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MANAGEMENT of Forage
Sorghum Types on 2011
Drought Acres
by Gary Strickland
Extension Educator
Agriculture/4H/CED
Jackson County
Production Management Topics
• Sorghum Types (pluses and
minuses)
• Possible Uses for sorghums on
failed Cotton Acres
• Crop Concerns
• Utilization with Livestock
Forage Sorghum Types
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•
•
•
Sorgo Sorghums
PPS Sorghums
BMR Sorghums
Multi Purposes
Possible Uses for Sorghums
on Failed Cotton Acres
•
•
•
•
Cover Crop
Haying
Grazing
Concerns (NO3 Toxicity and HCN
Poisoning)
Cover Crop
• When to terminate this crop
• Understanding C/N Ratio’s and N-Use
(C/N = 60-80:1)
• Type of Sorghum and ease of
decomposition in a dry year
Haying
• What growth stage, time of day, and
cutting height is best when haying
• Quality of Sorghum (depends on
harvest time, inputs and harvest time
but in general: CP – 12%; TDN –
65%; ADF – 28%
• Concerns associated with Sorghum’s
(NO3 Toxicity and HCN Poisoning)
Grazing
• When is the best time to turn cattle
into a sorghum field from a plant
perspective
• Good hay source
• Any compaction issues
• Toxicity Concerns: (NO3 Toxicity
and HCN Poisoning)
Nitrate Toxicity
• The technical answer
• NO3 →→ (reduced) to NO2
• NO2 is absorbed into the blood stream where it
oxidizes the ferrous iron (Fe++)in the hemoglobin
molecule to ferric iron (Fe+++) which now
becomes a methemoglobin molecule
• Methemoglobin is incapable of transporting
oxygen in the blood stream
• The animal dies from asphyxiation (blood is a
chocolate brown color due to lack of O2)
How NO3 Toxicity Happens
Heme Group
Easy Answer – kills the animal by
oxygen starvation
Metheme Group
How HCN Poisoning
Works - Technical
Electron
Transport
System
Easy Answer – kills
the animal by
oxygen starvation
Two step
enzymatic
process
Plant Management Factors
•
•
•
•
•
Plant Species and sub-species differ in their accumulation
potential of HCN and NO3
Younger plants have a greater potential for problems than
older plants
Dryland will generally be worse in accumulation potential
than irrigated
NO3 accumulates more in the stems
HCN accumulates more in the leaves
Plant Management Factors
(cont’d.)
• Imbalance of nitrogen and phosphorus can increase both toxicity
issues
• High rates of N, regardless of P level, can lead to a problem
• Sun curing of hay can help with HCN but not with NO3
• Allow anywhere from 4 – 10 days after a drought ending rain
(depends on whether HCN or NO3 is the problem)
• Be aware of when frost’s happen
• Myth buster: The wax (white powder) on the sorghum plant
means it has problems – not true.
Any Questions
Now it’s time for our Livestock
Specialist