RANGELAND MANAGEMENT
The Problem
How do we manage our grasslands for maximum production and while maintaining sustainability?
Student Learning Objectives
To identify how grasslands have come to be as they are.
To differentiate types of grasslands and categories of prairies in the United States.
To calculate stocking rate and animal equivalency units.
To distinguish the categories of grassland forages.
To identify management practices for utilizing grasslands that promote sustainability.
Is there a difference? Grassland Pastureland Rangeland Cropland
Terms Grassland- Any plant community in which grasses
and/or legumes make up the dominant vegetation. Pastureland- Land devoted to the production of
native and introduced forages that are harvested by grazing. High economic inputs.
Rangeland- Land that is devoted to the production of natural species. Less intensively managed.
Hayland- Land which primary purpose is to harvest forage.
Cropland- Land devoted to the production of a cultivated crop and is harvested for livestock feed.
Grassland
Rangeland
Pastureland
Cropland
Hayland
The Grasslands Types
Tallgrass Prairie Transition Prairie Shortgrass Prairie
Grasslands used to comprise 25% of U.S. land area Now ≈ 17%
Tallgrass vs. Shortgrass Prairie Tallgrass Prairie
Used to cover the area from Indiana to central Nebraska. Up to 6 ft in height.
Some of the richest soil in the world Became cropland
Shortgrass Prairie Stretch from the Rocky Mountains to the central
panhandle of Nebraska. Areas of lower annual precipitation More exist because they are in a less productive
area of the nation.
What factors effect species composition?
Climate Temperature Precipitation
Topsoil Depth Soil Composition (silt, sand, clay, etc.) Soil Fertility
Transition Zone is at -99˚ Longitude
-99 ˚
Stuart, NE42.592454 ,-99.132385
Crofton, NE42.717692,-97.495422
Precipitation
Nearly all of the tallgrass prairie has been converted to farm production or other human developments. (Irrigation is not usually necessary)
All shortgrass prairie requires irrigation to make cultivated farming possible. Less desirable for cultivation
Vegetative Community Climax Community (Vegetation)
The stage of succession in which an area has reached its most natural state.
Some theorize that forestland was the climax community of the tallgrass prairies Fires caused by lightning and the Native Americans
may have destroyed the forests and became grassland Early Native Americans hunted on foot and utilized fire as
a weapon against bison Today we calculate climax community by
determining range condition.
Vegetative Community Types of vegetation
Grasses Grasslikes Forbs Shrubs
All compete for resources for maximum growth
Grazing rates affect the relative amounts of each
Management Techniques
Objective = long-term maximization of livestock productivity from managed rangeland. Do not damage the capacity for grass
production Treat grasslands that are not at their max
potential Control soil erosion and depletion Avoid depleting the groundwater supply Utilize the appropriate grazing pressure Control undesirable vegetation
Management Techniques Evaluating Carrying Capacity (Grazing
Capacity) Types of vegetation present Growth rate of desirable species Effects of grazing Climate Soil type Slope Precipitation
Management Techniques Grazing capacity
determines stocking rate Stocking rate is expressed
as animal equivalent units (AEU) (AU) 1 AEU is equal to the
amount of forage required for a 1,000 lb animal for a given amount of time.
Time will generally be expressed in months
1 AEU for one month is an animal unit month (AUM)
Equivalencies 1 cow/calf pair = 1.2 AEU 1 weaned calf= 0.5 AEU 1 yearling calf= 0.67 AEU 1 steer = 1AEU 5 goats/sheep= 1AEU 1 horse/bull= 1.25 AEU 1 elk= 0.67 AEU 4 deer= 1 AEU
Stocking rate calculations
What we want to know….
I have a pasture which I want to run cattle on. What is the greatest amount of cattle (stocking rate) I can run on the ground to achieve maximum profit yet avoid overgrazing?
To calculate stocking rate… Stocking rate = suggested initial rate x adjustment factor
(table 6) (chart) What is the suggested initial stocking rate for a sandy site
in vegetative zone I? 0.5 AUM/Ac
What is the suggested initial stocking rate for a limy upland site in zone IV? 0.9 AUM/Ac
If the previously mentioned sandy site is determined to be at 65% range condition, what is the adjustment factor? 0.8
What is the stocking rate for the sandy site in zone I? 0.5 AUM/Ac * 0.8= 0.4 AUM/Ac
How many cow/calf pairs could this 400 acre sandy site with a stocking rate of .4 AUM/Ac pasture for 5 months? 0.4 AUM/Ac * 400 Ac= 160 AUM 160 AUM / 5 M = 32AU/1.2AU= 26.6 = 26
pairs
400 acres; 5 months; 65% range condition; saline subirrigated site in zone IV
Farmer Lloyd in Crofton, Nebraska wants to start pasturing yearling steers on his recently purchased 450 acres of silty overflow land. The pasture season is 5 months.The NRCS came out and sampled his pasture and discovered it is at 55% range condition. (This means it is producing at 55% of it’s potential at climax community)How many steers could Farmer Lloyd pasture for the given period of time?
What if I I’m given all the necessary information including the number of animals but want to discover how many acres I need in order to successfully graze those animals?
10 deer; 12 months; Range Site II; Saline subirrigated site at 60% range condition
Figure AU’s Multiply by months to calculate AUM’s. Use the reciprocal of AUM/Acre for Ac/AUM Multiply AUM by Ac/AUM
Managing Grasslands
Vegetative Community (Grasses) Grasses
Complex root system that holds soil in place and preserves soil moisture
High source of nutrition for grazing animals Light grazing benefits grass “Graze half, leave half”
If all of the leaves are consumed, recovery of grasses takes longer
Decreaser- Varieties of grasses that are easily damaged with even light grazing.
Increaser- Varieties of grasses that thrive under heavier grazing. Adaptations that allow them to access resources more
efficiently Often unpalatable and therefore are avoided by
herbivores Invader- Plants that move into an area after it has
been badly overgrazed. Occasionally will move into areas that are badly
undergrazed
Vegetative Community (Grasses)
Management Techniques Undergrazing and overgrazing are detrimental
to the plant community Discourages growth of desirable grasses Promotes growth of invaders
Most animals do not graze uniformly on their own Concentrate themselves near water or
salt/mineral areas Separate salt/mineral locations from water
sources to promote more even grazing Grazing management systems promote even
grazing
Grazing Management Systems Continuous Grazing
Livestock are left in one area year-round and allowed to graze at will Uneven grazing will occur Less work and expense
Grazing Management Systems Deferred-Rotation Grazing
Pasture is divided into two or more grazing areas (paddock)
Livestock are moved periodically to allow grass recovery time
Grazing Management Systems Management Intensive Grazing
Grazed at a high stocking rate for a very short period Promotes the growth of increasers Higher quality forage may improve gains Increases utilization of available forages
including those which have low palatability. Increased labor requirements More water sources required
Range Restoration Controlled grazing is the first step of
restoration If seeding is required, grazing must be
withheld until grasses are re-established Eliminate vegetation if the area is
overgrown by invaders In less severe cases, controlling grazing
may be adequate to restore rangeland Light overseeding and fertilization may
speed the process
Summary Much of the United States grassland has been
depleted over the years due to conversion to cropland or urban structures.
Prairies are divided into two main categories- Tallgrass in the east and shortgrass in the west. Transition prairies are between the two
Stocking rate can be calculated by evaluating a pastures grazing capacity and figuring an animals AEU’s
Grassland forages are divided into grasses, grasslikes, forbs, and shrubs.
The most important management factor is to properly manage grazing of grasslands.