Table 22. By location mean nitrogen content and estimated nitrogen release of 36 cover crop varieties and 8 mixes planted in early Nov. 2020, in small plot replicated trials, at the East Tennessee AgResearch and Education Center, in Knoxville, Tennessee, and evaluated from Fall 2020 to Spring 2021.
| Variety | Common Name | Total Nitrogen¶ (%) | Estimated N Released†† Apr. Term. (lbs/ac) | Estimated N Released†† MayTerm. (lbs/ac) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Apr | May | 2 wks | 4 wks | 12 wks | 2 wks | 4 wks | 12 wks | ||||||||||
| Cereals | |||||||||||||||||
| Bates RS4 | Cereal Rye | 1.7 | LM | 1.3 | M | 2 | H-K | 4 | G-J | 8 | G-J | -2 | J | -3 | J | -3 | KL |
| Elbon | Cereal Rye | 1.8 | K-M | 1.4 | LM | 3 | G-K | 5 | G-J | 8 | G-J | -2 | J | -3 | J | -4 | L |
| NF95319B | Cereal Rye | 1.6 | M | 1.2 | M | 2 | G-K | 4 | G-J | 9 | E-J | -1 | IJ | -1 | IJ | 0 | J-L |
| NF97325 | Cereal Rye | 2.0 | J-M | 1.2 | M | 2 | H-K | 4 | G-J | 7 | G-K | -1 | IJ | -2 | IJ | -1 | J-L |
| NF99362 | Cereal Rye | 1.7 | LM | 1.4 | LM | 2 | I-K | 3 | G-J | 6 | G-K | -1 | IJ | -1 | IJ | 0 | I-L |
| Yankee | Cereal Rye | 2.4 | G-J | 1.6 | LM | 2 | H-K | 4 | G-J | 5 | G-K | 2 | H-J | 4 | H-J | 6 | H-L |
| TN1902 | Wheat | 2.2 | I-L | 1.8 | KL | 5 | C-G | 7 | C-G | 11 | C-G | 4 | G-J | 9 | F-J | 15 | E-J |
| Legumes | |||||||||||||||||
| Paradana | Clover, Balansa | 2.1 | I-L | 2.5 | F-J | 1 | K | 1 | J | 2 | JK | 9 | E-H | 13 | E-H | 17 | E-J |
| Taipan | Clover, Balansa | 2.2 | I-L | 2.4 | H-J | 1 | K | 2 | IJ | 3 | I-K | 8 | E-I | 11 | E-I | 14 | F-K |
| Viper | Clover, Balansa | 2.5 | E-J | 2.7 | E-H | 1 | JK | 2 | H-J | 3 | H-K | 12 | E-G | 18 | E-H | 23 | E-H |
| Lightning | Clover, Berseem | 2.9 | D-F | 3.4 | CD | 1 | K | 1 | J | 1 | K | 9 | E-H | 14 | E-H | 18 | E-I |
| Dixie | Clover, Crimson | 2.9 | DE | 2.9 | E-G | 1 | K | 1 | J | 1 | K | 13 | E-G | 19 | E-G | 24 | E-H |
| AU Merit | Vetch, Hairy | 3.9 | AB | 4.0 | B | 8 | AB | 13 | AB | 19 | AB | 48 | AB | 71 | AB | 90 | AB |
| Patagonia | Vetch, Hairy | 3.8 | AB | 3.5 | CD | 9 | A | 16 | A | 23 | A | 43 | BC | 65 | BC | 83 | BC |
| WinterKing | Vetch, Hairy | 4.3 | A | 4.5 | A | 6 | B-F | 10 | B-F | 14 | B-F | 53 | A | 80 | A | 101 | A |
| Brassicas | |||||||||||||||||
| Vivant | Hybrid (turnip x rapeseed) | 2.6 | E-I | 2.1 | JK | 2 | G-K | 4 | G-J | 6 | G-K | 6 | F-J | 9 | F-J | 11 | G-L |
| Aerifi | Radish | 2.4 | G-J | 2.1 | I-K | 4 | F-J | 6 | F-I | 9 | F-I | 6 | F-J | 9 | F-J | 11 | G-L |
| Jackpot | Turnip | 2.3 | H-K | 2.3 | H-J | 2 | H-K | 3 | H-J | 4 | H-K | 5 | F-J | 7 | G-J | 10 | G-L |
| Mixes | |||||||||||||||||
| Bates RS4 (20%) + Dixie (80%) | Cereal Rye + Crimson Clover | 2.1 | I-L | 2.0 | JK | 6 | B-F | 10 | B-E | 16 | B-D | 6 | F-J | 10 | E-J | 15 | F-K |
| Bates RS4 (20%) + AU Merit (80%) | Cereal Rye + Hairy Vetch | 3.0 | C-E | 2.9 | E-G | 9 | A | 16 | A | 23 | A | 31 | D | 46 | D | 60 | D |
| Bates RS4 (10%) + Dixie (90%) | Cereal Rye + Crimson Clover | 2.4 | F-J | 2.4 | H-J | 6 | B-F | 10 | B-F | 15 | B-E | 15 | E | 24 | E | 33 | E |
| Bates RS4 (10%) + AU Merit (90%) | Cereal Rye + Hairy Vetch | 2.8 | E-G | 3.0 | D-F | 7 | A-C | 12 | AB | 17 | A-C | 41 | BC | 61 | BC | 80 | BC |
| Yankee (20%) + Dixie (80%) | Cereal Rye + Crimson Clover | 2.7 | E-H | 2.6 | G-I | 4 | E-I | 6 | E-H | 9 | E-H | 11 | E-G | 19 | E-G | 26 | E-G |
| Yankee (20%) + AU Merit (80%) | Cereal Rye + Hairy Vetch | 3.4 | B-D | 3.1 | DE | 6 | B-E | 11 | B-D | 16 | B-D | 46 | A-C | 69 | A-C | 89 | A-C |
| TN1902 (20%) + Dixie (80%) | Wheat + Crimson Clover | 2.7 | E-H | 2.7 | E-H | 4 | D-H | 7 | D-G | 10 | D-G | 14 | EF | 22 | EF | 29 | EF |
| TN1902 (20%) + AU Merit (80%) | Wheat + Hairy Vetch | 3.5 | BC | 3.6 | C | 7 | B-D | 11 | BC | 16 | B-D | 37 | CD | 56 | CD | 72 | CD |
| Cereals | |||||||||||||||||
| Average | 1.9 | 1.4 | 2 | 5 | 8 | 0 | 0 | 2 | |||||||||
| Min | 1.6 | 1.2 | 2 | 3 | 5 | -2 | -3 | -4 | |||||||||
| Max | 2.4 | 1.8 | 5 | 7 | 11 | 4 | 9 | 15 | |||||||||
| Range | 0.8 | 0.6 | 3 | 4 | 6 | 6 | 12 | 19 | |||||||||
| Legumes | |||||||||||||||||
| Average | 3.1 | 3.3 | 3 | 6 | 8 | 24 | 36 | 46 | |||||||||
| Min | 2.1 | 2.4 | 1 | 1 | 1 | 8 | 11 | 14 | |||||||||
| Max | 4.3 | 4.5 | 9 | 16 | 23 | 53 | 80 | 101 | |||||||||
| Range | 2.2 | 2.2 | 9 | 15 | 22 | 46 | 68 | 87 | |||||||||
| Brassicas | |||||||||||||||||
| Average | 2.4 | 2.2 | 3 | 4 | 6 | 5 | 8 | 11 | |||||||||
| Min | 2.3 | 2.1 | 2 | 3 | 4 | 5 | 7 | 10 | |||||||||
| Max | 2.6 | 2.3 | 4 | 6 | 9 | 6 | 9 | 11 | |||||||||
| Range | 0.3 | 0.2 | 2 | 3 | 5 | 1 | 1 | 2 | |||||||||
| Mixes | |||||||||||||||||
| Average | 2.8 | 2.8 | 6 | 10 | 15 | 25 | 38 | 50 | |||||||||
| Min | 2.1 | 2.0 | 4 | 6 | 9 | 6 | 10 | 15 | |||||||||
| Max | 3.5 | 3.6 | 9 | 16 | 23 | 46 | 69 | 89 | |||||||||
| Range | 1.3 | 1.5 | 5 | 9 | 14 | 40 | 59 | 74 | |||||||||
| Across Groups | |||||||||||||||||
| Average | 2.6 | 2.5 | 4 | 7 | 10 | 16 | 24 | 32 | |||||||||
| Standard Error | 0.7 | 0.9 | 3 | 4 | 6 | 18 | 26 | 33 | |||||||||
| Min | 1.6 | 1.2 | 1 | 1 | 1 | -2 | -3 | -4 | |||||||||
| Max | 4.3 | 4.5 | 9 | 16 | 23 | 53 | 80 | 101 | |||||||||
| Range | 2.7 | 3.4 | 9 | 15 | 22 | 55 | 83 | 105 | |||||||||
| ANOVA p-values | |||||||||||||||||
| – Variety | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | |||||||||
| – Location | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | |||||||||
| – Variety x Location | 0.017 | 0.008 | N.S. | N.S. | N.S. | N.S. | N.S. | N.S. |
† Varieties that have any MS letter in common are not significantly different (Fisher’s Protected LSD, P<0.05). Mean separation letters are highlighted in dark orange for values that are not statistically different from the highest value across all entries within a given trait. Mean values between the 50th and 75th percentile are highlighted in light orange, mean values above the 75th percentile are highlighted in dark orange. § For analysis, values transformed using (value)^2 due to non-normal distribution. Untransformed means and summary statistics are reported. ‡ For analysis, values transformed using log (value+1) due to non-normal distribution. Untransformed means and summary statistics are reported. ‡‡ Non-normal distribution, means reported ¶ Analyzed using near infrared spectroscopy (NIRS) with the appropriate calibration for each species. Reported on a 100% DM basis. †† Estimated using quality constituents from NIRS inputted into the UGA cover crop nitrogen calculator.
Virginia Sykes vsykes@utk.edu
- Table 1. 2021 Total entry numbers - December 26, 2021
- Table A-35. Mean yields and agronomic data from Memphis, TN, MG-5 - December 23, 2021
- Table A-34. Mean yields and agronomic data from Jackson, TN, MG-5 - December 22, 2021