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
CARROT WEED CONTROL STUDY, 2000
Richard Greenland
Table 37. Root characteristics of carrots
Table 38. Carrot and barley injury and weed control
Table 39. Numbers and yields of carrots
Only a few herbicides are available for weed control in carrots. Treflan, Lorox, Poast, and Fusillade are the most commonly used. In this study we evaluated three additional herbicides, Authority, FirstRate, and Frontier, for their usefulness in carrot production.
MATERIALS AND METHODS
| Soil: | Embden loam; pH=7.2; 2.3% organic matter; soil-P, soil-K, and soil-S were very high. |
| Previous crop: | 1999 - field corn; 1998 - edibile bean; 1997 - edible bean. |
| Seedbed Preparation: | Disked on 29 October 1999. Multiweeded (field cultivated) once on April 4. Deep chiseled on April 29. Multiweeded twice on May 4 to incorporate herbicide. |
| Planting: | Direct seeded Bolero carrots on May 4 with a Stanhay vegetable planter. Planting pattern for all carrots was paired rows (3 inches between rows (lines) in the pair) with paired rows on 16" centers. Planted on a flat seed bed. Planting rate was about 800,000 seeds/acre. |
| Fertilizer: | On April 4, broadcast 18 lbs N/acre and 20 lbs S/acre as 21-0-0-24. Applied 40 lbs N/acre as 28-0-0 on May 1. Fertigated 88 lbs N/acre on July 13. |
| Plots: | Plots were 17 ft long by 8 ft wide. There were 4 reps. |
| Irrigation: | Overhead sprinkler irrigation as needed. |
| Pest control: | Treflan (1.5 pts/acre on May 4) and Fusilade + NIS (12 oz/acre + 1 pt/25 gal on June 5) were applied to all plots. See Table 36 for other weed control treatments. We sprayed Sevin (1 qt/acre on Aug 9 and Aug 26) and Asana (8 oz/acre on June 30, July 6, July 14, July 20, July 26, Aug 3, and Aug 18) to control leafhopper. |
| Harvest: | Carrots were harvested on September 5. Harvest area was 3 ft of the center two rows of each plot. |
None of the three new herbicides tested performed well enough to be used in carrots. FirstRate killed most of the carrots. Authority reduced carrot stand by one third and total carrot yield 38%. Frontier reduced carrot stand by one fourth and total carrot yield 32%. Authority increased carrot size due to less carrots in the plot so each carrot grew bigger.
Applying Lorox or Authority right after planting carrots and barley was less injurious to the barley than spraying 10 days later (after the barley had emerged). FirstRate killed most of the barley cover crop. Frontier caused about 25% injury to the barley.
Lorox and Authority controlled all weeds in the study. Frontier did not control hairy nightshade and was weak on lambsquarters. FirstRate was weak on lambsquarters. By destroying the carrots and most other weeds, FirstRate left the soil open for eastern black nightshade to grow.
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Table 36. Treatments for the Oakes Irrigation Research Site 2000 carrot weed control study.
| Treatment number | Herbicide(s) | Rate(s)1 | Time of application2 |
| 1 | Lorox | 1 lb + 2 lb | PRE + POST |
| 2 | Lorox | 1 lb + 2 lb | PRE2 + POST |
| 3 | Authority | 4 oz | PRE |
| 4 | FirstRate | 0.6 oz | PRE |
| 5 | Frontier | 1 lb ai | PRE |
| 6 | Authority | 4 oz | PRE2 |
| 7 | FirstRate | 0.6 oz | PRE2 |
| 8 | Frontier | 1 lb ai | PRE2 |
| 9 | Authority + Lorox | 4 oz + 2 lb | PRE + POST |
| 10 | FirstRate + Lorox | 0.6 oz + 2 lb | PRE + POST |
| 11 | Frontier + Lorox | 1 lb ai + 2 lb | PRE + POST |
| 12 | Authority + Lorox | 4 oz + 2 lb | PRE2 + POST |
| 13 | FirstRate + Lorox | 0.6 oz + 2 lb | PRE2 + POST |
| 14 | Frontier + Lorox | 1 lb ai + 2 lb | PRE2 + POST |
1All rates are in product per acre except for Frontier which is in active ingredient per acre.
2PRE was right after planting carrots (May 5); PRE2 was after barley had emerged but before carrots emerged (May 16); POST was when carrots were 3 inches tall (June 22).
All plots received 1.5 pts/A Treflan PPI on May 4 and 12 oz/A Fusilade on June 5.
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Table 37. Root characteristics of carrots in the Oakes Irrigation Research Site 2000 carrot weed control study.
| Treatment number1 | US #1 | Multiple roots | Average size | Average length | Uniformity |
| % | % | oz/root | inches | 1 to 3 | |
| 1 | 71.2 a | 20 a | 5.4 bcd | 9.1 bc | 2.9 a |
| 2 | 70.6 a | 24 a | 4.7 cd | 9.0 bc | 2.4 ab |
| 3 | 70.8 a | 20 a | 5.2 bcd | 9.3 bc | 2.1 b |
| 4 | 0.0 d | 97 c | -- 2 | -- 2 | -- 2 |
| 5 | 51.1 abc | 42 ab | 4.1 d | 9.1 bc | 2.1 b |
| 6 | 68.0 a | 26 a | 7.4 a | 9.5 ab | 2.6 ab |
| 7 | 35.0 c | 40 ab | 6.7 abc | 8.3 bc | 2.2 ab |
| 8 | 74.6 a | 21 a | 3.9 d | 8.1 c | 2.9 a |
| 9 | 59.9 ab | 30 a | 6.4 abc | 8.6 bc | 2.6 ab |
| 10 | 0.0 d | 100 c | -- 2 | -- 2 | -- 2 |
| 11 | 56.6 abc | 41 ab | 5.4 bcd | 8.4 bc | 2.3 b |
| 12 | 50.2 abc | 39 a | 7.1 a | 9.0 bc | 2.1 b |
| 13 | 36.5 bc | 63 b | 6.8 ab | 8.1 c | 2.1 b |
| 14 | 69.0 a | 24 a | 4.6 d | 10.8 a | 2.5 ab |
| C.V. (%) | 35 | 38 | 19 | 10 | 16 |
| Probability | 0.0001 | 0.0001 | 0.0005 | 0.02 | 0.04 |
1See Table 36 for treatment explanations.
2There were no US #1 carrots to measure for these characteristics.
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Table 38. Carrot and barley injury and weed control in the Oakes Irrigation Research Site 2000 carrot weed control study.
| Trt no.1 | Barley injury June 2 |
Carrot injury | Carrot stand Aug 25 |
July 6 weed ratings | August 25 weed ratings | ||||||
| June 2 | July 6 | HNS2 | LQ2 | EBNS2 | HNS2 | PW2 | LQ2 | EBNS2 | |||
| -------- 0 to 103 ------- | 0 to 104 | ------------------ 0 to 105 ------------------- | |||||||||
| 1 | 1.2 a6 | 0.0 a | 0.3 a | 9.8 a | 9.0 b | 10.0 a | 10.0 a | 9.3 ab | 9.8 a | 10.0 a | 10.0 a |
| 2 | 3.6 cd | 0.0 a | 0.0 a | 9.5 a | 10.0 a | 10.0 a | 10.0 a | 10.0 a | 10.0 a | 10.0 a | 10.0 a |
| 3 | 1.5 ab | 4.0 bc | 3.8 bc | 6.8 b-e | 9.0 b | 10.0 a | 10.0 a | 9.0 ab | 9.5 a | 10.0 a | 10.0 a |
| 4 | 7.8 e | 8.3 f | 9.4 d | 1.3 g | 10.0 a | 9.0 ab | 6.5 c | 9.3 ab | 9.8 a | 7.3 c | 2.5 b |
| 5 | 3.3 c | 3.8 bc | 2.8 b | 7.0 bcd | 6.3 c | 8.3 bc | 10.0 a | 5.5 c | 10.0 a | 8.8 ab | 10.0 a |
| 6 | 2.6 abc | 5.5 de | 4.8 c | 6.3 cde | 9.0 b | 10.0 a | 9.8 a | 7.8 b | 10.0 a | 10.0 a | 10.0 a |
| 7 | 7.3 e | 8.8 f | 8.9 d | 2.0 f | 10.0 a | 8.8 bc | 7.6 b | 9.0 ab | 9.5 a | 7.0 c | 1.7 c |
| 8 | 3.0 bc | 4.5 cd | 3.5 bc | 5.8 e | 4.0 d | 8.0 c | 10.0 a | 5.0 c | 10.0 a | 8.8 ab | 9.8 a |
| 9 | 2.8 abc | 4.0 c | 3.8 bc | 6.5 cde | 10.0 a | 10.0 a | 10.0 a | 10.0 a | 10.0 a | 10.0 a | 10.0 a |
| 10 | 8.0 e | 8.5 f | 9.3 d | 2.0 f | 10.0 a | 10.0 a | 9.5 a | 9.8 ab | 8.5 b | 8.5 b | 9.0 a |
| 11 | 3.0 bc | 3.0 b | 2.8 b | 8.0 b | 9.3 ab | 10.0 a | 10.0 a | 9.8 ab | 10.0 a | 9.3 ab | 10.0 a |
| 12 | 3.3 bc | 5.3 de | 4.3 c | 5.8 de | 10.0 a | 10.0 a | 10.0 a | 10.0 a | 10.0 a | 10.0 a | 10.0 a |
| 13 | 6.3 de | 8.0 f | 8.9 d | 2.0 f | 10.0 a | 10.0 a | 10.0 a | 9.8 ab | 8.8 b | 8.5 b | 9.5 a |
| 14 | 3.8 cd | 5.8 e | 4.0 c | 7.5 bc | 9.5 ab | 9.8 a | 10.0 a | 8.5 ab | 10.0 a | 9.0 ab | 10.0 a |
| C.V. | 25 | 9 | 11 | 7 | 3 | 4 | 3 | 7 | 2 | 5 | 9 |
| Prob. | 0.0001 | 0.0001 | 0.0001 | 0.0001 | 0.0001 | 0.0001 | 0.0001 | 0.0001 | 0.0001 | 0.0001 | 0.0001 |
1See Table 36 for an explanation of treatments.
2Weed abbreviations are: HNS - hairy nightshade; LQ - lambsquarters; EBNS - eastern black nightshade; PW - Red root pigweed.
3Rating from 0 to 10 with 0 equal to no injury and 10 equal to no plants.
4Rating from 0 to 10. The higher the number the better the stand.
5Rating from 0 to 10. 10 equals complete control of weed (no weeds in plot), and 0 is plot covered with large, vigorous weeds.
6Values in the same column followed by the same letter are not significantly different at the 0.5 level. Data transformed using a square root transformation for analysis. Values presented as untransformed means.
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Table 39. Numbers and yields of carrots in the Oakes Irrigation Research Site 2000 carrot weed control study.
| Treatment number1 | Number of carrots | Yield of carrots | ||||||
| US #1 carrots | total | US #1 carrots | total | |||||
| >1.5" | 1 to 1.5" | total | >1.5" | 1 to 1.5" | total | |||
| -------------- 1000s per acre -------------- | -------------- tons per acre -------------- | |||||||
| 1 | 121.2 a2 | 40.8 bc | 177.0 a | 257.3 a | 24.8 a | 4.4 b | 29.6 a | 41.4 a |
| 2 | 102.1 b | 86.7 a | 194.1 a | 292.8 a | 20.5 ab | 8.6 a | 29.0 a | 42.1 a |
| 3 | 61.1 ef | 35.4 bcd | 112.4 c | 147.6 e | 14.1 cd | 3.3 bc | 18.2 bcd | 26.3 cd |
| 4 | 0.0 h | 0.0 f | 0.0 e | 50.4 g | 0.0 f | 0.0 e | 0.0 f | 1.7 f |
| 5 | 73.5 de | 32.7 bcd | 107.5 c | 201.5 bc | 11.8 de | 2.0 cd | 13.8 de | 27.1 cd |
| 6 | 51.7 fg | 12.3 ef | 66.7 d | 95.3 f | 14.3 cd | 1.0 de | 15.4 cde | 23.1 de |
| 7 | 5.4 h | 4.1 ef | 10.9 e | 38.1 g | 1.5 f | 0.6 de | 2.1 f | 4.1 f |
| 8 | 40.4 g | 51.7 b | 113.9 bc | 153.9 de | 8.2 e | 4.5 b | 13.4 de | 18.6 e |
| 9 | 66.7 ef | 16.3 def | 99.4 c | 163.4 cde | 17.5 bc | 1.5 cde | 19.4 bcd | 32.3 bc |
| 10 | 0.0 h | 0.0 f | 0.0 e | 57.2 fg | 0.0 f | 0.0 e | 0.0 f | 1.8 f |
| 11 | 99.4 bc | 21.8 cde | 125.2 bc | 208.3 b | 19.4 b | 1.7 cde | 21.2 b | 37.4 b |
| 12 | 38.1 g | 10.9 ef | 50.4 d | 95.3 f | 10.0 de | 1.0 de | 11.0 e | 21.3 de |
| 13 | 5.4 h | 1.4 f | 6.8 e | 43.6 g | 1.2 f | 0.1 de | 1.3 f | 3.6 f |
| 14 | 85.8 cd | 43.6 b | 145.7 b | 193.3 bcd | 17.1 bc | 3.4 bc | 21.0 bc | 30.5 c |
| C.V. (%) | 21 | 55 | 25 | 20 | 28 | 63 | 29 | 20 |
| Probability | 0.0001 | 0.0001 | 0.0001 | 0.0001 | 0.0001 | 0.0001 | 0.0001 | 0.0001 |
1See Table 36 for an explanation of treatments.
2Values in the same column followed by the same letter are not significantly different at the 0.5 level.
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Go to Oakes Irrigation Research Site Weed Control Studies
Go to Oakes Irrigation Research Site 2000 annual report