The main morphological distinction between bluebunch wheatgrass and beardless wheatgrass is the presence of geniculate awns in the former and the absence of awns in the latter. Open pollinate progenies of plants classified as either A. spicatum or as A. inerme segregated clearly for this trait. This indicates the mere presence or absence of awns does not afford reproductive isolation; thus, the species designation is questionable. In addition, variation for rhizomes was detected in the progenies of bunch type plants, but segregation was not clear cut. Significant variation among progeny means for forage yield was also detected. There is apparent, real potential for varietal development, but care must be exercised in mixing awned and awnless types.

Stolons were observed on blue grama under natural conditions and in greenhouses. Some stolons reached 70 cm with as many as 12 internodes. Stolons were induced in an environmental chamber by controlling the temperature, shortening the photoperiod, and reducing the light intensity.

Gambel oak can be effectively eliminated in localized, small scale projects by (1) foliage spraying with picloram-silvex at a 1:2 lb a.e./acre rate, (2) basal stem spraying with silvex, 2,4,5-T, or picloram, (3) soil application of picloram granules at 4 lb a.e./acre, or (4) complete top removal followed by root raking.

Spatial variability in two soils supporting 10-year old stands of saltbush (Atriplex nummularia) was examined by evaluating various soil physical and physico-chemical properties under and between the plants. The differences in soil properties between these two positions were mostly significant for the surface layer (0-7.5 cm) but only in a few cases for the 7.5-15 cm layer. No differences were observed below this depth. Presence of A. nummularia resulted in increased electrolyte concentration, higher sodium adsorption ratio, and higher levels of exchangeable sodium and organic matter in the surface soil. Standard laboratory measurements showed that these physico-chemical changes induced a significant deterioration in the structure of the surface soil under the plants as indicated by reduced aggregate stability, poorer drainage, and lowered hydraulic conductivity. Field studies suggested that the bulk density of the surface soil was reduced under the plants but that water penetration and storage in the profile after rains remained unaffected. Probable reasons for these effects are discussed.

Soil moisture patterns were studied under chaining-with-windrowing, chaining-with-debris-in-place, and natural woodland at one site each in both southwestern and southeastern Utah. Results of the study indicate the greatest moisture accumulation occurred under the debris-in-place treatment (as compared to woodland controls), during the first 6 months of each year at Milford and regardless of season at Blanding. The woodland had the least soil moisture throughout most of each year. Most moisture flux took place in the upper 60- to 90-cm of soil profile, with only minor changes occurring at greater depths. Differences in soil moisture patterns have been attributed to changes in microclimates due to chaining, different rooting depths and length of growing season, mulching effect of litter on the debris-in-place treatment, and possible differences in snow accumulation. Variation in vegetation density on the chained treatments did not influence soil moisture patterns. There was no evidence of deep seepage on any chaining treatment at either site.

Small mammal numbers were studied by snap trapping on six areas in Utah where juniper range had been cleared and seeded. On one area, which was trapped both before and for the first 3 years after treatment, numbers of deer mice (Peromyscus maniculatus) and pocket mice (Perognathus parvus) increased greatly in the first 2 years following treatment, then declined sharply to a level which was still above that before treatment. On two areas which were trapped only the first 2 years after treatment, many more small mammals were caught in the second year. Older seedings had about the same number of small mammals as did untreated juniper. Small mammals showed a clear preference for windrowed slash. This was especially true of deer mice and long-tailed voles (Microtus longicaudus).

Little rabbitbrush and snowberry plants were clipped for 5 years to simulate annual browsing at the same time each year, under deferred-rotation, alternate-rest, and rest-rotation grazing systems at each of three different intensities (30, 60, and 90% of herbage removal). The number of new sprouts was increased by some clipping treatments and all intensities of clipping in both species. Sprout length was reduced by all clipping schedules and intensities of clipping on little rabbitbrush but not on snowberry. Mortality of sprouts was high during their first year of growth. Carbohydrate reserves were lowered for both species by some clipping schedules and by all intensities of clipping.

Five collections of seeds of true mountainmahogany from two sites in northern New Mexico were divided into three size classes. Large seeds germinated better than medium or small seeds, within a collection as well as overall. The results suggest, however, that relative size distributions of collections may not be a reliable index of differences in source germinability.

Grass tetany (hypomagnesemia) frequently occurs from March through June in cattle grazing crested wheatgrass in western United States. High levels of transaconitate and/or citrate, K, K/(Ca + Mg) ratios and low Mg in the grass are implicated in the etiology of the disease. In the moist 1967 season, during periods of "flush" growth following warming trends, trans-aconitate and K increased while Ca and Mg decreased in crested wheatgrass. These characteristics may explain the incidence of grass tetany during periods of "flush" growth. During the dry 1968 season, these trends were not observed. Growth chamber studies confirmed some of the reasons for changes in crested wheatgrass composition observed in 1967 and 1968.

Esophageally fistulated steers were used to determine organic matter intake and digestibility of bluestem pastures during the summer grazing season. Following a 48-hour total fecal collection period, esophageally fistulated steers were used to collect grazed samples of native pastures during June, July, August, September, and October. Esophageal samples were higher in ash and crude protein and lower in crude fiber, N-free extract, and acid detergent fiber than were hand-clipped samples. In vitro dry and organic matter digestibilities were higher in forage collected by cattle than in hand-clipped forage. Multiple regression equations were developed to predict in vitro digestibility. Only crude protein and acid-detergent fiber were highly correlated with digestibility. Average daily intakes of organic matter, digestible crude protein, and digestible energy by steers on pasture were estimated from fecal nitrogen regression established from hay trials. Protein apparently became limiting about mid-July and energy in late August. The positive effects of burning were increased forage yield and weight gain with lowered lignin content.