Wyethia with Desirable Forage Species

Replacing Wyethia with Desirable Forage Species

WALTER F. MUEGGLER AND JAMES P. RLAISDELL Range Conservationists, Intermountain Forest and Range Experiment Station, CJ. S. Forest Service, Ogden, Utah

ENSE stands of wyethia (Wyethia DRY CREEK STUDY D amplexicaulis and W. helianthoides) Methods now occur on extensive areas of western mountain range lands (Fig. 1A). These A 14-acre area on Dry Creek, approxi- plants prefer moist, heavy soils, and mately 6,500 feet in elevation and sloping consequently are found on some of the gently to the southeast, was selected in most productive sites. An air-dry herbage 1947. The annual precipitation is prob- production of more than 1.5 tons per ably between 20 and 25 inches, and the acre is possible on many of these sites, soil is a heavy, black loam. Prior to but when most of this is made up of the treatment, the area supported a dense relat)ively unpalatable wyethia, there is stand of wyethia (mostly W. amplexi- only a small amount of usable forage. caulis but some W. helianthoides) with a Such stands of wyethia may be native small amount of geranium (Geranium on some areas, but on many others it is viscosissimum), cinquefoil (Potentilla sp.), thought that wyethia has increased as dock (Rumex sp.), mountain brome more palatable plants have been reduced (Bromus carinatus), slender wheatgrass by heavy grazing. Wyethia appears to be (Agropyron trachycaulum), bluegrasses long lived and a strong competitor, so (Poa spp.), oniongrass (Mel&a sp.), and that its elimination by nattiral means, if several other grasses and forbs. possible at all, is slow. In order to deter- Five methods of cultivation were used mine what methods might be successful on duplicated l-acre plots in September, in converting dense stands of wyethia to 1947: moldboard plowing to 10 inches, more desirable plants quickly, studies wheatland plowing to 3 and 6 inches, were begun in 1947 on the Spencer Dis- and offset (2-way) disking to 3 and 5 trict of the Targhee National Forest in inches. Two plots were reserved as un- eastern Idaho. treated checks. The authors wish to acknowledge the In June, 1948 one plot was plowed with assistance of Lyman Richwine, District a moldboard plow to a depth of 6 inches. Forest Ranger, in establishing and main- In addition, one uncultivated plot was taining these studies, and the work of divided into 10 sections, and four chemi- C. E. Holscher, now with the Pacific cals were applied with a hand sprayer to Northwest Forest and Range Experiment duplicated 0. l-acre sections. Ammonium Station, who planned the Dry Creek sulfamate was applied at the rate of study. They also wish to thank George 25 pounds per acre, ammonium 2,4-di- Whornham of the American Chemical chlorophenoxyacetate at 3 pounds per Paint Company for furnishing the chemi- acre, a mixture of diesel oil and creosote cals used in the West Camas Creek at 45 gallons per acre, and kerosene at study and for his advice in the selection 45 gallons per acre. The two remaining of these chemicals. sections were left as untreated checks. 144 WALTER F. MUEGGLER AND JAMES P. BLAISDELL

Plots cultivated in the fall of 1947, as 1). In 1948 it appeared that plowing in well as the untreated check plots, were the spring was considerably more effec- broadcast to a mixture of smooth brome tive than in the fall, but these initial (Rromus inermis) , slender wheatgrass, differences had mostly disappeared by timothy (Phleum pratense), and orchard- 1950. Although there was only a slight, grass (Dactylis glomerata) at the rate of difference in favor of spring plowing in 10 pounds per acre immediately after 1950, cultivation at t)his season may actu- cultivation. The spring-plowed plot and ally be more effective as these results t’he chemically treated sections were were accomplished by plowing at’ a 6-inch drilled to the same mixture in the fall of depth, whereas the fall plowing was at 10 1948. inches. Disking with a wheatland plow

TABLE 1 E$ects of cultural and chemical treatments on numbers of wyethia and air-dry production of wyethia and grass, Dry Creek

HERBAGE PRODUCTION WYETHIA PLANTS PER (Percent of check) SUBPLOT (Percefit of check) TREATMENT AND SEASON Wyethia Grass -/- I-1948 1949 1950 1949 1950 Yawing: Sprir& moldhoard, g-inch depth. 17 25 24 19 18 75 53 Fall moldboard, lo-inch depth.. . 44 39 26 20 23 749 1365 Fall wheatland, 6-inch depth. . 102 107 175 128 126 62 66 Fall wheatland, 3-inch depth.. 122 111 156 113 110 73 80 Fall offset disk, 5-inch depth.. . 92 85 109 101 80 93 100 Fall offset disk, 3-inch depth. .. . . 125 114 161 124 122 82 104 -~------~~ ------_------Untreated check (number and Ibs. per acre). . 47 46 44 2069 1376 186 167 _~___--_-_-~~ -- -__ ------_------Chetiical treatment: 2,4-D’...... - 58 36 22 31 171 326 Kerosene...... - 87 98 79 107 92 74 Creosote and diesel oil...... - 87 93 85 95 63 86 Ammonium sulfamate. . . . . - 83 101 77 96 130 162 ------__- --- -__ _-__- Untreated check (number and lbs. per acre). - 56 58 3080 1612 100

l Ammonium 2,4-dichlorophenoxyacetate.

Wyethia plants were counted on cir- and an offset disk was not effective at cular 4%square-foot subplots within each either depth. As a matter of fact, wheat- acre plot during late summer of 1948, land plowing at both depths and shallow 1949, and 1950. Weight estimates were offset disking resulted in a substantial made of both wyethia and reseeded increase in plant numbers and a similar, grasses in 1949 and 1950. though less pronounced, increase in wyethia herbage. Apparently the disks Results cut the taproot so shallowly that in Moldboard plowing was the only many cases both sections of root con- method of cultivation which caused an tinued to grow, producing two plant)s appreciable reduction in wyethia (Table instead of one. The inadequacy of offset disking wits further subntantint~d hy hers were essentially the same as on the poor results obtained from disking a untreated checkrj. 5-acre area on West Camas Creek in the Of t,he grasses broadcast in the fall of spring of 1949. 1947, s successful stand was obt,ained A critical examination of data in Table only on t,he fall moldboard-plowed plots, 1 shovs certain variations h&wren years ix., only &here wyethis had hren greatly for \vhivh no explanation is readily ap- reduced. Grass production on these plots parent. It, is thought that these minor WRS over seven times that of t,he un- variations arc attrihutahle to sampling treated plots in I919 and over thirteen error resulting from use of different times, in 1950. Total grass production sample subplots rach yciu. \~as decreased on all other plots, but

Wyethia herbage production ras those treated rith the offset disk had greatly reduced the year following treat- reoovered sufficiently to pro&we as ment with 2,4-D (Table l), and numbers much as the untreated plots by 1950. of plants continued to decrease the second Three years after fall moldboard ploving year after spraying. Both herbsge pro- and reseeding, grass production was over duction of wyethia and numbers of plants 1 ton of air-dry herhage per acre, whereas were slightly decreased by the other wyethia was producing less than 14 per- chemical treatments, but these decreases cent of this amount. This relatively small were only temporary, for in 1950 both amount of wyethia grew in roes at the wyethia herbage yield and plant num- edges of furrows where roots were not 146 WALTER F. MUEGGLER AND JAMES P. BLAISDELL completely sheared and turned. In con- sp.), dock, geranium, cinquefoil, dan- trast to this, other fall cultivated plots delion (Taraxacum oficinale), yarrow were producing between 1,000 and 2,000 (Achilles lanulosa) , yampa (Perideridia pounds of wyethia and less than 200 gairdneri) , and others. pounds of grass. These differences are Effectiveness of three herbicides for well illustrated in Figure 1B. wyethia eradication were tested at two Although a good kill of wyethia was rates of application at two dates (growth obtained on the spring moldboard-plowed stages). In order that regular field meth- area, the establishment of grass was un- ods of spraying could be employed, 0.5- successful. This grass failure was prob- acre plots, each 1 by 5 chains, were used. ably not related to season of plowing but All treatments were duplicated and perhaps to less favorable weather follow- there were four untreated check plots. ing the 1948 planting or too deep seed Treatments were assigned at random to covering through drilling. the plots within each replication. Grass production was greatly increased Commercial formulations were used on the sections treated with 2,4-D, and throughout. These consisted of a 2,4-D to a lesser extent, on those treated with ethyl ester, a 2,4,5-T butoxy ethanol ammonium sulfamate. This increase, in ester, and a mixture of two parts 2,4-D contrast to that on the fall moldboard- and one part 2,4,5-T in butoxy ethanol plowed plots, was mostly due to an in- ester form. Rates of application were 1 crease in natjive grasses, rather than to and 2 pounds acid equivalent per acre, establishment of reseeded species. Ap- and application was made at two growth parently the hard, uncultivated ground stages, when the wyethia was about was such a poor seedbed that reseeded half way through blooming (June 7) and grasses were unable to become established when blooming was over (June 20, 1949). even where competition of wyethia was Chemicals were applied in a water solu- greatly reduced. Grass yield on plots tion with a boom sprayer mounted on a treated with kerosene and creosote- pick-up truck. The sprayer was so regu- diesel oil was slightly decreased. lat’ed that approximately 25 gallons of water were required per acre. WEST CAMAS CREEK STUDY Prior to any treatment (May 28, 1949) Methods and approximately 1 year afterwards wyethia counts and The study area selected on West (July 7, 1950), Camas Creek is very similar to the one weight estimates were made of the vege- on Dry Creek, having about the same tation on five circular 96-square-foot elevation, annual precipitation, soil type, subplots within each 0.5-acre plot. and vegetation. The land slopes gently In September of 1949, one replication northeast, however, and the dense stand of the study was drilled to a mixture of of wyethia prior to treatment was chiefly crested wheatgrass (Agropyron cristatum), W. helianthoides. In addition to wyethia, slender wheatgrass, intermediate wheat- the area supported bluegrasses, Idaho grass (Agropyron intermedium), smooth fescue (Festuca idahoensis), alpine tim- brome, and timothy, at the rate of 12.5 othy (Phleum alpinum), meadow barley pounds per acre. The other replication (Hordeurn nodosum), needlegrass (Stipa was left unseeded to determine rate of sp.), slender wheatgrass, mountain brome, recovery from natural revegetation fol- sedges (Carex spp.), redtop (Agrostis lowing wyethia eradication. REPLACING WYETHIA 147

Results per acre. In most cases reductions in Wyethia on all of the sprayed plots numbers and in yield were statistically began to show effects of the herbicides significant. The 2,4-D and mixture ap- within a few hours. Herbage of wyethia plied at the 2-pound rate when wyethia treated early (half bloom) was completely was in half bloom, were the most effective dry in approximately 1 month, but that treatments, and were fairly comparable treated later (blooming over) retained in degree of wyethia kill (Fig. 1C; note some life most of the summer. Differ- wyethia on untreated plot in left back- ences resulting from chemicals or rates ground). The former reduced wyethia to of application were not readily apparent 54 pounds per acre and 28 plants per in 1949. subplot, while the latter reduced wyethia It was obvious the year after spraying to 56 pounds per acre and 10 plants per that all herbicides had caused consider- subplot. able reduction in wyethia (Table 2). Comparison of the various treatments

TABLE 2 Efects of chemical treatments on numbers of wyethia and on air-dry herbage weight of wyethia, grasses, and forbs, together with estimated costs, West Camas Creek, 1960’

HERBAGE PRODUCTION WYETHIA PLANTS PER (Percent of check) COST CHEMICAL GROWTH STAGE SUBPLOT (Dollars per (Percent of check)’ acre, approx.) Wyethia Grass Forbs .

2,4-D 2 Half bloom 19 5 136 29 2.90 Mixture 2 Half bloom 7 5 235 146 4.70 2,4-D 2 Blooming over 33 7 145 88 2.90 Mixture 2 Blooming .over 21 10 102 59 4.70 2,4-D 1 Half bloom 40 13 142 68 1.70 Mixture 1 Half bloom 21 10 197 107 2.60 2,4-D 1 Blooming over 41 20 98 44 1.70 Mixture 1 Blooming over 55 28 146 99 2.60 2,4,5-T 2 Half bloom 47 32 201 93 6.50 2,4,5-T 2 Blooming over 58 30. 166 96 6.50 2,4,5-T 1 Half bloom 52 36 162 76 3.50 2,4,5-T 1 Blooming over 75 73 136 96 3.50 _---__ .------Untreated check (number and lbs. per acre) ...... 150 1083 149 82 -

1 Production figures adjusted to original production by covariance analysis. 2 Acid equivalent in pounds per acre.

Subplots on the untreat,ed areas con- is most easily made when herbage produc- tained an average of 150 plants, whereas tion and plant numbers are expressed as a all but one of the chemical treatments percentage of the untreated checks (Table reduced wyethia to less than 100 plants. 2). Percentages may be converted to ac- Average air-dry herbage production of tual weight in pounds per acre from the wyethia on the check plots was over weights given for the untreated check 1,000 pounds per acre; all but one of the plots. Both the mixture and 2,4-D were chemical treatments reduced wyethia definitely superior to 2,4,5-T in eradicat- herbage yield to less than 400 pounds ing wyethia. It is also obvious that ‘application at the rate of 2 pounds per Dry Creek study \\-hcrc wyethia num- acre was far more effective than 1 pound, bers dropped from 58 percent of the and tlrat spraying at the half bloom chrck in 1919, 1 year after treatment growth stage ws much more effective with 2,4-D, to but 3F percent of the than at, the blooming orer s&go. rherk in 1050 (TahlP 1). Erickson, PL al. All of the herbicides used had a defi- (1948) noted that 2,4-D usually acts nite physiological effect upon wyethia much more slovly than other wedkillers. plants not killed. Scarcely any flower Grass production incrcasrd on nearly stalks were produced on sprayed i~reits, all treated plots, hut these increases whcrcns wycthia flowered profusely on came from rwovery of niltive grasses untreated check plots. Evrn the least rather than from growth of artificially effective twatment, 2,4,3-T applied late seeded species. 2Zs n mat,ter of fact, aver- at 1 pound per acw, prerented flowering age grass production ras higher on the (Fig. lD), though the wnaining plants replication which was not, seeded. Al- wre vigorous and showd no deformity though grass yields from several of t,he like that, raused by 2,4-D. treatments wxe significantly higher than

There was little difference in effective- those of the checks-notably applications ness of 2,4-D and the mixture in reduc- at half hloom of the mixture and 2,4,5-T ing wyet,hia hrrhege yield, hut the mix- -they followed no regular pattern. It is ture caused a more immediate reduction assumed that the increase in grass re- in plant numbers. Most of the plants flects release from mycthia competition, remaining on the areas treated with hut grass yield does not appear to he 2,4-D were small and deformed, however, closely correlated with degree of wyethia and many of these will probably die kill. Grass yield on plots sprayed at half (Fig. 2). This actually happened in the bloom with the mixture at 2 pounds per REPLACING WYETHIA 149 acre was increased to 235 percent of the The mixture of 2,4-D and 2,4,5-T untreated check, whereas yield on plots and the 2,4-D alone were both successful sprayed with 2,4-D at the same rate in eradicating wyethia when applied at and date was only 136 percent of the 2 pounds per acre at the half bloom check. In most cases increase of grasses growth stage. These chemical treatments sprayed with 2,4-D was less marked have certain advantages over moldboard than with the other chemicals, which plowing in that they do not destroy the suggests that 2,4-D may have injured natural understory of grasses and other the grasses to some extent. forbs, nor are they limited to specific Forb production after spraying was types of terrain. The tests indicate the generally lower than on the unsprayed importance of applying the weedkillers in plots, although so much variation exists sufficient concentration and at an early between plots that it is difficult to assess date. It is thought that even better significance. Again, there is a suggestion wyethia kill might be secured from ear- that forbs were more greatly reduced on lier spraying while the plants are more the plots sprayed with 2,4-D than with actively growing-perhaps when they the other chemicals. Had the stand of first begin to bloom. In similar studies wyethia been less dense, sheltering other with herbicides on other species (Egler, species less effectively, it seems likely 1949; McIlvain, 1949; Offord, 1949), in- that harmful effects of the chemicals creased effectiveness of application dur- would have been more evident. For the ing the vigorous growth period before most part, reductions in forb yield in plant maturity has been observed. these tests were not pronounced and were Although the mixture and 2,4-D were offset by increases in grass. Although almost equally effective in reducing records were not kept of individual forb wyethia, the cost of the chemicals differed species, inspection of treated and un- greatly. The cost of treatment with 2,4-D treated plots indicated that the more at 2 pounds was approximately $2.90 desirable species were not disproportion- per acre, whereas the mixture at 2 ately reduced. pounds cost approximately $4.70 (Table 2). Expenses can undoubtedly be re- DISCUSSION duced if the operation is on a large Jt is evident that competition from scale, especially if spraying is done by wyethia must be reduced in order to airplane. The 2,4-D may be more in- obtain a heavy stand of either native jurious to forbs and grasses than the or reseeded grasses. Moldboard plowing mixture, but this disadvantage does not was the only cultivation method that appear to offset the advantage of its satisfactorily reduced this competition. lower cost. Spraying with 2,4-D ethyl This means of eradication, however, is ester at 2 pounds per acre appears to be not only expensive but is also limited to the most economical means of eradicat- areas of deep soil without numerous rock ing wyethia. outcrops which would cause excessive Reseeding of the sprayed area is not breakage in equipment. Moldboard plow- necessary if a grass understory is present. ing must be followed with reseeding as In fact, a residual stand of grasses and all perennial vegetation is destroyed. forbs will probably prevent establish- Because of these limitations and its high ment of a successful stand of reseeded cost, this method cannot be widely used species. If a suitable understory is not as a means of eradicating wyethia. present, reseeding will be necessary to 150 WALTER F. MUEGGLER AND JAMES P. BLAISDELL prevent reinvasion by wyethia. In such area will be subject to immediate re- cases, seedbed preparation may be neces- invasion by wyethia. sary on some areas to assure successful 4. The suggested application of 2,4-D reseeding. does not greatly injure the native grasses; reduced competition from wyethia after CoNcLusIoNs treatment will allow a rapid increase in yield of other species. Reseeding, 1. Moldboard plowing is an effective, therefore, is necessary only on areas that though expensive, means of eradicat’ing lack a fairly abundant and well-distrib- wyethia. This method is limited to ac- uted understory of other species. cessible areas with deep, rock-free soils that will not cause excessive breakage LITERATURE CITED in equipment. EGLER, FRANK E. 1949. Herbicide effect in 2. 2,4-D ethyl ester applied at 2 Connecticut vegetation. Ecology 30: 24% pounds acid equivalent per acre between 256. first and half bloom is a comparatively ERICKSON, L. C. 1948. Using 2,4-D for selective and non-selective weed control. Uni- economical and thorough means of eradi- versity of Idaho Ext. Bull. 172. cating wyethia. With adequate facilities MCILVAIN, E. H. AND D. A. SAVAGE. 1949. it can be used on any site. Spraying 2,4-D by airplane on sand sage- 3. Reseeding of moldboard plowed brush and other plants of the southern areas is necessary to obtain desirable Great Plains. Jour. Range Management 2: 43-52. forage species. Plowing destroys all peren- OFFORD, H. R. 1949. Killing Ribes with nial vegetation; unless an adequate stand 2,4-D and 2,4,5-T. Jour. Range Manage- of desirable perennials is produced the ment 2: 201-205.