TEXASEjZXGHICULTURAL EXPERIMENT STATION R. D. LEWIS, Director, College Station, Texas m7/7 GRAZING STUDIES ON THE AMARELLO cowseavmnom EXPERIMENT STATION j 1942-4»; __ _ v ‘m0 é Gm uwreo I-RTMEQT, OF A68!“ EULTUE-‘RE (The TEXAS AGRICULTUHAUQKND EMEMCJHBENICAL COLLEGE SYSTEM c5132 cmcnmsr. Chancélldr E THE COVER PICTURE Choice grade yearling steers are shown on . summer pasturage at the Amarillo Conser- vation Experiment Station. Fall-purchased steer calves which are well wintered, become grass fat by September, provided the pasturage is grazed according t0 conservation practices. This has been true even in dry years. These studies on the Amarillo Conserva- tion Experiment Station are carried on as a cooperative project between the Texas Agri- cultural Experiment Station and the Branch of Research, Soil Conservation Service, U. S. Department of Agriculture. M20-1249-5M-L180 Pre face This bulletin gives a summary of the grazing studies made on the Amarillo Conservation Experiment Station from 1943 through 194g. Investigations have been made of the grazing values of: (1) native blue grama-buflalograss pasturage; (2) seeded cool-season grasses, such as crested wheatgrass and western wheatgrass; and (3) temporary pasture crops, such as Sudan grass and winter wheat. Tables show the gains made from these various types of pasturage. Forage production and the chemical composition during dif- ferent seasons of the year for the important plants studied are also presented. YVith favorable rainfall, a well balanced, year-round, green grazing program lor this section of the Southern Great Plains may be had from a combination of the following pasturage; winter-xvinter wheat, crested wheatgrass and western wheatgrass; spring-crested wheatgrass, western wheatgrass, little barley and early weeds; summer—blue grama, buffalograss, Sudan grass and lake weeds; and fall-crested wheatgrass, western wheatgrass and winter wheat. CONTENTS Page Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 The Amarillo Station f . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7 Climate and Soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7 Other Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9 Summer Grazing Tests on Native Pastures . . . . . . . . . . . . . . . . . . . .. 9 Summer Grazing Tests on Seeded Pastures . . . . . . . . . . . . . . . . . . . .. 1.1 Summer Grazing Tests on Temporary Pastures . . . . . . . . . . . . . . . .. 14 Winter Grazing Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 14 Protein and Mineral Content of Forage . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 15 Forage Production of Native and Seeded Grasses . . . . . . . . . . . . . . . . . . .. 18 Forage Growth and Pasture Management . . . . . . . . . . . . . . . . . . . . . .. 19 Practical Application of the Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 19 LLETIN 717 DECEMBER 1949 ; GRAZING STUDIES ON THE AMARILLO CONSERVATION EXPERIMENT STATION v 1943-49 A CHARLES J. WHITFIELD, JOHN H. JONES and i JOHN P. BAKER* IVESTOCK gains on heavy soils in the High Plains area are X closely related to the kind and amount of feed available. One 50f the primary objectives of the grazing studies at the Amarillo Conservation Experiment Station has been the development 10f an all-year green pasturage system. Climate plays important .»jroles in the availability of green pasturages in the Southern [High Plains. p. Plants that can grow throughout the year are being used 59in both permanent and temporary pastures 0n the Amarillo gstation. Cool-season grasses such as crested wheatgrass, Western wheatgrass and Canada wild-rye, and small grains such as Ewheat, barley an.d rye provide fall, winter and spring grazing. A§Warm-season grasses such as blue grama, buffalograss, side- coats grama and Sudan are available in the late spring, summer .jand early fall. , The availability of this forage, however, is dependent on the p‘ amount and distribution of precipitation and on temperatures. sLack of moisture during the summer may limit the amount of p. forage produced (Table 1). Similarly, temperature and moisture . *Respectively, project supervisor, Amarillo Conservation Experiment Sta- ‘ption, Amarillo, Texas; professor of animal husbandry, College Station, 5 Texas, and formerly assistant animal husbandman, Amarillo Conserva- 3 tion Experiment Station. 1. Monthly rainfall, 1939-48, at the Amarillo Conservation Experiment Station Month 1939 1940 l 1941 1942 1943 1944 1945 1946 1947 1948 Average E». y . . . . . . . . . . . . . .. 2.36 .15 .03 .11 '1‘ .76 .79 .55 .09 .15 .50 y . . . . . . . . . . . . .. .05 .49 .19 .14 . . . . .. .73 .16 .10 T 2.04 .39 . . . . . . . . . . . . . . .. .09 .09 1.81 .43 .05 T .31 .29 .33 .55 .40 1.87 .68 1.17 4.78 .61 1.80 .63 .37 1.22 .29 1.34 . . . . . . . . . . . . . . . .. 1.17 4.15 5.66 .20 2.90 3.02 .36 1.03 5.64 3.32 2.74 4.13 1.13 4.05 1.22 2.12 3.52 1.55 2.03 2.03 2.25 2.40 1.42 .24 3.06 .58 5.26 2.66 1.30 .30 .84 1.88 1.75 2.99 .82 3.26 3.53 1.33 3.58 2.70 1.57 1.94 5.09 2.68 fiber . . . . . . . . . . .. .11 .55 3.43 1.68 1.15 2.68 4.44 1.44 .26 1.18 1.69 ’ _ . . . . . . . . . . . . . .. 1.04 .31 9.14 4.35 .05 .69 .68 7.23 .12 .83 2.44» her . . . . . . . . . . . .. .06 3.44 .21 . . . . .. .18 1.22 T .68 .97 2.79 .96 ber . . . . . . . . . . . .. .79 .08 .55 1.48 3.41 1.03 .01 .29 .91 .01 86 Total . . . . . . . .. 16.08 12.13 32.56 18.50 17.06 21.69 12.93 15.88 14.35 20.38 18.15 BULLETIN 717, TEXAS AGRICULTURAL EXPERIMENT STATION A MARILLO EXP STA. USDA. ll I Native ; Reseeded L E G E N D §_FIELD A - wnEAT,soRcuuM,FALLoI§ " AND GRASS ROTATION PLOTS FIELD B - WHEAT AND soaonuu CULTURAL STUDIES FIELD c-1,2 - wnEAT BREEDING AND soacnum ADAPTATION _ FIELD c-3 - IRRIGATION sTuDIEs” FIELD D - WINDRREAKS AND RE- ' VEGETATION FIELD E - HEADQUARTERS AREA; _ BUILDINGS , ?.FIELD F-1 - IRRIGATION sTuDIEsf " FIELD F-2.3 - REvEcETATIoF PASTURE PLOTS FIELD 0. 1-6 - COVER CROPS ANDQ sTuEELE MULCH sTuDIEs, cLAss II LAND °°° ° °°° '°°° FIELD c, 7-14 - cLAss III, '°@L¢'"'l=* GRADED AND LEVEL TERRACE j FIELD I-2 - sEEDED GRASS MIXTURE sTuDIEs WITH WEEAT-soxcnulj FIELD I-3 - CAFETERIA GRASS PLOTS FALLow ROTATION; GRASSED I FIELD I-4 - sEEDED cREsTED WHEATGRASS WATERWAYS ; FIELD I-5 - sEEDED AREAS OF WESTERN WHEAT, FIELD H - NATIVE PASTURE, FLAT] CRESTED WHEAT, BLUE GRAMA, ETc. LAKE, CONTOUR FURRGWS, EEQI FIELD J-1 - COVER CROPS FOR GRASS SEEDING SEEDING 1 FIELD J-2-3 - wnEAT-DELAYED FALLOW-SUDAN FIELD I-1 - NATIVE BLUE cRAuA#{ BUFFALO PASTURE O - RAIN GAGE AND INSTRUMENT LOCATIONS Figure 1. Land uAse on the Amarillo Conservation Experiment Station at the end of the 1949 season. GRAZING STUDIES ON THE AMARILLO STATION 7 Flare important in the amount of growth made by the grasses "jland small grains in the colder months. In 1940 and 1941, cool- and warm-seaso-n grass pastures were seeded on the Amarillo station (Figure 1). Studies were initi- ated in the fall of 1942 to test their effectiveness for erosion If control and beef production and the use that could be made of Winter wheat and Sudan as supplemental pastures for graz- 1mg. In these investigations, two native and five seeded pastures, jflalong with wheat and Sudan, were used fro-m 1943 through ,;1949. They were grazed with Choice Hereford steer calves ' purchased in the fall from local ranchmen. Winter grazing tests were conducted from November "to yApril. In these tests, the principal studies were on wheat pas- ; turage and grass and cake. The summer grazing tests were f conducted from April to October, and were primarily compari- sons between 44-acre native and seeded pastures and Sudan. 5 The steers were weighed on the first of each month. Weights were obtained o-n two successive days at the start and close of Peach major test period, the average being used as the initial "and final weight, respectively. Weights were taken on the fif- g teenth of the month when a change had to be made in pasturage. Steers were sold when there was not enough grass in pros- Tpect to produce gain, or if continued grazing would be incon- ljsistent with conservation practices. Each year, however, at least j one group of 1O steers was provided with the best available f feed thro-ughout the summer in an attempt to produce grass- ,l_fattened yearling beef. THE AMARILLO STATION The station is in Potter and Randall counties, 14 miles west sof Amarillo, Texas, on U. S. Highway No. 66. This is the west- if central part of the Texas Panhandle. It is about the center of f the Southern Great Plains, which includes portions of Colorado, fQKansas, Oklahoma, New Mexico, and Texas. The Amarillo sta- tion is so situated with relation to the varied soils and climatic f conditions of the Southern Great Plains that results of its re- 5 search are applicable to a considerable portion of this territory. _ {The 1,637 acres comprising the station were purchased in 1936. Improvements were started in 1938 and the first experiments ;; were initiated in the fall of that year. _j Climate and Soils The station lies in the 15- to 20-inch rainfall belt, an area I: susceptible to both wind and water erosion. The annual pre- gicipitation averaged 18.15 inches for the 10-year period, 1939-48 ._ (Table 1). The elevation is 3,825 feet; the growing season is 9 about 200 days; the mean annual temperature is 57° F.; and g. in the spring, it is not unusual to have wind velocities of 30 to fl35 miles per hour at vegetation height. 8 BULLETIN 717, TEXAS AGRICULTURAL EXPERIMENT STATION‘ The predominant soil type in the station area is Pullman a} silty clay loam, a deep, fine-textured, slowly permeable soil, high < in fertility, moderately high in organic matter under native J conditions, a blocky clod structure, a slow rate of infiltration > and a topsoil that crusts upon drying after rains. Other charac- g teristics are: approximate thickness of surface soil 9 inches, sub- * soil ‘36 inches (the upper subsoil is about 26 inches); a high Y. moisture-holding capacity, high wilting-coefficient, moderately : susceptible to wind erosion, and slightly susceptible to water ; erosion; susceptible to forming plow-sole, and is slightly acid with a pH of 6.5 to 7.0. Other soils of importance are Lofton silty . clay loam, also a deep, fine-textured slowly permeable to very a slowly permeable soil, and Randall clay, the lakebed soil. The soil on the station is fairly typical of the deep, heavy soils P of the Southern High Plains. There are, in this region, about 11,750,000 acres of deep soils intermixed with shallow soils, deep moderately sandy soils and rough broken land, from the i; southern limits of Lubbock county, Texas, Curry and Quay ~ counties of Eastern New Mexico, and as far north as Ford ‘a county, Kansas. Other Conditions The surface of the High Plains is dotted with numerous en- closed flat-bottomed depressions, the low parts of which are occupied by intermittent lakes, or playas. One such area, 110 acres in size, is on the station. These depressions reach a maxi- mum size of several square miles. Most of them consist of three parts: (1) a central low flat occupied by an intermittent lakebed constituting from one-fourth to one-half of the total area of the depression; (2) a surrounding concentric poorly drained flat usually known as “second bottom”; and (3) an outer sur- t rounding slope from one-eighth to one-fourth mile wide with a gradient sufficiently steep to encourage some water erosion. Slopes vary on the Amarillo station from 0 to 3 percent. The land, with slopes from 0-1 percent, is suitable for cultiva- tion with moderate intensity of practices, which include stubble mulch tillage, seeding on the contour, successive deep to shal- low cultivation through each season and the use of a flexible cropping system. On the slopes of 1 to 3 percent, the land is suitable for cultivation with intensive practices. These are the same as those listed for the 0 to 1 percent slope, with ter- races for gully control, permanent guides for contouring and avoiding of fallow when there is insufficient residue. The cul- tivated land on the station is about equally divided between 0 to 1' and 1 to 3 percent slopes. About 70 percent of the Southern High Plains is cultivated; the remainder is in pasture and range land. The principal crops are wheat, sorghum, grass and cotton. No cotton is grown on the Amarillo station as it is north of the cotton belt. l * W.;.....wl i RESULTS and seeded pastures, (2) two methods of wintering steer calves, and (4) forage yields. f , Summer Grazing Tests on Niative Pastures Native pasturage on the Amarillo station, typical of High Plains vegetation, is represented by Field I-1, a 44-acre level upland site dominated by blue grama and buffalograss (Figure 2). Ten yearling steers on this pasture made an average gain of Figure 2. Steers grazing native blue grama-buffalograss, Pasture I-1. 239 pounds per head in 167 days. in 1943, 221 pounds in 213 days - in 1944 and 231 pounds in 163 days in 1945. The yearlings used each year had been Well-wintered as calves. They gained from 662 to 901 pounds in 1943, from 626 to 847 pounds in 1944 and from 641 to 872 pounds in 1945. The total gains Were similar for the 3 years (Table 2). The highest daily gains were in April and May, or just after the steers came off winter pastures and during the period of rapid spring growth. After 1945, limited grazing tests indicated simi- lar trends in beef gains. a Native lake pasture. The lake pasture H is a 311-acre field, 110 acres of which is an intermittent or “Wet weather lake,” . which is well protected in dry Weather by Weeds and rem- g nants of buffalograss and Western Wheatgrass. Of the remaining acreage, 140 acres is primarily native blue grama, buffalograss gand Western wheatgrass (Figure 3). Sixty-one acres of cul- GRAZING STUDIES ON THE AMARILLO STATION 9 Results are presented of (1) summer grazing tests o-n native (3) mineral and chemical composition of the principal forages Month Average 1943 1944 1945 1949 April. . . . . . . . . . . . . . . . . . . . . . . . .. 2. 13 1.60 1.97 . . . . . . . . .. 1190 May . . . . . . . . . . . . . . . . . . . . . . . . . . 1.48 2.27 1.97 2-2 1.98 June . . . . . . . . . . . . . . . . . . . . . . . . . . .92 -.,~.1¢22 1.36 T34 1.11 July . . . . . . . . . . . . . . . . . . . . . . . . . .. 1.3-3 1.71 _1-.19 1.27 1.37 August . . . . . . . . . . . . . . . . . .. . . . . . . ~ "232 1.415 1. 14 . . . . . . . . . . 1.43 "September . . . . . . . . . . . . . . . . . . . . . .1- 569 -e;1.07 1.28 . . . . . . . . . . .98 Days grazed . . . . . . . . . . . . . . . . . . . . 4167 183 163 92 151 Gain per head . . . . . . . . . . . . . . . . . . 239 271 231 136 219 Daily gain . . . . . . . . . . . . . . . . . . . .. 1.43 1.48 1.41 1.47 1.45 10 BULLETIN 717, TEXAS AGRICULTURAL EXPERIMENT STATION Table 2. Steer gains on native blue grama and bulfalograss, Pasture I-ls ' Average daily gain in pounds per head tivated land on the west side of this pasture were reseeded grass in 1944. A good stand had developed by 1947. Pasture H is not comparable with other station pastures be? cause of its size and diversity of vegetation. It is typical of; conditions on large acreages over the Southern Great Plains; and the steer gains pretty well show what may be expec from an abundance of forage and a variety of species. The" dominant plants found in this field include blue grama, buIfaIoQfL grass, western wheatgrass, barnyard grass, spiked rush, spotted; primrose, bur ragweed, wedge-leaf fogfruit and weedy mallowgg This pasture has been kept in practically continuous light use; The results from grazing for six summers. indicate a high rate of gain (Table 3). Along with good gains, the steers on the lak; pasture had good finish, especially in 1943 and 1944 when wee were abundant. Results from pastures I-1 and H show that fa Figure 3. Native lake pasture H, the station headquarters in the background. GRAZING STUDIES ON THE AMARILLO STATION 11 Table 3. Steer gains on native lake pasture, pasture H Average daily gain in pounds per head Month Average 1943 | 1944 1945 I 194s 1941 194s l 1949 April . . . . . . . . . . . . . . . . . . . . . . .. 2 61 1 75 1.99 1.49 2.29 1.75 .67 1.79 May . . . . . . . . . . . . . . . . . . . . . . . .. 2.39 2.03 1.99 2.40 2.62 2 42 1.42 2.18 June . . . . . . . . . . . . . . . . . . . . . . . .. 1.21 1.48 1.83 1.40 . . . . .. 2 32 . . . . .. 1.64 July . . . . . . . . . . . . . . . . . . . . . . . .. .64 1.37 1.58 2 10 .59 2 25 . . . . .. 1.42 August . . . . . . . . . . . . . . . . . . . . . .. 1.46 1.31 .47 1 49 1.31 1 10 . . . . .. 1.19 September . . . . . . . . . . . . . . . . . . .. 2.49 1.45 1.65 1.13 1.34 2.59 . . . . .. 1.77 October . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2.03 1.85 . . . . . . . . . . .. .62 . . . . .. 1.50 Days grazed . . . . . . . . . . . . . . . . . . 167 213 163 183 -153 218 53 164 Gains per head . . . . . . . . . . . . . . . 301 347 264 305 249 395 59 274 Dailygain . . . . . . . . . . . . . . . . . . .. 1.80 1.63 1.62 1.67 1.63 1.81 1.11 1.61 900- to 950-pound yearlings cannot be produced from pasturage alone, unless it is abundant and high in quality. Summer Grazing Tests on Seeded Pastures Three seeded pastures have been outstanding for soil pro- tection, steer gains and seed production. These are pasture F, western wheatgrass and Canada wild-rye; pasture I-2, a mix- ture predominated by Western wheatgrass and blue grama; and pasture I-4, crested wheatgrass. Pasture F is a 44-acre field, 31 acres of which were planted to Western wheatgrass and 13 acres to Canada wild-rye. Steer gains from this pasture were good, giving a higher average daily gain than pasture I-1, the native short-grass field (Table 4). Canada wild-rye has not held up as well as western wheat- grass, probably because livestock prefer it, especially in the late spring and early summer. Western wheatgrass is grazed readily, especially in early spring (Figure 4). As it matures, it becomes less desirable forage, but will continue to be grazed if prevented by adequate stocking from making a rank growth. Pasture [-2. The following mixture was seeded in 1940 and 1941 o-n the east half of this field at the rate of 15 pounds per acre: blue grama, sideoats grama, buffalograss, western wheat- gross, Canada wild-rye, sand dropseed and weeping lovegrass. By 1943, when the pasture was first placed under regular use, it had become primarily western wheatgrass and blue grama. Table 4. Steer gains on seeded weste-rn wheatgrass and Canada Wild-rye Average daily gain in pounds per head Month Average 1943 1944 1945 1946 1947 1948 1949 April . . . . . . . . . . . . . . . . . . . . . . . .. 1.94 1.71 1.35 1.65 1.90 2.10 . . . . .. 1.77 May . . . . . . . . . . . . . . . . . . . . . . . .. 1.45 1.40 1.35 . . . . .. 2.27 2.11 1.20 1.63 June . . . . . . . . . . . . . . . . . . . . . . . .. .05 2.03 2.07 . . . . .. 2.05 . . . . . . . . . . .. 1.55 July . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1.40 . . . . . . . . . . .. .60 . . . . . . . . . . .. 1.00 August . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.02 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1.02 September . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . October . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 f Days of grazing . . . . . . . . . . . . . . . 84 184 71 30 106 61 31 81 Gains per head . . . . . . . . . . . . . . . 96 254 117 50 198 128 37 125 Daily gain . . . . . . . . . . . . . . . . . . .. 1.14 1.38 1 65 1 65 1 87 2.10 1 20 1 57 12 Figure 4. BULLETIN 717, TEXAS AGRICULTURAL EXPERIMENT STATION Steers grazing western wheatgrass, pasture F. Beef pro-duction from this pasture was varied, but gains have been good in the spring and early summer (Table 5). Definite? relationships are found to occur between climate, forage and. beef production. Summer gains were good in 1943 and excellent in 1944, when yearling steers became grass fat. Gains were‘ lower in 1945 and the steers did not get as fat as those on; pasture I-1, which had native blue grama and bufialograss. The?‘ pasture was hard hit by the 1945 drouth and summer usage.‘ With the drouth continuing in 1946, it was grazed only in April. It made good recovery after October 1946 rains, and in 1947 was again productive. Growth and utilization of western wheat-p produced both years, and also in 1949. Pasture I-4. This 44-acre field was seeded to crested wheat- grass at a rate of 10 pounds per acre in October 1944. A goodf stand was obtained and 10 yearling steers were placed on the. grass was much the same in 1944 and 1947. Seed crops were . vi _ _ Table 5. Steer gains on seeded western wheatgrass and blue grama Average daily gain in pounds per head r-i ‘ , Month Average * 7 1943 1944 1945 1946 1947 1948 1949 ;;:= ’ April . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1.98 2.13 1.99 2.93 2.42 . . . . .. 2.29 May . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2.40 2.13 . . . . .. 2.63 2.10 . . . . .. 2.32 June . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1.33 1.88 . . . . .. 2.25 1.62 . . . . .. 1.77 July . . . . . . . . . . . . . . . . . . . . . . . .. 1.52 1.65 1.19 . . . . .. 1.19 1.60 . . . . .. 1.43 August . . . . . . . . . . . . . . . . . . . . . .. 1.75 1.31 .47 . . . . . . . . . . . . . . . . . . . . . . .. 1.18 September . . . . . . . . . . . . . . . . . .. 1.33 1.20 1 . 01 . . . . . . . . . . . . . . . . . . . . . . . . 1.18 _October. . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26 Days of grazing . . . . . . . . . . . . . . . 92 213 163 30 122 122 . . . . . . 124 Gains per head . . . . . . . . . . . . . . . 141 310 228 59 273 240 . . . . . . 209 Dailygain . . . . . . . . . . . . . . . . . . .. 1.53 1.46 1.40 1.99 2.24 1.96 . . . . .. 1.76 GRAZING STUDIES ON THE AMARILLO STATION 13 Table 6. Steer gains 0n crested wheatgrass, pasture I-4 Average daily gain in pounds per head Month Average 1945 1946 1947 1948 1949 April . . . . . . . . . . . . . . .. 3.00 2.02 3.03 2.66 2.65* 2.67 May . . . . . . . . . . . . . . .. 3.00 . . . . . . . . .. 3.02 . . . . . . . . .. 2.30 2.77 June . . . . . . . . . . . . . . .. 1 58 . . . . . . . . .. 1.73 . . . . . . . . .. 1.90 1.74 July . . . . . . . . . . . . . . . . . . . . . . . . . . 2 14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.14 Days of grazing . . . . . . 71 44 91 30 91 65 Gains per head. . . . . . . 170 91 237 80 208 157 Daily gain . . . . . . . . . .. 2.39 2.05 2.60 2.66 2.29 2.40 *44 head. pasture April 21, 1945. Good to excellent beef gains have been recorded from this pasture (Table 6). In favorable years, it has been the practice 0n the station t0 remove livestock from this field at the end of June to let the grass produce seed. Good seed crops were harvested in 1947 and 1949. This field produced 303 pounds of seed per acre in 1947, in addition to 54 pounds of steer gain in 3 months of grazing. An average of 436 pounds of seed per acre was harvested from adjoining areas which were not grazed during the year. Crested wheatgrass has proved to be highly satisfactory as an introduced cool-season grass on the station (Figure 5). It is easy to establish, and is high in both quality and quantity of forage. Stands established at other points over the Southern Great Plains indicate that it is doing well. Weeping Lovey/rose. Weeping lovegrass has been seeded in pure stands and in mixtures on the Amarillo station. Although Figure 5. Crested wheatgrass on the Amarillo station. 14 BULLETIN 717, TEXAS AGRICULTURAL EXPERIMENT STATION it is a good erosion control plant, grazing values have varied .1 widely. In mixed seedings, it has not withstood competition Y ‘with other species. When making good growth in either spring or fall, it shows good to high values for protein and phosphorus; I yet, its long fibrous leaves and lack of succulence tend to make it less palatable than most other grasses under test. In one field, y 65 percent of the stand established in 1944 died out in the sum- 1 mer of 1946. The chief cause for the loss appeared to be the i severe drouth of 1945-46. Summer Grazing Tests on Temporary Pasturage Sudan grass has been used in the Southern Great Plains for I nearly 40 years. During the studies on the Amarillo station, various acreages have been planted from year to year for summer supplemental pasturage. Sudan grass may afford green ._ forage high in protein during periods which are critical for v native and seeded grass pastures. Cattle, when shifted to Sudan grass, ordinarily make good rates of gain (Table 7). Table 7. Steer gains on Sudan grass Average daily gain in pounds per head Month Average 194s 1944 194s 194s 1941 194s July . . . . . . . . . . . . . . . . . . .. 1.59 . . . . . . . . . . . . . . .. 13.59 1.99 .99 1.99 August . . . . . . . . . . . . . . . .. .93 2.19 . . . . . . .. 1.10 2.02 1.92 1.12 September . . . . . . . . . . . . .. 1.94 .10 . . . . . . . . . . . . . . .. 1 . a4 1 . as 1.31 Average . . . . . . . . .. 1.49 1.41 . . . . . . .. 2.94 1.99 1.29 1.99 Sudan, planted in 42-inch rows in 1947, produced about 50 percent more forage than Sudan drilled in 10-inch rows. In addition, protein content was about 30 percent greater for the plants in the wider-spaced rows. Wider-spaced plantings will probably give better results year after year. Winter Grazing Tests Winter wheat forage is highly valued for pasturage. Wheat makes considerable forage growth during mild Winters with favorable moisture, but makes little growth during drouth or long periods of severe cold. In the seven wintering periods, 1942-43 to 1948-49, winter wheat supplied grazing throughout the winter for only 2 years, about half of the time for 3 years, and no grazing at all for the other 2 years. Livestock are usually kept on wheat as long as it can be grazed without reducing grain yields. This varies from mid-February through March, according to growing conditions, but as. a rule for best grain pro- duction, it is best to get off of wheat not later than March 15 for medium maturing wheat, and not later than March 1 for early maturing wheat, according to studies at the station. In two winters, 1945-46 and 1946-47, plots clipped to simulate grazing produced about half a ton more green weight per acre than unclipped plots. There was nearly twice as much production GRAZING STUDIES ON THE AMARILLO STATION 15 from unclipped plots in 1945-46 as in 1946-47. The average production of green weight per acre for the 2 years was about three tons. Table 8. Daily gains in pounds per head of steer calves on winter wheat and grass plus 2 pounds of 41 or 43 percent protein cottonseed cake Daily gain in pounds per head Year Winter wheat Grass plus cake 1942-43 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.23 . . . . 1943-44 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . none 0.84 1944-45 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 .44 0.99 1945-46 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.45 0.78 1946-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.23 1.47 1947-48 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . none 0.90 l948-49* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.14 0.49 Average . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . 30 0. 78 *l948-49 results are for long yearlings. Gains of livestock on winter wheat have been higher than gains on grass and cake (Table 8), except during the winter of 1946-47. On the other hand, grass calves have tended to make higher summer gains than the wheat-pastured calves, but in no instance quite equalled the latter in weight or finish in the fall. PROTEIN AND MINERAL CONTENT OF FORAGES Samples of the principal forage plants on the station were analyzed for crude protein, lime and phosphoric acid. The samples, clipped at different dates, represented the forage avail- able for grazing. Analyses based on air-dry weight are shown in Table 9. The results for buffalograss are not presented since numerous analyses have shown that blue grama and buffalograss are similar in chemical composition. - Blue grama may be either good or rather poor in protein and phosphorus, depending on moisture received during the grow- ing season. Dead or “carry-over” grass in winter or spring is low in protein and phosphorus. Many of the samples clipped through the year showed low values because of the factor of dead grass. Except when dry or mature, western wheatgrass shows relatively high values for protein and phosphorus in all seasons. Green crested wheatgrass and winter wheat show very high values. Weeping lovegrass, from the standpoint of chemical composition, seems to be as good as blue grama, yet, it is not palatable when mature. All of the grasses showed adequate to high content of lime} Grasses and other plants which make up the animal’s supply of forage may vary widely in feed value between seasons (Table 10). However, with good growing conditions, the forage plants which grow in the region may furnish good feed for livestock lGrasses, basis air-dry weight, are considered adequate in lime (CaO) at 0.35 percent; phosphoric acid (P205) at 0.27 percent, and crude protein 6.0 percent. Bulletin 644, TAES, 1944. 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Extremes in crude protein, lime and phosphoric acid content of’. forage, 1943-49 , Date Crude Phosphoric Description of sample sampled protein Lime acid Blue grama: 55% green; 45% cured . . . . . . . . . . . . . . . . . .. 5/2/47 17.31 .56 .48 2% green; 98% cured . . . . . . . . . . . . . . . . . .. 12/13/48 2.20 .53 .16 Crested wheatgrass: - 65% green; 35% cured . . . . . . . . . . . . . . . . . . 4/1/47 33.15 .61 .89 24% green; 76% cured . . . . . . . . . . . . . . . . . . 8/29/47 4.18 .25 .20 Western wheatgrass: 90% green; 10% cured . . . . . . . . . . . . . . . . .. 11/1/46 19.00 .60 .53 12% green; 88% cured . . . . . . . . . . . . . . . . .. 12/13/48 3.45 .49 .20 Weeping lovegrass: 85% green; 15% cured . . . . . . . . . . . . . . . . . . . 11/1/46 12.99 .59 .45 47% green; 53% cured . . . . . . . . . . . . . . . . . . . 10/6/47 2.70 .42 . 14 Winter wheat: 60% green; 40% cured . . . . . . . . . . . . . . . . . .. 3/4/47 27.72 .50 .58 60% green; 40% cured . . . . . . . . . . . . . . . . . .. 5/31/46 8. 74 .28 .45 Highest values found for other forages con- sumed by steers: Canada wild-rye, green . . . . . . . . . . . . . . . . . . . . . 4/27/43 21.38 .65 .52 Sweet Sudan, 80% green . . . . . . . . . . . . . . . . . . . 7/30/47 20.15 .69 .70 Little barley, green . . . . . . . . . . . . . . . . . . . . . . . . 5/18/45 13.70 .30 .55 False ragweed, green . . . . . . . . . . . . . . . . . . . . . . 6/3/47 14.38 2.38 .95 Weedy mallow, green . . . . . . . . . . . . . . . . . . . . . . 7/1/46 1_0.20 3.01 .55 Wedgeleaf fogfruit, 75% green . . . . . . . . . . . . . . 7/1/46 6. 40 6.04 .73 Russian thistle, green . . . . . . . . . . . . . . . . . . . . . . 5/2/47 21.29 4. 25 .78 the year-round. Native blue grama and buffalograss are the foundation summer grasses and may furnish year-round feed. ‘ Western wheatgrass, either native or seeded, is. a valuable sup- j plementary grass and may furnish both winter and summer feed. Seeded crested wheatgrass is rich in protein and phosphorus until maturity. Although a cool-season grass, it apparently' greens up at any season moisture is available. Lakeweeds are ~ high in protein and phosphorus and very high in lime. Russian thistle, likewise, shows high feed values when young and grow- ing. Sudan grass is characterized by high feed values in mid- summer, except in years of high rainfall during the growing _ 863.8011. FORAGE PRODUCTION OF NATIVE AND SEEDED GRASSES Forage production of various grasses is closely related to the amount and distribution of precipitation. Heavy fall moisture in 1946 greatly stimulated production of crested wheatgrass and western wheatgrass in 1947, but did not have much effect on the short grasses. Good moisture during the growing season in- creases production of blue grama and buffalograss (Table 11). Table 11. Forage production, pounds of air-dry forage per acre, 1943-48 I Pasture Forage species 1943 1944 ‘ 1945 1946 t 1947 l 1948 . Ii I-1 Native blue grama-buflalograss . . . . . . . . 664 1 ,354 629 242‘ 321 716 Bush Overgrazed blue grama-bufialograss. . . . . . . . . . . . . . . . 447 174 . . . . . . . . . . . . F Seeded Canada wild ryegrass . . . . . . . . . . 920 1 , 135 307 . . . . . . . . . . . . . . . . . . F Seeded western wheatgrass. . . .. . . . . . . . 667 1 ,542 207 328 1,669 742 I-4 Seeded crested wheatgrass . . . . . . . . . . . . . . . . . . . . . . . . 506 546 2,244 641 F-2 Seeded weeping lovegrass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 962 1 , 263 . . . . . . Clippings were made April 1, and November 1, at a height of 1 inch, except for weeping lovegrass which was clipped at 2 inches. GRAZING STUDIES ON THE AMARILLO STATION 19 Forage Growth and/Pasture Management Detailed studies of blue grama and buffalograss on pasture I-1 indicated that the major growth period for unclipped plants was from April to June. With unclipped plants, natural decay 0r dying back from June t0 August practically equalled the growth made from April to June. There was very little growth from August to November, and there was only 6 percent more forage on November 1 than on April 1. The major growth period for clipped plants was from April to June. There was only about 50 percent as much growth fro-m June to August and only about 25 percent as much growth from August to November as from April to June. The growth of grasses may be used as a guide in their usage. In a conservation program, it appears that saved pasturage may be grazed heavily in the spring, otherwise old plants will pro- duce little in the growing season. It is evident that plants closely grazed the preceding year cannot be heavily used the succeed- ing spring. Blue grama-buffalograss pastures are dependable sources of summer feed. The Wheatgras-ses definitely have a place in early spring and fall grazing. Native blue grama-buffalograss pas- tures may also furnish early spring pasturage in years favorable to little barley. On June 1, 1944, the I-1 pasture had 961 pounds per acre of little barley, but there were only traces of this grass- in the November clippings. Little barley must be used in sea- son or its forage is lost to cattle. This plant also competes strongly for moisture and may harm the growth of the sum- mer grasses. g Cattle are selective in grazing and grass growth is affected not only by grazing but by season and the supply of moisture. Thus. with variable growth and natural decay, in addition to grazing and trampling, conservative usage o-f pasturage is indicated. PRACTICAL APPLICATION OF THE RESULTS The Amarillo station grazing experiments show that, with favorable rainfall, year-round green feed may be realized from a combination of the following pasturages: SEASON PASTURAGE Winter Winter wheat Crested wheatgrass Western wheatgrass Canada wild-rye Spring Crested wheatgrass Western wheatgrass Canada wild-rye Little barley Early weeds- Summer Blue grama Bulfalograss Sudan grass Lake weeds 20 BULLETIN 717, TEXAS AGRICULTURAL EXPERIMENT STATION Fall Crested wheatgrass Western wheatgrass Canada wild-rye Winter wheat Under ideal conditions, the cool-season grasses—crested and l western wheatgrass—bridge the gap between wheat pasturage and the summer grasses in both spring and fall. The cool-season a grasses are able to use late fall moisture which the summer . grasses cannot use because of cold weather. Winter wheat and cool-season grasses cannot be relied upon _ to make much growth in winter because of the short days and the cold. However, given moisture and freedom from excessive cold, a great deal of valuable pasturage is produced. Excessive a trampling and grazing must be avoided as such treatment may result in losses from wind erosion. It is desirable to have a green pasture to keep steers gaining after they are taken off the wheat fields, March 1. Crested - wheatgrass and western wheatgrass have proved to be adapted to this purpose and for fall grazing. These grasses were also used in mid-summer duri.ng drouths. Blue grama and buffalograss native pasture may sustain steer gains throughout the summer. Seeded blue grama and buffalo- grass and western wheatgrass pastures equaled or exceeded native pastures in the production of steer gain. Native or seeded pastures produced little steer gain in the fall except under unusual conditions. Values of all the pasturages for beef production varied each year with climatic conditions dur- ing good and drouth years. A flexible program of grazing, which will provide ample forage during good seasons and leave enough carry-over grass for emergencies, is desirable. Grazing management was based on the idea of keeping plenty of forage before the steers, then removing them before the pastures were stripped. Flexibility in the grazing program is necessary because recurrent drouths reduce the capacity of the pastures and quick advantage should be taken of favorable years. The Amarillo station practice is to buy Choice feeder steer calves, winter feed them well and put on good early spring gains, even at the expense of grazing out small acreages of wheat. Then, if summer feed is not in sight, sharply reduce the numbers by sale. In addition, steers are not held over the winter, nor calves bought unless there is ample pasturage and bundle feed. Over a period of years, the number of cattle that can be handled without injury to the pasturage and with maxi- mum returns is gained by experience. Drouths of two successive growing seasons should be expected, and plans laid in advance. Under semi-arid conditions, native and seeded pastures which are heavily used quickly lose their vigor and fail to respond to moisture. On the other hand, an accu- GRAZING STUDIES ON THE AMARILLO STATION 21 mulation of carry-over grass beyond the need for soil protec- tion and emergency use results in scant growth of new forage, and forage of low food value. Western wheatgrass and crested Wheatgrass permitted to reach maturity become Weathered hay of low palatability and food value. Heavy use keeps the forage green as long as moisture is available. Light use permits some of the grass to cure, weather and lose food value, but the vigor of the pasture is maintained; cattle are able to select the best feed and make high gains. The extent to use pastures, thus, becomes a matter of judgment; but over a period of years, light to moderate use is indicated. Evidence of the need for a rest period for the storage of root reserves was found in the failure of Canada wild ryegrass and some weeping lovegrass to come through the 1945-46 drouth under grazing; also, in the failure of pastures I-1 and I-2 East to furnish any appreciable amount of feed in 1946 after 3 sum- mers of moderate to heavy use. Carrying through fewer good quality steers with maximum gains makes a reduction in number possible Without any heavy loss. It is significant that in 1947, a dry year, very high gains were realized per steer. It is only through light use that maxi- mum gains per steer can be realized from pasturage.