Responses of vegetation and ground cover to winter grazing by livestock and to exclusion of livestock for 10 years were observed on soils derived from shale, sandstone, and a mixture of shale and sandstone. Although distinct soil-vegetation relationships were evident, changes attributable to grazing were relatively small. Vegetation and other cover on nongrazed range was practically the same at the end as at the beginning of the study. Overall reductions in galleta, shadscale, and snakeweed were attributed to drought, while differential responses of Salina wildrye, Gardner saltbush, Greenes rabbitbrush, and annual plants were ascribed to grazing. Inherently low site capability and subnormal precipitation were believed responsible for the general lack of response of vegetation to exclusion of livestock./En el estudio se compararon zonas pastoreadas en invierno con exclusiones de diez años de edad. Se concluyó que había poca influencia del pastoreo sobre le vegetación. La composición vegetal dentro de las exclusiones fué la misma al principio y al final del estudio. Hubo una disminución de las especies Atriplex confertifolia, Hilaria jamesii y Gutierrezia sarothrae por causa de las sequías. Hubo varias respuestas diferenciales de las especies Elymus salinus, Atriplex nuttallii, Chrysothamnus greenei y plantas anuales debido al pastoreo. El autor piensa que la vegetación no mejoró sin pastoreo porque el potencial fué bajo en los suelos y también hubo un bajo promedio de precipitación pluvial.

Aboveground biomass and nutrient production of important grasses were estimated on two range sites in the eastern Colorado sandhills. Apparent seasonal net production of blue grama and western wheatgrass on the sandy plains site was 144 g/m2 compared to 90 g/m2 for blue grama, prairie sandreed, and needleandthread grasses on the deep-sand range site. Production rates for the grasses studied were 1.8 and 0.8 g/m2/day for the sandy plains and deep-sand range sites, respectively. Herbage biomass decline 28% from the peak standing crop to fall (October 2) on both sites. During the late summer and winter months the biomass declined 50% on the deep-sand site and 35% on the sandy plains site. The sandy plains site produced a larger amount of crude protein than the deep-sand range site. This was accounted for by a larger herbage biomass and a higher percentage of crude protein in grasses grown on the sandy plains site. This more productive site appears to retain more herbage of higher nutritive value throughout the winter than the deep-sand site.

The multiple correlation and multiple regression between monthly forage yield of dhaman (Cenchrus ciliaris Linn.) and the four factors of the amount of monthly rainfall, the number of rainy days in the month, the amount of rainfall during the previous month and the month of the growing period were positive and highly significant (0.01 level). The same multiple relationships for karera (Elyonurus hirsutus Vahl.) were significant only if rainfall during the previous month was not included. There were highly significant positive correlation and regression relationships between forage yield and monthly rainfall, for both species. For either species, positive significant correlation existed betwen monthly forage yields and number of rainy days. Dhaman was more responsive than karera to all three rainfall factors involved.

An intensive study was undertaken on a southern California range to elucidate the nutritive value of Atriplex polycarpa (Torr.) S. Wats. The investigation was designed to show variations in forage values throughout the year and to denote, if any, the correlations between nutritive qualities and the environmental conditions. Forage samples were analyzed for protein, fat, calcium, phosphorus, fiber, total ash, and nitrogen free extract; total digestible nutrients were calculated from digestion coefficients. Although the results showed significant variations in forage value throughout the year, the nutritional requirements of a grazing animal were generally satisfied. Desert saltbush can therefore serve as a dietary supplement and provide important nutritional components such as protein, calcium, phosphorus, and carotenoids when these components are less than adequate in the other available forage.

Effects of rootplowing, with or without seeding, on forage production and composition of native grasses were determined on a deep upland range site. Percent composition of stoloniferous species, particularly buffalograss, was reduced initially and after 6 growing seasons by the rootplowing treatments. Frequency counts indicated a reduction of Texas wintergrass on rootplowed plots (seeded and nonseeded) compared to an undisturbed, native check area. This reduction the first growing season was attributed to the competitive effect of sorghum almum introduced in the seeding mixture. Unsuccessful establishment of other seeded grasses (sideoats grama and switchgrass) appeared to be related to poor seedbed preparation, competition from sorghum almum plants, and below normal rainfall immediately after seeding. Rootplowing decreased grass production. After 6 growing seasons, significantly less forage per acre was produced on rootplowed-seeded plots than on nonrootplowed plots. Differences in forage production were related to plant composition and density. /// El estudio fué empezado en el año de 1964 en el rancho experimental de Texas en el Municipio de Throckmorton; el diseño incluyó testigo; y se pasó arado para desenraizar sin la siembra y se pasó arado para desenraizar con la siembra. Después de 6 años los dos tratamientos disminuyeron la producción de forraje y composición de zacates deseables. El zacate sorghum almum (Sorghum almum) apareció en la siembra. El arado desenraizador controló el mezquite (Prosopis glandulosa var. glandulosa).

Alkali sacaton (Sporobolus airoides Torr.) seeds imbibed water rapidly. Large seeds gained 47% and small seeds gained 71% of their dry weight within the first 30 min after wetting. The large seeds had gained 124% and the small seeds 165% of their dry weight after 72 hr.

The earliest grazing in the Northwest (which probably began about 1700) was by Indian horses. Livestock-a few head of cattle-were first brought to the Northwest at Nootka Bay on Vancouver Island, B.C., by Spaniards in 1789. By 1825, there were 27 head of cattle at Vancouver, Wash., near the mouth of the Columbia River. Marcus Whitman brought cattle to the area east of the Cascade Mountains in 1836. Mass movements of cattle took place from western Oregon to east of the Cascades during the 1860's. Numbers skyrocketed which resulted in sizeable exportations of livestock in the late 1800's to regions east of the Rocky Mountains, largely for building base herds. These drives contributed significantly to development of the livestock industry east of the Rockies, although they have been largely neglected by writers who chose, rather, to popularize the cattle drives from Texas and the Southwest. Raising livestock on rangeland is still, and will continue to be, one of the major basic industries in the Pacific Northwest. There are many millions of acres of private and public rangeland and grazable woodland in the Pacific Northwest on which concurrent grazing by livestock and game should continue to be one of the major uses of the resource.

Regression equations for six methods of expressing the relationship between digestible energy and digestible dry or organic matter were developed from digestion trials conducted with cattle grazing native range forage. Concentrate feeds supplemented the grazing animal's diet in some trials. The results of this study indicated that the laborious determination of digestible energy could be replaced by a simple determination of digestible dry or organic matter. Supplementation with concentrates did not change the relationship between digestible energy and digestible dry or organic matter.

Effects of N-fertilization and clipping on production and water use of blue grama were evaluated under two soil moisture levels, field capacity and 1/5 available water. Nitrogen increased shoot production 77% on unclipped plants. Clipping decreased shoot production 287% below the control averaged across N levels. Soil moisture levels produced no differences in yields. Root weights were decreased an average of 253% below the control by clipping. No differences were observed in total water used between fertilized and unfertilized plants but clipping reduced water used by 95%. Unclipped plants fertilized with 80# N/acre used more water than unfertilized unclipped plants. The amount of water required to produce a unit of a shoot was reduced 37% when fertilized. Clipping lowered this water requirement an average of 98%. Nitrogen greatly increased seed stalk numbers and the increase in shoot production due to fertilization came primarily from increased numbers of seed stalks.