ß Cheatgrass--A Challenge to Range Research

A. C. Hull, Jr. and Joseph F. Pechanec •

To determine the ecologic and economic importance of cheatgrass is a challenge to the men in range research. This poorly understood species produces a large volume of herbage over exten- sive acreages and is undoubtedly the most important forage plant on southern Idaho ranges. Its probable effect upon grazing, watershed, wildlife, recreation, and timber production further adds to its importance. Many additional facts are needed before we can fully determine the importance and the desirability of this newcomer. If cheatgrass is found to be desirable a program for its proper management should be developed. Should it be found undesirable, methods of replacement must be found. The first and most important immediate problem now facing research is finding out how cheatgrass ranges might be managed to hold the soil in place and to maintain soil

productivity.

N aggressive new immigrant, cheatgrass brome 2 (Bromus tectorum), has invaded and occupied disturbed range lands

throughout the West. It now furnishes more than half the forage on spring ranges in southern Idaho, Figure 1. It has displaced the other grasses thereby affecting, directly or indirectly, grazing, watersheds, wildlife, recreation, and even timber production.

The reaction of people to the coming of cheat- grass in Idaho was either. one of praise or of condemnation. Cheatgrass was praised for its ability to hold the soil and to produce a large volume of herbage on ranges that had been producing but little. On the other hand, cheat- grass was condemned because it fluctuated greatly in forage production and more especially because it encouraged more and larger fires. Con- sequently, the coming of cheatgrass, which at first tended to protect the soil and provide forage for livestock, later brought recurrent fire which worked hand in hand with overgrazing to destroy perennial grasses and to expose the soil to ero- sion.

This dual role of cheatgrass, together with the varied conditions under which it occurs, the use it receives, and the lack of knowledge con- cerning it lends to the confusion regarding its desirability. Although greater knowledge will not bring unanimity of conclusion, it will permit a more reliable judgment of the desirability of cheatgrass in a particular location and the course of action to be taken--either to encourage its growth or to replace it.

aForest ecologists, Intermountain Forest and Range Experiment Station, U.S. Forest Service, Ogden, Utah.

aCheatgrass brome is commonly known locally as cheatgrass and junegrass. Throughout this paper "cheat. grass" will be used. In other localities it is known as broncograss, military grass, junegrass, Mormon oats, downy brome, and downy chess.

The purpose of this paper is to examine the many aspects of the cheatgrass problem in the light of present information, mainly as they relate to livestock grazing and soil protection in south- ern Idaho. Much of the discussion. may, how- ever, apply equally well to other cheatgrass ranges. The material presented is based on a review of available published work, on discus- sions with men acquainted with cheatgrass, and on widespread observations by staff members of the Intermountain Forest and Range Experi- ment Station throughout southern Idaho in 1943, 1944, 1945, and 1946. This article does not, because of the present lack of knowledge, place cheatgrass in its final ecologic and economic niche. It merely tries to explore the problem, point out what is known, and indicate what new facts are critically needed.

OCCURRENCE OF CHEATGRASS IN SOUTHERN IDAHO

Cheatgrass, an aggressive annual native to Europe, entered Idaho about 1900. Following in the footsteps of cultivation and abandonment, recurrent fire, and overgrazing, it spread rapidly to several million acres of range land. Cheat- grass in small amounts might have invaded

properly grazed ranges, but it is not likely that invasion would have taken place in any great quantity unless preceded by disturbance of the previous plant cover (2, 10, 11, 13, 19, 21, 22, 26, 28, 30, 31).

Cheatgrass grows under a greater variety of conditions. It occurs at elevations of from 2,000 to 7,000 feet, under annual precipitation of from 7 to 22 inches, and on soils ranging from gravel to clay. It extends from the salt desert shrub type through the sagebrush zone, where it is most abundant, up into the pon. derosa pine and Douglas-fir zones.

On extensive tracts of the sagebrush-grass 555

556 JOl RNAL OF FORESTR'•

Photo by U. $. Forest Service

Fn;. 1. Cheatgrass is highl• impurtaut to the range livestock industry of so•lthern [daho. It annually fnrni•he• a large amounl of forage for cattle aud aheep. Here sheet) are utilizing

dry cheatgrass for winter forage.

Photo by U.S. Forest Service

Fig. 2.- Heavy grazing will damage cheatgrass ranges. This view shows a cheatgrass range grazed heavily by cattle during the spring, summer, and fall. Erosiou has become marked on tile south- west-facing slopes. Ahhough not noticeable in this picture, tile density and height of the cheat-

grass stand is reduced markedly, even on tile nearly level portions of the range.

CHEATGRASS 557

type, usually where recurrent fire has been com- mon, cheatgrass is the dominant species. Sel- dom, however, does it occur as a pure stand except on abandoned farm lands. Sandberg blue- grass (Poa secunda) is usually present, often in considerable abundance. Other perennial grasses frequently present are bottlebrush squirrekail (SitanJou hystrix), bearded bluebunch 3 (Agro- pyron spicatum ) , streambank ( A. riparium ) and thickspike wheatgrass (A. dasystachyum), and giant wildrye (Elymus condensatus). Such an- nual weeds as Russian-thistle (Salsola kali-tenui- rolla), tumble-mustard ( Sisymbrium altissi- mum), sunflower (Helianthus spp.), and wild lettuce (Lactuca spp.) are often preseht, espe- cially in years of abundant, late spring rains.

Cheatgrass grows beneath the sagebrush on depleted ranges either as the only species in the understory, or, more often, in association with grasses and weeds. It also appears to have be- come a small but consistent part of the vegeta- tion on well-managed ranges of southern Idaho. On these ranges, cheatgrass usually occurs as small scattered plants in average years. But in wet years, it temporarily produces more vol- ume and makes a good showing. 'Cheatgrass is reported to persist in tbe northern desert shrub association, even under good management (22). It is also regarded as part of the climax vegeta- tion of the prairies of Washington (4).

Is CHEATGRASS A DESIRABLE RANGE FORAGE PLANT ?

Desirability of cheatgrass can only be deter- mined by considering its growth habits; protec- tion furnished to the soil; abilky to withstand heavy grazing; season of usability; amount, re- liability, and quality of forage production; its effect on the fire hazard; and the effect of awns and smut upon its use. Evaluation of these features is especially important because over vast areas cheatgrass makes up 80 to 95 percent of the cover. Hence, its shortcomings are also the shortcomings of the vegetal cover.

GROWTH HABITS

Cheatgrass, growing primarily as a winter an- nual, is well adapted to climatic conditions on southern Idaho ranges. In some years heavy late-

•Throughout this article whenever bluebunch wheat- grass (A. spicatum) is mentioned, it will include beard- less bluebunch wheatgrass (A. inerme).

summer or early-fall rains cause rapid germina- tion and seedlings may be 2 to 4 inches tall before winter sets in. Good fall growth of cheatgrass seems to require approximately two inches of well-concentrated early-fall rain. From observa- tion of cheatgrass responses together with weather records, it appears that fair to good fall growth of cheatgrass can be expected onee in every 3 years in southeastern Idaho and once in every 8 years in southwestern Idaho.

Occasionally light early-fall rains may bring on germination but the seedlings may not sur- vive subsequent warm fall weather (20). In other years fall rains may be too late to produce fall germination or growth.

Young cheatgrass plants remain dormant dur- ing the winter. They. renew growth early the following spring and grow rapidly until soil moisture becomes low. Height growth then ceases and leaves begin to curl and dry. The plants turn purplish-red and finally straw-yellow. Plants head early and seeds begin to fall to the ground shortly after the reddish stage is reached.

The growth cycle is completed and the plants are usually dry by June 5 in southwestern Idaho and by June 15 in eastern Idaho. Abnormally dry or moist weather may shorten or lengthen the growing season by 3 or 4 weeks. Heavy late spring rains often cause cheatgrass to renew growth, either after it is in the red stage or after it has been nearly killed by late spring frost.

Cheatgrass may occur either as a single- stemmed plant in thick stands, or a well-stooled, vigorous plant near anthills, dung piles, or where fire or some other agent has thinned the plants to 50 or less per square foot. The single-stemmed plants often exceed 1,000 per square foot, and the average of all stands of plants counted in southern Idaho during 1943, 1944, 1945, and 1946 was 603 per square foot. Piemeisel (20) found 174 plants per square foot during the dry period from 1933-1935.

Through its growth habits, cheatgrass com- petes actively with seedlings of perennials. It also produces a large amount of seed. Unburned ranges at Dubois and near Raft River yielded 688 and 310 pounds of seed per acre in 1944. Fwo unburned ranges near Boise produced 432 and 481 pounds of seed per acre in 1945. With an average of over 150,000 seeds per pound, natural seeding is at the rate of 478 pounds per

558 JOURNAL OF FORESTRY

acre or 1,646 .seeds per square foot. Cheatgrass seed is highly viable. Germination was 99.75 percent when tested shortly after seed maturity (30). Germination began within 1 day and was practically complete within 2 to 5 days (29, 30). This is much more rapid than with most peren- nials. Cheatgrass is not only more rapid in germination, but both tops and roots of its seed- lings grow more rapidly than those of perennial wheatgrasses (30). Piemeisel (20) concluded from observations during 1928 to 1935 that drought and crowding would not cause cheat- grass to fail as a dominant on areas that it now occupies.

SOIL PROTECTION

An oft-ignored requirement of a good range forage plant is its ability to protect the range against soil erosion, and to keep the soil highly absorptive and fertile. A plant cover which per- mits soil loss cannot provide a permanent forage base for the range livestock industry.

There are but few facts on which to judge the adequacy of cheatgrass in this respect. Cheat- grass, ungrazed and unburned, helps to control erosion (10, 13, 28) by providing cover on im- poverished soils and on areas where perennials are not present. This annual grass, with a fibrous root system occupying the upper 12 inches of soil (20, 24), was found to be next to the wheat- grass type and superior to perennial lupine- needlegrass and annual weed types in promoting water absorption and preventing erosion on the .granitic slopes of southwestern Idaho (1).

FORAGE PRODUCTION

The criteria most often used for judging the value of a range plant are the amount, seasonal

quality, palstability, and reliability of its forage production. Upon these features depends to a large extent the average number of livestock that can be grazed, the animal gains, and the danger of running short of forage in poor years.

Meager data from southern Idaho indicate that cheatgrass produces a relatively large amount of forage (Table 1). An average of nearly eight-tenths of a ton of air-dry herbage per acre was produced each year during the period from 1940 to 1946. Based on this short- time record, the yields for cheatgrass are about the same as for crested wheatgrass (Table 1).

Data from other states also show high yields for che•tgrass. For Nevada, yields of 799 and 1,441 pounds per acre were recorded in 1940 and 1941 (5). In Montana a yield in 1937 of 639 pou.nds per acre, determined by clipping, was confirmed by pasture records of the amount horses ate during 1937 and 1938 (10).

Forage production of cheatgrass from year to year fluctuates greatly, however, and variations in production caused by weather are greater than those of perennial grasses. For example, at Arrowrock, the yield of cheatgrass in 1943 was only one-tenth that of 1944, whereas that of crested wheatgrass was one-half (Table 1). Furthermore, the variations in cheatgrass yield that occurred during a 5-year period at Raft River and Arrowrock are twice as great as any that occurred during a 17-year period on peren- nial vegetation at the U.S. Sheep Experiment Station (18). This 17-year period includes the 1934 drought.

Records from other locations also show great variations on cheatgrass yield. A Gem County study showed cheatgrass to have 11 times as much

TABLE 1.--HERBAGE YIELDS Or CHEATGRASS AND CRESTED WHEATGRASS AT SEVERAL LOCATIONS ON THE SNAKE RIVER PLAINS DtmING THE 7-YEAR PERIOB 1940-1946

Pounds per acre (air-dry) Location 1940 1941 1942 1943 1944 1945 1946 Average

CHEATGRASS

Regina .................................... 305 970 925 794 749 Raft River .............. 2,500 300 1,250 1,711 422 1,237 Arrowrock • ...... 1,897 2,560 ........ 361 3,461 1,510 441 1,705 Dubois Airport ................................ 1,568 1,950 556 1,358

CRESTED WHEATGRASS

Raft River ...................................................... 1,785 ........ ArroWrock • 1,603 2,207 2,427 1,285 2,472 1,537 1,090 1,803 Dubois Airport ................................ 1,873 2,126 722 1,574

•26 miles southeast of Baise.

CHEATGRASS 559

density in 1938 as in 1937 (25). Oregon ranch- ers report considerable fluctuation in cheatgrass yields (11). Annual weeds and grasses in Cali- fornia, similar in many respects to cheatgrass, were 15 times taller and 13 times greater in density in 1935 than in 1934 (27). Nevada studies found the variations in production per square foot of density to be about the same for cheatgrass as for perennials (5). But since an- nuals vary widely in density per square foot (25, 27), the Nevada studies do not show cheatgr•ass to be a very reliable forage producer.

These fluctuations in cheatgrass production are important to the range stockman because it is difficult to adjust numbers of livestock to meet variations in seasonal production.

Although cheatgrass varies widely in produc- tion, it forms a cover rapidly after drought. Unlike perennial bunchgrasses, which may take from 2 to 4 years to recover from such severe drought as occurred in 1934 (16), cheatgrass responds to the first season of favorable moisture and temperature.

Although there seems to be a common belief that cheatgrass produces more forage early in the spring than perennials, observations during 1943, 1944, 1945, and 1946 on southern Idaho ranges show that this may not be true. On all measurements during these 4 years such peren- nial grasses as crested, bluebunch, and thickspike wheatgrass, Sandberg bluegrass and bulbous blue- grass (Poa bulbosa) were 2 to 4 times as tall at the start of the spring. grazing season as cheat- grass. This seems generally to be the case when cheatgrass fails to germinate or makes a poor growth the preceding fall.

PRODUCTION OF HAY

In many sections of southern Idaho three- fourths to ll/• tons of cheatgrass hay per acre have been harvested during good years. But in poor years there is not enough grass to cut.

The only data available on the quality of cheat- grass hay are from Montana where cheatgrass cut for hay in the flowering stage was found to be highly digestible to rams. With the exception of less digestible crude protein and lower palata- bility it was equal to crested wheatgrass hay (14).

Stacks of cheatgrass hay put up during years of surplus forage would be valuable during hard winters. It appears that in order to secure good- quality hay and to avoid the stiff, injurious awns,

early tnowing is necessary. Early mowing may, however, seriously reduce herbage production the following year. Many Idaho ranges mowed in 1942 before the seed was ripe were almost free of cheatgrass and were covered with heavy stands of Russian-thistle the following season. Cheatgrass ranges in Montana, mowed while green, were also found to be reduced in yield the next year.

SEASON DURING WH'ICH CHEATGRASS IS GRAZED

During the spring, all classes of stock readily graze the green forage furnished by cheatgrass. Its palatability may be somewhat lower than that of the perennial grasses and weeds that occur in much lesser abundance; nevertheless, use is good. Judging from appearance of the animals and data on chemical composition, the spring growth of cheatgrass has a satisfactory nutritive value. Limited data from Nevada (5) and Montana (30) show that chemical composi- tion of cheatgrass during the limited period in which it remained green compared favorably with native perennial grasses.

Dry cheatgrass is little used by sheep. On the other hand, cattle and horses graze the dry grass quite readily, provided there is ample water for the animals. The dry forage, however, appar- ently may not have sufficient protein and phos- phorus to meet the requirements of grazing ani- mals (5). This deficiency also occurs in dry annual vegetation of California where this forage varied from a protein-rich feed during early growth to a poor roughage, low in minerals and protein later in the summer (7). There are no detailed records of gains made by cattle and horses grazing on cheatgrass during the summer, but it is probable that gains decline rather rap- idly, ceasing almost completely before the end of the summer. In Nevada it was recommended

that cattle on cheatgrass range be marketed 6 to 8 weeks earlier in the fall than is the common

practice to avoid loss in fleshing (5). In Mon- tana, idle horses on cheatgrass range maintained their weight until September, and then lost rapidly (10).

In the fall sheep make but little use of cheat- grass except in the rather infrequent years in which there is an abundance of new green growth. This is in contrast to the use of peren- nial grasses on sagebrush-perennial grass ranges where sheep often graze as long in the fall as they do in the spring. Both cattle and horses

560 JOURNAL OF FORESTRY

graze cheatgrass ranges in the fall. Quality of the forage remains poor except in years when fall growth is abundant. There is no information on the extent to which it is improved by new, green growth. A small amount of green growth, however, is often detrimental because animals travel excessively trying to get a fill on the green growth rather than take the dry.

During the winter, in relatively snow-free areas such as on parts of the central and lower Snake River and lower Boise and Payette River drain- ages, both cattle and sheep graze all winter on the dry cheatgrass forage. There is often a con- siderable loss in weight, especially with sheep, unless there is either ample green grass from the preceding fall, or protein supplements are fed. Some operators who feed protein supplements claim that there is no loss of weight during the winter.

In some southern Idaho areas, cattle graze yearlong on cheatgrass ranges with what appears to be fairly satisfactory results.

ABILITY TO WITHSTAND HEAVY GRAZING

It is often stated that cheatgrass will withstand almost unlimited grazing use. Recent studies in southern Idaho show, however, that continued overgrazing reduces the number and'height of cheatgrass plants. Numbers of plants on over- grazed ranges were only one-tenth to one-fiftieth those on adjacent, lightly used ranges. Spring growth was slower and the plants averaged only three-fifths as tall. Piemeisel (20) in southern Idaho and Daubenmire (3) in Washington noted that excessive spring grazing may destroy a cheatgrass cover or prevent its dominance.

Overgrazing reduces yield no doubt by pre- venting seed production, or by permitting ero- sion and compaction of the soil. Although fewer and shorter plants are produced on the less fer- tile soils, lowered yields are not easily observed unless a comparison with less heavily grazed ranges is available or unless soil loss becomes advanced.

Distinct signs of overgrazing on cheatgrass ranges of southern Idaho are much more com- mon with cattle ranges than with sheep ranges. (Figure 2.) This difference is probably due to a longer grazing season for cattle and consequently more complete utilization of the forage.

Grazing capacity of cheatgrass ranges appears to be high. Several records of stocking on good

cheatgrass pastures show capacities to be 2 or 3 acres per animal unit month. This is as high as native sagebrush-grass pastures in good condi- tion in the same locality. No signs of deteriora- tion are yet evident from such use.

It appears that one means of achieving con- tinual high production is to leave enough cur- rent growth ungrazed to adequately protect the soil and maintain soil fertility. This has been found to be the case with California annual-type ranges (8) and it may well apply to cheatgrass ranges.

EFFECT ON FIRE HAZARDS

Cheatgrass increases fire hazard more than do perennials (11). It gets dry enough to burn 4 to 6 weeks earlier in the summer than do peren- nials and remains inflammable later in the fall.

The ungrazed residue is a fire hazard early the following spring and intensifies the summer fire protection problem. Cheatgrass has undeniably increased the number of fires, produced larger and faster spreading fires, and extended the fire season by 1 to 2 months.

Much of the range burned each year in south- ern Idaho has been previously burned, usually within recent years. In many cases cheatgrass supports fires of sufficient size to travel through and damage the adjacent less inflammable types of cover. This usually permits the spread of cheatgrass.

The recurrent fires common to cheatgrass ranges are costly, not only from the standpoint of suppression but from the damage they do. They destroy forage; expose the soil to wind and water erosion; weaken the perennial grasses and weeds; destroy fences, buildings, and other property; burn game animals, birds, and live- stock; and carry fire to timbered areas and watersheds.

Many southern Idaho cattlemen, relying on cheatgrass range in the summer, fall, or winter, have found themselves seriously short when ac- cidental fires have destroyed the forage on their range.

The range sheepman is not so seriously affected by the loss from fire because he relies much less on dry cheatgrass for forage. He is, however, greatly affected by the sharp reduction in early spring forage the following year which is caused by early cheatgrass fires. Studies in southern Idaho during 1943, 1944, 1945, and 1946 showed that burning in early summer reduced the num-

CHEATGRASS 561

bers of plants by an average of 92 percent, and early spring height growth by at least 50 per- cent. Forage available at the time sheep went on the range was often less than one-tenth of that present on adjacent unburned ranges (15). Such a reduction is serious, because of the al- ready small amount of early forage normally available for ewes and lambs. This reduction

in forage persisted throughout the' early spring grazing season. However, later-starting plants on the burned ranges stooled out very markedly and speeded up in height growth so that by the end of the growing season, total forage produc- tion on most burned ranges was found to equal or exceed that on unburned ranges (Fig. 3). Some few ranges did not recover in one year and at the end of the growing season produced much less than unburned ranges.

The reduction in number of cheatgrass plants was found to be related to the dates of burning the previous year. The earlier fires caused a more serious thinning (15). This was borne out by a planned burning study conducted near Boise in 1943, 1944, and 1945, where early summer burns reduced plant numbers to from one-third to one-fiftieth that of fall burns (Table 2). The same general trend was found in 1946 on plots of cheatgrass near Riggins burned the first of each month during the summer of 1945.

13oo

12oo !-- W, lloo __ ,[•-r;•j UNBURNED IN 1944.

•1ooo •BURNED lN1944 / 900

____ •6oo __

4oo

MAR.31 APR.14 APR28 MAY 14 MAY 26 JUN10 JUN.26 DATES OF MEASURiNg3 IN 1945.

Fic. 3.--Forage yields of cheatgrass in the early spring are drastically reduced if the area is burned over early in the previous year. Here data, on an area near Boise bin'ned in 1944, show that herbage production when spring grazing started was less than one-twentieth of that on adjacent unburned rage. By midseason there

was still less than one.third as much.

OTHER CHARACTERISTICS

Cheatgrass has three other characteristics which are worthy of note--its susceptibility to smut, the injurious effect of its awns, and its ability to replace plant hosts of the beet leaf- hopper.

Susceptibility to smut.--Smut( Ustilago bromi. vora), with which cheatgrass is periodically af- flicted, appears to have only slight or temporary adverse effects on either the productivity or palatability of cheatgrass (2, 5, 11, 30). In one exception, near Boise, a smut epidemic together with poor cheatgrass years in 1936 and 1938 reduced the production of cheatgrass to almost nothing (25).

Injurious effect o.j awns.--The barbed and owned seeds of cheatgrass on the range and in hay have been reported to cause mouth and eye injury to livestock (2, 5, 11, 14, 28). Recent observations in southern Idaho indicate that this

is not as serious as formerly believed. Ability to replace plant hosts o.j beet' leajhop-

per.--Plant host studies in Idaho show that cheat- grass under proper grazing management will replace Russian-thistle, mustards, and annual weeds (20, 21). These plants are hosts to the beet leafhopper (Eutettix tenellua), carrier of the curlytop disease. Although this feature is of minor importance to the range livestock operator, it is of tremendous importance to sugar beet, bean, and tomato growers. Studies in this field are under way by the Bureau of Plant Industry, Soils, and Agricultural Engineering.

CAN CHEATGRASS BE REPLACED BY PERENNIALS. 9

This is the question that must be answered wherever cheatgrass is found 'to be less than

TABLE 2.--AVERAGE NUMBER OF CHEATGRASS PLANTS PRODUCED IN 1944-46 ON DIFFERENT PLOTS NEAR BOISE, [DAI-IO, WHICH HAD BEEN BURNED AT DIFFERENT DATES

DURING THE PREVIOUS YEAR

Average number of plants per Date of burning in square foot one year after burning 1943, 1944, and 1945 !9•4 19•5 1946

June 15 ........................ 14 26 65 July 15 .......................... 11 21 42 August 15 .................... 41 36 40 September 15 .............. • 59 51 October 15 .................. 46 • ' November 15 .............. 124 1,325 112 Unburned .................. 299 1,090 423

•No burning treatment on this date.

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perennials in desirability. There are now rather definite indications that cheatgrass can be re- placed by perennials in some places either through better grazing management or through reseeding.

REPLACEMENT THROUGH BETTER GRAZING

MANAGEMENT

Several ranges in southern Idaho are showing that perennial grasses will replace cheatgrass under proper grazing management where suffi- cient perennial grasses remain to supply seed. Several reports also state that proper grazing, together with prevention of fire, will permit restoration of the perennial grasses (13, 19, 21, 23, 28, 30).

Replacement of cheatgrass by perennials is likely to be difficult because perennial grasses are usually more palatable than cheatgrass, even when dry. Replacement can undoubtedly be hast- ened by correct intensities of stocking, proper seasons of use,' and good systems of grazing for each class of stock.

REPLACEMENT THROUGH RESEEDING

When desirable perennial grasses are too sparse to revegetate the area, or where rapid replacement of cheatgrass by perennials is de- sired, then reseeding is necessary. Experimental work indicates that careful attention to species, methods, and season of planting will in most cases assure a successful stand of perennials.

Since competition between reseeded species and cheatgrass is severe, reduction of dense stands of cheatgrass appears essential to the early establishment of reseeded species (9, 11, 12, 22, 23, 30). It is, however, worthy of note that in some cases, reseeding of perennials has been successful without prior reduction of cheatgrass (11, 12, 22, 29).

Reduction of cheatgrass has commonly been accomplished by mold-board plowing at nearly any season of the year (9, 11, 29), wheatland plowing in late spring as cheatgrass starts to head or after fall germination of cheatgrass (9), contour plow furrowing in the fall (12, 23), fall disking (23), and spring or fall cultivation (30). Four years' observations show that burn- ing early in the summer may be a successful low-cost method of thinning cheatgrass (29). (See Table 2.) In western Montana, cheatgrass covered lands are spring plowed and planted to

spring rye. The rye is cut for hay and crested wheatgrass is drilled in the stubble that fall (6).

Recent trials with deep-furrow drills are en- couraging. When used after fall germination of cheatgrass, both disk and lister type drills elimi- nate considerable cheatgrass and place the seed in a deep furrow where the perennial grass seedlings are more protected and better able to compete witl• the cheatgrass (9, 11, 29).

WHAT IS THE FUTURE PROGRAM FOR

CHEATGRASS LAND?

A definite program for the management of cheatgrass and cheatgrass lands must await an evaluation of the desirability of cheatgrass from the standpoint of its major uses. Only after research has gathered sufficient information will it be possible to set up a program for proper management of cheatgrass ranges which will include replacement of cheatgrass by perennials where needed. Until a comprehensive program is initiated, however, all cheatgrass ranges must be so managed that no soil loss occurs.

RESEARCH NEEDED TO DETERMINE THE VALUE

OF CHEATGRASS

It is' evident from the preceding sections that there are many gaps in the information regard- ing the advantages and shortcomings of cheat- grass. Present data have been drawn from widely different sites and conditions. A compre- hensive research program is needed--one which will answer many of the important unanswered questions. Some of these questions are:

What are the factors, including growth habits, which affect the ability of cheatgrass to compete with native and reseeded species on its present range? Under what conditions will it spread to other areas? How great is the annual forage crop of cheatgrass and perennials and how much does it fluctuate? What stage of cutting is best for good-quality cheatgrass hay?

What species and methods are adapted for replacing cheatgrass by reseeding to perennial grass ?

How much early spring grazing is furnished by cheatgrass? Will perennials allow earlier grazing and more total grazing and still maintain soil fertility and hold the soil, especially on steep watersheds? What is the effect of different intensities a.nd seasons of grazing on forage pro- duction and soil erosion? What grazing meth-

CHEATGRASS 563

ods and season of use will allow replacement of cheatgrass by perennial grass? What criteria' can be used for determining rate of improvement of cheatgrass ranges, degree of utilization, and indicators of condition and trend? What gains are made by livestock grazing on cheatgrass ranges? What is the nutritive value of cheat- grass forage? Are feed supplements needed to balance nutritional deficiencies during periods when forage is low in quality? What is the amount and nature of injury inflicted by cheat- grass awns on cattle and sheep?

What is the effect of cheatgrass on uses other than grazing, such as wildlife, water yield of watersheds, siltation of reservoirs and streams, commercial timber production, and recreational values ?

How much current forage is lost through cheat- grass fires and what damage is done to the soil? How much do fires retard the growth of cheat- grass the following spring? How can cheatgrass fires be prevented and controlled? Will replace- ment by perennials reduce fire costs and dam- ages ?

How frequently does smut occur and what is its effect upon yield and palatability of cheat- grass?

IS REPLACEMENT OF CHEATGRASS BY

PERENNIALS JUSTIFIED

If research determines that cheatgrass is un- desirable and that replacement can be effected, the question then arises as to whether the added advantages offered by the perennial cover will justify the cost of replacement. To answer this question research must assemble the important facts on the relative values of cheatgrass and perennials for livestock production, forage pro- duction, fire damage, soil erosion, watershed protection, water yields, wildlife, timber pro- duction, and recreational values. These values together with costs and methods of replacement, will form a basis for determining for each zone, each class of stock, or each specific situation, the justification for replacement of cheatgrass.

MANAGING CHEATGRASS RANGES TO MAINTAIN

SOIL PRODUCTIVITY

Cheatgrass ranges are losing fertile topsoil by wind and water erosion and forage production is decreasing, partly because of the mistaken

impression that cheatgrass ranges cannot be overgrazed and partly as the result of recur- rent fire. True, the decline in productivity may be slow but if permitted. to continue, res- storing the range to full production on a de- pleted soil a few years hence wil! be more difli- cult than it is now, and may even be impossible. Whether we plan to maintain cheatgrass or to replace it by artificial or natural reseeding, cur- rent management must maintain soil productivity.

Management of cheatgrass ranges to reduce soil losses to a minimum will be needed on all

ranges for a long time, regardless of the decision of the desirability of cheatgrass. Such manage- ment will be permanently needed both on ranges which are to remain in cheatgrass and on ranges where cheatgrass is to be replaced by perennials through proper management. Good management will also be needed as a temporary measure to hold the soil on cheatgrass areas that are await- ing reseeding.

There are gaps in our knowledge, however, regarding the essentials of management necessary for preserving soil productivity of cheatgrass ranges. Observations on the cheatgrass ranges of the Intermountain Region and research work on the annual ranges in California (8) indicate that moderate grazing, together with protection from fire will probably leave enough litter to protect the soil and to maintain it in a produc- tive condition.

To determine the essentials of grazing man- agement necessary for the maintenance of soil productivity is the most important and pressing task that research faces on cheatgrass ranges. It calls for determination of the proper rate of stocking and season of use, proper degree of utilization, and usable indicators of trend and condition.

LITERATURE CITED

3o

Craddock, George W. and C. Kenneth Pearse. 1938. Snrface run-off and erosion on granitic monn- tain soils of Idaho as influenced by range cover, soil disturbance, slope, and precipitation intensity. U.S. Dept. Agric. Cir. 482, 24 pp.

Costello, David F. 1944. Know your range grasses and plants: Cheatgrass (Bromus rectorurn). The Westerner 7, No. 11.

Daubenmire, Rexford F. 1940. Plant succession due to overgrazing in the ,4gropyron bunchgrass prairie of southeastern Washington. Ecology 21: 55-64.

564 JOURNAL OF FORESTRY

4. . 1942. An ecological study of the vegetation of southeastern Washington and adjacent Idaho. Ecol. Monog. 12:53-79.

5. Fleming, C. E., M. A. Shipley, and M. R. Miller. 1942. Broncograss (Bromus tectorum) on Nevada ranges. Nev. Agric. Expt. Sta. Bul. 159, 21

6. Friedrich, C. Allan. ,1945. Seeding crested wheatgrass in cheatgrass land. Northern Rocky Mountain Forest & Range Expt. Sta. Research Note 38. Mimeo. 4 pp.

7. Hart, G. H., H. R. Guilbert, and H. Goss. 1932. Seasonal changes in the chemical composi- tion of range forage and their relation to nutrition of animals. Calif. Agric. Expt. Sta. Bul. 543, 62

8. Hormay, August L. 1944. Moderate grazing pays on California annual-type ranges. U. S. Dept. Agric. Leaflet, No. 239, 8

9. Hull, A. C., Jr. and C. Kenneth Pearse. 1943. How to reseed southern Idaho range lands. Inter- mountain Forest & Range Expt. Station Research Paper 2. Mimeo. 22

10. Hurtt, Leon C. 1939. Downy brome (cheatgrass) range for horses. Northern Rocky Mountain Forest & Range Expt. Sta., Applied Forest• Note 89. Mimeo. 4 pp.

11. Jackman, E. R. 1945. Oregon ranchers evaluate cheatgrass. The Grazier, No. 12, Nov. 1, 1945 mimeo, 8 pp. Oregon State Agric. Col. Ext. Service.

12. Jaclanan, E. R., D. E. Stephens, and D. E. Richards. 1936. Crested wheatgrass in eastern Oregon. Oreg. State Col. Ext. Bul. 494, 39

13. Leopold, Aldo. 1941. Cheat takes over. The Land 1:310-13.

14. McCall, Ralph, R. T. Clark, and A. R. Patton. 1943. The apparent digestibility and nutritive value of several native and introduced grasses. Montana Agric. Expt. Sta. Tech. Bul. 418, 30 pp.

15. Petrance, J. F. and A. C. Hull, Jr. 1945. Cheatgrass fires reduce next year's early spring forage. National Wool Grower 35 (4) :13.

16. , G. D. Pickford, and George Stew- art. 1937. Effects of the 1934 drought on native vegetation of the upper Snake River Plains, Idaho. Ecology 18(4) :490-505.

17. and George Stewart. 1944. Sage- brush burning--good and bad. U.S. Dept. Agric, Farmers' Bul. 1948, 32 pp.

18. ranges. Unp•bl. Grazing Idaho spring-fall sheep mss.

19. Pickford, G. D. 1932. The influence of continued heavy grazing and the promiscuous burning on spring-fall ranges in Utah. Ecology 13(2):159-71.

20. Piemeisel, R. L. 1938. Changes in weedy plant cover on cleared sagebrush land and their probable causes. U.S. Dept. Agric. Tech. Bul. 654, 44

21. and J. C. Chainberlin. 1936. Land- improvement measures in relation to a possible control of the beet leafhopper and durlytop. U.S. Dept. Agric. Cir. 416, 23 pp.

22. Robertson, Joseph H. and C. Kenneth Pearse. 1945. Artificial reseeding and the closed com- munity. Northwest Science, 19(3) :58-66.

23. Short, L. R. 1943. Reseeding to increase the yield of Montana range lands. U.S. Dept. Agric. Farmers' Bul. 1924, 24 pp.

24. Spence, Liter E. 1937. Root studies of important range plants of the Boise River Watershed. Jour. Forestu 35:747-54.

25. Stewart, George and A. E. Young. 1939. The hazard of basing permanent grazing capacity on Bromus tectorum. Jour. Amer. Soc. Agron. 31(12): 1002-15.

26. Stoddart, L. A. 1941. Tbe Palouse grassland association in northern Utah. Ecology 22(2): 158-63.

27. TaJbct, M. W,, D. H. Biswq•, and A. L. Hor- may. 1939. Fluctuations in the annual vegetation of California. Ecology 20(3):394-412.

28. U.S. Forest Service. 1937. Range plant hand- book, p. G-38. March.

29. . 1945. Unpublished data by the In- termountain Forest and Range Expt. Station, Forest Service, Ogden, Utah.

30. Warg, Samuel A. 1938. Life history and eco- nomics studies on Bromus tectorum. M. S. thesis, State Univ. of Montana.

31. Young, V. A. 1943. Changes in vegetation and soil of Palouse Prairie caused by overgrazing. JGur, Forest• 41:834-38.