Soil water, herbage assimilated nitrogen, and herbage were measured in the field and used to estimate the effectiveness of nitrogen fertilization to increase yields in cheatgrass communities. The application of regression analysis to estimate the amount of nitrogen fertilizer needed to increase herbage in relationship to available soil moisture is presented. When herbage nitrogen is in the range of 0.5 to 0.7% at the end of the spring growing season, nitrogen rather than soil water appears to limit herbage production.

The influence of 2,4-D [(2,4-dichlorophenoxy) acetic acid] and 2,4,5-T [(2,4,5-trichlorophenoxy) acetic acid] on in vitro digestion of dried ground corn silage (Zea mays L.) and bermudagrass (Cynodon dactylon L.) foliage was determined using a modification of the Tilley and Terry method for determining in vitro dry matter digestibility of forage plants. Neither herbicide influenced the digestion of plant samples when treated with a herbicide concentration range of 10-8 to 10-4 M. Solutions containing 10-4 M of either herbicide did not influence the growth of microbial populations in incubated rumen liquor. The influence of rumen microorganisms on degradation of 2,4-D and 2,4,5-T was also investigated. Samples containing sucrose or plant material, buffered rumen liquor, and 10-4 M concentrations of either herbicide were incubated for 10 day periods. Data from periodic quantification of herbicide remaining in the samples indicated that neither herbicide used in these experiments was degraded by the rumen microorganisms. Results indicate that: (1) 2,4-D and 2,4,5-T do not alter the rumen microbial functions or development and (2) these herbicides are not readily degraded in the rumen by the rumen microorganisms.

Holocellulose, hemicellulose, and in vitro fiber digestibility were significantly different between cool and warm season grasses. A significant class x date interaction for protein and lignin suggested that each forage could be expected to follow a different growth pattern during the growing season. Sugars (xylose, arabinose, galactose, and glucose) were found as hemicellulose components in all grasses at all cutting dates. Xylose was the most prominent structural sugar in all grasses studied. In vitro dry matter digestibility could be most easily adapted to routine studies of forages, but cannot be expected to define the contributions of individual parameters making up plant dry matter. The nutritive differences among grasses at various sampling dates suggest the value of a mixture of desirable grasses. This would assure grazing animals continued nutrition throughout the grazing period.

Paper and thin-layer chromatography of big sagebrush seed provides a rapid, simple means of identifying more palatable forms of this shrub. Methanol extraction of seed for 24 hr followed by two-dimensional paper (n-butanol:acetone:water, 4:1:3; acetic acid: water; 15:85) or single-dimensional thin-layer chromatography (chloroform:methanol:water; 85:10:5) reveals distinctive differences between Artemisia tridentata subsp. tridentata and the more palatable subsp. vaseyana and wyomingensis. A bright, iridescent blue spot characterizes the more palatable subspecies; the same spot is much smaller and duller in A. tridentata subsp. tridentata.

Low-cost methods are required for converting wooded areas of Canada's Peace River region to productive pasture. Methods of circumventing the costly procedures of breaking the soil and removing roots preparatory to seeding were investigated. Various tillage implements (mouldboard plow, Rome disc-at 3 depths, rotovator, one-way disc, and tandem disc) were compared as to effectiveness for seed-bed preparation. In addition, seed was both drilled and broadcast. Forage yields varied greatly, from an average of 1,184 lb/acre on the plowed plots to 103 lb on the check area. It was concluded that all methods tried tend to enhance tree establishment. Because of this, none of the methods tested would bring about an economically viable pasture.

Planting season and cultural treatment effects on emergence and survival of three range species were determined for two cold, dry pinyon-juniper sites in north central Arizona. Plowing was the most effective seedbed preparation for controlling plant competition. Furrow drilling also eliminated a large amount of competition. Emergence and survival (E & S) of Luna pubescent and Nordan crested wheatgrass averaged highest with fall planting, but summer planting was best for E & S of fourwing saltbush. E & S averaged highest on plowed seedbeds and decreased progressively on undercut, undercut-strip, presprayed, sprayed, and control seedbeds. Surface drilling on tilled seedbeds increased E & S over furrow drilling for fourwing saltbush and usually for Nordan crested wheatgrass. Drilling in wide, shallow furrows increased Luna pubescent wheatgrass E & S. Furrow drilling increased E & S for all species on nontilled seedbeds. There were some significant interactions among treatment combinations. Practical application of results is discussed.

Estimates of yearlong carrying capacity obtained by three different techniques are compared in terms of accuracy as measured by actual carrying capacity of a northern Utah cattle ranch. A new "algebraic" approach appears superior to two established techniques currently in use.

Wether lambs were used in a feeding study (voluntary consumption, nutrient digestibility, metabolizable energy, and nitrogen retention) to evaluate the nutritive value of hays harvested from unfertilized and nitrogen-fertilized blue grama rangeland. Fertilization increased consumption by 29%; increased digestibility of dry matter, protein, and energy by about 5%; and increased the retention of nitrogen by about 7%, although the percentage retention of absorbed nitrogen (biological value) was apparently depressed.

Chemical curing of N-fertilized crested wheatgrass was examined in 3 years. Both N and paraquat, singly and in combination, significantly influenced various stand components. The combined treatments increased fall herbage yield 40%, crude protein concentration 68%, and crude protein yield 148% above that of the control.

Small weighing lysimeters provide a useful tool for investigating simultaneously soil water use and plant productivity in annual grasslands. Details of construction, sensitivity and accuracy of weighing, and field and harvest techniques are given. PVC irrigation pipe is used for both the lysimeter and its sleeve-5 inch and 6 inch nominal diameter, respectively. Weight changes equivalent to .002 inch (.05 mm) can be detected, allowing diurnal water use to be determined if desired. Comparisons using shoot harvest and soil water use for Spring, 1971, show good agreement between the lysimeters and the field.