Harvesting Alfalfa
Harvesting Alfalfa Presentation by Dan Undersander
1. Spring Management of Alfalfa
New Growth Fall Residue Harvested Forage 2
% of final DM 93.5 6.5
CP
RFV
21.8 10.3 21.1
150 60 140
Relationship between yield and quality
Figure 1. Alfalfa stem and leaf yield and digestibility. Source: Sheaffer & Marten (1987). Cutting decisions (1st cut) A. Stage of Maturity first cutting alfalfa does not flower consistently
Table 3. Stage Number
DEFINITION OF MORPHOLOGICAL STAGES OF DEVELOPMENT FOR INDIVIDUAL ALFALFA STEMS. (From Kalu and Fick, 1983). Stage Name
Stage Definition
0
Early Vegetative
1
Mid-Vegetative
2
Late Vegetative
3
Early bud
4
Late Bud
5 6 7 8 9
Early Flower Late Flower Early Seed Pod Late Seed Pod Ripe Seed Pod
Stem Length < 15 cm; No Visible Buds, Flowers, or Seed Pods Stem Length 16-30 cm; No Visible Buds, Flowers, or Seed Pods Stem Length > 31 cm; No Visible Buds, Flowers, or Seed Pods 1-2 Nodes with Visible Buds; No Flowers or Seed Pods > Nodes With Visible Buds; No Flowers or Seed Pods One Node with One Open Flower; No Seed Pods > Nodes with Open Flowers; No Seed Pods 1-3 Nodes with Green Seed Pods > Nodes with Green Seed Pods Nodes with Mostly Brown Mature Seed Pods
SOURCE: Kalu et al. 1983.
B. Calendar date 280
2003
260
2002
240
2001
RFV
220
2000
200
1999
180 160 140
C. Growing degree day accumulation
120 100 5/3
5/13
5/23
6/2
6/12
6/22
Date
Fig 2 Change in alfalfa forage quality over time D. Harvest by quality a. Sample and Analyze (Scissors cut) b. Forage Quality Stick
3. Cut alfalfa Short (unless it includes certain grasses)
Yield (tons DM/ac)
2.5
Cut 1 Cut 2 Cut 3 Cut 4
2.0 1.5 1.0 0.5 2
3
4
5
6
7
Cut Height (inches above soil) 4. Manage for rapid drying A. AM vs PM cutting
Percent TNC
7 6 5 4 3 2 1 0 2
4
6
8
10
12
2
4
6
8
10
12
Time of Day
Figure 4. Diurnal Changes in Forage Carbohydrates B. Make wide swath a. Faster drying rate Total Pan Evaporation required to dry hay from 80% to 20% moisture with varying swath width
Total Pan Evaporation (mm)
60 50
Windrow width Mowed width 1.0 0.5
40
0.25 0.1
30 20 10 0 0.8
1.5 Yield (tons/acre)
2.2
b. Higher quality hay Alfalfa can loose 2 to 8% dry matter during during This is 2 to 8% less TDN
Figure 6. The drying process
Maximum Swath Width (%)
Keeping Stomates open Moisture >70% Sunlight – more they get the more they stay open Shading closes Stomata 20 – 30% of water removed before stomata close Removes 30% of the water from the stem (grass) 100 80 60 40 20 0 100
120
140
160
180
200
Cutting Width (in.)
Figure 7. Variation is swath width of mowers 5. Manage for low ash content Plants naturally contain 6 to 8% minerals (ash) Additional is picked up during harvesting process Each additional 1% ash is 1% less TDN
220
240
Ash Content of Forage Samples, 2005 UW Marshfield Lab Type
Statistic
% Ash
Haylage
Avg
12.3
Max
18.0
Min
5.7
Hay
Average
10.3
Max
17.6
Min
8.8
6. Minimize wheel traffic when harvesting Minimize driving on field Use smallest tractor for equipment Merge windrows where possible Go to larger equipment Take most direct route to edge of field Make road to drive on Do driving on field soon after harvest Manage to dry forage quickly Harvest for haylage or baleage Use preservative and harvest wet hay Use of duals not recommended Apply manure quickly after cutting
Estimating Alfalfa RFV in the Field Using PEAQ Step 1: Choose a representative 2square-foot area in the field. Step 2: Determine the most mature Stem in the 2square-foot sampling area using the criteria shown in the table at right. Step 3: Measure the length of the tallest stem in the 2-squarefoot area. Measure it from the soil surface (next to plant crown) to the tip of the stem. (NOT to the tip of the highest leaf blade). Straighten the stem for an accurate measure of its length. The tallest stem may not be the most mature stem.
Stage of Most Mature Stem Height of Tallest Stem (from soil surface to stem tip)
LATE VEGETATIVE
BUD STAGE
FLOWER STAGE
Vegetative (>12”) No buds visible
1 or more nodes with visible buds. No flowers visible
1 or more nodes with open flower(s)
-inches-
---------------Relative Feed Value---------------
16
237
225
210
17
230
218
204
18
224
212
198
19
217
207
193
20
211
201
188
21
205
196
183
22
200
190
178
23
195
185
174
Step 4: Based on the most mature stem and length of the tallest stem, use the chart at the right to determine estimated RFV content of the standing alfalfa forage.
24
190
181
170
25
185
176
166
26
180
172
162
27
175
168
158
Step 5: Repeat steps 1 to 4 in four or five representative areas across the field. Sample more times for fields larger than 30 acres.
28
171
164
154
29
167
160
151
30
163
156
147
31
159
152
144
32
155
149
140
33
152
145
137
34
148
142
134
35
145
139
131
NOTE: This procedure estimates 36 142 136 128 alfalfa RFV content of the standing crop. It does not 37 138 133 126 account for changes in 38 135 130 123 quality due to wilting, harvesting, and storage. 39 132 127 121 These factors may further 40 129 124 118 lower RFV content by 15 to 25 units, assuming good 41 127 122 115 wilting and harvesting conditions. This procedure 42 124 119 113 is most accurate for good stands of pure alfalfa with healthy growth. ________________________________________________________________________________________________________ The PEAQ system for estimating alfalfa quality in the field was developed by Agronomists at the University of Wisconsin - Madison April, 1999
1. Spring Management of Alfalfa
New Growth Fall Residue Harvested Forage 2
% of final DM 93.5 6.5
CP
RFV
21.8 10.3 21.1
150 60 140
Relationship between yield and quality
Figure 1. Alfalfa stem and leaf yield and digestibility. Source: Sheaffer & Marten (1987). Cutting decisions (1st cut) A. Stage of Maturity first cutting alfalfa does not flower consistently
Table 3. Stage Number
DEFINITION OF MORPHOLOGICAL STAGES OF DEVELOPMENT FOR INDIVIDUAL ALFALFA STEMS. (From Kalu and Fick, 1983). Stage Name
Stage Definition
0
Early Vegetative
1
Mid-Vegetative
2
Late Vegetative
3
Early bud
4
Late Bud
5 6 7 8 9
Early Flower Late Flower Early Seed Pod Late Seed Pod Ripe Seed Pod
Stem Length < 15 cm; No Visible Buds, Flowers, or Seed Pods Stem Length 16-30 cm; No Visible Buds, Flowers, or Seed Pods Stem Length > 31 cm; No Visible Buds, Flowers, or Seed Pods 1-2 Nodes with Visible Buds; No Flowers or Seed Pods > Nodes With Visible Buds; No Flowers or Seed Pods One Node with One Open Flower; No Seed Pods > Nodes with Open Flowers; No Seed Pods 1-3 Nodes with Green Seed Pods > Nodes with Green Seed Pods Nodes with Mostly Brown Mature Seed Pods
SOURCE: Kalu et al. 1983.
B. Calendar date 280
2003
260
2002
240
2001
RFV
220
2000
200
1999
180 160 140
C. Growing degree day accumulation
120 100 5/3
5/13
5/23
6/2
6/12
6/22
Date
Fig 2 Change in alfalfa forage quality over time D. Harvest by quality a. Sample and Analyze (Scissors cut) b. Forage Quality Stick
3. Cut alfalfa Short (unless it includes certain grasses)
Yield (tons DM/ac)
2.5
Cut 1 Cut 2 Cut 3 Cut 4
2.0 1.5 1.0 0.5 2
3
4
5
6
7
Cut Height (inches above soil) 4. Manage for rapid drying A. AM vs PM cutting
Percent TNC
7 6 5 4 3 2 1 0 2
4
6
8
10
12
2
4
6
8
10
12
Time of Day
Figure 4. Diurnal Changes in Forage Carbohydrates B. Make wide swath a. Faster drying rate Total Pan Evaporation required to dry hay from 80% to 20% moisture with varying swath width
Total Pan Evaporation (mm)
60 50
Windrow width Mowed width 1.0 0.5
40
0.25 0.1
30 20 10 0 0.8
1.5 Yield (tons/acre)
2.2
b. Higher quality hay Alfalfa can loose 2 to 8% dry matter during during This is 2 to 8% less TDN
Figure 6. The drying process
Maximum Swath Width (%)
Keeping Stomates open Moisture >70% Sunlight – more they get the more they stay open Shading closes Stomata 20 – 30% of water removed before stomata close Removes 30% of the water from the stem (grass) 100 80 60 40 20 0 100
120
140
160
180
200
Cutting Width (in.)
Figure 7. Variation is swath width of mowers 5. Manage for low ash content Plants naturally contain 6 to 8% minerals (ash) Additional is picked up during harvesting process Each additional 1% ash is 1% less TDN
220
240
Ash Content of Forage Samples, 2005 UW Marshfield Lab Type
Statistic
% Ash
Haylage
Avg
12.3
Max
18.0
Min
5.7
Hay
Average
10.3
Max
17.6
Min
8.8
6. Minimize wheel traffic when harvesting Minimize driving on field Use smallest tractor for equipment Merge windrows where possible Go to larger equipment Take most direct route to edge of field Make road to drive on Do driving on field soon after harvest Manage to dry forage quickly Harvest for haylage or baleage Use preservative and harvest wet hay Use of duals not recommended Apply manure quickly after cutting
Estimating Alfalfa RFV in the Field Using PEAQ Step 1: Choose a representative 2square-foot area in the field. Step 2: Determine the most mature Stem in the 2square-foot sampling area using the criteria shown in the table at right. Step 3: Measure the length of the tallest stem in the 2-squarefoot area. Measure it from the soil surface (next to plant crown) to the tip of the stem. (NOT to the tip of the highest leaf blade). Straighten the stem for an accurate measure of its length. The tallest stem may not be the most mature stem.
Stage of Most Mature Stem Height of Tallest Stem (from soil surface to stem tip)
LATE VEGETATIVE
BUD STAGE
FLOWER STAGE
Vegetative (>12”) No buds visible
1 or more nodes with visible buds. No flowers visible
1 or more nodes with open flower(s)
-inches-
---------------Relative Feed Value---------------
16
237
225
210
17
230
218
204
18
224
212
198
19
217
207
193
20
211
201
188
21
205
196
183
22
200
190
178
23
195
185
174
Step 4: Based on the most mature stem and length of the tallest stem, use the chart at the right to determine estimated RFV content of the standing alfalfa forage.
24
190
181
170
25
185
176
166
26
180
172
162
27
175
168
158
Step 5: Repeat steps 1 to 4 in four or five representative areas across the field. Sample more times for fields larger than 30 acres.
28
171
164
154
29
167
160
151
30
163
156
147
31
159
152
144
32
155
149
140
33
152
145
137
34
148
142
134
35
145
139
131
NOTE: This procedure estimates 36 142 136 128 alfalfa RFV content of the standing crop. It does not 37 138 133 126 account for changes in 38 135 130 123 quality due to wilting, harvesting, and storage. 39 132 127 121 These factors may further 40 129 124 118 lower RFV content by 15 to 25 units, assuming good 41 127 122 115 wilting and harvesting conditions. This procedure 42 124 119 113 is most accurate for good stands of pure alfalfa with healthy growth. ________________________________________________________________________________________________________ The PEAQ system for estimating alfalfa quality in the field was developed by Agronomists at the University of Wisconsin - Madison April, 1999
