YIELD AND
QUALITY OF IRRIGATED ALFALFA
Joyce Eckhoff, EARC Agronomist
Charles Flynn, EARC Chemist
A near infrared spectrometer (NIR) was recently purchased by the Eastern
Agricultural Research Center with funding from a federal grant. The NIR has many uses,
including measurement of forage quality. The NIR was calibrated to measure crude protein,
acid detergent fiber, neutral detergent fiber, and moisture of alfalfa hay. These values
are then used to calculate a number of quality values, including relative feed value
(RFV). Digestibility and intake are calculated from ADF and NDF respectively, and used to
calculate RFV, an index that combines predicted digestibility and intake from forage
analyses. The Hay Marketing Task Force of the American Forage and Grassland Council
assigns quality standards to alfalfa and other types of hay. Legume and grass hay can be
graded as follows:
| Quality standard |
Crude protein |
RFV |
| Prime |
>19 |
>151 |
| 1 |
17-19 |
125-150 |
| 2 |
14-17 |
103-124 |
| 3 |
11-14 |
87-102 |
| 4 |
8-11 |
75-86 |
| 5 |
<8 |
<75 |
While variety is an important component of alfalfa quality, age of the
alfalfa stand and maturity at harvest are also very important factors in alfalfa quality.
The NIR was used to evaluate quality of alfalfa varieties in two variety trials conducted
under flood irrigation at the Eastern Agricultural Research Center in Sidney. The 1996
trial was two years old and the 1997 trial was one year old. Plots were in late bud or
early flower stages at harvest.
1997 statewide alfalfa yield trial, grown under flood irrigation at
Sidney, MT
Planted: May 17, 1997 1998 harvest dates: June 5th, July
17th, and August 19th
| |
YIELD
Tons/A |
Crude
Protein |
RFV |
| Cultivar |
1st cut |
2nd cut |
3rd cut |
Total |
1st cut |
2nd cut |
3rd cut |
1st cut |
2nd cut |
3rd cut |
| 645 |
2.8 |
2.6 |
2.0 |
7.4 |
17.9 |
17.7 |
21.8 |
158 |
127 |
188 |
| 5396 |
2.5 |
2.5 |
2.0 |
7.0 |
17.6 |
17.5 |
21.1 |
151 |
128 |
175 |
| DK142 |
2.4 |
2.5 |
2.0 |
6.9 |
18.1 |
17.9 |
21.7 |
159 |
130 |
183 |
| Rhino |
2.5 |
2.4 |
1.9 |
6.8 |
18.3 |
18.0 |
21.1 |
164 |
129 |
174 |
| Wrangler |
2.4 |
2.4 |
1.8 |
6.6 |
18.0 |
17.9 |
20.4 |
153 |
129 |
160 |
| Ace |
2.2 |
2.4 |
2.0 |
6.6 |
18.6 |
18.0 |
20.4 |
177 |
125 |
166 |
| Cimmaron 3i |
2.4 |
2.3 |
1.9 |
6.6 |
18.6 |
18.2 |
21.4 |
166 |
133 |
173 |
| Oneida VR |
2.3 |
2.3 |
1.9 |
6.5 |
17.8 |
17.4 |
20.2 |
158 |
129 |
155 |
| Riley |
2.3 |
2.3 |
1.9 |
6.5 |
18.2 |
19.0 |
21.0 |
154 |
142 |
163 |
| 3L 102 |
2.0 |
2.5 |
2.0 |
6.5 |
19.4 |
18.6 |
21.0 |
186 |
140 |
180 |
| DK 143 |
2.2 |
2.5 |
1.8 |
6.5 |
18.7 |
18.6 |
20.5 |
166 |
135 |
162 |
| 5301 |
2.0 |
2.4 |
1.7 |
6.1 |
19.2 |
18.8 |
21.9 |
177 |
143 |
183 |
| Ladak 65 |
2.4 |
2.0 |
1.5 |
5.9 |
17.6 |
18.2 |
22.6 |
152 |
135 |
188 |
| DK140 |
1.9 |
2.2 |
1.8 |
5.9 |
19.4 |
18.2 |
20.7 |
182 |
133 |
174 |
| LSD 5% |
0.5 |
0.2 |
0.2 |
|
1.2 |
NS |
NS |
17.0 |
NS |
NS |
|
