Skip Navigation

Grazing Factsheets - General

Grazing Factsheets


How Plants Grow
Plant Succession
Water Cycle
Causing and Controlling Erosion
Pasture and Hayland Planting - data, tables and maps

Outline of State of Illinois with Grass

How Plants Grow



A problem each livestock producer faces is knowing how short they can graze or mow their pastures and still obtain maximum productivity during an extended period. Varying climatic conditions, growth habits of different plants and livestock preferences for different plants, compounds the problem. The time of the year and age of the plant also affect plant growth when leaves are removed. 

Leaf Growth

Plants manufacture food in their leaves through the use of solar energy. Yet some people wrongfully assume plants produce food in their roots. Plants pull water and minerals from the soil, but the “food factory” is located above ground in the leaves and green stems.

Minerals from the soil make up about 5 percent of the solid material in plant roots, stems and leaves. Carbon, hydrogen and oxygen from the air and water make up most of the other 95 percent.

The leaves take in carbon dioxide from the air through tiny pores. Using solar energy, the leaves re-combine the carbon with oxygen and hydrogen to make sugars and starches. The sugars then combine with minerals from soil to make fibers, proteins, plant oils, and fats. The plant uses these sugars, starches, proteins, oils and fats to grow and reproduce.

The ability of perennial grasses, legumes, and forbs to recover quickly after grazing or mowing makes these plants extremely valuable for forage production and soil protection. Removing too many leaves decreases forage production and reduces the extent of the plant’s root system. Plants eventually die if overharvest of the leaves continues.

Leaf Removal and Growth

Root growth is closely related to forage production. Plants maintain optimum root vigor and growth when grazing or mowing during the growing season removes no more than half their leaves. When the plant’s food producing mechanism is reduced, leaf and root growth is reduced accordingly.

In all grasses, the volume of leaf removed has a direct effect on the growth of new roots. Roots are the vital supply lines of moisture and minerals to the leaves. Perennial plants store food in the roots after seasonal growth. They use these reserves to live while dormant and make the first new growth the next spring.

A grass plant produces twice the volume of leaves that it needs to complete its growth and remain productive. Generally, when up to 50 percent of the plant, by weight, is grazed, root growth continues unimpaired. When 60 to 90 percent of the plant is removed, 50 to 100 percent of the root growth is stopped, respectively. 

Other Growth Factors

Other factors influence plant growth. For instance, light grazing is usually more beneficial to plants than several years of no grazing because heavy plant residue depresses growth of many grasses. 

Growing Plants

All plants have growing points where new cells are developed. The growing points of grass are located just above the last completed joints of each stem. Early in the season, the growing joints are situated at the base of the plant. As the season progresses, the joints of most species elongate and push upward to produce a seed stalk, elevating the growing point to a vulnerable position. Removal of the growth point by grazing or mowing forces the plant to send up new leaves from the base of the plant and to start over as if spring had just started. Adequate rest periods must be planned to maintain plant vigor.

The growing points of trees, shrubs, and forbs are located on the outer tips of branches.


Grazing management schemes can be used to favor the more desirable plants during their reproductive period. Plants reproduce in several ways. Such as:

Seed. All annuals, and many perennials, reproduce primarily from seed. Warm-season plants usually produce seed during late summer or fall. Cool-season plants produce seed near the end of their maximum growth period in midsummer.

Stolons. Some plants reproduce by stolons, which are prostrate stems, or above ground runners. The stolons grow on the surface of the soil, occasionally tagging down roots at the joints to secure the stolon and to begin a new plant. Bermuda grass reproduces by stolons.

Rhizomes. Several grasses reproduce by rhizomes, which are underground stems. Most sideoats grama strains have rhizomes. Big bluestem, Indian grass, and switchgrass have short rhizomes while smooth brome grass and Kentucky Bluegrass have rhizomes that are quite extensive.

Mixed methods. Many plants reproduce by stolons or rhizomes as well as by seed. Buffalo grass produces seed and stolons. Most sideoats grama plants produce seed and rhizomes. Common bermuda grass uses all three methods of reproduction.

Where to Get Help

For more information about hay and pasture management, contact your local office of the USDA Natural Resources Conservation Service, listed in the telephone directory under “U.S. Government,” or the University of Illinois Extension.

USDA is an equal opportunity provider, employer, and lender.
Download This Factsheet  [PDF]

 Outline of State of Illinois with Grass
Water Cycle



The water cycle is the never-ending movement of water from clouds to earth and to clouds again. Influencing those parts of the cycle that affect grassland is important in hay and pasture management. The cycle begins when precipitation strikes the land, and ends when the water leaves, either through runoff or evaporation. In the interim, livestock producers should store as much water as possible within the soil for use in forage production. 


Water is generally the most limiting factor in hay and pasture production. One of three things happens with the moisture that falls as raindrops, snowflakes, sleet or hail used productively on the site where it falls; goes downstream as clean water; Or, goes downstream, carrying soil. When runoff is dirty, the land’s production potential is being removed.


Impact. When falling raindrops strike bare soil, the impact causes both splash erosion and soil compaction, resulting in faster runoff and increased erosion. Good plant cover breaks the force of the raindrops, and allows the water to seep into the soil. The soil can act as a large reservoir, holding moisture, reducing flooding and enhancing water quality. Water stored in the soil promotes a greater and more consistent supply of forage.

Soil. Coarse soil takes in water faster than fine soil, but stores less within the root zone of most plants. Water that moves below the root zone of plants recharges groundwater supplies, and sometimes reappears down slope as a spring or creek. Because the movement through the soil is slow, the water supply downstream is cleaner, and streams flow longer than where moisture runs off over the soil surface. Where the surface is bare, less moisture enters the soil and surfaces are hotter causing much of the stored water to evaporate during hot, windy days instead of being used for plant growth.

Plants. A healthier, more productive grassland water cycle can be achieved by proper grazing. Plants and the litter they produce affect the water cycle in several ways. Plants break the impact of raindrops on the soil surface, and serve as small windbreaks to hold snow. Plants shade the soil’s surface causing the soil surface to be cooler, which creates a better environment for plant growth. Litter acts as a sponge, and slows runoff, giving moisture more time to move into the soil. Plant roots increase soil porosity so water moves more readily into and through the soil. Roots also hold soil particles in place, reducing erosion. Vigorous plant cover is an important part of influencing the grassland water cycle, and making effective use of precipitation.

Where to Get Help

For more information about hay and pasture management, contact your local office of the Natural Resources Conservation Service, listed in the telephone directory under “U.S. Government,” or the University of Illinois Extension.

USDA is an equal opportunity provider, employer, and lender.
Download This Factsheet  [PDF]

Outline of State of Illinois with Grass

Causing and Controlling



Erosion control methods outlined in conservation plans are intended to keep soil and water from leaving the land so that these resources can be available to produce high quality forage, crops, timber, and reduce the amount of sediment in streams, rivers, and water bodies.


Erosion is a natural occurrence. However, erosion often increases with activities that upset the natural balance of soil erosion and formation. Erosion is not just a cropland problem, but can also occur in hay and pasture systems. Poor grazing management is a major cause of erosion. Trails rutted into the sod, poor control of water drainage from roads, disturbance of natural drainage, livestock trailing, and other land disturbances are also responsible for increasing grassland erosion.

Plant cover on the soil surface, at the time of a rain storm, is the primary factor in preventing erosion because a raindrop that hits bare soil has a different effect than one that falls on a plant or litter and then rolls off onto the soil.

An uninhibited raindrop smashes against bare soil with great force, splashing water and soil particles and packing the surface soil. The process seals the pores of the soil. The result is that little water goes into the soil and runoff occurs. On the other hand, when a raindrop hits a plant, or litter, its force is broken and the water trickles into the soil.


The best treatment for grassland soil erosion is to maintain vigorous plant cover, but long-term improvement of plant cover occurs only with proper management.

The first criteria is to graze pastures properly to provide for growth and maintenance of healthy plants. The plants and litter form the necessary protective cover that breaks the splash of raindrops, slows over land flow, and promotes surface conditions favorable to water intake.

Other practices to control erosion on hay and pasture include brush control, deferred grazing, reseeding and mechanical land treatments. Erosion control structures such as small dams and diversions are helpful. However, the effectiveness of these practices is limited, and often is temporary. Fencing locations and livestock watering sites should be placed to minimize erosion problems.

A combination of erosion-control practices gradually results in higher production of forages improved pasture conditions, a better water supply for livestock, and personal satisfaction in managing natural resources. 

Where to Get Help

For more information about hay and pasture management, contact your local office of the USDA Natural Resources Conservation Service, listed in the telephone directory under “U.S. Government,” or the University of Illinois Extension.

USDA is an equal opportunity provider, employer, and lender.
Download This Factsheet  [PDF]

Outline of State of Illinois with Grass

Pasture and Hayland Planting - data, tables and maps

Table 1 - Acceptable Planting Dates by Plant Suitability Zones

Type of seeding
Plant Suitability Zone1
Cool Season Species
Warm Season Species2
Spring I Late Winter - June 1 Late Winter - June 15
II Late Winter - May 15 Late Winter - June 5
III Late Winter - May 15 Late Winter - June 1
Late Summer I August 1 - September 1 Not Recommended
II August 1 - September 10 Not Recommended
III August 1 - September 20 Not Recommended
Dormant I November 1 - Freeze-up November 1 - Freeze-up
II November 15 - Freeze-up November 15 - Freeze-up
III November 15 - Freeze-up November 15 - Freeze-up
Frost3 I February 1 - March 15 February 1 - March 15
II February 1 - March 1 February 1 - March 1
III February 1 - March 1 February 1 - March 1
1-Refer to the "Plant Suitability Zones" map located in Section II, IL-eFOTG-Climate Data or refer to the link:
2-Dates to be used when warm and cool season natives are planted in mixture.
3-Refer to Table 2 for applicable plant species. Frost seeding may be performed in December and January when snow cover is absent.

USDA-NRCS, Illinois, April 2003

512-11 Chart updated July 2010

Table 3. Crop Use Information (E=excellent, G=good, F=fair, P=poor)

Forage Species
Annual or
Alfalfa Perennial E E P E E NR
Alsike Clover Short-lived perennial G G P G E NR
Birdsfoot Trefoil Perennial G E F G G NR
Cicer Milk Vetch Perennial F G F G E NR
Crownvetch Perennial F G F G G-F NR
Hairy Vetch a Winter annual F P P F F NR
Kura Clover Perennial G G E E E-G NR
Lespedeza (Korean) Annual F F F F G NR
Ladino Clover Perennial F G G-F E E NR
Mammoth Red Clover Short-lived perennial F G P P G NR
Medium Red Clover Short-lived perennial G E P G E NR
Sweetclover Biennial F-P G P F F NR
Cool Season Grasses
Canada Wildrye Perennial F F P E E NR
Kentucky bluegrass Perennial F G-F E E E NR
Orchardgrass Perennial E G F E F-G NR
Perennial ryegrass Short-lived perennial E E F-G G-E E NR
Red Top Perennial F F F F G-F NR
Reed canarygrass Perennial G-F G F G G-P NR
Smooth bromegrass Perennial E E F E E NR
Tall fescue Perennial G-F G G-E G-E F-P NR
Timothy Perennial E E F-P G E NR
Virginia Wildrye Perennial F F F E E NR
Warm Season Grasses
Big Bluestem Perennial F F F E G-E G
Caucasian Bluestem Perennial F F P G F G
Eastern Gamagrass Perennial E F P E E G-E
Indiangrass Perennial F F F G G G
Little Bluestem Perennial P P F G G-F NR
Prairie Dropseed Perennial F F F G G-F NR
Sideoats Grama Perennial F F F G G NR
Switchgrass Perennial F F F G G-F E
Annual Forages
Chicory Short-lived perennial P P G G G-P NR
Foxtail/German Millet Annual F F F G G-F NR
Hyb. Pearl Millets Annual F F F G G-F NR
Rape Annual P P F G E NR
SorghumXSudan Annual P G F G G-F G-E
Sudangrass Annual P F F G G-F G
Turnips Annual P P F G E NR

a Used primarily as a cover crop
NR = Not Recommended

Map of Illinois Plant Suitablility Zones


USDA-NRCS, Illinois, April 2003

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, sex, religion, age, disability, political beliefs, sexual orientation, or marital or family status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audio tape, etc.) should contact USDA’s TARGET Center at 202-720-2600 (voice and TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W, Whitten Building, 1400 Independence Avenue, SW, Washington, DC 20250-9410 or call (202) 720-5964 (voice and TDD). USDA is an equal opportunity provider and employer.”

Download This Factsheet  [PDF]