Journal of the NACAA
ISSN 2158-9429
Volume 4, Issue 1 - June, 2011

Editor:

Alternative Cover Crops, Performance and Planting Techniques

Nottingham, J.R., Extension Agent, University of Maryland Extension

ABSTRACT

ALTERNATIVE COVER CROPS PERFORMANCE AND PLANTING TECHNIQUES Nottingham, * J.R.¹, Armentrout, D.2 ¹• Extension Agent, University of Maryland Extension, Somerset County, Princess Anne, Maryland 21853 2. Facility Manager, University of Maryland Extension, LESREC Facility, Salisbury, Maryland 21801

After fall harvest, carry-over nutrients typically remain in the soil. Fall plantings of cover crops are vital to scavenge carry-over nutrients, particularly nitrogen, which is susceptible to loss. Cover crops can reduce nitrogen loss through leaching. Cover crops are a valuable resource to reduce erosion and are vital to water quality in the entire region. Traditionally, planting techniques have included the following: No-till drill into previous crop residue or tilled soil, broadcast seed and lightly incorporate, and broadcast only (includes aerial applications). Recent innovations in conservation tillage options have introduced vertical tillage. Vertical tillage is an intermediate tillage form between minimum till (chisel plow or field cultivator) and full no-till. A large percentage of crop residue is left on the soil surface, reducing erosion. Wheat , rye, hairy vetch, canola, annual rye grass, tillage radish, and spring oat cover crop plots were planted at three Maryland locations using 4 planting treatments. The following planting techniques were utilized: broadcast only, broadcast and vertical till, broadcast and lightly disk, and no-till drill. Seed emergence counts tracked establishment for each treatments. Seedling emergence rates were highest in the no-till plots with wheat averaging 28 seedlings/ft2 compared to 24 seedlings/ft2 in the broadcast only plots. Hairy vetch plots had the lowest emergence rates, averaging 18 seedlings/ft2 in the no-till plots and only 5 seedlings/ft2 in the broadcast only plots. Overall, seedling rates were highest in the no-till drill, broadcast and lightly disked, and vertical tilled plots and lowest in the broadcast only plots. As expected increased seed to soil contact resulted in higher establishment rates. Results indicate that increased seed to soil contact was more critical for good seed establishment in hairy vetch and canola and less critical for wheat, rye, and spring oats. Vertical tillage provided comparable establishment rates for rye, and wheat to no-till plots and disked plots, but lower establishment rates for hairy vetch, canola, and spring oats. In all cases, vertical tilled plots had higher establishment rates than broadcast only plots.


 
Alternative Cover Crops, Performance and Planting Techniques
 
 
     After fall harvest, carry-over nutrients typically remain in the soil. Fall plantings of cover crops are vital to scavenge carry-over nutrients, particularly nitrogen, which is susceptible to loss. Winter is typically the time of greatest ground water recharge in the region, and cover crops can reduce nitrogen loss through leaching in our sandy soils to ground water and ultimately the Chesapeake Bay. Cover crops are a valuable resource to reduce erosion and are vital to water quality in the entire region. Traditionally, planting techniques have included the following:
No-till drill into previous crop residue or tilled soil, broadcast seed and lightly incorporate, and broadcast only (includes aerial applications). Recent innovations in conservation tillage options have introduced vertical tillage to the region, such as the Great Plains “Turbo Till”©. Vertical tillage is an intermediate tillage form between minimum till (chisel plow or field cultivator) and full no-till. A large percentage of crop residue is left on the soil surface, reducing erosion. In addition, corn stalk mowing can be eliminated, reducing equipment passes over the field and saving fuel. Vertical tillage can be used for shallow incorporation of cover crop seed. 
 
     In 2008, Maryland Grain Producers Utilization Board funded a project to evaluate the performance of alternative cover crops and various planting techniques on establishment rates. Objectives of this study were: to explore alternative cover crops in the Delmarva Region to assess their viability as an alternative to traditional cover crops, to investigate costs of alternative cover crops with the propose of providing economical alternatives when the price of traditional cover crops makes planting uneconomical, and to inform farmers on the uses of alternative cover crops and new planting techniques. 
    
     In early October 2008, wheat , rye, hairy vetch, canola, annual rye grass, tillage radish, and spring oat cover crop plots were planted at three Maryland locations using 4 planting treatments. Plot size was 200 feet by 20 feet with 3 replications.  Seeding rates were as recommended by the Maryland Cover Crop program where applicable. The following planting techniques were utilized: broadcast only, broadcast and vertical till, broadcast and lightly disk, and no-till drill. Seed emergence counts tracked establishment for each treatments. Seedling emergence rates were highest in the no-till plots with wheat averaging 28 seedlings/ft2 compared to 24 seedlings/ft2 in the broadcast only plots. Tillage radish plots had the lowest emergence rates, averaging 14 seedlings/ft2 in the no-till plots and only 2 seedlings/ft2 in the broadcast only plots. Overall, seedling rates were highest in the no-till drill, broadcast and lightly disked, and vertical tilled plots and lowest in the broadcast only plots. As expected, increased seed to soil contact resulted in higher establishment rates. Results indicate that increased seed to soil contact was more critical for good seed establishment in hairy vetch and canola and less critical for wheat, rye, and spring oats. Vertical tillage provided comparable establishment rates for rye and wheat in no-till plots and disked plots, but lower establishment rates for hairy vetch, canola, and spring oats. In all cases, vertical tilled plots had higher establishment rates than broadcast only plots. Annual rye grass information was only available from one site due to a reluctance by cooperators to plant for fear of later emergence in small grain crops, however at the one site where annual rye grass was planted, emergence was excellent averaging 63 seedlings/ft2 . Tillage radish plots suffered from cold weather soon after planting with a crop failure at one site. 
     The data were analyzed to determine if there were significant differences using Analysis of Variance (ANOVA).  The Fisher's Protected F-Test with a probability level of P<0.05 was used to identify treatment differences.  When this occured, treatment means were separated using an LSD (least significant difference) test at the p=0.05 level. 
 
Average Seedlings/ft2
 
Sample
Rye
Hairy Vetch
Canola
Spring oat
Wheat
Annual Rye grass
Tillage Radish
no-till drill
 
28
18
28
27
28
63
14
Broadcast
Lightly disk
26
12
15
24
27
n/a
Frost Killed
Broadcast only
 
18
5
6
14
20
n/a
2
Vertical till
 
26
8
12
18
24
n/a
12
 
Percent Ground Cover
sample
Rye
Radish
Vetch
Annual Rye Grass
Canola
Spring Oat
Wheat
No-till Drill
83.8
33.3
7.6
55.7
44.0
51.7
58.3.
Broadcast lightly disk
74.3
Cold damage
9.0
n/a
25.6
Deer Damage
44.0
Broadcast only
59.3
7.0
4.3
n/a
21.0
29.0
53.0
Vertical till
80.6
50.0
8.6
n/a
10.3
18.3
65.6
 
 
    A comparative cost analysis indicates that canola and annual rye grass may offer economical alternatives to traditional cover crops with canola at $12.80/acre and annual rye grass at $17.80/acre. 
Cost Analysis (2008 prices)
Crop
Seeding Rates
Price/Lb
Cost/Acre
Wheat
2 bu/acre 120 lb
.29
34.80
Rye
2 bu/acre 112 lb
.38
42.56
Oats
3 bu/acre 96 lb
.35
33.60
Canola
8 lb/acre
1.60
12.80
Annual Rye Grass
20 lb/acre
.89
17.80
Hairy Vetch
25 lb/acre
2.50
62.50
Tillage Radish
8 lb/acre
3.50
28.00
 
 
    Biomass samples were collected in April 2008 to estimate crop nitrogen (N) uptake. Excluding hairy vetch, rye averaged the highest containing 59.7 lbs.N/acre, followed by spring oats with 20.2 lbs.N/acre. Wheat contained 14.4 lbs.N /acre and Canola 13.1lbs N/acre. 
 
Crop Nitrogen (N) uptake Lbs/Acre
 
Rye
59.7
Spring Oats
20.2
Wheat
14.4
Canola
13.1
Tillage Radish
22.34
Annual Rye Grass
14.1
 
 
     It is well established that cover crop planting methods which encourage seed to soil contact will result in higher seedling establishment rates. This research indicates that vertical tillage following broadcasting of seed is a practical method of achieving acceptable establishment rates. With the exception of wheat and rye, establishment rates were poor where seed was broadcast only with no tillage or incorporation. Tillage radish and canola were most affected by cold temperatures and will need an early planting date. One plot with very sandy soil, (Fort Mott loamy sand),suffered damage from blowing sand to the tillage radish and vetch plots, other plots at the same location were not damaged. 
Broadcast, Lightly Disked
Cover Crop Species
% Ground Cover
Seedlings/Ft2
Canola
26 b1
14 a
Rye
74 d
27 b
Vetch
9 a
12 a
Wheat
44 c
27 b
Spring Oat
Deer damaged
23 b
LSD0.05
8.2
4.8
1 The same lower  case letters within a column indicate that two means are not significantly different at p=0.05.
No-Till Drill
Cover Crop Species
% Ground Cover
Seedlings/Ft2
Canola
44 bc1
28 b
Radish
33 b
14 a
Rye
83 d
27 b
Rye Grass
56 c
62 c
Spring Oat
52 c
27 b
Vetch
8 a
17 a
Wheat
58 c
29 b
LSD0.05
16.4
3.7
1 The same lower  case letters within a column indicate that two means are not significantly different at p=0.05.
Broadcast, Broadcast and Vertical Tilled
Cover Crop Species
% Ground Cover
Seedlings/Ft2
Broadcast only
Vertical Tilled
Broadcast only
Vertical Tilled
Canola
21 b1 A2
10 a A
5 a A
12 ab B
Radish
7 a A
50 b B
1 a A
12 ab B
Rye
59 c A
81 c B
18 b A
26 d B
Spring Oat
29 b A
18 a A
14 b A
18 bc A
Vetch
4 a A
9 a A
4 a A
8 a A
Wheat
53 c A
66 b B
21 b A
23 cd A
1 The same lower  case letters within a column indicate that two means are not significantly different at p=0.05.
2 The same uppercase letters between two columns for a measured variable indicate that the two means are not different at p=0.05.