Planting Date and Seeding Rate Effects on Sunn Hemp Biomass and Nitrogen Production for a Winter Cover Crop
Table 5
Rye biomass yield and sunn hemp biomass carbon to nitrogen ratio for planting date (PD) and seeding rate (SR) when planted after wheat and corn harvest during 2007 and 2008 in east-central Alabama.
Rye biomass yield (Mg/ha)
Sunn hemp C : N ratio
Treatment
2008
2009
2007
2008
Wheat-sunn hemp
Sunn hemp planting date
PD1a
2.2
6.5
31.2
18.3
PD2b
2.1
8.4
41.0
36.4
LSD0.05
1.2
2.4
16.4
8.0
Sunn hemp seeding rate (kg/ha)
17
2.2
6.8
38.2
26.3
34
2.4
7.3
34.8
27.6
50
2.0
8.3
35.7
28.5
67
2.1
7.3
35.7
27.2
LSD0.05
0.59
1.7
11.3
11.2
Controlc
1.5
5.6
Corn-sunn hemp
Sunn hemp planting date
PD1d
2.0
3.3
12.6
30.5
PD2e
2.3
3.3
17.9
29.3
LSD0.05
0.6
2.3
2.0
14.7
Sunn hemp seeding rate (kg/ha)
17
2.5
3.7
15.0
29.9
34
1.9
3.7
15.6
26.8
50
2.1
3.1
16.0
33.2
67
2.1
2.7
14.2
29.8
LSD0.05
0.78
1.1
2.8
9.6
Controlc
2.3
3.2
ANOVA (P > F)
Wheat-sunn hemp
PD
0.7237
0.1038
0.1947
0.0001
SR
0.6203
0.3554
0.9311
0.9825
PD × SR
0.8267
0.9734
0.4776
0.8164
Corn-Sunn hemp
PD
0.2901
0.9597
0.0000
0.8359
SR
0.5952
0.1594
0.5733
0.5913
PD × SR
0.5709
0.0537
0.8235
0.9360
aPlanting date on 8 June 2007 and 11 June 2008.
bPlanting date on 22 June 2007 and 26 June 2008.
cSamples collected from fallow areas and not included in statistics.
dPlanting date on 17 August 2007 and 22 August 2008.
ePlanting date on 31 August 2007 and 5 September 2008.
