Volume 26, Number 1 (January 1973)

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JOURNIU OF

MNGE NIWEEMENT

Published bimonthly-January, March, May,

July, September, November-by the Society for Range Management 2120 South Birch Street Denver, Colorado 80222 Copyright @ 1973 by the Society for Range Management Managing Editor

FRANCIS T. COLBERT 2120 S. Birch St. Denver, Colo. 80222 Editor

ELBERT H. REID 624 S. Shields St. Fort Collins, Colo. 80521 Book Review Editor DONALD N. HYDER

Agricultural Research Service Colorado State University Fort Collins, Colo. 80521 Copy Editor

PATRICIA G. SMITH 2120 S. Birch St. Denver, Colo. 80222 Editorial Board 1970-72

E. WM. ANDERSON, Lake Oswego, Ore. RICHARD E. ECKERT, JR., Reno, Nev. NED W. JEFFERIES, Durango,Colo. HUDSON G. REYNOLDS, Tempe, Ariz. 1971-73

C. KENNETH PEARSE, Laguna Hills, Calif. SYLVESTER SMOLIAK, Lethbridge, Albta. ELVIS R. BEATY,Athens, Ga.

DON DWY ER, Logan, Utah 1972-74

LOWELL K. HALLS, Nacogdoches, Tex. ROBERT L. ROSS, Bozeman, Mont. G. W. TOMANEK, Hays, Kan. HENRY A. WRIGHT, Lubbock, Tex. INDIVIDUAL SUBSCRIPTION is by membership in the Society for Range Management.

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Vol. 26, No. 1, January 1973

ARTICLES 6 9 13 19 22

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27 30

32

34 37 39

41

43 47 50

54

57 58

61

65

Trends in Western Ranch Prices and Values by Mont H. Saunderson Raintrap Performance on the Fishlake National Forest by Allen R. Dedrick Carbohydrate Reserves of Grasses: A Review by Larry M. White

Creeping Bluestem Compared with Four Other Native Range Grasses by Robert D. Roush and Lewis L. Yarlett

Heat Effects on Nutrient Release from Soils Under Ponderosa Pine by E. M. White, W. W. Thompson, and F. R. Gartner

Rough Fescue (Festucu scabrella Torr.) in Washington by Harmon S. Hodgkinson and Alfred E. Young

Effect of Mesquite on Physical and Chemical Properties of the Soil by Arthur R. Tiedemann and James 0. Klemmedson

Origin of Soil Mounds Associated with Clumps of Ribes velutinum by Dale V. Saunders, James A. Young, and Raymond A. Evans

Snow Amount in Relation to Streamflow and Herbage Production in Western Colorado by Ernest C. Frank

Distribution of Galleta Roots and Rhizomes at Two Utah Sites by Russell T. Moore and Neil E. West

Chemical Composition of Six Southern Great Plains Grasses as Related to Season and Precipitation by E. Earl Willard and Joseph L. Schuster

Establishment and Growth of Selected Grasses by J. Stubbendieck, Paul T. Koshi, and Wayne G. McCully

Taxonomic and Agronomic Variation in Agropyron spicatum and A. inerme by Stephen R. Chapman and Lawrence J. Perry, Jr.

Responses of Crested Wheatgrass Seeds to Environment by A. M. Wilson Crested Wheatgrass Response to Nitrogen and Clipping by Forrest A. Sneva

Interaction of Fertility Level with Harvest Date and Frequency on Productiveness of Mixed Prairie by Russell J. Lorenz and George A. Rogler

Nitrate-Nitrogen Accumulation in Range Plants after Massive N Fertilization on Shortgrass Plains by Walter R. Houston, L. D. Sabatka, and D. N. Hyder

Gambel Oak Control Studies in Southwestern Colorado by Robert W. Marquiss Honey Mesquite Seedling Growth and 2,4,5-T Susceptibility as Influenced by Shading by C. J. Scifres, C. R. Kienast, and D. J. Elrod

Evaluation of Sampling Techniques on TallCrass Prairie by Donald A. Becker and Jerry J. Crockett

A Comparison of Sampling Methods in Dense Herbaceous Pasture by Paule S. Poissonet, Jacques A. Poissonet, Michel P. Godron, and Gilbert A. Long

TECHNICAL NOTES

68 Western Wheatgrass Germination as Related to Temperature, Light, and Moisture Stress by 0. D. Knipe

69 Production Potential of Four Winter Annual Grasses by W. C. Robocker

70 Large Alligator Juniper Benefits Early Spring Forage by Warren P. Clary and Douglas C. Morrison

MANAGEMENT NOTES

72 Range Plants as Ornamentals by Robert E. Steger and Reldon F. Beck BOOK REVIEWS

75 Grassland Improvement (Semple); Range Development and Improvements (Vallentine); Alaska, The Embattled Frontier (Laycock); Anhydrous Ammonia: Proceedings of a symposium (Gasser et al.)

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Trends in Western Ranch Prices and Values

MONTH. SAUNDERSON

Highlight: In the 19305 the westem stock ranches were generally underdeveloped and underpriced in terms

of

their potential. Over the past 40years, however, a number

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In the early 1930’s I heard the chief appraiser for the Farm Credit Administra- tion express the opinion that the long-run “normal” value of the year-round and well-balanced “home for a cow” in western livestock ranch realty should be around $60. He was thinking about the lands and physical plant for a well- balanced ranch of economic size with all of the locally suitable complement of the rangelands, the crop lands, the water, and the improvements.

Now, some 40 years later, the prices that are being paid per cow-unit of capacity in western stock ranches are running 10 to 15 times this $60 figure. In the more productive ranching areas and in those situations where most of the land being used is deeded land, the investment per cow in recent ranch sales will average nearly 20 times the $60 figure. These are the prices for commercial cattle ranches, not for those with some unusual country living appeal, with possible oil prospects, or with rural subdivision and development possibilities. However, all of those things and several others have no doubt had some influence in generating the western stock ranch market and price situation that prevails today.

Not all of this rather spectacular rise since the 1930’s in the prices of western livestock ranch realty has come as a result of land speculation and monetary inflation. In the earlier phases of this upward price trend much of the rise was soundly based upon the kinds of ranch development and modernization that resulted in higher unit outputs, in improved product quality, and in substantial gains in cost efficiency.

Much of this development that came during the years following the second World War and into the early 1960’s was made possible by sources and types of loan capital not previously available to the western ranches. New lenders became interested in the western ranch loan market and offered longer-term and more suitable types of ranch loan contracts. Some of the productivity gains of the ranches during this period came as a result of the increasing number of younger and more capable managers; and some of the gain in higher unit yields resulted from the fact that after some 15 years of efforts to get the Public Domain

Since 1950 the author has been a private consultant in western stock ranch management and development. He formerly served as a western lands economist with the Forest Serv- ice, and from 1925 to 1938 as ranch economist Montana State University, Bozeman. His curreni gedrr;; is Rio Ranch0 Estates, S. E., New

under adequate administration, starting with the Taylor Act of 1934, those lands were finally being managed and improved.

Some indices of the per-unit gains in production made by western stock ranches since the middle 1940’s may be had by analyses of the western states’ livestock marketings for the 15year periods before and following 1945. These data show that during the 15 years from 1930 to 1944 the semidesert ranches of the Intermountain Region were yielding an annual market offtake of between 15 and 20%. This is to say that for each 1,000 lbs., live weight, of stock cattle maintained in herds through the year, the annual marketing of beef would be 150 to 200 lbs., live weight. The comparable figure for the prairie ranches of eastern Montana, Wyoming, Colorado and New Mexico was around 25% during this period; the comparable index for the ranches of the Rocky Mountain regions, the Sierra foothills, and the coastal moun- tains of California was around 30%.

A similar analysis of recent livestock marketing data for the western states shows a substantial gain in the market offtake for cattle ranches of all regions of the western states. The largest percentage gain in market offtake has been made by the semidesert ranches of the Inter- mountain Region. Their annual market offtake has now risen to around 25%. Probably the most important factor in this output gain by these ranches has been the change from open range usage to individual and group allotment usage and management of the Public Domain. The resulting security of tenure for the users of these lands has made possible the development of water, fencing, and rangeland reseeding. The alloting of the lands by the land administration to individuals and to community groups of users has made possible a much-needed improved husbandry of the herds.

Unit productivity gains resulting from the several aspects of development and modernization of the ranching operations has also been significant for all other western regions and types of livestock ranches. The ranches of the Rocky Moun- tain regions now have a market offtake of around 35 to 40% and the prairie ranches now have an annual average market offtake of around 30%. These livestock unit production gains have been accomplished by improved operational and management procedures that result in higher calf crops, lower death losses, and more rapid rates of growth and gain in the young animals. Additionally, there have been

JOURNAL OF RANGE MANAGEMENT 26(l), January 1973

income gains due to higher carcass yields and better meat quality as a consequence of improved breeds and better health care.

In addition to the gains in the production output, some important gains have been made, especially in the past 20 years, in the operational cost efficiency of most western livestock ranches. This has come mainly as a result of the mechanization of haying and other crop production and harvesting, of the development and maintenance of range water and fencing, of range reseeding, and irrigation. These benefits have accrued in only a limited way to the small ranches, and as a result there has been considerable consolidation of such ranches.

Nearly all of these features of stock ranch modernization and development have required the application of considerably larger amounts of capital. For most ranches, this has had to await the availability of borrowed funds. As previously noted, most of such development has taken place since the end of the last World War.

Not much in long-term amortizable land credit was available to the western livestock ranches, especially those of the 11 western public land states, prior to 1945. The land lending agencies were inclined to view the western stock ranches as having too much in climatic uncertainty and too little in assured land tenure for good lending risk. Too, there were those ranching operations that en- gaged in considerable buying and selling of livestock through the year, rather than operating a year-round and stable breeding herd operation.

Soon after 1945 this land credit situation began to change rather rapidly as some of the larger life insurance com- panies and the Federal Land Banks began to study the land credit possibilities in some of the more productive and stable western livestock ranching areas. Some of these institutions had gained ranch lending experience in the better Texas livestock ranching areas and in the Nebraska Sandhills prior to 1945. Soon after 1950 the Federal Land Banks, under new leadership from the Farm Credit Adminis- tration, modernized their ranch valuation concepts and loan formulas, and began to compete aggressively with other lending agencies for ranch loans on the basis of long-term and flexible amortization loan contracts.

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stock ranches, particularly those of the 11 western states.

Though this use of a much larger volume of land credit by the western ranches probably was not of itself a generator of inflationary pressures on ranch market prices, it came at a time of inflationary trends in U.S. and world general price levels; consequently it came at a time when large-scale borrowing for improvement and development was ad- vantageous from the standpoint of general price level trends. This was true not only because of the possibility of repaying the loans with cheaper dollars, but because of the tax advantages that could accrue to the larger-scale borrowers in this situation.

For example, during the middle- 1950’s, a leading lawyer-accountant-tax consultant of one of the western states told an assemblage of livestock asso- ciation members that currently and for the foreseeable future he saw no reason why stock ranches would have to pay anything much in income taxes. Thus, his recommendation was to borrow heavily for development, classify as much as possible of the development cost as a current annual cost, and anticipate that a continued rise in the U.S. general price level would carry beef cattle prices upward sufficiently to lighten the debt service considerably. Needless to say, this formula has paid rather well for many western ranch owners and buyers.

Because of these and other inflationary pressures, the prices of western livestock ranches have now gone far beyond those of the early development years of the 1950’s, when the prices of $300 to $500 per cow-unit in ranch realty were thought to be high, but probably sustainable. Now the changes of the past 10 years, and especially of the past 5, have generated a ranch price situation far above the values that could be soundly based upon the current and foreseeable earnings capability of the ranches. A few calculations on the level of incomes and operational costs now generally prevailing will illustrate this.

Those ranches with the highest market offtake, principally mountain valley and foothill ranches, now have an annual marketing of around 400 lbs., live weight, for each cow-unit maintained in the herds through the year. However, for the breeding herd ranch not all of this 400 lbs. will consist of prime young feeder animals. Some of the marketing will be females and aged sires culled from the herd. As a result, though the young animals may sell at live weight prices of $30 or more per

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cwt., the average price received for the 400 lbs. of market offtake will most probably be around $25 per cwt. The resulting gross revenue is, then, around $100 per cow-unit kept in the herds.

The recurrent annual operating costs for this type of ranch are now $50 to $60 per cow-unit, before interest. The con- sequent result is a net revenue of $40 to $50 per cow-unit. This is the amount available for the interest return upon the investment in land, livestock, and equip- ment, and for remuneration to the operator for his work and management. Assuming that the ranch has a land indebtedness of $400 per cow-unit of capacity, which appears to be a fairly typical figure, plus another $100 of indebtedness upon the livestock and equip- ment, the annual debt service becomes $30 per cow-unit at a 6% rate; and this is with no progress of debt repayment. Thus, we have a margin of $10 to $20 per cow-unit available for family living from the 300 cow-unit ranch. For such a ranch the probable annual amount for family living is, then, between $3,000 and $6,000, assuming no financial progress.

There are many ranches whose indebtedness will considerably exceed the averages estimated above. This is more likely to be the situation for the larger ranches. Of 20 recent ranch appraisals taken at random from my files, six have a ranch realty indebtedness within the range of $600 to $750 per cow-unit.

The factors that have generated the present western stock ranch price situation are too many and too complex for adequate treatment in an article, but a few additional comments will be offered.

The tax advantages that might be realized through the use of borrowed funds to increase the rate of ranch development have already been noted. Presumably such investment in development should be capitalized in the ac- counting procedures, but there is always the shadow zone between current and non-recurrent expenditures for ranching development. This type of tax saving was noticed early by non-ranching business operators, who saw the opportunity for what sometimes became a dual tax advan- tage through the acquisition of stock ranches.

I have observed instances of industrial corporations buying ranches under sale- leaseback arrangements, and, through considerable expenditures on the development of the ranches, effect industrial- business tax advantages which resulted in the ownership of well-developed ranches within a few years at little or no actual

cost to the corporate buyers. This was true even though the buyer contracted for the ranch at full market value at the time of purchase. Because of the sale- leaseback arrangement, the buyer did not have to undertake operation and management of the ranch during the contract purchase interim.

The availability of liberal if not exces- sive credit for ranch purchase and development has been another important factor in the present inflated livestock ranch price situation. During the 1950’s and the 1960’s, ranch lending agencies were competing actively among them- selves for western stock ranch loans, though this has lessened in recent years. Some of the large life insurance com- panies have been especially aggressive in seeking ranch loans and in many instances have made loans of such size that, had it not been for the continuous uptrend in the ranching property markets, many of the large loans would have been “in trouble .”

Another influence in the livestock ranch market price uptrend over the past 20 years has been the buying of ranches for recreational uses, both for the establishment of commercial recreational ranching units and for the establishment of recreational centers for industrial cor- poration employees. In the latter instance, the livestock enterprise may be continued much as before, and there may be an opportunity for tax savings in the determination of how much employee rest and recreational cost may be treated as part of the ranching enterprise operational cost.

In recent years there has been a growing interest in ranch acquisition by industrial and commercial integration types of buyers. Such buyers are the large-scale feedlot operators seeking continuous availability of uniform lots of animals. The feedlot finishing operations may in turn be owned by livestock slaughtering and processing industries. An illustration of this type of ranch buying is a large feedlot finishing operation that has acquired several mountain valley and foothill ranches for breeding herds, and has also acquired prairie ranches that are used for holding and growing-out the young animals from the breeding herd ranches.

In recent years there has been an increase in the buying interest of the land subdivider-developer-speculator. Such a buyer interest in ranch property is illus- trated by the following advertisement which appeared in the Santa Fe, New

Mexican:

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WANTED.. . RANCH LAND SUITABLE FOR SUBDIVISION. Need 10,000 acres or more of level or gentle rolling land within 50 miles of Santa Fe. Submit maps and details to: /corpora-

tion with west coast address].

Many such “developments” have been organized mainly for division and sale to other speculator-buyers with little or no developmental work other than land sur- veys and tract boundary markers.

The “whither bound” aspect of the present stock ranch price and value situa-

tion is something on which I choose not to guess. The answers lie to a considerable degree in a number of national economic forces, trends, and administrative actions, and there is no way to forecast these for any appreciable time period. They include such factors as continued regional shifts in population, the continued availability of large amounts of land credit, the continuation of a high level of economic activity and income, and the continued inflation of the general price level. Whatever the future trends may be,

Raintrap Performance

on the Fishlake National Forest

ALLEN R. DEDRICK

Highlight: Fifteen raintraps on the Fishlake National Forest in central Utah were

observed over an 1 l-year period in an effort to evaluate field operation, maintenance requirements, and serviceability of raintrap systems. The raintraps generally functioned properly during the first 7 to 8 years. Some problems occurred during the latter part of the period. Five problem types were classified: (1) material failure-oxidation, ozone attack, and tearing; (2) mechanical damage-vermin attack and puncture by plants and animals; (3)‘snow accumulation which prevented water storage; (4) insufficient main- tenance to catchment aprons, storage bags and ponds, watering troughs, and fences; and (5) improper design resulting from inaccurate estimate of or change in water re- quirements, poor site selection, and inadequate evaporation and precipitation data. Operational problems associated with the storage part of the raintrap system were more serious than those related to the catchment apron.

Extensive areas of rangeland in the western United States periodically pro- duce a substantial quantity of vegetative forage that cannot be utilized by livestock because drinking water is not available in the grazing area. In contrast, range in the vicinity of water may be destroyed by overuse and trampling.

Most of the precipitation in the drier rangeland areas comes as small storms. The soil is generally dry and absorbs all the rain without producing runoff. Pre- cipitation in many high mountain meadows comes mainly in the form of snow. The snowmelt water is generally lost early in the year and is not available

The author is agricultural engineer with the Southwest Branch, Soil and Water Conservation Research Division, Agricultural Research Serv- ice, U. S. Department of Agriculture, Logan, Utah.

This paper is a joint contribution from the Agr. Res. Serv., the Forest Service, U. S. Dep. Agr., and the Utah Agricultural Experiment Station. (Published as Utah Agricultural Exp. Sta. Journal Paper No. 1207.)

Manuscript received January 20, 1972.

for late season livestock consumption. Even in areas of scant precipitation, substantial amounts of water can be collected for storage and use if the ground surface is waterproofed. The installations for collection and storage of precipitation have been called raintraps (Lauritzen, 1963). Approximately 1,500 gallons of water can be collected for each inch of precipitation that falls on a 2,500-ft2 catchment. At some typical semiarid to arid locations this would amount to :

Gallons collected

Location annually

Reno, Nev. 10,900

Albuquerque, N. Mex. 14,000

Boise, Ida. 17,900

Denver, Colo. 21,800 Sacramento, Calif. 25,700

Considerable research has been dir- ected to evaluating materials suitable for waterproofing rainfall cat&n-rents and storage facilities. The materials include

the ranch manager of today faces a situation full of hazards. I hardly need add that the ranch owner and operator who must pay interest upon any substantial part of today’s ranch values has an uphill job in making an adequate family- living income from a ranching enterprise. What appears to have been happening is that in the ranch credit or budgeting for the annual funds, the possible future capital value growth of the ranch has been anticipated in the provisions made in the annual funds for family living.

several plastic films, vulcanized elasto- meric sheet structures (butyl), asphalt- coated fabrics, and metal (Cluff, 1967; Frasier et al, 1970; Lauritzen, 1960, 1963; Lauritzen and Thayer, 1966; Lauritzen, 1967, 1967; Myers, 1968; Rauzi and Landers, 1967). Soil treat- ments to provide a relatively watertight nonabsorbent surface have also been tested (Cluff and Dutt, 1966; Frasier and Myers, 1970; Hillel, 1967; Hillel et al,

1969; Myers, 1967, 1968; Myers and Frasier, 1969; Myers et al, 1967; Rauzi et al, 1970).

In addition to information on the durability of various waterproofing materials, information is needed on the field operation, maintenance requirements, and serviceability of raintrap systems. The information on practical use of raintraps reported in this paper resulted from the field operation of 15 prototype catchment liners, generally about 2,500 ft2, and storage structures, mostly 25,000-gal capacity, located on the Fishlake National Forest in central Utah. These installations were observed to determine material weathering charac- teristics, damage from animals and insects, types of mechanical damage, and the need for soil sterilization to prevent penetration by plants.

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WANTED . . . RANCH LAND SUITABLE FOR SUBDIVISION. Need 10,000 acres or more of level or gentle rolling land within 50 miles of Santa Fe. Submit maps and details to: [corpora- tion with west coast address].

Many such “developments” have been organized mainly for division and sale to other speculator-buyers with little or no developmental work other than land sur- veys and tract boundary markers.

The “whither bound” aspect of the present stock ranch price and value situa-

tion is something on which I choose not to guess. The answers lie to a considerable degree in a number of national economic forces, trends, and administrative actions, and there is no way to forecast these for any appreciable time period. They include such factors as continued regional shifts in population, the continued availability of large amounts of land credit, the continuation of a high level of economic activity and income, and the continued inflation of the general price level. Whatever the future trends may be,

Raintrap Performance

on the Fishlake National Forest

ALLEN R. DEDRICK

Highlight: Fifteen raintraps on the Fishlake National Forest in central Utah were observed over an 1 l-year period in an effort to evaluate field operation, maintenance requirements, and serviceability of raintrap systems. The raintraps generally functioned properly during the first 7 to 8 years. Some problems occurred during the latter part of the period. Five problem types were classified: (1) material failure-oxidation, ozone attack, and tearing; (2) mechanical damage-vermin attack and puncture by plants and animals; (3)‘snow accumulation which prevented water storage; (4) insufficient main- tenance to catchment aprons, storage bags and ponds, watering troughs, and fences; and (5) improper design resulting from inaccurate estimate of or change in water re-

quirements, poor site selection, and inadequate evaporation and precipitation data. Operational problems associated with the storage part of the raintrap system were more serious than those related to the catchment apron.

Extensive areas of rangeland in the western United States periodically pro- duce a substantial quantity of vegetative forage that cannot be utilized by livestock because drinking water is not available in the grazing area. In contrast, range in the vicinity of water may be destroyed by overuse and trampling.

Most of the precipitation in the drier rangeland areas comes as small storms. The soil is generally dry and absorbs all the rain without producing runoff. Pre- cipitation in many high mountain meadows comes mainly in the form of snow. The snowmelt water is generally lost early in the year and is not available

The author is agricultural engineer with the Southwest Branch, Soil and Water Conservation Research Division, Agricultural Research Serv- ice, U. S. Department of Agriculture, Logan, Utah.

This paper is a joint contribution from the Agr. Res. Serv., the Forest Service, U. S. Dep. Agr., and the Utah Agricultural Experiment Station. (Published as Utah Agricultural Exp. Sta. Journal Paper No. 1207.)

Manuscript received January 20, 1972.

for late season livestock consumption. Even in areas of scant precipitation, substantial amounts of water can be collected for storage and use if the ground surface is waterproofed. The installations for collection and storage of precipitation have been called raintraps (Lauritzen, 1963). Approximately 1,500 gallons of water can be collected for each inch of precipitation that falls on a 2,500-ft2 catchment. At some typical semiarid to arid locations this would amount to :

Gallons collected

Location annually

Reno, Nev. 10,900

Albuquerque, N. Mex. 14,000

Boise, Ida. 17,900

Denver, Colo. 21,800 Sacramento, Calif. 25,700

Considerable research has been dir- ected to evaluating materials suitable for waterproofing rainfall catchments and storage facilities. The materials include

JOURNAL OF RANGE MANAGEMENT 26(l), January 1973

the ranch manager of today faces a situation full of hazards. I hardly need add that the ranch owner and operator who must pay interest upon any substantial part of today’s ranch values has an uphill job in making an adequate family- living income from a ranching enterprise. What appears to have been happening is that in the ranch credit or budgeting for the annual funds, the possible future capital value growth of the ranch has been anticipated in the provisions made in the annual funds for family living.

several plastic films, vulcanized elasto- meric sheet structures (butyl), asphalt- coated fabrics, and metal (Cluff, 1967; Frasier et al, 1970; Lauritzen, 1960, 1963; Lauritzen and Thayer, 1966; Lauritzen, 1967, 1967; Myers, 1968; Rauzi and Landers, 1967). Soil treat- ments to provide a relatively watertight nonabsorbent surface have also been tested (Cluff and Dutt, 1966; Frasier and Myers, 1970; Hillel, 1967; Hillel et al,

1969; Myers, 1967, 1968; Myers and Frasier, 1969; Myers et al, 1967; Rauzi et al, 1970).

In addition to information on the du r a b ility of various waterproofing materials, information is needed on the field operation, maintenance requirements, and serviceability of raintrap systems. The information on practical use of raintraps reported in this paper resulted from the field operation of 15 prototype catchment liners, generally about 2,500 ft2, and storage structures, mostly 25,000-gal capacity, located on the Fishlake National Forest in central Utah. These installations were observed to determine material weathering charac- teristics, damage from animals and insects, types of mechanical damage, and the need for soil sterilization to prevent penetration by plants.

The overall precipitation collection project has been a cooperative effort by the Agricultural Research Service and the Forest Service of the U. S. Department of

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Agriculture, the Utah Agricultural Experi- ment Station, and private industries in- v olved in development of raintrap materials.

Observations

Table 1 identifies the raintraps in the study along with the approximate elevation, date of installation, and materials used in the catchment and water storage structure. Two types of storage structures were used for water storage: closed bags and open pits lined with waterproof materials (Fig. 1). Periodic inspections of the raintraps were made during the 1960’s. Detailed inspections were con- ducted in June 1970 and June 1971 by both Agricultural Research Service and Forest Service personnel. During each inspection, information was obtained on the condition of the apron and the storage system. Recommendations were made on the rehabilitation procedures required. Inspection summaries were completed on all raintraps noted in Table 1 and were published elsewhere (Dedrick, 1973). A typical summary of information from one raintrap installation (Coyote) follows:

1963 - A butyl ground cover catchment was installed with a nylon- reinforced butyl one-piece storage bag.

1964, 1965, and 1966 - The raintrap was functioning as intended.

1968 - A few holes were noted around the edge of the apron with a few large holes in the storage bag. The damage apparently was caused by rodents. The holes in the storage bag were repaired.

1969 - One small hole was noted in the center part of the apron with numer- ous holes along berm. Damage apparently was caused by rodents. The condition of the storage bag was reportedly good, without any holes.

1970 - The condition of the apron was generally good, with some holes observed. The holes appear to be caused by gnawing or clawing, as teeth or claw marks were visible around holes (Fig. 2). The catchment sheeting had oxidized extensively. No ozone failure was observed. The storage bag was generally in good condition, with a few holes observed around the edge (Fig. 2).

1971 - The apron was in good condition with several small holes, some oxidation, and some ozone damage noted. The storage bag was in excellent condition and full of water. The storage had been patched prior to the 197 1 water collection.

Recommendations for Coyote raintrap installation: The raintrap can be main- Table 1. Raintraps in operation on Fishlake National Forest, Utah.

Approximate Date Materials

Rain trap elevation (ft) installed Apron1 Storage2

Sheep Valley 11,000 1960 Butyl Butyl-nylon

1,600 gal

Vinyl-coated nylon, open at top with protective cover (shade)-3,500 gal Butyl-nylon Vinyl-butyl (two piece)

Vinyl-coated nylon, open at top with protective cover (shade)-3,500 gal Butyl-nylon do do do do do do Bu tyl-nylon (two piece) Bu tyl-nylon Chlorinated PE, open storage- 60,000 gal Chlorinated PE, open storage-

Lost Creek 7,200

Glenwood Mountain (Lone Pine)

Mytoge 9,800 1963 do

Wide Mouth (south) Wide Mouth (north) Coy0 te

Birch Creek Wide Canyon (south) Wide Canyon (north) Big Flat

Jolly Mill Storage City Creek South Water Hollow

Steve’s Wash 7,000 1969 Chlorinated PE

8,200 7,200 7,200 7,200 8,000 6,000 6,000 10,200 8,200 6,800 8,200 1961 1966 1962 1966 1963 1963 1963 1963 1963 1963 1964 1964 1965 1965 1965

Asphalt jute

Nylon-reinforced butyl, formerly closed Butyl do do do do do do do Steel Butyl

Chlorinated PE

capacity,

tained for continuous operation. When the water is drawn down in the storage facility, any holes in the bag should be patched to insure proper storage of collected water.

Discussion and Summary

The experimental raintraps used on the Fishlake National Forest required a minimum of maintenance to keep them operational during the first 7-8 years (1960-1967). The Forest Service personnel and individual permittees reported that availability of water resulted in better range utilization during this period. Various types of system malfunctions, however, began to be reported in 1968 and 1969.

The thorough inspection of the raintraps in 1970 and 197 1 helped identify some of the problems associated with field use. The raintrap system problems can be classified into five types: material failure, mechanical damage, system malfunction, maintenance deficiencies, and improper design. Material failure includes oxidation (radiation); ozone attack; and tearing of nonsupported membranes (Fig. 3). Mechanical damage resulted from vermin attack (Figs. 2 and 4); puncture by plants (Fig. 5); and puncture by hooves (Fig. 6). Snow accumulation on storage bags sometimes prevented water storage (Fig. 7). Problems arose from a lack of maintenance of catchment aprons, storage bags and ponds, watering troughs, and fences around raintrap systems. Im- proper design was the result of inaccurate estimation of or a change in water requirements, undesirable site selection, and lack of reliable precipitation and evaporation data. The type of operational problems, seriousness of problems, and means of control are summarized in Table 2.

Malfunctions associated with the storage part of the raintrap were far more serious than those affecting the apron. Generally, holes below the required waterlevel line cannot be tolerated to any degree in the storage system. The trapped water may have to be held for a considerable period of time before being utilized, and holes in the storage facility result in a direct water loss. Measures for controlling evaporation from open pits should be considered, if evaporation losses for the particular location are exces- sive .

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Material failure Oxidation (Radiation)

Butyl and ashphalt-jute

Ozone attack Butyl Rarely observed.

Tearing (Fig. 3)

Butyl and plastic

Mechanical damage Vermin attack (Figs. 2 and 4)

Butyl and plastic

Puncture by plants (Fig. 5)

Plastic and asphalt-jute

Puncture by hooves (Fig. 6)

Malfunction

Snow accumulation (Fig. 7)

Maintenance

Butyl and plastic

Flexible storage systems All raintrap systems

Improper design All rain trap systems

Not serious on butyl. Oxidation results in “bleedoff” from an asphalt surface causing discoloration. There is no evidence that the water is harmful.

Moderate damage caused by tearing. The materials are susceptible but generally tough enough to function satisfactorily, if not attacked by birds, rodents, insects, and the sharp hooves of cattle and game animals.

In several instances, such attack had caused failure of the storage part of raintrap system. Many species of vermin may be involved (possibly packrats, rockchucks, birds, porcupines, bees, among others). The reasons for attack may include: material taste, material used for nesting purposes, chewing or gnawing impulse, need for water, attraction of black surface for warmth, weather conditions, population change. Has not been too serious from the percent- of-catch standpoint, since most of the failure occurred around the apron berms. The incidence of puncture during the period was very low.

Serious when closed storage of high snow accumulation.

located in areas

Resulted in nonfunctional in some instances.

raintrap systems

Resulted in nonuse of some raintrap systems due to underdesign.

Proper formulation of butyl will minimize oxidation. The surface of asphaltic membranes can be stabilized by various coating materials.

Proper installation to prevent material stressing will control ozone attack. Fabric-reinforced material which assures that the sheeting is not stretched can be used.

Fabric-reinforced material will eliminate tear propa- gation. Fencing is required to keep livestock and game animals off trap area.

Control may consist of one or more of the following: repellent utilization, open storage to allow access to water, physical barriers, plant growth control around the edge of the system.

Soil sterilant.

Fencing is required to animals off trap area.

Open storage.

keep livestock and game

Better cooperation solicited with such cooperation specified as part of the agreement for use of the land. Further explanation as to operation and function of the systems might be helpful.

More reliable information regarding water requirements, site conditions, precipitation, and evaporation l’s required.

given to developing a highly durable storage system. Generally, all of the materials used as aprons performed satisfactorily.

Literature Cited

CIuff, C. Brent. 1967. Water harvesting plan for livestock or home. Prog. Agr. in Arizona XIX (3):6-8.

Quff, C. Brent, and Gordon R. Dutt. 1966.

Using salt to increase irrigation water. Prog. Agr. 28: 12-13.

Dedrick, A. R. 1973. Operation, serviceability, and material evaluation of raintraps on the Fishlake National Forest - 1960-1971. Res. Rep., Utah State Agr. Exp. Sta. Utah State Univ.

Frasier, Gary W., and Lloyd E. Myers. 1970.

Protective spray coatings for water harvesting catchments. Trans. Amer. Sot. Agr. Engrs. 13:292-294.

Frasier, Gary W., Lloyd E. Myers, John R. Griggs. 1970. Installation of asphalt-fiber

glass linings for reservoirs and catchments. Water Conserv. Lab. Rep. 8. 9 p.

Hillel, D. 1967. Runoff inducement in arid lands. Final Tech. Rep. submitted to U. S. Dep. Agr., Proj. No. AlO-SWC-36, The Volcani Inst. of Agr. Res. and the Hebrew Univ. of Jerusalem, Rehovat, Israel. 142 p.

Hillel, D., A. Schwartz, R. Steinhardt, and E. Rawitz. 1969. Laboratory tests of sprayable materials for runoff inducement on a loessial soil. Israel J. Agr. Res. 19:3-g. Lauritzen, C. W. 1960. Ground covers for

collecting precipitation. Farm & Home Sci. 21:66-67,87.

Lauritzen, C. W. 1963. Rain traps. Fourth Nat’l. Agr. Plastics Conf. Proc., P. 150-171. New York, N.Y.

Lauritzen, C. W. 1967, Butyl -for the coIlec- tion, storage, and conveyance of water. Utah Agr. Exp. Sta. Bull. 465,41 p. Lauritzen, C. W. 1967. Rain traps of steel. Utah

Sci. 28:79-81.

Lauritzen, C. W., and A. A. Thayer, 1966. Rain traps for intercepting and storing water for livestock. U. S. Dep. Agr., Agr. Res. Serv.

Inf. Bull. 307,lO p.

Myers, Lloyd E. 1967. Recent advances in water harvesting. J. of Soil & Water Conserv. 22:95-97.

Myers, L. E. 1968. Saving water with asphalt. Div. of Petroleum Chem., Inc.-Amer. Chem. sot. 13:c17o-C173.

Myers, Lloyd E., and Gary W. Frasier. 1969.

Creating Hydrophobic soil for water harvesting. J. Irrigation and Drainage Div., Proc. Amer. Sot. Civ. Engrs. (IRI) 95:43-54.

Myers, Lloyd E., Gary W. Frasier, and John R. Gr@s. 1967. Sprayed asphalt pavements for water harvesting. J. Irrigation and Drainage Div., Proc. Amer. Sot. Civ. Engrs. (IR3) 93:79-97.

Rauzi, Frank, Merle L. Fairbourn, Howard Haas, and Rome H. Mickelson. 1970.

Durability of asphaltic soil sealants in Northeastern Colorado and South Central North Dakota. U. S. Dep. Agr., Agr. Res. Serv. 41-169.8 p.

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Carbohydrate Reserves of Grasses:

A Review

LARRY M. WHITE

Highlight: Carbohydrate reserves are nonstructural carbohydrates. Sucrose and fruc- tosan are the predominant reserve constituents of temperate-origin grasses; sucrose and starch, of tropical-origin grasses. Nitrogenous compounds are used in respiration, but probably are not alternately stored and utilized as are carbohydrate reserves.

Most carbohydrate reserves are stored in the lower regions of the stems-stem bases, stolons, corms, and rhizomes. Nonstructural carbohydrates in the roots of grasses are probably not used directly in herbage regrowth following herbage removal.

Plant development stage, temperature, water stress, and nitrogen fertilization can drastically change the reserve level. The seasonal variation of carbohydrate reserves is often different for the same species when grown in different environments.

The level of carbohydrate reserves in the lower regions of the stems apparently affects the regrowth rate for the first 2 to 7 days following herbage removal. Following the initial period, plant regrowth rate depends on other factors, such as leaf area and nutrient uptake. This initial effect from the level of carbohydrate reserves can be main- tained during subsequent exponential growth.

Grazing may be more detrimental than clipping if it removes herbage from some plants and not others. The ungrazed plants may take the available nutrients and water away from the grazed plants. However, grazing may be less detrimental than clipping if grazing leaves ungrazed tillers on a plant while removing others, thus allowing for the transfer of carbohydrates.

Carbohydrate reserves are thought to be used by plants as substrate for growth and respiration. Adequate carbohydrate reserves are important in perennial plants for winter survival, early spring growth initiation, and regrowth initiation after herbage removal, when the photosynthetic production is inadequate to meet these demands. Many pasture and range management practices are based upon knowledge of how various environ- mental factors and herbage removal treat- ments affect carbohydrate reserves. This understanding helps managers to maintain high yields of desirable species and to control undesirable species.

May and Davidson (1958) and May (1960) questioned the importance of carbohydrate reserves in controlling herbage regrowth rate because only in- direct evidence supported the role of reserves. However, research has shown recently that, under certain conditions, the herbage regrowth rate depends on the level of carbohydrate reserves. The following is a brief review of the functions

The author is a range scientist, Agricultural Research Service, U. S. Department of Agricul- ture, Sidney, Montana.

This paper is a joint contribution from the Northern Plains Branch, Soil and Water Con- servation Research Division, Agr. Res. Serv., U. S. Dep. Agr., in cooperation with the Mon- tana Experiment Station (Journal Series No. 324).

of carbohydrate reserves in grasses with emphasis on recent findings. Earlier findings were summarized in the following reviews : Graber et al. (1927), Graber (193 l), Weinmann (1948, 1961), Troughton (1957), May (1960), Priestley (1962), Jameson (1963), Cook (1966), and McIlroy (1967).

Reserve Constituents

Graber et al. (1927) first defined reserve energy constituents as “. . . those carbohydrates and nitrogen compounds elaborated, stored, and utilized by the plant itself as food for maintenance and for the development of future top and r o ot growth.” These carbohydrates, termed total available carbohydrates, are those available as energy to the plant (Weinmann, 1947). Smith (1969) suggested that the term total nonstructural carbohydrates (TNC) be used, because it is more applicable to both animal and plant investigations.

Nonstructural carbohydrates-reducing sugars (glucose and fructose), nonreducing sugar (sucrose), fructosans, and starches- are the major reserve constituents. Struc- tural carbohydrates-hemicellulose (pen- tosans and hexosans) and cellulose-are not considered to provide significant reserves (McCarty, 1938; Sullivan and Sprague, 1943; Weinmann, 1948). Type, distribution in the plant, and relative pro-

portions of individual carbohydrate reserve components vary among and within grass species and under various climatic conditions during the growth season. Pre- dominant carbohydrate reserves stored by temperate-origin grasses are sucrose and fructosans, whereas those of subtropical- or tropical-origin grasses are sucrose and starch (Cugnac, 193 1; Weinmann and Reinhold, 1946; Smith, 1968; and Ojima and Isawa, 1968). The Hordeae, Aveneae,

and Festuceae grass tribes store fructosan as short- or long-chain units. Genera of the Hordeae and Aveneae tribes store predominantly short- and long-chained fructosans, respectively, while some genera of Festuceae tribe characteris- tically store long-chained fructosans and others store short-chained fructosans (Smith, 1968).

Although Graber et al. (1927) origi- nally defined reserve constituents as including nitrogenous compounds, most investigators have only considered carbohydrates. Recent studies indicate that proteins may be involved. Davidson and Milthorpe (1966b) concluded that nonstructural carbohydrates formed only a part of the labile pool which provided substrates for respiration and new growth of orchardgrass (Dactylis glomerata) in a growth chamber during the first 2 to 4 days following severe herbage removal. They suggested that other labile substances, presumably proteins, must have remobilized because the amount of nonstructural carbohydrates was inadequate to account for the respiration and new growth of roots and shoots. Dilz (1966) in studying perennial ryegrass (Lolium

perenne) concluded that proteinaceous

material should be regarded as reserve constituents.

Most investigators generally have found that proteins are used in respiration but there is not a net utilization (Hackett, 1959). Proteinaceous sources accounted for 27% of the CO2 released by respiration in phloem explants from the storage root of a carrot (Daucus

carota var. sativa) (Steward et al., 1958;

Bidwell et al., 1964). Breakdown products from protein turnover contributed to the storage pool of amino acids and supplied carbon products for direct use in respiration, but carbohydrates were used preferentially over stored amino acids in synthesizing new proteins.

Studies show that even though nitrogenous compounds are used in respiration they still are not as important as carbohydrate reserves in supporting regrowth. Smith and Silva (1969) found that pro-

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portionally fewer nitrogenous compounds than TNC (1: 18) were translocated from the roots of alfalfa (Medicago sativa) for production of new top growth after cutting in greenhouse trials. Alberda (1966) pretreated perennial ryegrass for a short period to change the plant’s level of reserves. Plants with low TNC were obtained by placing them in a nutrient solution in the dark at 30 C, and plants with high TNC were obtained by placing them in water at 15 C in continuous light. The pretreatment changed the amount of nonstructural carbohydrates, but did not change the amount of organic nitrogenous compounds.

In summary, reserve constituents are those nonstructural carbohydrates which include reducing sugars, nonreducing sugars, fructosan, and starch. The predominant reserve constituents of temperate-origin grasses are sucrose and fructosan; of tropical-origin grasses, sucrose and starch. Nitrogenous compounds are used in respiration, but are not alternately stored and utilized as are carbohydrate reserves.

Storage Organs of Perennial Grasses

Nonstructural carbohydrates may be stored temporarily in all plant parts. Many scientists in the past concluded that underground organs were the major storage region for carbohydrate reserves (Weinmann, 1948; Troughton, 1957).

Many

other studies, however, have shown that the major storage region is generally in the stem bases (which includes stolons, corms, and rhizomes), not in the roots per se (Sampson and McCarty, 1930; Smelov and Morazov, 1939; Sullivan and Sprague, 1943; Baker and Garwood, 1961).

The decrease of carbohydrate reserves in the roots of orchardgrass, grown in growth chambers, after severe herbage removal only accounted for less than one-tenth of root respiration (Davidson and Milthorpe, 1966b). They concluded that transfer of carbohydrate reserves from the shoots, remobilization of other substances in the roots, or both, must have occurred to account for root respiration. Marshall and Sagar (1965), using autoradiographs and labeled CO,, found that nonstructural carbohydrates in the roots of Italian ryegrass (Lolium multi- florum) were not mobilized to the shoots to support regrowth following herbage removal, nor were labeled compounds translocated to the roots from the shoots when a part of the herbage was removed from all tillers. They concluded: “The classical view of a transference of com-

14

pounds from the root to shoot following defoliation (Troughton, 1957) . . . seems unlikely . . . in perennial grasses without special storage organs.”

In summary, the major storage areas of carbohydrate reserves are usually the lower regions of the stems-stem bases. stolons, corms, and rhizomes. These reserves are used as an energy source to initiate new growth until photosynthesis is sufficient to sustain plant respiration. Nonstructural carbohydrates in the roots of grasses are probably not used directly in herbage regrowth following herbage removal. However, more research using labeled carbon is needed to determine if nonstructural carbohydrates in the roots are translocated aboveground for respiration or as structural components of regrowth following herbage removal.

Variation of Carbohydrate Reserves

Diurnal and Seasonal

The accumulation of carbohydrate reserves in plant tissue is a dynamic system of energy balance. The level of carbohydrate reserves (hexoses and sucrose) of four grasses at Ayr, Scotland, showed marked diurnal variation (Waite and Boyd, 19.53). In Indiana, bromegrass

(Bromus inermis) utilized almost one- third of the TNC in the herbage during the night, but diurnal fluctuations for other grass species were less (Holt and Hilst , 1969). For the grass species studied, TNC concentration in the herbage was lowest at 6 A.M. and increased linearly to a high at 6 P.M.

The seasonal variation of carbohydrate reserves differs among grass species. In many grass species, the reserve level is lowest when the second or third leaf emerges (about one month after the start of plant growth), but in other species, the reserve level is lowest after seed ripening (Jameson, 1963). Carbohydrate reserves of Colorado wildrye (Elymus ambiguus)

and mountain muhly (Muhlenbergia montuna) in Colorado decreased during fast growth and increased during slow growth (McCarty, 1935). However, temperature and the availability of water and nutrients also affect the seasonal variation of carbohydrate reserves.

The accumulation of carbohydrate reserves in plant tissue depends upon the balance between photosynthesis and respiration. The carbohydrate reserves of orchardgrass and bermudagrass (Cynou’on

dactylon) grown in growth chambers decreased when growth and respiration demands were greater than photosynthetic rate and increased when growth

and respiration demands were less than photosynthetic rate (Blaser et al., 1966). The level of reserves is determined by growth rate, plant development stage (Hyder and Sneva, 1959), and environment (Troughton, 1957).

Temperature

The effect of temperature on the percentage of carbohydrate reserves in the stem bases is influenced by the origin of grass species. Optimum temperatures for growth and net photosynthesis by temperate-origin grasses are about 20 to 25 C, whereas those for tropical-origin grasses are about 30 to 35 C (Evans et al., 1964; Treharne and Cooper, 1969). This difference in temperature optima for growth of two temperate species [oat

(Avena sutiva) and perennial ryegrass] and two tropical species [maize (Zea

mays) and buffelgrass (Cenchrus ciliaris)]

resulted from differences in temperature optima of the major CO*-fixing enzymes (Treharne and Cooper, 1969). The activity of ribulose-1,5-diphosphate carboxylase is higher in temperate-origin grasses while the activity of phospho- enolpyruvate carboxylase is higher in tropical-origin grasses. Temperate-origin grasses contain only the Calvin (C,) photosynthetic pathway, while tropical- origin grasses contain both the C, (Hatch and Slack) and C, photosynthetic path- ways. In tropical-origin grasses, the C, pathway is located in chloroplasts of mesophyll tissue, whereas the C, pathway is located in chloroplasts of bundle sheath tissue (Berry et al., 1970; Kort- schak and Nickell, 1970).

Temperature markedly affects the seasonal variation of carbohydrate reserves. Seasonal variation of total fructose in stem bases of orchardgrass (Fig. 1) was different when grown in Massachusetts, USA, than in Hokkaido, Japan (Colby et al., 1966). The total fructose level of orchardgrass grown in Hokkaido increased following heading, whereas in Massachusetts, it decreased. High June temperatures in Massachusetts apparently caused the decrease following heading. Smith and Jewiss (1966) showed that high day and night temperatures decreased the percentage of water-soluble carbohydrates in the stem bases of timothy throughout a growing season. Smith (1970) showed that changing timothy plants at inflorescence emer- gence from a cool to a warm regime decreased water-soluble carbohydrate content in the stem bases at early anthe- sis.

The effect of high day temperatures is

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Heading Flowering Mature Seed

TIME OF SAMPLING

Fig. 1. Percentage of total fructose in stem bases of orchardgrass plants grown in Massachusetts, I

GSA, and Hokkaido, Japan (Colby et al., 1966) different from that of high night temperatures. High night temperatures in a growth chamber decreased reserves of temperate-origin grasses, such as timothy

(Phleum pratense), bromegrass, orchard-

grass, and Kentucky bluegrass (Poa

pratensis), more than high day tempera-

tures (Baker and Jung, 1968). Increasing the day temperature, if below optimum, increases both respiration and net photosynthesis; whereas increasing the night temperature increases only the respiration rate and, thereby, decreases the reserve level. The level of carbohydrate reserves during the season may be more charac- teristic of climatic factors than of individual species.

(1968), carbohydrate reserves would then increase. Brown and Blaser (1970) suggested that the buildup of carbohydrate reserves and inorganic nitrogen in plants under water stress results from the trans- formation of carbon-containing nitrogenous substances.

Water

Eaton and Ergle (1948) in a review article noted that the effect of water stress on carbohydrate reserves varies. Some scientists have reported that drought increased the carbohydrate reserves in several grass species (Julander, 1945 ; Brown and Blaser, 1965 ; Blaser et al., 1966); others have reported that drought decreased carbohydrate reserves (Bukey and Weaver, 1939; Brown, 1943).

The effects of nitrogen (N) fertilization on carbohydrate reserves are complex and variable. Weinmann (1948) in a review article noted cases where N fertilization caused no effect, increased, or decreased carbohydrate reserves. Gen- erally, N applied at low to moderate rates increases carbohydrate reserves. Nitrogen applied at high rates decreases carbohydrate reserves (Adegbola and McKell, 1966). The physiological reasons why N variably affects carbohydrate reserves are not well understood.

The degree of water stress and the plant growth stage during which it occurs will variably affect carbohydrate reserve levels. Orchardgrass under increasing water stress in a growth chamber showed a decrease in both net photosynthetic and respiration rates (Murata and Iyama, 1963). The photosynthetic rate, however, decreased much more rapidly than respiration, thus lowering carbohydrate reserves. If water stress stops stem elonga- tion and has only minor effects on photosynthesis, as reported by Wardlaw

If N is deficient, application of moderate amounts of N can increase plant growth when carbohydrates, water, and other nutrients are available and environ- mental conditions are favorable. In- creased plant growth from N application was associated with increased leaf area, chloroplast protein, and chlorophyll content which increased photosynthesis (Murata, 1969). The increased photosynthetic activity can then, theoretically, increase carbohydrate reserves.

Excess N tends to decrease carbohydrate reserves when other nutrients and environment do not limit plant growth. In this case, N fertilization stimulates the synthesis of amino acids and amide compounds to the detriment of carbohydrate reserves (Prianishnikov, 195 1). Carbo- hydrate reserves are used as the carbon-

JOURNAL OF RANGE MANAGEMENT 26(l) January 1973

Nitrogen

skeleton for protein synthesis (Pria- nishnikov, 195 1).

Application of high rates of N fer- tilizer (200 to 400 kg N/ha) in conjunc- tion with frequent clipping, low soil water, and high temperatures reduced stands and carbohydrate reserves of orchardgrass in Massachusetts (Drake et al., 1963; Colby et al., 1965) and tall fescue (Festuca arundinacea) in Virginia (Hallock et al., 1965). Applications of high rates of N also reduced stands of orchardgrass and tall fescue in Maryland (Alexander and McCloud, 1962).

Scientists also reported that application of 50 to 200 kg N/ha reduced severely the grass stand, especially when associated with drought or frequent herbage removal on native range in Colorado (Klipple and Retzer, 1959) on crested wheatgrass (Agropyron desertorum) in Wyoming (Seamands and Lang, 1960) and North Dakota (Rogler and Lorenz, 1969), and on intermediate wheatgrass

(Apropyron intermedium) in Saskatche-

wan (Lawrence, 1963). These scientists assumed that carbohydrate reserves were reduced. Frequent clipping, with or without N fertilization, decreased the percentage basal ground cover of non- irrigated green needlegrass (Stipa viridula) in Saskatchewan (Heinrichs and Clark,

1961). In contrast, N fertilization (0 to 375 kg N/ha) did not increase the winter- kill of intermediate wheatgrass under irrigation in Saskatchewan, although frequent and close clipping did (Lawrence and Ashford, 1969).

High rates of N should not be applied under the combined conditions of drought and high temperatures. Under these conditions, clipping or grazing could deplete carbohydrate reserves below a critical level, and cause stand reduction and poor growth recovery.

In summary, the interaction of the plant with the environment and the balance between photosynthesis and respiration determine the variation of carbohydrate reserves during the growing season. In some grass species, a low reserve occurs when the second or third leaf emerges; in other grasses, it may occur just before or after seed ripening. The seasonal variation of carbohydrate reserves can differ for the same species grown in different environments. Above- optimum temperatures, especially during the night, decrease carbohydrate reserves; whereas water stress can either increase or decrease reserves depending on the degree of stress and stage of plant growth.

Studies to date generally show that N applied at low to moderate rates increases