PHYSIOLOGY, FORAGE QUALITY AND PRODUCTION
Evaluation of Oklahoma Alfalfa Production - John
Caddel..................................................72
Forage Exports from the Pacific Northwest - W.
P. Ford ...................................73
Carbon for Root Nodule Function: The Role
of Malate Dehydrogenase - Carroll P. Vance,
Brian G. Driscoll, Sue S. Miller, Robert G.
Gregerson, and J. Stephen Gantt..........74
Dinitrogen Fixation of Annual Medicago species - Y.
Zhu, C. C. Sheaffer,
M. P. Russelle, and C. P. Vance .....................................................75
Winter Survival of Alfalfa: Seed vs. Forage
- G. B. Coukell and S. R. Smith...............76
Wyoming Alfalfa Hay Hotline - A. Gray, C. Anderson,
R. Kettle, R. Cunningham, E. Palen....77
Seeding Rate and Density Effects on Forage Yield
and Quality of a "High Quality" Alfalfa
Cultivar - S. D. Cash, R. L. Ditterline, L. E. Welty,
R. L. Dunn and L. S. Prestbye..78
Evaluation of Oklahoma Alfalfa Production
JOHN CADDEL
Department of Agronomy, Oklahoma State University
Stillwater, Oklahoma, 74078-6028
Alfalfa producers receive information from many different sources. Specialists
advise producers directly or indirectly through agricultural extension
agents or marketing staff. Advice is normally oriented to single production
practices such as, insect control, disease problems, feeding alfalfa, choosing
cultivars, controlling weeds, or fertilizer. Producers, however, work on
a whole-farm scale, involving several enterprises including other crops,
livestock, and crop rotation. Frequently producers give the impression
of disregarding specific recommendations because of their diverse activities,
and advisors question why certain recommended practices were not followed.
The objective of this study of was to partially answer the question --
"What is really going on in Oklahoma alfalfa production?" There
are many sources of information about this subject, but their reliability
is difficult to judge. This study is based on-farm data collected in commercial
alfalfa fields. Seventy alfalfa producers chose 133 of their fields for
the study and were closely involved with sampling. Measurements included
soil tests in spring and autumn, alfalfa stem counts in spring and autumn,
and description of production practices. At each harvest (three to five,
depending on individual producers and fields) forage yield, weed contamination,
alfalfa stem length, stage of maturity at harvest, and forage quality (crude
protein, acid detergent fiber, and neutral detergent fiber) was measured
or recorded. Usable date were collected for most indicators from about
75 production situations.
More than 75% of fields sampled during first growth in spring had less
than adequate soil phosphorus, potassium, or pH, indicating soils were
not maintained at high production potential with recommended fertilization
practices. In many of these same fields state-of-the-art cultivars, machinery,
and pesticides were used, indicating producers were in touch with modern
production ideas and techniques.
No strong relationships was detected between stem density, phosphorus,
potassium, or soil pH and forage yield, and it is difficult to detect effects
of a single factor on forage yield or forage quality. Normally alfalfa
producers do not assign the same importance to individual recommended production
practices that advisors do. An important reason is because they compare
production in different fields or different years when many different variables
change, hiding the main effects. A producer may follow recommendations
for fertilization but not use the best cultivar or may not control critical
insects in a timely fashion. As a result producers conclude proper fertilization
was not important. Because other factors limited forage production or quality,
an important factor was not recognized as such.
Preliminary conclusion from this study indicate: ( I ) Too many variables
at one time conceal effects of individual production factors; (2) Advisors
should spend more time addressing the whole of all production practices
and the whole farm; and (3) Stressing single production factors interferes
with good communications between alfalfa producers and advisors. Thc Oklahoma
Alfalfa Integrated Management team began addressing this problem in alfalfa
research and extension activities by conducting more multi-factor programs.
Alfalfa harvest management and stand establishment extension publications
address cost-benefit relationships for different scenarios.
References
I . Caddel, J.L., J.F. Stritzke, P. Mulder, R. Huhnke, R. Berberet,
and C. Ward. 1995. Forage Harvest Management
Discussion with cost benefit analysis. Oklahoma Coop. Extension Circular
E-943.
2. Caddel, J.L., J.F. Stritzke, P. Mulder, G. Johnson, C. Ward, and
R. Berberet. 1996. Alfalfa Stand Establishment
Questions and Answers. Oklahoma Coop. Extension Circular. (In Press)
Forage Exports From The Pacific Northwest
W. P. Ford
Cooperative Extension, Washington State University
Pasco, Washington, 99301, U.S.A.
Exports are an important market for the Western United States forage
producer. Forage products exported are: alfalfa hay and cubes, timothy
hay, oat hay, sudangrass hay, bermuda hay, and perennial ryegrass and fescue
straw.
From December 1994 to November 1995, the United States exported 60,773
containers of hay to the Pacific Rim. The countries of China, Singapore,
Malaysia, Indonesia, and the Philippines only received 141 containers of
hay or 0.2% of these containers. Korea was the third largest destination
and received 2,388 containers or 3.8% of the total. Taiwan was the second
largest destination with 3,439 containers or 5.7% of the total. Japan was
the largest market at 54,855 containers or 90.3% of all containers shipped.
In 1995, Japan imported 720 thousand metric tons (mt) of alfalfa cubes,
1.38 million mt (mmt) of baled hay, and 274 thousand mt of alfalfa pellets.
The United States supplied approximately 73% of these cubes, 86% of the
baled hay, but less than 3% of the pellets. Overall, the United States
supplied about 73% of Japan's total 1995 forage imports (hay, cubes, pellets)
of 2.38 mmt.
The United States exported 1,717,393 mt of forage in 1995 from the west
coast. The United States Department of Commerce data indicate that the
PNW share of these exports is about 55% or 944,566 mt. Forage exports represented
about 9.2% of total hay production in Washington, Oregon, and Idaho. In
1995, approximately 567,000 mt of forages were exported from Washington.
While PNW exports in 1995 only represented 9.2% of total hay production,
exports from Washington state represented 19.1%. This is the second year
that forage exports from Washington have exceeded $100 million. Forage
exports the past nine years have helped support and stabilize forage prices
in the PNW even with increasing acreages.
The United States and Canada will continue to be major suppliers of forage
products to Japan. Baled hay exports have dramatically increased during
the past 7 years, with the United States supplying the vast majority of
products. Alfalfa cube exports from the United States have leveled off
and Canada has increased its market share the past few years.
The Korean market is also starting to develop and is now the third largest
destination for forage products. Currently, hay cubes and pellets dominate
the market. Korea won't become a large importer of United States hay quickly,
but a substantial market should develop over the next decade. Korea will
displace Taiwan and become the second largest market in the future because
of: population, livestock numbers, limited arable land base, and strong
economy. The potential size of this market is estimated to be one-quarter
to one-third of the Japanese market or 500,000 to 600,000 mt of hay and
cubes.
The forage market in Taiwan is now the second largest Pacific Rim consumer
for the United States. Total exports to Taiwan have risen sharply this
past year due to crop and weather conditions. It is not clear whether these
import levels will continue or drop to lower levels in 1996.
Washington and the PNW forage industry need to recognize the importance
of Pacific Rim exports to the forage economy of their areas. The PNW needs
to promote quality, consistency of product, and cheaper transportation
methods to retain and/or increase their market share in a growing world
market.
Carbon for Root Nodule Function:
The Role of Malate Dehydrogenase
Carroll P. Vance,l2 Brian G. Driscoll,2 Sue S. Miller,2
Robert G. Gregerson, 2 and J. Stephen Gantt3
USDA/ARS Plant Science Research Unit, 2Department of Agronomy and Plant
Genetics, and 3Department of Plant Biology, University of Minnesota,
St. Paul, MN 55108
Malic acid, derived from malate dehydrogenase (MDH), is critical to
plant function and is considered by many to be the major product of glycolysis
in plants. This organic acid also plays a role in oxidation of fatty acids,
generation of energy through the tricarboxylic acid cycle, C4 photosynthesis,
crassulacean acid metabolism, and nitrogen fixation. Malic acid can move
between the cytosol and cell organelles, thus being a source of reducing
equivalents in mitochondria, plastids, peroxisomes, and symbiosomes. Since
it has many functional roles, the control of malic acid is affected by
numerous isozymes of MDH. Because of our interest in nitrogen fixation
and nitrogen assimilation, we thought it important to isolate the genes
controlling the various isoforms of MDH in root nodules. Using heterologous
MDH probes from other plants we isolated plastid, mitochondrial, and glyoxysomal
MDHs, pMDH, mMDH, and gMDH, respectively. Complementation of an Escherichia
coli MDH- mutant allowed us to isolate cytosolic MDH (cMDH) and nodule
enhanced MDH (nMDH). All five alfalfa MDHs were sequenced. The similarity
between the various MDHs from alfalfa is no greater than 65%. RNA blots
showed that mMDH, gMDH, and cMDH are expressed relatively uniformly in
root, leaves, stems, cotyledons, and root nodules. By comparison the pMDH
and nMDH are most highly expressed in leaves and root nodules, respectively.
Developmental studies showed that nMDH expression is associated with the
formation of effective nodules and the activity of bacterial nitrogenase.
Ineffective nodules had only basal levels of nMDH expression.
To further study the role of MDH in nodules, alfalfa nodule enhanced and
cytosolic MDH protein were purified from the complemented E. coli MDH-
mutants and antibodies were produced to the enzyme protein. Antibodies
produced to nMDH and cMDH were immunologically distinct, reflecting their
differences in deduced amino acid sequence. Nodule MDH antibodies immunoprecipitate
about 50% of the MDH activity in nodules while cytosolic MDH antibodies
immunoprecipitate approximately 25% of nodule MDH activity. Two bands of
cytosic MDH polypeptide, of near equal intensity, were found in all organs
of alfalfa suggesting that there are at least three isoforms of cMDH. A
single polypeptide band was detected for nMDH.
Dinitrogen Fixation of Annual Medicago species
Y. Zhu, C. C. Sheaffer, M. P. Russelle, and C. P. Vance
Department of Agronomy and Plant Genetics, University of Minnesota, and
USDA-ARS
411 Borlaug Hall, 1991 Buford Circle, St. Paul, MN 55108
Annual medics are a group of annual species of the genus Medicago. They
originated in the Mediterranean region and are the major legumes used in
the ley-farming system in Australia. Annual medics improve soil fertility
and improve yields of subsequent crops. Annual medics have been evaluated
in north central USA for their potential in various farming systems. Information
on medic N2 fixation potential in this region is important in predicting
their N credit and developing farm management practices. The objective
of this study was to measure the amount of N2 derived from atmosphere by
spring seeded annual Medicago species using isotope dilution method.
Field experiments were conducted at a loamy sand soil at Becker MN in 1993
and 1994 and a silt loam soil at Rosemount MN in 1993. The experimental
design at both locations was a RCB with six replicates. Four annual medic
species, M. truncatula, cv. Mogul, M. polymorpha, cv. Santiago, M. scutellata,
cv. Sava, and M. rugosa, cv. Sapo were seeded in late May at rates of 484
live seeds m-2 Noninoculated Sapo was used as reference crop because Sapo
is not nodulated by indigenous Rhizobium. All other annual medics were
treated with commercial Rhizobium inoculum. Ammonium sulphate enriched
with 99.4 atom % lsN excess was applied at a rate of 1.2 kg N ha-1 to a
2 m area 10 days after seeding. Herbage were sampled by manually cutting
1 m2 to a 2-cm stubble height in late July or early August when maximum
herbage dry matter yield occurred. Samples were dried at 60 °C for
48 hours and were ground to pass a 2-mm screen. Dry matter yield, total
N, and lsN concentration were measured to calculate the proportion and
amount of N derived from atmosphere.
The herbage production of annual medics ranged from 4 to 8 Mg ha-l with
Santiago and Sava being the highest yielding and Sapo being the lowest
yielding. Total N production of annual medics ranged from 120 to 250 kg
ha-l. The proportion of N derived from the atmosphere (%Ndfa) ranged from
69 to 83%. Medics did not differ in %Ndfa at Becker, however, at Rosemount,
the %Ndfa was higher for Santiago than for Sava and Sapo. Medics had higher
%Ndfa at Becker than at Rosemount because the Becker soil had lower organic
matter and N contents. The amount of Ndfa ranged from 100 to 200 kg ha-l
and Santiago had the highest amount of Ndfa. We concluded that annual medics
have the potential to contribute a significant amount of N to systems when
seeded in the spring and harvested or incorporated 2 to 3 months later.
The N contribution of annual medics was influenced by species and environment.
References
Crawford, E. J., Lake, A. W. H., and Boyce, K. G. 1989. Breeding annual
Medicago species for semiarid conditions in southern Australia. Adv. in
Agron. 42:399-437.
Materon, L. A., and Danso, S. K. A. 1991. Nitrogen fixation in two annual
Medicago legumes, as affected by inoculation and seed density. Field Crops
Research 26:253-262.
Winter Survival of Alfalfa: Seed vs. Forage
G. B. Coukell and S. R. Smith
Department of Plant Science, University of Manitoba
Winnipeg, Manitoba, Canada, R3T 2N2
Alfalfa (Medicago sativa, L. ) cultivars are traditionally evaluated
for winter survival based on their ability to overwinter when managed as
a forage stand, but differences in survival between forage stands and seed
stands have been reported. A study was conducted to determine the difference
in survival between alfalfa cultivars managed for seed production and the
same cultivars managed for forage production, and to determine whether
seed stand survival of cultivars in the fall dormancy range of five to
six was sufficient for seed production in Manitoba. Seed stands were planted
in 60 cm rows at 3 kg/ha with no cover crop, pollinated by leafcutter bees
(Megachile rotundata F.), and cut only once at the end of the season. Forage
stands were planted in 15-30 cm rows, depending on location, at 13 kg/ha
and cut -3 times per season at early bloom. Percent stand survival of 4
cultivars over the full range of fall dormancy (1-9) was measured for both
management regimes at Arborg, MB. , Homewood, MB. , and Melfort, SK. over
two winters. An increase in winter survival of seed stands over forage
stands was apparent after the first winter, with 1 of 4 cultivars in the
forage stand at Arborg being completely winter killed, while 15 of 4 cultivars
survived in the seed management test. The trend toward better survival
of stands managed for seed production was also observed at Homewood and
Melfort, with differences in survival being smaller due to a greater accumulation
of snowfall over the initial winter. After two winters, percent seed stand
survival at locations with normal snowfall for cultivars in the fall dormancy
range of 5-6 was from 40% to 90%. This level of survival indicates that
under proper management for snow cover it is possible to produce seed from
alfalfa cultivars in the semi-fall dormant range (5-6) which have not previously
been recommended for seed production in Manitoba based on survival ratings
of forage stands.
Wyoming Alfalfa Hay Hotline
A. Gray, C. Anderson, R. Kettle, R.Cunningham, and E. Palen
Department of Plant, Soil and Insect Sciences, and Cooperative Extension
Service
University of Wyoming, Laramie, WY 82071-3354;
and the Wyoming Department of Agriculture, Cheyenne, Wyoming, 82002
Wyoming-produced alfalfa has traditionally been utilized by regional
livestock operations. Eighty percent of the cash receipts of Wyoming agriculture
relate to livestock or livestock products. Wyoming is often described as
a livestock state dependent on irrigated and range-produced forage crops.
Sixty percent of the animal unit months (AUM's) produced in Wyoming originate
from hay and crop aftermath. Alfalfa is the most economically important
agronomic crop in the state. Seventy five percent of total hay production
in Wyoming is alfalfa. Ninety percent of alfalfa production is irrigated.
Thus, any economic downturn in livestock markets also has a negative impact
on hay producers. The Wyoming Hay Hotline or "WYOLIST" (I) was
modified and reactivated in September 1995 in response to periodic unstable
demand and price fluctuations for alfalfa hay. This action was precipitated
by weak demand and low prices for alfalfa hay. This situation resulted
from low cattle prices, above average precipitation which produced an abundant
supply of range-produced forage, and an open winter which allowed economically-depressed
livestock operations to graze a readily available, standing range forage
crop. These events prompted joint-action by the UW Cooperative Extension
Service (UWCES) and the Wyoming Department of Agriculture (WDA). The UWCES
developed, maintained, and provided weekly updates of hay listings on the
Wyoming Hay Hotline. The haylist included alfalfa hay and cubes, grass-legume
hay, grass hay, oat/pea hay, and straw. The WDA sought alternatives to
increase exposure of the haylist to potential buyers. The Hay Hotline can
also be accessed on the UWCES World Wide Web home page via Internet (http://www.
uwyo.edu/aglces/haylist/) .
One hundred thirty hay producers, who participated in the Wyoming Hay
Hotline during the 1995-96 hay marketing season, were mailed a survey on
May 31, 1996. The following results and conclusions were based on a 48%
response to the survey by June 12. Haylist increased exposure of listed
hay to potential buyers. Listees averaged two potential buyer contacts
per listee, but contacts ranged from none to 12. Forty percent of the survey
respondents indicated that hay had been sold due to increased exposure
by the haylist. Forty-eight-t percent indicated they would probably continue
to list 1995 crop carryover hay if the list continues into 1996. Ninety-three
percent of the respondents expressed interest in listing new crop hay (1996).
Ninety-four percent of the respondents thought haylist should continue
another season. High quality hay appeared to confer a marketing advantage
for alfalfa producers, particularly from specialty hay buyers. For alfalfa,
both appearance and forage quality were important in marketing hay.
1. Gray, A., J. Adams, D. Cooperrider, J. Buk, S. Hinninger, R. Hybner,
J. Langbehn, J. Nix, M. Schwope and K. Drake. 1992. Hay evaluation improves
quality and marketing. J. Nat. Resour. Life Sci. Educ., 21 :37-40.
Seeding Rate and Density Effects on Forage
Yield and Ouality
of a "High Quality" Alfalfa Cultivar
S. D. Cash, R. L. Ditterline, L. E. Welty, R. L. Dunn, and L.S. Prestbye
Montana State University Extension Service and Montana Agricultural
Experiment Station, Bozeman, Montana, 59717, U.S.A.
Alfalfa seeding rates vary widely in North America. Recommended seeding
rates in the arid Great Plains and prairie regions range from 2 to 4 kg
ha-' for dryland and 5 to 9 kg ha-1 for irrigated alfalfa. In several trials
in Montana in the late 1970's, Cooper et al. (1) demonstrated no economic
benefit for seeding rates above 7.8 kg ha-'. Currently, many producers
plant up to 15 kg ha-1 in "clear" seedings to optimize establishment
and first-year hay production.
'Arrow' and 'LegenDairy' alfalfa were seeded at 7.8, 13.4, 19.0, and 24.6
kg ha-1 in 15-cm rows, 30-cm rows, and by broadcasting. The factorial experiment
was established at two Montana locations in 1993, and evaluated for initial
stand counts, forage yield and quality for five cuttings through 1994,
and final stand counts in 1995. First year and final stand counts had significant
linear responses to seeding rate. At both locations, 1 5-cm rows had higher
plant densities and forage yield than 30-cm rows, however the broadcast
seedings varied by location.
First-year (Fig I) and two-year forage yields did not vary significantly
among seeding rates. Increased seeding rates did not significantly alter
crude protein (CP), acid detergent fiber (ADF), or neutral detergent fiber
(NDF) concentrations. Row spacing influenced CP, but not ADF or NDF concentrations.
Results from this study indicate that increased seeding rates did not significantly
affect forage yield or quality of these new multiple pest resistant or
"high quality" alfalfa cultivars.
References
1. Cooper, C.S., R.L. Ditterline, and L.E. Welty. 1979. Seed size and
seeding rate effects upon stand density
and yield of alfalfa. Crop Science 71:83-85.
2. Tesar, M.B. and V.L. Marble. 1988. Alfalfa establishment. pp.303-332.
In: A.A. Hanson, D.K. Barnes, and
R.R. Hill, Jr. (ed.). Alfalfa and Alfalfa Improvement. American Society
of Agronomy Monograph 29.