Rangeland Management Before, During, and After Drought

Rangeland Management Before, During, and After Drought Larry D. Howery Rangeland & Forest Resources Program School of Renewable Natural Resources The University of Arizona, Tucson

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

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 thesouthwestern US

Drought Defined Precipitation Data (inches) for Springerville, AZ, 1890-1997 -------- average drought

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

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 ll ll ll ll ll ll ll

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

General Information on Drought Management (cont.) Intensity of grazing can limit or accelerate drought impacts Intensity,

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

4” --------- --------- 2” General Information on Drought Management (cont.) Timing of grazing can be important properly grazed overgrazed

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

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

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

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

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

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

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

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

Rangeland Management Before, During, and After Drought