he used his planter.
“There’s nothing worse than planting large-seeded sunflower,” Jensen affirmed with a wry smile. “I don’t care what brand of planter you use. We’ve had different brands, and we’ve always had the same kinds of headaches: which planter plates to use, what air pressure setting, ‘what this, what that.’ There’s a lot of room for improvement.”
Jensen, who seeded his ’07 crop with a John Deere MaxEmerge II, would like to see planter manufacturers place more research and development emphasis on confection sunflower. “Sometimes you just tear your hair out and think, ‘I guess that’s as good as we can do,’ ” he observed. “Sometimes you hit your mark; sometimes you don’t. So you just do what you can — and go from there.”
About 40 miles to the southwest of Jensen’s Box Butte County farm, University of Nebraska-Scottsbluff ag engineer John Smith is generating research data that hopefully will help alleviate the problems faced by Jensen and other confection sunflower producers. This fall, in a study funded by the National Sunflower Association, Smith conducted tests on metering units and their associated seed tube from a Case IH 1200 series flat-plate system, a John Deere MaxEmerge vacuum planter and a JD finger pickup series. He chose to test those three based on their wide usage for planting sunflower.
Smith focused on the main components of each unit that might be interchanged, e.g., plates, brushes, vacuum plates, fingers. He then zeroed in on the best option offered by the manufacturer for that particular unit.
Seed spacing was measured on the opto-electronic sensing test stand developed by Smith and his associates at the University of Nebraska. This unit can account for when the seed passes through the sensor system as well as where it passes through. It senses the seed below the seed tube at the depth of where the seed would contact the bottom of the seed furrow. Its grease belt also provides a visual evaluation opportunity.
Smith used 9” as the targeted in-row seed spacing, with 4.5 miles per hour being the standard ground speed. (He also evaluated seed drop at 3.0 and 6.0 mph.) Tested seed types included (1) a large, long/narrow confection variety, (2) a small confection variety and (3) a #2 oil-type variety. The larger confection seed length was commonly around 3/4” and sometimes closer to 7/8”.
For both the Case and Deere vacuum planters, Smith examined sensitivity to vacuum as well as singulator sensitivity. He also evaluated seed drop with both a new and worn tube for each type of planter.
The tests incorporated four replications, with more than 300,000 seeds dropped over the course of the study. The table on the next page summarizes Smith’s findings in terms of how accurately the various units placed the seeds.
Of the three parameters Smith used to describe seed spacing performance, two are defined by the International Standards Organization (ISO).
• The first, “ISO close spacing,” refers to placement that is less than one-half the target spacing. In this case, that would be seeds spaced less than 4.5” apart (the target having been 9”). Most spacings in this category are actual “doubles” but also include very close spacings.
• The second, “ISO wide spacing,” refers to seed placement greater than one and one-half times the target spacing — i.e., 13.5 inches or greater in the UN study. This group would include mostly “skips” but also a few very long spacings.
• The third performance parameter was called “CP3.” This indicates the percentage of seeds falling within ± 0.5” of the target spacing (9” in this study). So the higher the percentage within this category, the better the spacing accuracy.
Smith’s preliminary evaluation of the Case vacuum planter is that it performed very well with the long confection seeds. The best seed drop consistency with the long/narrow confection variety occurred when using plate #2440 with 26” of water vacuum, singulator setting #2 and a new tube. “At this optimum setting, ISO-close and ISO-wide spacings were below 2%, and the CP3 was above 55% — which is a very good singulation and spacing performance,” the Nebraska ag engineer indicates. Optimum vacuum pressure with the smaller confection variety and the #2 oil-type was 17” (The singulator setting for small confection was #1 and for the #2 oil-type it was #2). The CP3 rating for the small confection was nearly 60%; for the #2 oil-type, almost 70%. “One thing to look for when planting sunflower with the Case IH model 1200 planter is seed fragments sticking in the seed plate hole,” Smith says. “The sunflower plates for this planter have 24 holes. If one hole plugs, seed population will be reduced by 4%. Watch the seed population on your planter monitor very carefully. If you have one row that is about 4% (or a multiple of 4) less seed population than the other rows, remove the plate and check for a plugged hole — it does happen and will cause skips.”
With the Deere vacuum planter and large, narrow confection variety, the best results were with “flat plate” #A52391, with the doubles eliminator set with 3/4 of the hole covered and 12” of water vacuum. “At this best setting, ISO close spacings were about 6%, ISO wide spacings were about 3% and the CP3 was about 35%,” Smith says. “This is not as good as the Case planter, but it’s probably acceptable, considering the difficulty of singulating this particular seed.” Smith says adjusting the doubles eliminator and vacuum “could reduce the percentage of either wide spacings or narrow spacings — but only at the expense of increasing the percentage of the other.”
The same flat plate proved the best option for the small confection variety and #2 oil-type as well. Top performance with the JD vacuum unit for these two seed types was attained with 3/4 of the hole covered and vacuum settings of 5” and 6”, respectively. The CP3 rating for the small confection was just under 40%, while it was about 48% for the #2 oil.
For Deere planter owners not familiar with the “flat plate” system, “the doubles eliminator must be in place and must be carefully adjusted,” Smith notes. “This adjustment may need to be changed if the planter field speed is very slow or very fast.” Several “cell-type” plates — including those for corn and peanuts — were evaluated; but none were even close to acceptable, according to Smith. The Precision Planting “eSet” option for the Deere vacuum planter did improve seed spacing performance over the Deere plate options. (The eSet kit includes a new plate, a brush and singulator.) “We did not test the eSet to the extent I would necessarily recommend it,” Smith says, “but the eSet kit with plate 7200034 was better than the best Deere option we tried.”
The most serious problem the Scottsbluff researchers found with the Deere vacuum unit and the long, narrow confection sunflower was that of an occasional seed sticking in the tube. It happened about once in every 5,000 seeds; but when it did, it resulted in very inconsistent placement from that point onward. While the seed tube did not plug, each ensuing seed would hit the lodged seed, leading to a very inconsistent spacing. “The bad part is that the planter monitor will not sense the stuck seed, so the operator will never know,” Smith points out. He does not know how often this actually happens in the field, but assumes if it happened that often on his test stand, it must happen at least occasionally in the field.
The Scottsbluff group used the curved corn seed tube — the largest available from Deere. So the only solution (until Deere develops a different tube for the long confection sunflower seeds) is for the operator to occasionally stop, remove the tubes and check to make sure there are no stuck seeds — a practice which, in reality, is not very practical.
Another issue — but far less serious then the stuck seed, in Smith’s opinion — is that of worn seed tubes. “A worn seed tube — one that feels like used sandpaper on the inside front surface that contacts the seed — will deliver the correct number of seeds; but seed spacing accuracy is not as good as that with a new seed tube,” he notes.
Tests on the John Deere finger pickup planter indicated excessive skips with the long/narrow confection seeds. “The best Deere configuration was with the long fingers,” Smith says. “But with the large, narrow confection seed, we had approximately 8% close spacings (doubles) and 23% long spacings (skips).”
The best results for the smaller confection variety with the finger pickup unit occurred with the Deere short fingers (42.3% in CP3); for the #2 oil-type variety it was the Deere long finger (nearly 60% in CP3). The Deere backing plate and brushes were used in both instances.
Illinois-based Precision Planting offers several optional parts for the finger pickup assembly. “These components reduce the numbers of both close and wide spacings; but we still exceeded 10% skips with the best combination we tested,” Smith reports.
The size of the seed exit hole in the back plate can make a difference in the number of skips. “We compared two Kinze backing plates and found that the smaller hole (designed for corn) had 36% skips,” Smith observes. “The larger hole (original size and shape for both Deere and Kinze) had 15% skips.”
Since the Deere finger pickup planter uses the same or similar seed tube as the vacuum planter, the Scottsbluff investigators again encountered the problem with single seeds sticking crossways in the seed tube — which resulted in “an almost-random seed spacing pattern.”
One of Smith’s concerns about planting these large, narrow confection sunflower seeds is: how does the planter operator accomplish the correct planter adjustments like vacuum or singulator settings? And, how does the operator know the planter is delivering seed properly while planting? The operator can probably trust the planter monitor in the field to provide accurate seed population measurement. But most monitors provide only an average population or seed spacing, without any information on the variability of individual seed spacings.
For example, if all seeds were spaced at exactly 9”, the monitor would indicate 9” seed spacing. But if the seed spacing pattern was 1”-17”-1”-17”-1”-17”, etc. (one double, then one skip), the monitor would indicate the average spacing is 9”. So the seed population would be correct, but seed spacing would be unacceptable.
Smith suggests using a planter monitor that does provide information on seed spacing variability (one example being Precision Planting’s planter monitor) — or, use the combination of a standard planter monitor and frequent checking of seed spacing in the furrow behind the planter. If a producer is starting with an unfamiliar planter or a different seed size or shape, it is a good idea to have that seed run in his particular planter meter on a good planter test stand.
Smith’s planting accuracy studies with sunflower may take on another dimension in 2008, as he is submitting a proposal to the National Sunflower Association Research Committee to conduct a similar study on oil-type sunflower varieties, and to evaluate any additional components that will help planter performance for the large, narrow confection seed.
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