Table 18. Across location mean nitrogen content and estimated nitrogen release of 18 cover crop varieties and 8 mixes planted in early Nov. 2020, in small plot replicated trials, at two University of Tennessee AgResearch and Education Center locations, in 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 | 1.5 | L | 1.1 | N | 2 | K-M | 4 | J-M | 7 | I-L | 0 | I | 0 | I | 2 | L |
| Elbon | Cereal Rye | 1.7 | KL | 1.1 | N | 3 | I-L | 5 | I-L | 8 | H-L | 1 | I | 1 | I | 3 | KL |
| NF95319B | Cereal Rye | 1.5 | L | 1.1 | N | 2 | K-M | 4 | J-M | 7 | I-M | 0 | I | 0 | I | 2 | L |
| NF97325 | Cereal Rye | 1.7 | KL | 1.1 | N | 3 | J-M | 5 | I-L | 8 | I-L | 0 | I | 0 | I | 2 | L |
| NF99362 | Cereal Rye | 1.5 | L | 1.2 | MN | 2 | LM | 4 | K-M | 6 | J-N | 1 | I | 2 | I | 4 | J-L |
| Yankee | Cereal Rye | 2.2 | H-J | 1.5 | LM | 3 | J-M | 4 | J-M | 7 | J-N | 3 | HI | 5 | HI | 8 | I-L |
| TN1902 | Wheat | 2.1 | IJ | 1.5 | KL | 4 | H-K | 6 | H-K | 9 | G-K | 5 | HI | 8 | HI | 13 | H-L |
| Legumes | |||||||||||||||||
| Paradana | Clover, Balansa | 2.5 | E-H | 2.5 | GH | 1 | M | 2 | M | 2 | N | 5 | HI | 7 | HI | 10 | I-L |
| Taipan | Clover, Balansa | 2.2 | H-J | 2.5 | GH | 1 | M | 2 | LM | 3 | MN | 6 | G-I | 8 | HI | 11 | I-L |
| Viper | Clover, Balansa | 2.6 | D-G | 2.7 | FG | 1 | M | 2 | M | 3 | MN | 8 | GH | 12 | GH | 15 | G-K |
| Lightning | Clover, Berseem | 3.0 | CD | 3.3 | C-E | 1 | M | 2 | M | 3 | MN | 8 | F-H | 13 | GH | 16 | G-J |
| Dixie | Clover, Crimson | 2.8 | C-E | 3.0 | EF | 3 | J-M | 4 | J-M | 6 | J-N | 15 | EF | 22 | EF | 29 | EF |
| AU Merit | Vetch, Hairy | 3.6 | A | 4.4 | AB | 8 | B-D | 13 | B-D | 18 | BC | 36 | B | 55 | B | 70 | B |
| Patagonia | Vetch, Hairy | 3.5 | AB | 4.1 | B | 10 | A | 17 | A | 24 | A | 35 | BC | 53 | BC | 69 | BC |
| WinterKing | Vetch, Hairy | 3.8 | A | 4.6 | A | 8 | AB | 14 | AB | 20 | AB | 43 | A | 65 | A | 83 | A |
| Brassicas | |||||||||||||||||
| Vivant | Hybrid (turnip x rapeseed) | 2.5 | E-H | 2.1 | IJ | 2 | K-M | 4 | K-M | 5 | L-N | 4 | HI | 6 | HI | 7 | I-L |
| Aerifi | Radish | 2.4 | F-I | 2.0 | IJ | 2 | K-M | 4 | K-M | 5 | K-N | 3 | HI | 5 | HI | 6 | I-L |
| Jackpot | Turnip | 2.4 | F-J | 2.1 | I | 2 | LM | 3 | LM | 4 | L-N | 4 | HI | 5 | HI | 7 | I-L |
| Mixes | |||||||||||||||||
| Bates RS4 (20%) + Dixie (80%) | Cereal Rye + Crimson Clover | 2.0 | JK | 1.8 | JK | 5 | F-I | 8 | E-H | 12 | D-H | 8 | F-H | 13 | F-H | 19 | F-I |
| Bates RS4 (20%) + AU Merit (80%) | Cereal Rye + Hairy Vetch | 2.7 | D-F | 3.0 | EF | 8 | A-C | 14 | A-C | 20 | AB | 25 | D | 38 | D | 50 | D |
| Bates RS4 (10%) + Dixie (90%) | Cereal Rye + Crimson Clover | 2.2 | G-J | 2.2 | I | 5 | E-H | 9 | E-H | 13 | D-G | 15 | E | 24 | E | 33 | E |
| Bates RS4 (10%) + AU Merit (90%) | Cereal Rye + Hairy Vetch | 2.5 | E-H | 3.2 | DE | 7 | C-E | 11 | D-F | 16 | CD | 32 | BC | 49 | BC | 63 | BC |
| Yankee (20%) + Dixie (80%) | Cereal Rye + Crimson Clover | 2.5 | E-H | 2.3 | HI | 4 | G-J | 7 | G-J | 10 | F-J | 12 | E-G | 19 | E-G | 26 | E-G |
| Yankee (20%) + AU Merit (80%) | Cereal Rye + Hairy Vetch | 3.2 | BC | 3.5 | CD | 6 | E-G | 10 | D-G | 14 | C-F | 32 | BC | 48 | BC | 63 | BC |
| TN1902 (20%) + Dixie (80%) | Wheat + Crimson Clover | 2.5 | E-H | 2.3 | HI | 5 | F-I | 8 | F-I | 11 | E-I | 12 | E-G | 18 | E-G | 25 | E-H |
| TN1902 (20%) + AU Merit (80%) | Wheat + Hairy Vetch | 3.2 | C | 3.5 | C | 6 | D-F | 11 | C-E | 15 | C-E | 29 | CD | 43 | CD | 56 | CD |
| Cereals | |||||||||||||||||
| Average | 1.8 | 1.2 | 3 | 5 | 8 | 1 | 2 | 5 | |||||||||
| Min | 1.5 | 1.1 | 2 | 4 | 6 | 0 | 0 | 2 | |||||||||
| Max | 2.2 | 1.5 | 4 | 6 | 9 | 5 | 8 | 13 | |||||||||
| Range | 0.7 | 0.5 | 2 | 3 | 3 | 5 | 8 | 12 | |||||||||
| Legumes | |||||||||||||||||
| Average | 3.0 | 3.4 | 4 | 7 | 10 | 19 | 29 | 38 | |||||||||
| Min | 2.2 | 2.5 | 1 | 2 | 2 | 5 | 7 | 10 | |||||||||
| Max | 3.8 | 4.6 | 10 | 17 | 24 | 43 | 65 | 83 | |||||||||
| Range | 1.6 | 2.1 | 9 | 15 | 21 | 38 | 57 | 73 | |||||||||
| Brassicas | |||||||||||||||||
| Average | 2.4 | 2.1 | 2 | 3 | 5 | 3 | 5 | 7 | |||||||||
| Min | 2.4 | 2.0 | 2 | 3 | 4 | 3 | 5 | 6 | |||||||||
| Max | 2.5 | 2.1 | 2 | 4 | 5 | 4 | 6 | 7 | |||||||||
| Range | 0.1 | 0.1 | 0 | 1 | 1 | 1 | 1 | 1 | |||||||||
| Mixes | |||||||||||||||||
| Average | 2.6 | 2.7 | 6 | 10 | 14 | 21 | 31 | 42 | |||||||||
| Min | 2.0 | 1.8 | 4 | 7 | 10 | 8 | 13 | 19 | |||||||||
| Max | 3.2 | 3.5 | 8 | 14 | 20 | 32 | 49 | 63 | |||||||||
| Range | 1.2 | 1.7 | 4 | 7 | 10 | 24 | 35 | 45 | |||||||||
| Across Groups | |||||||||||||||||
| Average | 2.5 | 2.5 | 4 | 7 | 10 | 13 | 20 | 27 | |||||||||
| Standard Error | 0.6 | 1.0 | 3 | 4 | 6 | 13 | 20 | 26 | |||||||||
| Min | 1.5 | 1.1 | 1 | 2 | 2 | 0 | 0 | 2 | |||||||||
| Max | 3.8 | 4.6 | 10 | 17 | 24 | 43 | 65 | 83 | |||||||||
| Range | 2.3 | 3.6 | 9 | 15 | 21 | 43 | 64 | 82 | |||||||||
| 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