Table 18. Early Nov. Planted, Across Location, Nitrogen Content and Release

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.

VarietyCommon NameTotal Nitrogen¶ (%)   Estimated N Released†† Apr. Term. (lbs/ac)     Estimated N Released†† MayTerm. (lbs/ac)     
AprMay2 wks4 wks12 wks2 wks4 wks12 wks
Cereals
Bates RS4Cereal Rye1.5L1.1N2K-M4J-M7I-L0I0I2L
ElbonCereal Rye1.7KL1.1N3I-L5I-L8H-L1I1I3KL
NF95319BCereal Rye1.5L1.1N2K-M4J-M7I-M0I0I2L
NF97325Cereal Rye1.7KL1.1N3J-M5I-L8I-L0I0I2L
NF99362Cereal Rye1.5L1.2MN2LM4K-M6J-N1I2I4J-L
YankeeCereal Rye2.2H-J1.5LM3J-M4J-M7J-N3HI5HI8I-L
TN1902Wheat2.1IJ1.5KL4H-K6H-K9G-K5HI8HI13H-L
Legumes
ParadanaClover, Balansa2.5E-H2.5GH1M2M2N5HI7HI10I-L
TaipanClover, Balansa2.2H-J2.5GH1M2LM3MN6G-I8HI11I-L
ViperClover, Balansa2.6D-G2.7FG1M2M3MN8GH12GH15G-K
LightningClover, Berseem3.0CD3.3C-E1M2M3MN8F-H13GH16G-J
DixieClover, Crimson2.8C-E3.0EF3J-M4J-M6J-N15EF22EF29EF
AU MeritVetch, Hairy3.6A4.4AB8B-D13B-D18BC36B55B70B
PatagoniaVetch, Hairy3.5AB4.1B10A17A24A35BC53BC69BC
WinterKingVetch, Hairy3.8A4.6A8AB14AB20AB43A65A83A
Brassicas
VivantHybrid (turnip x rapeseed)2.5E-H2.1IJ2K-M4K-M5L-N4HI6HI7I-L
AerifiRadish2.4F-I2.0IJ2K-M4K-M5K-N3HI5HI6I-L
Jackpot Turnip2.4F-J2.1I2LM3LM4L-N4HI5HI7I-L
Mixes
Bates RS4 (20%) + Dixie (80%)Cereal Rye + Crimson Clover2.0JK1.8JK5F-I8E-H12D-H8F-H13F-H19F-I
Bates RS4 (20%) + AU Merit (80%)Cereal Rye +
Hairy Vetch
2.7D-F3.0EF8A-C14A-C20AB25D38D50D
Bates RS4 (10%) + Dixie (90%)Cereal Rye + Crimson Clover2.2G-J2.2I5E-H9E-H13D-G15E24E33E
Bates RS4 (10%) + AU Merit (90%)Cereal Rye +
Hairy Vetch
2.5E-H3.2DE7C-E11D-F16CD32BC49BC63BC
Yankee (20%) +
Dixie (80%)
Cereal Rye + Crimson Clover2.5E-H2.3HI4G-J7G-J10F-J12E-G19E-G26E-G
Yankee (20%) +
AU Merit (80%)
Cereal Rye +
Hairy Vetch
3.2BC3.5CD6E-G10D-G14C-F32BC48BC63BC
TN1902 (20%) +
Dixie (80%)
Wheat +
Crimson Clover
2.5E-H2.3HI5F-I8F-I11E-I12E-G18E-G25E-H
TN1902 (20%) +
AU Merit (80%)
Wheat +
Hairy Vetch
3.2C3.5C6D-F11C-E15C-E29CD43CD56CD
Cereals
Average1.81.2358125
Min1.51.1246002
Max2.21.54695813
Range0.70.52335812
Legumes
Average3.03.44710192938
Min2.22.51225710
Max3.84.6101724436583
Range1.62.191521385773
Brassicas
Average2.42.1235357
Min2.42.0234356
Max2.52.1245467
Range0.10.1011111
Mixes
Average2.62.761014213142
Min2.01.8471081319
Max3.23.581420324963
Range1.21.74710243545
Across Groups
Average2.52.54710132027
Standard Error0.61.0346132026
Min1.51.1122002
Max3.84.6101724436583
Range2.33.691521436482
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 Location0.0170.008N.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
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