Rangeland Management Before, During, and After Drought

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Rangeland Management Before, During, and After
Drought

• Larry D. Howery
• Rangeland Forest Resources Program
• School of Renewable Natural Resources
• The University of Arizona, Tucson

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Road Map

• Drought Defined
• General Information on Drought Management
• Grazing Management Before Drought
• Grazing Management During Drought
• Grazing Management After Drought
• Summary

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Drought Defined

• prolonged dry weather when precipitation is
  less than 75 of the average amount. (SRM 1989)
  Using this definition, drought occurred from
  1944-1984 in
• 13 of the years in the northwestern US
• 21 of the years in the northern great plains
• 27 of the years in the southern great plains
• 43 of the years in the southwestern US

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Drought Defined
Precipitation Data (inches) for Springerville,
AZ, 1890-1997
--------
average
drought
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General Information on Drought Management
Livestock managers use domestic livestock to
market forage production on rangelands

• Drought negatively affects individual plants and
  therefore forage production (Plants get thirsty
  and hungry during drought!)
• Above ground response
• Below ground response

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General Information on Drought Management (cont.)

• Range condition can limit or accelerate drought
  impacts rangeland in good condition
• Is less adversely affected by drought
• Recovers faster after drought breaks

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General Information on Drought Management (cont.)
Range condition going into drought is important
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General Information on Drought Management (cont.)

• Intensity of grazing can limit or accelerate
  drought impacts

Intensity,
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General Information on Drought Management (cont.)
Grazing can limit the ability of plants to
extract soil moisture
ungrazed
2-4
properly grazed
overgrazed
20-25 soil saturated
10-12
8-10
6-8
Information taken from NRCS
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General Information on Drought Management (cont.)
Timing of grazing can be important
properly grazed
overgrazed
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Grazing Management Before Drought
Drought management needs to be considered on a
case-by-case basis

• Effective stocking rate is important
• Implement a grazing system that promotes stable
  or improved range condition via periodic
  deferment or rest to establish forage reserves
• Adequate plant cover and residual vegetation are
  important

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Grazing Management Before Drought (cont.)
Adequate ground cover increases moisture
infiltration and percolation
Information taken from NRCS
Depth of water penetration 5 days after 2.5
inches of rain on a 10 slope
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Grazing Management Before Drought
Adequate ground cover helps to

• Increase infiltration and percolation
• Protect soil from wind and water erosion
• Decrease evaporation transpiration losses
• Provide a more favorable micro-climate for
  seedling establishment

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Grazing Management During Drought
Develop an annual, flexible timetable for making
decisions

• Continue to maintain range condition and plant
  vigor to the extent possible
• Monitor the use of key forage species and other
  forage resources (browse, annuals, other
  ephemerals)
• Keep livestock distributed

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Grazing Management During Drought (cont.)

• Provide adequate, accessible, good-quality water
• Once drought is recognized, reduce the herd as
  soon as possible so it is in balance with forage
  supply
• Use emergency forage
• Determine the amount of money that can be spent
  on animal feed and supplements

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Grazing Management After Drought
Restock slowly and conservatively on a
case-by-case basis

• Rest pastures for an entire growing season
• Use pastures only when key forage species are
  dormant and when the least desirable species are
  green and palatable

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Grazing Management After Drought (cont.)

• Defer grazing until after key forage species have
  produced mature seed
• Graze spring growth after grasses have reached
  the 4 to 5 leaf stage

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SUMMARY

• Droughts are a guaranteed but unpredictable
  occurrence in the arid western U. S.
• Droughts are normal so advance planning is
  critical before drought occurs
• During drought, delays in decision-making can
  lead to intensification of the problem, economic
  loss, and long-term damage to rangeland resources
• After drought breaks, restock slowly and
  conservatively on a case-by-case basis