Reducing Alfalfa Cooperative Extension Service M
College of Agriculture and
Harvest Losses Home Economics
Charles Glover, Extension Agronomist; John Arledge, Assistant Professor of Agronomy;
Bill Melton, Professor of Agronomy; and Cliff Currier, Assistant Professor of Agronomy
This publication is scheduled to be updated and reissued 8/01.
Alfalfa hay is an important commodity in New cause of leaching and in creased moisture uptake.
Mexico. Growers strive for high yields of good Conditioners also require continual adjustment to
quality hay. When producers and agronomists function properly.
discuss alfalfa production, they usually talk in Several chemical drying agents are now on the
terms of growing the crop. Most questions and market. Results indicate the curing time can be
management decisions involve topics like seed- reduced by 50 to 70%, with windrowed hay
bed preparation, seeding rate and date, variety se- reaching baling moisture levels 12 to 24 hours
lection, fertilization, irrigation, pest management, after swathing.
and timing of harvest. These chemical drying agents are applied to
Little consideration is given to the losses in the standing hay from units mounted on the
yield and quality that can occur during the har- swather. These chemicals break down the waxy
vesting and packaging operation. However, esti- cuticle layer on the stem, which increases the rate
mates of 30% to 70% of the potential crop is nor- of moisture loss. A second benefit is that leaves
mally lost during the harvesting operation. are not as brittle when the hay is baled, resulting
The most obvious losses are the result of rain- in less leaf loss. A major problem at this time is
fall between cutting and baling. Damages are the need to carry large quantities of the drying
usually attributed to mold, mildew, fermentation, agent mixture on the swather. Studies are now
and bleaching. Less obvious losses are leaching underway to evaluate low volume, controlled
of nutrients from the hay, respiration, and leaf droplet size applications.
shattering. Preliminary studies using the Haybine1 swather
Several studies conducted in the United States indicate the hay drying rate is significantly faster
and in Australia indicated that wetting hay re- than with a conventional swather-wind rower,
duced the leaf content in bales by up to 15%. and approaches the drying rate obtained with
Other losses included 34% of the nonstructural chemical drying agents. It may be possible to
carbohydrates, 10% digestibility, and 25% of the combine chemical drying agents with the
protein yield. Wetting also resulted in an in- Haybine system and bale hay the same day it is
creased fiber content of 6 to 10%. Hay yields cut.
were usually reduced by 20 to 40%. Variation in Another method to shorten curing time is to
the amount of damage encountered was the result bale at higher moisture content than normal.
of prior mechanical treatments, amount and fre- There are presently several hay preservatives
quency of rainfall, and the percent moisture in the available which are designed to prevent spoilage
hay when rainfall occurred. in high moisture hay. The preservatives are ap-
One partial solution to reducing these losses is plied to the hay as it enters the baler.
to shorten the time the hay cures in the field. Un- Research conducted at the NMSU Southeast
til recently, mechanical conditioners or crimpers Branch Station has shown that propionic acid and
have been the only practical method available to sodium diacetate preservatives were effective in
encourage faster drying. Estimates of dry matter
losses attributed to crimping are as high as 13%. Use of a trade name does not Constitute endorsement or recommenda-
tion by the New Mexico Agricultural Experiment Station or the coopera-
Rain damage is also higher on crimped hay be- tive Extension Service.
preventing spoilage when applied to hay with up servative as a safeguard system. They begin bal-
to 25% moisture (based on forced-air dried ing slightly earlier with the preservative than they
samples). Biotic preservatives, similar to silage normally would and, when wind row moisture is
preservatives, were effective up to 22% moisture. suitable for conventional baling, discontinue us-
Hay baled at higher than normal moisture using ing the preservative. Preservatives can also ex-
preservatives doubled the yield of baled hay (af- tend the baling time at night when dew moisture
ter adjustment to 14% moisture), and increased would normally halt the baling process. Produc-
the protein by 8% when compared to conven- ers using the large square balers often use preser-
tional practices. After two months storage, the vatives as insurance to prevent bale kick-back re-
preservative-treated hay had better color, higher sulting from spoilage.
percentage of leaves, less dust, mildew and odor One problem with baling high moisture hay is
than the conventionally baled hay. the shrinkage encountered in storage. However,
The cost of adding a preservative ranges from the increased yield for the producer and increased
$1 to $5 per ton of hay. Because of the added cost quality to the customer should help offset shrink-
of preservatives many growers are using the pre- age losses.
New Mexico State University is an equal opportunity/affirmative action employer and educator. NMSU and the U.S. Department of Agriculture
Reprinted for electronic distribution August 1996 Las Cruces, NM
Guide A-318 • Page 2