Table 22. Early Nov. Planted, Knoxville, TN, Nitrogen Content and Release

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.

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 Rye1.7LM1.3M2H-K4G-J8G-J-2J-3J-3KL
ElbonCereal Rye1.8K-M1.4LM3G-K5G-J8G-J-2J-3J-4L
NF95319BCereal Rye1.6M1.2M2G-K4G-J9E-J-1IJ-1IJ0J-L
NF97325Cereal Rye2.0J-M1.2M2H-K4G-J7G-K-1IJ-2IJ-1J-L
NF99362Cereal Rye1.7LM1.4LM2I-K3G-J6G-K-1IJ-1IJ0I-L
YankeeCereal Rye2.4G-J1.6LM2H-K4G-J5G-K2H-J4H-J6H-L
TN1902Wheat2.2I-L1.8KL5C-G7C-G11C-G4G-J9F-J15E-J
Legumes
ParadanaClover, Balansa2.1I-L2.5F-J1K1J2JK9E-H13E-H17E-J
TaipanClover, Balansa2.2I-L2.4H-J1K2IJ3I-K8E-I11E-I14F-K
ViperClover, Balansa2.5E-J2.7E-H1JK2H-J3H-K12E-G18E-H23E-H
LightningClover, Berseem2.9D-F3.4CD1K1J1K9E-H14E-H18E-I
DixieClover, Crimson2.9DE2.9E-G1K1J1K13E-G19E-G24E-H
AU MeritVetch, Hairy3.9AB4.0B8AB13AB19AB48AB71AB90AB
PatagoniaVetch, Hairy3.8AB3.5CD9A16A23A43BC65BC83BC
WinterKingVetch, Hairy4.3A4.5A6B-F10B-F14B-F53A80A101A
Brassicas
VivantHybrid (turnip x rapeseed)2.6E-I2.1JK2G-K4G-J6G-K6F-J9F-J11G-L
AerifiRadish2.4G-J2.1I-K4F-J6F-I9F-I6F-J9F-J11G-L
Jackpot Turnip2.3H-K2.3H-J2H-K3H-J4H-K5F-J7G-J10G-L
Mixes
Bates RS4 (20%) + Dixie (80%)Cereal Rye + Crimson Clover2.1I-L2.0JK6B-F10B-E16B-D6F-J10E-J15F-K
Bates RS4 (20%) + AU Merit (80%)Cereal Rye +
Hairy Vetch
3.0C-E2.9E-G9A16A23A31D46D60D
Bates RS4 (10%) + Dixie (90%)Cereal Rye + Crimson Clover2.4F-J2.4H-J6B-F10B-F15B-E15E24E33E
Bates RS4 (10%) + AU Merit (90%)Cereal Rye +
Hairy Vetch
2.8E-G3.0D-F7A-C12AB17A-C41BC61BC80BC
Yankee (20%) +
Dixie (80%)
Cereal Rye + Crimson Clover2.7E-H2.6G-I4E-I6E-H9E-H11E-G19E-G26E-G
Yankee (20%) +
AU Merit (80%)
Cereal Rye +
Hairy Vetch
3.4B-D3.1DE6B-E11B-D16B-D46A-C69A-C89A-C
TN1902 (20%) +
Dixie (80%)
Wheat +
Crimson Clover
2.7E-H2.7E-H4D-H7D-G10D-G14EF22EF29EF
TN1902 (20%) +
AU Merit (80%)
Wheat +
Hairy Vetch
3.5BC3.6C7B-D11BC16B-D37CD56CD72CD
Cereals
Average1.91.4258002
Min1.61.2235-2-3-4
Max2.41.857114915
Range0.80.634661219
Legumes
Average3.13.3368243646
Min2.12.411181114
Max4.34.5916235380101
Range2.22.291522466887
Brassicas
Average2.42.23465811
Min2.32.12345710
Max2.62.34696911
Range0.30.2235112
Mixes
Average2.82.861015253850
Min2.12.046961015
Max3.53.691623466989
Range1.31.55914405974
Across Groups
Average2.62.54710162432
Standard Error0.70.9346182633
Min1.61.2111-2-3-4
Max4.34.5916235380101
Range2.73.4915225583105
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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