Oakes Irrigation Research Site
Carrington Research Extension Center * North Dakota State University
P.O. Box 531, Oakes, ND 58474-0531, Voice: (701) 742-2189, FAX: (701) 742-2700, email: rgreenla@ndsuext.nodak.edu

Potato Matrix/Adjuvant Study
Dr. Richard Greenland and Leonard Besemann

This paper reports the results of a study conducted at the Oakes Irrigation Research Site in Oakes, ND using different rates of Matrix (0.25 to 0.5 oz ai/acre) in combination with different adjuvants (Activator 90, Herbimax, Scoil, and Silwet). We looked at crop injury, weed control, and yield of potatoes.

Results and Discussion

Table 59. Matrix rates and adjuvant treatments applied to potatoes.

Table 60. Weed control and crop injury ratings.

Table 61. Quantity and yield of potatoes.

Materials and methods

This study was established on a Maddock sandy loam soil (2.3% soil organic matter, pH 7.6) at the Oakes Irrigation Research Site in Oakes, ND. The initial soil-P and K were high. Soil-N was medium. On 13 April 1998 we spread 140 lbs of 10-50-0, 78 lbs of 21-0-0-24, and 156 lbs of 0-0-60. Another 70 lbs of N as urea was broadcast on April 22 and incorporated with a field cultivator the next day. We spread urea (at 40 lbs N per acre) on top of the beds on June 26. We fertigated with 25 lbs N per acre as 28% N solution on July 9 and again on July 15.

We planted Russet Burbank potatoes on April 23. Plots were 17 ft long by 12 ft (four rows) wide. Admire (at 1.3 oz per 1000 ft of row) was applied in-row on top of the seed pieces as we planted them. Admire controlled Colorado potato beetle throughout the growing season. A weekly spray program with Bravo Zn, starting on July 7, kept the diseases in check. Dragging off on May 18 and hilling on May 27 provided early weed control. The study was overhead sprinkler irrigated throughout the season as needed.

The Matrix plus adjuvant treatments were applied around noon on June 16. We used a CO2 backpack sprayer with 8004 flat fan nozzles. Boom pressure was 29 psi. Herbicides were applied in 45 gal of water/acre. At application time, hairy nightshade was ½ to 1 inch tall and had 2 to 3 true leaves. Redroot pigweed was ½ to ¾ inch tall and common lambsquarters was ¾ to 1 inch tall. I did not see any black nightshade or quackgrass. Hairy nightshade was the most prevalent weed with 3 to 20 plants per square foot. Pigweed and lambsquarters had less than one plant per square foot. Potatoes were ½ to 1½ feet tall and vigorous. No plants were under stress when we applied the treatments. Weather at application was as follows: air temperature 72 F; 70% cloudy sky; relative humidity 66%; wind 4 mph from the ESE. The plant foliage was dry. The soil was moist.

I took crop injury and/or weed control ratings on June 26, July 10, and September 4. We sprayed Diquat (1 pt/acre on Sept. 7) to kill the potato vines. Eight feet of the middle two rows of each plot were harvested in early to mid October. Potatoes were graded, counted, weighed, and a representative sample from each plot was checked for hollow heart.

The experimental design was a randomized complete block with four reps. I used the ANOVA procedure in SAS to analyze the data.

Results and discussion

Matrix in combination with Silwet slightly injured the potatoes. This injury was small necrotic lesions on the lower leaves. The injury was greater with higher rates of Matrix. By July 10 no signs of the injury remained on the plants and final yield and quality of the potatoes was not affected. I did not see any injury from any other Matrix/adjuvant combination.

Weed control was not different among the different adjuvants or rates of Matrix. All treatments controlled hairy nightshade, redroot pigweed, common lambsquarters, and quackgrass, although the weed pressure for lambsquarters and maybe for pigweed was not high enough to give a good test of the herbicide treatments. Matrix did not control eastern black nightshade and, later in the season, plots receiving some Matrix treatments had more black nightshade than the check. This is consistent with previous research that showed Matrix controls hairy nightshade but not eastern black nightshade. If fact, when Matrix controls hairy nightshade, the eastern black nightshade grows more vigorously.

Although tuber size, US #1 yield, and total yield was lower in the check plot as compared to plots receiving Matrix treatments, the differences were not statistically significant.

From this study it appears safe to use any surfactant with Matrix with the possible exception of Silwet or other silicon-based adjuvants. Weed control is good with any of the adjuvants used with Matrix.

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Table 59. Matrix rates and adjuvant treatments applied to potatoes at the Oakes Irrigation Research Site in 1998.
Treatment
number		 Matrix rate
(oz ai/acre)		 Adjuvant and other Adjuvant rate
1 0.25 Activator 90 0.25% v/v
2 0.25 Herbimax 1% v/v
3 0.25 Scoil 1% v/v
4 0.25 Silwet 0.25% v/v
5 0.375 Activator 90 0.25% v/v
6 0.375 Herbimax 1% v/v
7 0.375 Scoil 1% v/v
8 0.375 Silwet 0.25% v/v
9 0.5 Activator 90 0.25% v/v
10 0.5 Herbimax 1% v/v
11 0.5 Scoil 1% v/v
12 0.5 Silwet 0.25% v/v
13 0.25 Lexone + Scoil 3 oz ai/acre + 1% v/v
14 0 Check 0

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Table 60. Weed control and crop injury ratings for the Matrix/adjuvant study at the Oakes Irrigation Research Site in 1998.
Treatment Number † Ratings taken on June 26 Ratings taken on September 4
Hairy nightshade Redroot pigweed Lambs- quarters E. Black nightshade Crop injury Hairy nightshade Redroot pigweed Lambs- quarters E. Black nightshade Quack- grass
------------------ 0 to 10‡ ----------------- % ---------------------- 0 to 10‡ --------------------
1 10.0 10.0 10.0 9.3 0 8.8 10.0 9.3 7.8 9.5
2 10.0 9.9 10.0 8.8 0 8.5 10.0 8.8 9.0 9.8
3 10.0 10.0 10.0 9.3 0 8.5 10.0 9.8 9.3 9.5
4 10.0 10.0 10.0 9.6 13 9.3 10.0 9.3 8.8 9.3
5 10.0 9.9 9.9 9.6 0 9.0 10.0 9.8 9.5 10.0
6 10.0 10.0 9.9 9.3 0 9.5 10.0 9.3 8.8 9.3
7 10.0 10.0 10.0 9.6 0 8.8 10.0 10.0 9.5 9.3
8 10.0 10.0 10.0 9.6 13 9.5 10.0 8.8 8.5 9.3
9 10.0 10.0 10.0 9.6 0 9.8 10.0 9.8 10.0 10.0
10 9.9 10.0 10.0 9.6 0 9.0 9.8 10.0 8.8 9.0
11 10.0 10.0 10.0 9.5 0 9.5 10.0 9.8 9.0 9.3
12 10.0 10.0 10.0 9.9 23 9.5 10.0 9.8 8.8 9.5
13 10.0 10.0 10.0 9.6 0 8.3 10.0 10.0 8.5 9.5
14 2.8 6.3 8.0 9.0 0 2.0 9.5 8.3 9.8 7.3
LSD(0.05) 0.5 1.0 0.3 NS 4 1.2 0.3 1.1 NS 1.1
C.V.(%) 4 8 2 6 90 10 2 8 14 8

†See Table 59 for treatment descriptions.

‡Weed control ratings are from 0 to 10. Weed ratings are based on two things: 1) the percent of the plot free of weeds; and 2) the size, health, etc. of the weeds. A plot completely covered (zero percent of plot free from weeds) with large, vigorous weeds gets a score of "0". A plot completely free of weeds gets a score of "10."

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Table 61. Quantity and yield of potatoes in the Oakes Irrigation Research Site 1998 Matrix/adjuvant study.
Treatment
Number†		 Number of potato tubers Tuber yield Hollow heart Tuber size
US #1 US #2 Total US #1 US #2 Total
--------- 1000s of tubers/acre ---------- ---------- cwt of tubers/acre ---------- % oz/tuber
1 45.4 45.6 105.0 311 138 482 43 7.4
2 37.9 54.9 101.9 271 176 463 40 7.4
3 41.1 53.5 104.8 299 166 482 40 7.4
4 41.3 52.9 104.4 304 164 489 48 7.5
5 41.1 53.3 106.0 305 171 500 50 7.6
6 39.9 52.0 104.1 322 164 514 40 7.9
7 47.0 50.1 104.8 343 167 531 55 8.1
8 41.3 49.2 98.2 298 155 480 50 7.9
9 39.5 54.7 104.4 280 171 487 60 7.5
10 39.2 40.8 95.5 287 128 463 63 7.8
11 40.2 59.4 107.5 298 182 507 63 7.5
12 51.0 41.5 103.0 384 132 537 60 8.4
13 39.9 56.7 105.5 296 182 502 48 7.6
14 34.5 52.2 95.7 244 153 414 58 6.9
LSD(0.05) NS NS NS NS NS NS NS NS
C.V.(%) 17 20 10 16 22 9 28 9

†See Table 59 for treatment descriptions.

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