2004, Issue #6
from your Pioneer Sales Representative: Kingston Feed & Farm
The Secret To Growing Fine Stemmed Alfalfa
Your Cows Will Love
As much as producers would like to believe that there are genetic differences in alfalfa stem diameter STEM DIAMETER RESEARCH conducted by the University of Guelph shows clearly that there is no measurable genetic difference. While genetically there are no differences there are innumerable management factors that can influence stem diameter. Here then is a list of Key Management Factors that will help producers achieve their goal of producing top yields of fine stemmed high quality alfalfa.
Assessing Alfalfa Stand Quality And Yield
Year Ideal Stand Consider Rotating Field
Plants per square ft. When Plants/Square Foot
Establishment 25 - 40 Less than 8
First Year 12 - 20 Less than 7
Second Year 9 - 12 Less than 5
Third Year 5 - 8 Less than 5
Alfalfa Stem Count and Yield Potential
Dry Matter
Tons /Acre
7
6 5.5 5.5
5 5.2
4 4.3
3 3.3
2 2.3
1 1. 3
10 20 30 40 50 60 70
Stems Per Square Foot
· Source University of Wisconsin - Madison
· Select top yielding high disease resistant varieties with exceptional winterhardiness Either HR or R ratings for Phytopthora, verticillium, and Fusarium is advisable. Thick stands over the entire life of an alfalfa crop is IMPORTANT ! Lack of good winterhardiness and overall solid disease resistance will lead to quicker stand thinning and coarser stemmed alfalfa.
· Continually improve field drainage through either more tile or soil structure improvement. Poor drainage will thin alfalfa stands more quickly leading to coarser stemmed alfalfa.
· Keep soil pH in the 6.5-7.0 range. Alfalfa is a heavy feeder of both calcium and magnesium. Low soil pH will reduce stand life and thin alfalfa stands leading to coarser stemmed alfalfa.
· For long term crop productivity CLEAN FIELDS ARE A MUST !Don’t compromise on weed control in any crop particularly alfalfa. Remember alfalfa is a perennial crop ,a crop whose stand establishment is crucial to its long term productivity. Weedy stands thin alfalfa prematurely leading to coarser
stemmed alfalfa.
· Use Higher seeding rates when establishing alfalfa- 18-20lb per acre is a must.
High seeding rates will produce finer stemmed alfalfa in the first and second years production!
Effect of Seeding Rate on Stem Size In Alfalfa
(An Evaluation of Second Year Harvest)
Seeding Rate # Stems in 12” of Row Stem Diameter(mm)
Cut 1 Cut 2
6 lb/acre 48 69 3.26
12 lb/acre 57 71 2.98
18 lb/acre 57 73 2.91 **
24 lb/acre 64 73 2.84
30 lb/acre 62 72 2.74
· Don’t compromise on stand establishment technique. Uniformity of seed depth placement is crucial to establishing thick healthy stands. Seed no deeper than ¼ to ½ inch. The primary cause for thin stands is seeding TOO DEEP .Brillion seeders or press wheel drills with phosphorus band placement is a must! AGAIN DO NOT WORK FIELDS OVERLY DEEP. KEEP A FIRM BOTTOM SO SEED CAN BE PLANTED
SHALLOW INTO MOISTURE.
Seeding Depth Study
Seeding Depth % Seedling Emergence
Inches
½ 64
1 53
1 ½ 45
2 19
Keep soil test potash levels in the high range of between 120-150 ppm. Alfalfa will remove nearly 50lb of potash per acre on a dry matter ton basis. Make sure you replenish what the crop removes. Yearly applications of 200-250 lb per acre of potash are in order along with50-60 lb of phosphorus. Adequate potash nutrition has proven to enhance stand life through improving overwintering and reducing stand thinning.
· Split alfalfa fields with two varieties, one an early fall dormant and one a late fall dormant This will widen your harvest window for optimizing Relative Feed Values of 150.
· Plan an appropriate harvest schedule to maximize feed quality. Plan on a 32-34 day harvest scheduling after the first cut.
· Monitor new seedings and 2nd and 3rd cuts for potato leafhopper. Leafhoppers left to feed at will can so severely stunt alfalfa that stands can be thinned and stand life reduced.
· Bale or ensile at appropriate harvest moistures to aid in leaf retention and improve palatability. Leaves contain up to 70% of the total protein and soften the composition of baled hay for better animal intake.
· Adhere to the CRITICAL FALL HARVEST PERIOD for your respective area. Alfalfa needs 5-6 weeks of undisturbed growth in the fall to replenish its root reserves. Otherwise late harvests can reduce winterhardiness and lead to stand thinning.
· When alfalfa is managed intensively for top quality forage (20% protein,30 ADF,and 40 NDF values) stands will thin more quickly and stand life usually lessened. Be prepared to re-seed on a 3 year rotation basis.
· REMEMBER ALFALFA IS TRULY A BEAUTIFUL CROP.
· TAKE GOOD CARE OF IT AND IT WILL REWARD YOU RICHLY!
James D’Aoust
Pioneer Field Sales Agronomist