Fecal seeding by livestock may be an effective, low-cost means of rangeland restoration. We compared recruitment of switchgrass (Panicum virgatum L.) from seed fed to cattle and deposited in dung to that of broadcast-seeded plots receiving a comparable number of unfed seed. Although germinability of seed passed through livestock (52 to 62%) was reduced relative to that of broadcast seed (85 to 91%), recruitment of switchgrass from seed in cattle feces was equal to or superior to that of broadcast seed in terms of establishment (frequency of occurrence and density), plant growth and final plant size. The frequency of plot with emerging switchgrass plants ranged from 62 to 100% when seeds were delivered in feces, but only 2 to 40% when seeds were broadcast. After 1 year, the frequency of occurrence of switchgrass plant in fecal vs. broadcast-seeded plot was comparable for autumn trials. However, evaluations 1 year after the spring trials continue to result in higher frequency of plot with switchgrass plant from seed delivered in feces than of broadcast seedings (56 vs. 4% for May 1990, P < 0.05; and 90 vs. 51% for May 1991, P less than or equal to 0.01). Enhanced plant recruitment on fecal-seeded plots occurred even though broadcast-seeded plots received 1.5 to 1.7 times more pure live seed (PLS). Plants on fecal-seeded plots had a greater plant size score (based on visual ratings of height, culm density, and biomass) than plants on broadcast-seeded plots (P < 0.05 for May seedings; P < 0.05 for October 1990; P < 0.10 for October 1991). Results suggest significant advantages of fecal seeding over conventional broadcast seeding in terms of seedling emergence, establishment and growth.

Plants with various shoot and root combinations of Cowania mexicana var. stansburiana (Torr.) Jeps. (cliffrose), Purshia glandulosa Curran (desert bitterbrush), and Purchia tridentata (Pursh) DC. (antelope bitterbrush) were relatively easy to produce by grafting. The foreign roots or shoots in multi-shoot or multi-root systems were not as vigorous as the original scion or rootstock. With time the original scion or rootstock became dominant and the foreign portions usually senesced. If growth of the original scion or rootstock was restricted by pruning or removal, satisfactory growth for both shoot or root types occurred. Manipulating grafted systems where Fallugia paradoxa, (D. Don) Endl., Apache plume, (a non-nodulating genus) is combined with any of the above 3 nodulating species was much more difficult. Graft incompatibility occurred in most intergeneric Fallugia systems, but some combinations survived for several years. A large quantity of nodules was produced on 1 very sparsely rooted P. tridentata scion attached to a Fallugia rootstock. Apparently, the plant derived much of its nitrogen from Purshia nodules, and the majority of its other nutrients and water from the Fallugia roots.

Fourteen treatments of nitrogen (N) and phosphorus (P) fertilizers were applied in an overgrazed eight rangeland in northern Mexico, during 1990 and 1991. Eight treatments were applied using ammonium nitrate as a source of N (60-0-0, 60-30-0, 60-60-0, 80-40-0, 120-30-0, 120-60-0, 120-90-0 and 180-60-0 kg ha-1), 2 treatments with ammonium sulfate (60-30-0 and 120-60-0 kg ha-1), 2 with urea (60-30-0 and 120-60-0 kg ha-1), only P (0-30-0 kg ha-1), and the control (0-0-0 kg ha-1). Triple superphosphate was applied as a source for P. The 80-40-0 treatment was included because it was the commonly recommended rate for the area. Fertilizers were applied at the beginning of the rainfall season (July) and forage was harvested in late October (1990) and mid-November (1991). Dry matter production, crude protein (CP) content, and in situ digestibility were determined. An economic analysis was used to obtain the best economic treatment for forage production. In 1990 with a precipitation of 377 mm, dry matter production was significantly affected for both source and rate of N. The maximum amount of dry matter was obtained with a rate of 120-90-0 kg ha-1 using ammonium nitrate. However, the best treatment in terms of economic return was 120-30-0 kg ha-1 as ammonium nitrate. Urea did not produce as well as other N source treatments. Crude protein was highest in treatments with the higher N, but no significant trend was evident. In situ digestibility was not affected by rate or source of N fertilizer. During 1991, precipitation was higher than in 1990. Significant differences were determined among N rates but not in N source. In fact, urea produced greater in dry matter production than other N sources at the same rate. The maximum amount of dry matter was obtained with the 180-60-0 treatment using ammonium nitrate with 4,190 kg ha-1, but the best economic treatments were the 120-30-0 and 60-0-0 with a marginal return rate of 377% and 355%, respectively. Results of CP and in situ digestibility were similar to those of 1990.

The study concerns the impact of herbivory on the root systems of 3 perennial grasses, buffelgrass (Cenchrus ciliaris), digitgrass (Digitaria commutata) and needlegrass (Stipa lagascae), growing in the arid zones of Tunisia. The study simulated animals feeding of the grasses by affecting cuttings at various times throughout the spring growing period. The following effects on the root systems of the grasses were observed. When there is continual overgazing (simulated by cutting all sprouts down the ground level along the spring), more than 65% of the roots off all 3 species are found in the salty upper 15 cm of soil. In case of medium average grazing (simulated by 2 to 3 cuttings), the root system again remains superficial for buffelgrass (C. ciliaris), with 58 to 67% of the roots located in the upper 15 cm of soil. Digitgrass (Digitaria commutata) and needlegrass (Stipa lagascae), however, develop deeper roots with 68 to 86% in the upper 30 cm of soil. When grazing is light (just one cutting), all 3 species perform all most exactly as if there had been no grazing compared to (a control plot) with 85% of the root system located in the upper 50 cm and about 15% at 50 to 75 cm of ground depth. On the basis of this experiments, it is suggested that grazing on these grasses should be allowed just once each spring, thereby allowing: 1- To take advantage of the aboveground contained in these grasses in spring. 2- Preservation of a deep root system which will thereby have a much better chance of getting through the water stress summer season.

Twenty two-year-old primiparous Angus X Hereford cows and their heifer calves were used to study effects of milk consumption on calf performance, suckling behavior, and forage intake. Ten cow-calf pairs were allotted to each of 2 treatments on blue grama (Bouteloua gracilis [H.B.K.] Lag.) rangeland. Calves from 5 cows were prevented from suckling the rear udder quarters for 4 weeks to reduce milk intake by 32% when calves averaged 71 +/- 4 days of age. The other 5 calves were allowed to suckle normally. Four 12-day sampling periods were conducted from June through September. Calves from the control treatment weighed more (P < 0.05) than restricted calves in each period and at weaning. Calves from the restricted treatment did not (P > 0.10) suckle longer or more frequently than control calves during any sampling period. Forage organic matter intake was not (P > 0.10) different between cows or calves from either group at any date. Milk production was not different (P > 0.10) between groups 1 month after restriction periods were terminated. Calves on 4 week milk restriction did not increase forage organic matter intake and had decreased weaning weights compared to control animals.

Flourensia cernua DC. (tarbush) is a deciduous shrub with potential as a high-protein forage source for livestock. Twenty-four Polypay X Rambouillet wethers housed in metabolism crabs were used to evaluate tarbush as a N source for sheep fed a low quality grass diet. Treatments were 100% ground tobosa grass (Pleuraphis mutica BuckL) or tobosa substituted with 10, 20, or 30% whole pre-bloom tarbush leaves (n = 5) or 26% ground alfalfa (n = 4, Medicago sativa L.) on a dry matter basis (dmb). Sheep were fed ad libitum for 11 days, after which feed was restricted to 1% (dmb) of body weight for 11 days to reduce sorting and maintain uniform intake. Apparent dry matter digestibility was not improved (P = 0.2646) with tarbush or alfalfa. Fecal N was similar (P = 0.1626), but urinary N varied (P = 0.0008) among treatments. Apparent N digestibility differed (P = 0.0042) among treatments (43, 46, 50, 56, and 63% for sheep consuming 0,10, 20, or 30% tarbush or alfalfa, respectively). All treatments resulted in similar (P = 0.1569) but negative N retentions (-2.4, -2.2, -2.8, -2.0, and -1.5 g day-1 for sheep consuming 0, 10, 20, or 30% tarbush or alfalfa, respectively). Serum clinical profiles (day 22) confirmed all sheep were nutritionally stressed, but did not indicate toxicosis. Although neither tarbush nor alfalfa N compensated for the low quality basal diet, N from 30% tarbush was utilized with similar efficiency to alfalfa N. The major impediment for using tarbush as a N source appeared to be low palatability.

Leafy spurge (Euphorbia esula L.) is a noxious weed on rangelands throughout the Northern Great Plains. Most of these ranges are grazed by cattle which do not use leafy spurge as forage. Although sheep graze leafy spurge, most land managers are reluctant to use sheep to control this noxious weed, which may be related to economic uncertainties regarding their profitability. The purpose of this study was to evaluate the economic feasibility of implementing a sheep enterprise to control leafy spurge on cattle ranches. The physical characteristics of a typical Northern Great Plains ranch, recommended stocking rates for cattle and sheep on native and leafy spurge-infested rangelands, and a sheep enterprise budget were developed using information from the literature. A LOTUS® spreadsheet was developed to calculate returns over total costs of implementing various sheep enterprises. Annual returns from implementing sheep grazing on 520 ha of leafy spurge on a 4,905 ha ranch exceeded total costs by 4,675. Given the ownership costs and returns of our ranch, the breakeven lamb price would be 1.16 kg-1. Returns per head and per unit of land will vary with the distribution and size of a leafy spurge infestation, and sheep production costs and returns. Returns from sheep grazing were higher when leafy spurge was concentrated in fewer rather than in many pastures. Returns were positive when as little as 4% of the ranch was infested with leafy spurge. The availability and utility of our model will allow land managers to assess the feasibility of developing sheep enterprises to control leafy spurge.

Soil nutrients in topsoils (0-7.5 cm) on grazed hilly and steep land on 2 high country sheep farms with contrasting climate in the upper Waitaki district, South Island, New Zealand, were compared before and after a 14-15 year period. In addition, effects on soils of 2 farm management systems were compared by sampling similar soils on adjacent farms. On a farm with mean annual rainfall of 700-1,000 mm (study area A) that had been fertilised and oversown, and grazed with about 1.6 ewe equivalents per hectare for 14 years, levels of exchangeable cations (Ca, K, Mg) increased in topsoils on sunny slopes, but there was little change on shady slopes. The Ca increase on sunny slopes was the increase to be expected from the amount of Ca contained in the superphosphate applied but increases of exchangeable K and Mg could not be explained by fertiliser additions. There was an overall 29% increase of CEC, 7.5% decline of base saturation, and decline of soil pH by 0.4 units over the 14 year period. On a farm with mean annual rainfall of 500-600 mm (study area B) that had been grazed for 15 years with about 0.6 ewe equivalents per hectare but not fertilised or oversown, levels of exchangeable cations in topsoils declined. Base saturation values declined from 98% to 73% and pH declined by 0.4 units. Losses of Ca and Mg were greater than could be explained by direct effects of sheep grazing and we conclude that processes such as erosion or removal of vegetation and nutrients by rabbits are important loss pathways. In the spatial comparison on land with mean annual rainfall of approximately 1,000 mm, oversown and fertilised soils (grazed with about 1.6 ewe equivalents per hectare) had higher levels of exchangeable cations, organic C and total N than soils that had neither been oversown or fertilised (grazed with about 0.6 ewe equivalents per hectare). Questions of ecological and economic sustainability arise both on the moister and drier high country. On moister land like area A, if lime can be applied economically, and fertiliser can continue to be applied with positive financial returns, oversowing and fertilising may be sustainable on sunny slopes. The sustainability of pastoralism on shady slopes is more problematical. If on drier land losses of topsoil nutrients such as those measured on area B are widespread, they are considered to be unsustainable. Although the nutrients lost could be readily replenished using modest amounts of fertiliser and lime, the changes have occurred concurrently with declines of organic C and total N. Restoration of organic matter levels is likely to require either reduced grazing, or oversowing and application of fertiliser. Because oversowing and fertilising the drier high country is not financially viable except during periods of high commodity prices, both these options would require major changes in farm management and/or financial assistance with soil conservation measures.

A study was conducted to determine the influence of prescribed fire on the availability of primary foods of sage grouse (Centrocercus urophasianus Bonaparte) chicks at Hart Mountain National Antelope Refuge, Lake County, Ore. from 1987 to 1989. Responses of certain primary foods and general food categories to fire were evaluated in sagebrush (Artemisia tridentata ssp. vaseyana Beetle)-bitterbrush (Purshia tridentata Pursh.) communities with a randomized block design established in stands where shrub cover exceeded 35%. Within blocks, habitat response was evaluated for 2 growing seasons on 4 pots used as controls, 3 plots burned in November 1987, and 4 plots burned in March 1988. Fall burning increased (P < 0.05) frequency of taxa in the dandelion tribe (Cichorieae). Other primary foods, including microsteris (Microsteris gracilis Hook.), desert-parsley (Lomatium spp. Raf.), and ground-dwelling beetles (Scarabaeidae, Tenebrionidae) were not influenced by burning. Spring and fall burning increased (P < 0.05) total forte cover and diversity, but decreased (P < 0.05) sagebrush cover. Prescribed fire may increase the supply of forbs available to sage grouse in montane sagebrush habitats used for brood-rearing where shrubs dominate stands at the expense of the herbaceous component.