DLG e.V. - Test: John Deere 1725 NT ExactEmergeTM

John Deere 1725 NT ExactEmergeTM corn planter DLG APPROVED Function Test including fertilizer distribution across rows

Assessment – Brief Summary

For a machine to be awarded the “DLG APPROVED Function Test” quality mark after a function test that covers fertilizer distribution across rows, it has to score at least ‚satisfactory‘ results in three corn varieties. The present test confirms that the tested machine meets these requirements and deserves being awarded the DLG quality mark.

Lab test  

The standard deviations as computed from the measured seed spacings were assessed as ‘very good’ and ‘good’. The percentages of doubles and skips that resulted in the lab test were rated as ‘very small’ and ‘small’. The assessment of fertilizer distribution across rows was rated as ‘very good’ according to the DLG assessment matrix. The deviations between the set target rate and the actual rate ranged between 0.1 % and 4.6 % in the 18 test versions.

Field test

The standard deviations that were computed from the measured crop spacings were assessed as ‘very good’ by the DLG assessment matrix. The percentage of doubles in all field test runs ranged between 0.2 % and 1.1 %. The percentage of gaps was between 2.0 % and 9.4 %. Nevertheless, in 79 % of these gaps it was found that the seeds had indeed been placed at the correct depth and also covered with soil. The seeds had germinated but then stopped growing due to lack of water (19 mm rainfall in five weeks). The percentage of emerged crop ranged between 91.5 % and 98.1 %, which is rated as ‘very good’.

The product

John Deere 1725 NT ExactEmergeTM 8-row corn planter with John Deere FT 180 fertilizer system

Description and technical data

The tested machine is the John Deere 1725 NT ExactEmergeTM 8-row corn planter complete with the FT 180 fertilizer system.

John Deere 1725 NT ExactEmergeTM 8-row corn planter

The eight row units are mounted on a box section bar via a parallel linkage (Figure 2). Each row unit has a 56 l (1.6 bushel) seed hopper.

The fertilizer is planted subsurface by a double-disc coulter which runs ahead of the row unit. This double-disc coulter is followed by another double-disc coulter (John Deere Tru-VeeTM opener) which prepares the slot for seed placement. Two rubber wheels run alongside this double-disc coulter providing depth control for the entire row unit. These two depth control wheels are followed by two closing wheels. Seed depth and firming pressure are adjusted on two separate levers.

Figure 3: Side view of a row unit (incl. the air bag cylinder, brush belt and seed singulation bowl)

All eight row units have so-called air bags which control the coulter pressure. The manufacturer says that these air bags prevent the row units from bouncing at high working speeds. The down force for the row units is entered to the terminal by the operator. Three of the eight row units have down force sensors which detect the current downforce margin, which is then adjusted by the air bags. The current pressure is also read out on the terminal and displayed in bar graphs, one bar representing one row unit. The bar graph of a specific row unit is red when the pressure is too low or too high relative to the set value. Seed singulation takes place utilizing the so-called seed bowl (Figure 3, top middle). Here the seeds are sucked into the individual holes (32 hole on each bowl) by a vacuum and after a quarter of a turn delivered to a so-called brush belt. The bristles on the brush belt fix the seeds in place as the belt takes them into the furrow, preventing roll in the slot. The speed of the endless brush belt (similar to a conveyor belt) is synchronized with the tractor’s ground speed in direction of travel. When the seed is placed, its horizontal speed is identical with the tractor’s ground speed, so it is placed without roll. The singling dish and brush belt are driven electrically.

The seed singulation system is monitored by a reflective sensor on the belt housing. This sensor scans the actual spaces between the individual seeds and transmits the data to the operator terminal where it is computed into percentages of target spacings (population), doubles and skips. The coefficient of variation, too, is constantly measured and read out to the operator.

The row units are calibrated by using the calibration run off mode offered by the precision planter and used via the operator ter­minal. Here, the operator enters the target speed (GreenStar-Terminal GS2630) and the target seed rate per hectare. Then he presses a button to start the calibration. He has the option of calibrating only one row unit or all of them at once.

The speeds of both the singulation unit and the brush belt are always synchronized with the tractor’s forward speed. This is detected by an on-board dual-beam radar sensor or a GPS receiver. Each row unit is assigned its own individual speed (Curve Compensation) which ensures the seed spacing does not vary in curves, says the manufacturer.

The 8-row John Deere 1725 NT ExactEmergeTM 8-row corn planter is equipped with very dynamic electric motors. Two such 56V DC motors are installed on each row unit (one driving the singling dish and one the brush belt). These motors are driven by a PTO-driven alternator.

The corn planter also includes a Wireless Data Server. This device collects information from all sensors on the drill plus additional machine data and communicates it via Wi-Fi. The data can be processed and plotted by an in-cab iPad and the SeedStar Mobile application and transmitted in real time to the myJohnDeere.com cloud (Figure 4).

The John Deere precision drill has a GPS based automatic row-shut off system, which progressively switches all eight row units off as the tractor travels into a wedge. Figure 5 shows corn planted on a headland by using the row auto shut-off system. This GPS controlled shut-off system was not part of the DLG test.

Figure 4: The SeedStar Mobile app in use on an iPad

Figure 5: Individual rows were shut off automatically and GPS controlled

John Deere FT 180 fertilizer placement system
The John Deere FT 180 fertilizer system was tested with a 1,800-litre tank mounted at the tractor’s front hitch. The application rate is controlled by a cell wheel that is driven by an electric motor. During the DLG test the unit was powered by an electric line from the tractor’s rear end.

It is essential that the cell wheel’s circumferential speed matches the tractor’s forward speed. This is detected by a radar speed sensor on the front tank and fed to the processor.

The John Deere FT 180 system comes with a separate operator terminal. Here, the operator enters the target rate in kg/ha before it starts the calibration. The software will then suggest a specific gearbox configuration, which the operator has to set manually on the metering gearbox (choosing either the ‘micro’ setting for less than 85 kg/ha or ‘macro’ for more than 85 kg/ha).

He moves the red pinion either to the right or left (Figure 6). The proper cell wheel aperture is suggested by the software and set manually as well. Yet cell wheel speed is set automatically.

After that, calibration is started. a bag is supplied with the machine to collect the calibrated fertilizer which can then be verified with the help of a spring balance which also supplied with the machine.

The result of the calibration test is then entered in the terminal. After that, the system sets the cell wheel speed automatically to the target application rate.

Figure 6: The gearbox on the John Deere FT 180 fertilizer placement system

The Method

The DLG ‘function test incl. fertilizer distribution across rows’ requires to subject precision drills to both a lab test and a field test

Lab test

The lab test measures accuracy of seed placement and seed distribution in direction of travel as well as fertilizer distribution across the direction of travel by simulating various speeds on the stationary machine. The results are assessed in line with the DLG test framework for precision drills.

Placement accuracy and seed distribution

The accuracy of seed placement and the seed distribution is measured by optical sensors that are installed on the coulter outlet in a position where the seeds leave the machine. This optical sensor detects the distance between two seeds as they drop into the furrow. One series of tests comprises four runs and produces 250 seed spacings detected in each run, hence 1,000 seed spacings per test series.

Based on these 1,000 speed spacings, the testers compute the standard deviation of seed placement (after removing doubles and skips from the analysis) and assess the result in line with the applicable DLG test framework for precision drills. The standard deviation is a parameter that defines how uniformly the seeds are spaced in the furrow. The smaller this value the more uniform is the seed spacing.
Also, these 1,000 measurements are used to determine and evaluate the seed distribution (number of target spacings, doubles and gaps). (See table 1 for seed distribution).

Scroll table to the right to see full display !

Table 1: Seed distribution

Percentage of doubles [%] < 0.5 times the actual spacing
Percentage of target spacings [%] > 0.5 to < 1.5 times the actual spacing
Percentage of skips [%] > 1.5 times the actual spacing
Percentage of single skips >1.5 to < 2.5 times the actual spacing
Percentage of double skips [%]: > 2.5 to < 3.5 times the actual spacing
Percentage of triple skips [%]: > 3.5 to < 4.5 times the actual spacing
Percentage of four-fold skips [%]: > 4.5 times the actual spacing

All drill settings were documented throughout the entire lab test (including air pressure and the vacuum generated by the fan, the seed bowls used, positions of the top and bottom double eliminators).

Fertilizer distribution across the direction of travel

The distribution of fertilizer across rows is determined on the jacked up stationary machine, with wheels running at various speeds and the application system set to various rates. The drilled granules are collected in boxes that are placed under the coulters. Then the collected samples are weighed and the coefficient of variation is determined (CoV). The smaller the coefficient of variation the more uniform is the distribution of fertilizer granules across the working width. The coefficient of variation is assessed according to the DLG test framework.

Along with fertilizer distribution across rows the test also determines the difference between the set target rate and the actual application rate.

Further test parameters measured are the bulk density of the fertilizer, as well as the temperature and humidity inside the test hall.

Field test

The DLG Function Test requires a planter to drill at least three different varieties of different corn shapes, planting these at various ground speeds. It is advisable to conduct the test in two different fields. All data including the history of the field (previous crop, preparation), the conditions at the time of planting and the individual ground speeds are logged during the test.

The field is marked out to flag the individual test versions and a detailed test plan is set up. The varieties used in the test are specified by variety, producer and thousand grain weight. The test conditions are determined by sampling the soil and measuring the moisture level in the seed layer. The soil moisture is determined to DIN 1812 standards.

Germinability of the seeds is determined at the lab.

Random checks on fertilizer placement are also carried out during drilling. Two or four weeks after the corn was planted, the crop spacing is measured using a mobile meter. The method is to measure four by 250 crop spacings inside the row (=1,000 spacings) in each test version. A test version is defined by the corn variety drilled and a specific ground speed.

These field spacings are used to compute the accuracy of placement, seed distribution and emergence. Then the seed accuracy and emergence are assessed in line with the DLG test framework on precision drills. The percentages of target spacings, doubles and gaps are not assessed in a field test, because a higher percentage of gaps can be attributed to environmental factors such as bird damage or poor seedbed preparation.

The Test Results in Detail

The results of both the field and  lab tests are plotted and discussed on the following pages.

Lab test

Seed placement accuracy and distribution
This DLG test tested seed placement accuracy and distribution for the following four corn varieties:

  • Variety Carolinio from KWS (TGW 238 g)
  • Variety Torres from KWS (TGW 360 g)
  • Variety Atletico from KWS (TGW 341 g)
  • Variety Katy from KWS (TGW 221 g)

To determine seed accuracy and distribution, the DLG Test simulated the following speeds: 8, 12, 16 and 20 km/h. The target spacing entered to the terminal was 14 cm (which translates into 95,240 plants per hectare).

The results on accuracy of seed placement and seed distribution achieved at the lab are listed in table 3. The standard deviation as a measure for uniformity of seed spacings ranges between 7.53 mm (Katy variety drilled at 8 km/h) and 14.48 mm (Carolinio variety drilled at 20 km/h. The highest standard deviation measured during the DLG test was 14.48 mm and was rated as ‘good’ according to the DLG grading system.

Figure 7: Standard deviations of all four corn varieties at the lab relative to ground speed

Figure 7 plots the computed standard deviations relative to ground speed. The diagram shows that all corn varieties drilled in the lab test tended to produce a higher standard deviation as ground speed increased. Consequently, uniformity of the corn spacings declined. Standard deviation of the Katy variety (small and droplet type of grain) was smaller than the Atletico variety (large and round corn).

The percentages of target spacings, doubles and gaps are listed in table 3. The percentages of doubles and gaps ranged between 0 % and 1.0 % in all test runs. A 1.0 % percentage of gaps and doubles is qualified as ‘small’ by the DLG assessment system. The largest percentage of doubles and gaps was produced by the variety Atletico (large seed, round shape). The smallest percentage of doubles and gaps was produced by the variety Katy (small seed, droplet shape).

Fertilizer distribution across the direction of travel
The ground speeds and fertilizer application rates for this part of the DLG test are listed in table 2.

The distribution of fertilizer granules was measured by applying DAP fertilizer (percentage of nutrients: 18 % nitrogen, 46 % phosphate). The bulk density of the granulated product was 961 g/dm3. The measurements were carried out in a hall at temperatures ranging between 21.7 °C and 24.8 °C and a 36 % to 44.8 % humidity.

Scroll table to the right to see full display !

Table 2: Measuring fertilizer distribution across rows: application rates and ground speeds

Fertilizer/ha Ground speed Nominal area covered
60 kg DAP 8, 10, 12, 14, 16 and 20 km/h 1 ha
120 kg DAP 8, 10, 12, 14, 16 and 20 km/h 0.5 ha
200 kg DAP 8, 10, 12 and 14 km/h 0.25 ha
300 kg DAP 8 and 10 km/h 0.25 ha

Scroll table to the right to see full display !

Table 3: Lab results on accuracy of seed placement and seed distribution

Corn variety and ground speed Vacuum [mm H2O] CoV* [%] SD** [mm] SD** score Doubles [%] Doubles [%] score No. of target spacings [%] Skips (1) [%] Skips (2) [%] Skips (3) [%] Skips (4) [%] Score on gaps Target spacing [mm] Actual spacing [mm]
Carolinio, 8 km/h 480 0.06 8.48 very good 0.3 very low 99.3 0.4 0.0 0.0 0.0 very low 140 140.44
Carolinio, 12 km/h 480 0.06 8.73 very good 0.3 very low 99.3 0.4 0.0 0.0 0.0 very low 140 140.39
Carolinio, 16 km/h 480 0.08 10.84 good 0.3 very low 99.1 0.6 0.0 0.0 0.0 low 140 140.37
Carolinio, 20 km/h 530 0.10 14.48 good 0.1 very low 99.1 0.8 0.0 0.0 0.0 low 140 140.65
Torres, 8 km/h 390 0.07 9.98 very good 0.1 very low 99.7 0.2 0.0 0.0 0.0 very low 140 140.43
Torres, 12 km/h 390 0.06 9.01 very good 0.2 very low 99.7 0.1 0.0 0.0 0.0 very low 140 140.35
Torres, 16 km/h 425 0.07 10.29 good 0.3 very low 99.6 0.1 0.0 0.0 0.0 very low 140 140.15
Torres, 20 km/h 425 0.08 10.82 good 0.3 very low 99.6 0.1 0.0 0.0 0.0 very low 140 140.12
Atletico, 8 km/h 580 0.07 9.54 very good 0.6 low 98.8 0.6 0.0 0.0 0.0 low 140 140.43
Atletico, 12 km/h 620 0.07 10.48 good 0.4 very low 99.1 0.5 0.0 0.0 0.0 low 140 140.32
Atletico, 16 km/h 620 0.08 11.37 good 1.0 low 98.7 0.3 0.0 0.0 0.0 very low 140 140.36
Atletico, 20 km/h 620 0.09 12.02 good 0.3 very low 99.6 0.1 0.0 0.0 0.0 very low 140 140.67
Katy, 8 km/h 390 0.05 7.53 very good 0.0 very low 99.8 0.2 0.0 0.0 0.0 very low 140 140.57
Katy, 12 km/h 465 0.06 8.12 very good 0.2 very low 99.5 0.3 0.0 0.0 0.0 very low 140 140.36
Katy, 16 km/h 580 0.07 9.76 very good 0.0 very low 99.8 0.2 0.0 0.0 0.0 very low 140 140.36
Katy, 20 km/h 580 0.08 11.21 good 0.1 very low 99.9 0.0 0.0 0.0 0.0 very low 140 140.36

*= Coefficient of variation (CoV)       ** = Standard deviation (SD)
The ‘corn’ singling dish was used in all test runs. The varieties Atletico, Carolinio and Katy were drilled with the double eliminator set to ‘Center’. The variety Torres was drilled with the double eliminator set to ‘Minimum’ in all tests.


Table 4 shows the coefficients of variation of fertilizer distribution as well as the difference between the set fertilizer rate (target rate) and the actual rate applied.

The CoV values on fertilizer distribution across rows obtained in the 18 test runs range from 2.3 % to 8.9 %. These results are rated as ‘good’ (+) and ‘very good’ (++) according to the DLG grading system.

Scroll table to the right to see full display !

Table 4: Set target rates, actual fertilizer rates applied and coefficients of variation (VoC) as parameters for assessing the distribution across rows at various speeds (lab results)

Set application rate [kg/ha] Ground speed [km/h] Area [ha] Actual rate applied [kg/ha] Difference between target and actual rate [%] CoV CoV score
60 8 1,00 60,47 0,8 7,8 +
60 10 1,00 60,06 0,1 8,4 +
60 12 1,00 59,93 -0,1 8,9 +
60 14 1,00 58,22 -3,0 8,9 +
60 16 1,00 61,33 2,2 7,9 +
60 20 1,00 61,11 1,8 7,8 +
120 8 0,50 118,80 -1,0 7,5 +
120 10 0,50 121,48 1,2 7,5 +
120 12 0,50 119,17 -0,7 7,9 +
120 14 0,50 116,60 -2,8 7,2 +
120 16 0,50 119,37 -0,5 3,3 + +
120 20 0,50 119,25 -0,6 2,7 + +
200 8 0,25 199,76 -0,1 7,3 +
200 10 0,25 199,25 -0,4 2,8 + +
200 12 0,25 197,36 -1,3 2,3 + +
200 14 0,25 197,84 -1,1 8,9 +
300 8 0,25 301,93 0,6 3,4 + +
300 10 0,25 286,06 -4,6 3,1 + +

*   Grading system: + + = CoV ≤ 5  % / + = CoV ≤ 10  % /  = CoV ≤ 15  % / - = CoV > 15  %

The difference between target and actual rate ranged between 0.1 % and 4.6 % (table 4). These results are negative in some instances, because the target rate was less than desired in some tests. The biggest deviation was -4.6 % and was produced at a target rate of 300 kg DAP/ha applied at 10 km/h. The right column in this table lists the flow rate during each test run.

The maximum application rate at 14 km/h is 200 kg DAP/ha, as machine design limits the rate. The maximum application rate at 10 km/h is 300 kg DAP/ha.

Field test

The test site was a loamy loess soil field. After the previous sugar beet crop the field had received a 40 cm deep soiling pass in spring 2015 which was followed by two cultivator passes. A few days before the corn was drilled into the soil, the field received a shallow pass with the harrow. The prepared seedbed was described as fine tilth (Figures 8 and 9). The moisture level of the sampled soil was 24.1 %. The samples were taken at drilling depth.

On April 16, 2015, the following three corn varieties were drilled:

  • Variety Carolinio from KWS, thousand grain weight: 238 g, germinability: 98 % (LUFA agricultural research institute)
  • Variety Torres from KWS, thousand grain weight: 360 g, germinability: 97 % (LUFA agricultural research institute)
  • Variety Ferarixx from RAGT,  thousand grain weight: 355 g, germinability: 98 % (LUFA agricultural research institute)

The seeds were planted at ground speeds of 8, 10, 12, 14, 16, 18 and 20 km/h.
After planting, the testers randomly uncovered a number of seeds within the row. Figure 10 shows

Ferarixx corn seeds, drilled at a work rate of 20 km/h and uncovered for picture purposes.
The fertilizer was placed in bands by the subsurface placement unit. Placement was measured randomly and the results were by and large in line with the target distribution (5 cm next to the seeds and 5 cm beneath the seeds).

19 mm of rain fell in the period between date of planting April 16 and the day on which the crop spacings were evaluated (the maximum rainfall on a single day was 4 mm).

The crop spacings were measured on May 19 and 28, 2015. The John Deere 1725 NT ExactEmergeTM corn planter had achieved the following results (table 5):

Figures 8 and 9: The seedbed prepared for corn planting on April 16, 2015 (loamy less soil)

Figure 10:
Uncovered Ferarixx corn seeds, drilled at a work rate of 20 km/h

Scroll table to the right to see full display !

Table 5: Field results on accuracy of seed placement and seed distribution as well as emergence

Corn variety and ground speed Vacuum [mm H2O] CoV* [%] SD** [mm] SD** score Doubles [%] No. of target spacings [%] Skips (1) [%] Skips (2) [%] Skips (3) [%] Skips (4) [%] Target spacing [mm] Emergence [%] Actual spacing [mm] Emergence score
Carolinio, 8 km/h 480 0.16 21.48 very good 0.5 95.2 4.2 0.0 0.1 0.0 140 136.66 96.1 very good
Carolinio, 10 km/h 480 0.16 21.79 very good 1.1 94.6 4.3 0.0 0.0 0.0 140 135.64 96.2 very good
Carolinio, 12 km/h 480 0.15 21.55 very good 0.4 94.2 5.0 0.4 0.0 0.0 140 139.07 95.3 very good
Carolinio, 14 km/h 480 0.17 23.39 very good 0.3 92.7 6.9 0.1 0.0 0.0 140 137.23 94.4 very good
Carolinio, 16 km/h 480 0.17 23.00 very good 0.6 91.6 7.1 0.6 0.1 0.0 140 136.83 93.0 very good
Carolinio, 18 km/h 480 0.17 23.49 very good 0.2 91.7 7.9 0.1 0.1 0.0 140 135.51 93.5 very good
Carolinio, 20 km/h 480 0.18 24.26 very good 0.7 89.9 9.0 0.2 0.1 0.1 140 136.97 91.5 very good
Torres, 8 km/h 480 0.15 21.02 very good 0.3 97.7 1.9 0.1 0.0 0.0 140 137.14 98.1 very good
Torres, 10 km/h 480 0.16 22.22 very good 0.5 97.1 2.4 0.0 0.0 0.0 140 134.87 97.7 very good
Torres, 12 km/h 480 0.17 22.47 very good 0.7 96.9 2.2 0.2 0.0 0.0 140 136.08 97.6 very good
Torres, 14 km/h 480 0.17 23.06 very good 0.6 96.0 3.3 0.1 0.0 0.0 140 136.59 97.1 very good
Torres, 16 km/h 480 0.17 23.36 very good 0.4 95.4 4.1 0.1 0.0 0.0 140 136.28 96.7 very good
Torres, 18 km/h 480 0.17 23.61 very good 0.8 94.2 4.8 0.2 0.0 0.0 140 136.14 95.6 very good
Torres, 20 km/h 480 0.18 24.38 very good 0.4 93.7 5.3 0.6 0.0 0.0 140 134.72 94.7 very good
Ferarixx, 8 km/h 480 0.15 20.65 very good 0.7 94.8 4.5 0.0 0.0 0.0 140 137.16 95.8 very good
Ferarixx, 10 km/h 480 0.17 23.28 very good 0.3 93.0 6.4 0.3 0.0 0.0 140 136.89 94.0 very good
Ferarixx, 12 km/h 480 0.17 22.80 very good 1.0 92.9 5.8 0.2 0.1 0.0 140 136.24 94.3 very good
Ferarixx, 14 km/h 480 0.17 23.22 very good 0.6 93.2 5.8 0.4 0.0 0.0 140 135.90 94.6 very good
Ferarixx, 16 km/h 480 0.17 23.23 very good 0.7 92.4 6.6 0.3 0.0 0.0 140 135.87 94.1 very good
Ferarixx, 18 km/h 480 0.16 22.04 very good 0.6 91.9 6.8 0.6 0.1 0.0 140 135.65 92.9 very good
Ferarixx, 20 km/h 480 0.17 23.66 very good 0.4 94.0 5.3 0.3 0.0 0.0 140 136.16 95.0 very good

*= Coefficient of variation (CoV),   ** = Standard deviation (SD)
The ‘corn’ singulation bowl was used in all test runs. The variety Carolinio was drilled with the double eliminator set to ‘Medium’ in all tests. The variety Torres was drilled with the double eliminator set to ‘Maximum’ in all tests. The variety Ferarixx was drilled with the double eliminator set to ‘Minimum’ in all tests

In the field, the standard deviation in crop spacing ranged between 20.65 mm (Ferarixx, drilled at awork rate of 12 km/h) and 24.38 mm (Torres, drilled at a work rate of 20 km/h). The measurements showed that for all varieties the standard deviation was ‘very good’. The data are also listed in the table mentioned.

Figure 13 shows the standard deviations relative to working speed. These field results reflect the same trend as the lab results: The standard deviation increases only slightly when working speed increases (4 mm as ground speed increases from 12 km/h to 20 km/h).

The DLG Test does not assess the number of doubles and gaps in the field. The number of doubles produced by the variety Carolinio ranged between 0.2 % and 1.1 % in this test. The number of doubles produced by the variety Torres ranged between 0.3 % and 0.8 %. The number of doubles produced by the variety Ferarixx ranged between 0.3 % and 1.0 %.The percentage of gaps produced by the variety

Carolinio ranged between 4.3 % and 9.4 %. The percentage of gaps produced by the variety Torres ranged between 2.0 % and 5.9 %. The percentage of gaps produced by the variety Ferarixx ranged between 4.5 % and 7.5 %.

Crop spacing was assessed on May 28, 2015 by uncovering 67 gaps in the test field. These 67 gaps were distributed uniformly across all 21 test versions. In 53 of all 67 gaps  (79 %) the testers  found seeds that had been placed in the proper space. The John Deere planter had placed them accurately at the correct spacing and at the correct depth and covered them with soil. In the remaining 14 gaps (of the total of 67) no seed were discovered in the rows. This translates into a percentage of 21 %.

The grains that were uncovered in the gaps had germinated but had stopped growing due to lack of rain (only 19 mm rainfall in five days). The soil in these gaps was smeared, dry and hardened.

This suggests that non-uniform crop growth in some plots was caused by lack of water so that the germinating roots were unable to penetrate the hardened wall at this specific spot of the slot (Figure 11). As a result, the seedlings stopped growing due to lack of water (only 19 mm rainfall in five weeks).

Despite the gaps, emergence in all varieties was ‘very good’ according to the DLG assessment system. The differences in emergence between the three varieties of crops Carolinio, Torres, and Ferarixx are rather very small. The smallest rate of emergence was found in the variety Carolinio that had been drilled at ground speed of 20 km/h. Nevertheless, 91.5 % of the seedlings emerged, which is still rated as ‘very good’ within the DLG scheme.

Emergence of the variety Torres became less uniform as the ground speed increased. This tendency is also observed with Carolinio.

Figure 12 shows the emerged crop on May 19, 2015 (Ferarixx, drilled at 20 km/h).

Figure 11: An emerged corn plant whose roots were able to penetrate the smear layer in the seed slot

Figure 12: Emerged Ferarixx corn plants photographed on May 19, 2015 (drilled at 20 km/h ground speed)

Figure 13: Standard deviations of three corn varieties in the field relative to the set ground speed

Summary

The results obtained from the lab tests show that the John Deere '1725 NT ExactEmergeTM 8-row corn planter achieves ‘good’ and ‘very good’ results on accuracy of seed placement even at work rates of 20 km/h. The field tests rendered exclusively ‚very good’ results.

The percentage of doubles and gaps in the lab test were assessed as ‘low’ and ‘very low’ at all ground speeds.

The percentage of gaps in the field test ranged between 2.0 % and 9.4 %. Nevertheless, in 79 % of these gaps it was found that the seeds had indeed been placed at the correct depth and were covered with soil. The seeds had germinated but then stopped growing due to lack of water (only 19 mm rainfall in five weeks). The percentage of emerged crops in the field test ranged between 91.5 % and 98.1 %, which is rated as ‘very good’.

The DLG APPROVED quality mark in the category ‘Function test including fertilizer distribution across rows’ requires the test machine to achieve at least ‘satisfactory’ or better results in three different corn varieties. These requirements were met in the above test, the machine is eligible for the DLG quality mark.

DLG Test Center Technology and Farm Inputs

DLG e.V.
Max-Eyth-Weg 1
64823 Groß-Umstadt
Germany
Tel.: +49(0)69 24 788-611
tech(at)DLG.org

Printable version/Download as PDF

A ‘DLG APPROVED test on individual criteria’ quality mark is awarded to farm machinery that has passed a limited test programme within a DLG usability test which is conducted in accordance to independent and approved assessment criteria. The purpose of the test is to highlight a product’s specific innovations and key features.  The test may be carried out either to criteria laid down in the ‘DLG Full Test’ framework for technical products or may include further features and properties that confer a specific value to the product. The minimum standards to be applied to the product, the test conditions and procedures as well as the criteria by which the test results are to be evaluated are defined in cooperation with a DLG group of experts. These parameters reflect the acknowledged state of the art as well as scientific findings and agricultural insights and requirements. After a product has passed the test, a test report is produced and published and the quality mark is awarded and will remain valid for five years from the date of award.

The machine that was submitted to the ‘Function Test including fertilizer distribution across rows’ is the John Deere 1725 NT ExactEmergeTM 8-row corn planter complete with the FT 180 fertilizer system. The machine was tested at the lab where four corn varieties were investigated, and in the field where three varieties were planted and DAP fertilizer was applied. The lab test consisted of measurements and assessments of the seed distribution along rows (placement accuracy and seed distribution) and the fertilizer distribution across rows on the stationary drill, simulating speeds between 8 km/h and 20 km/h. The field test was carried out on April 16, 2015, when the corn was planted at ground speeds between 8 km/h and 20 km/h in a flat field. The seedbed was described as fine tilth. The distribution of crop along rows (spacing, seed distribution) and emergence was measured on May 19 and May 28, 2015, using the mobile DLG meter which mea­sures the spacings between the emerged plants, the statistics of which were subsequently prepared and analysed. No other criteria were tested.

Manufacturer and applicant

John Deere GmbH & Co. KG
John Deere Vertrieb
John-Deere-Straße 8
76646 Bruchsal
www.JohnDeere.de

Test execution

DLG e.V.,
Testzentrum Technik und Betriebsmittel,
Max-Eyth-Weg 1,
64823 Groß-Umstadt
Germmany

DLG Testing Framework
DLG testing framework for planters

Field
Technology in outdoor operations

Project manager
Dr. Ulrich Rubenschuh

Test engineer(s)
Dipl.-Ing agr. Georg Horst Schuchmann*

* Test engineer(s)