Browse biomass production of Salix spp. and Betula glandulosa on a wetland in central British Columbia is estimated. Based on an extensive review of much of the literature pertaining to shrub biomass and shrub density estimation, a technique combining regression estimates of average stem biomass with a density estimate obtained using the corrected point distance method was applied. It was found that the best regression relationships were obtained using natural logarithmic transformations of the dimension and biomass variables. It was possible to obtain acceptable biomass equations for the four Salix species encountered without differentiating between the species. More accurate predictions of biomass were achieved using site specific equations and equations based on pooled site data than with general equations. It was concluded that the value of the approach taken is limited if site specific equations are required because of the considerable time required for sample collection and preparation. / Forestry, Faculty of / Graduate

In the first part of this study, the relative in situ rumen degradabilities of some common Kenyan feedstuffs were estimated using two fistulated steers. The second part of the study attempted to manipulate rumen fermentation processes by heat treating dietary protein, and also by varying the hay particle size. The in situ dacron bag technique was used to estimate the feeding value of some common Kenyan forages. The rate and extent of dry matter (DM) and crude protein (CP) degradation in the rumen was then determined from the incubated samples. Effective DM and CP degradation was also estimated at various rumen digesta flow rates. Green maize chop, fodder sorghum, napier grass, kikuyu grass, Pennisetum trachyphyllum, rhubarb leaves, banana leaves, sweet potato vines, desmodium and lucerne had moderate to high DM and CP degradability (>50%). These feedstuffs would therefore offer greater potential for conservation for feeding dairy cattle in the dry season. Wheat straw, maize stover, red oats grass and naivasha stargrass had significantly (P<0.05) lower rumen degradability. This last group would require supplemental energy and nitrogen in order to meet the dairy cow's nutrients requirements. Wheat bran had a high DM degradability but its CP degradability was low. The digestibility and amino acid availability of its protein requires further investigations. The effects of forage particle length and heat treatment of protein sources on intake, milk yield and composition and, ration digestibility were determined using dairy cows. Normal or heated canola meal and dehydrated alfalfa were fed together with orchard grass hay to 24 lactating Holstein cows. Orchard grass hay was chopped to two mean cut lengths i.e 14.19 and 1.71 mm. In situ results showed that both canola meal and alfalfa proteins in the supplement was made indigestible by heat. Heat treatment did not affect in vivo dry matter (DM), crude protein (CP) and acid detergent fibre (ADF) digestibility for the complete canola rations. Milk yield was also not significantly affected by heating canola meal. However, neutral detergent fibre (NDF) digestibility, voluntary feed intake, butter fat and milk protein contents decreased with heat treatment. Reduced forage particle size in combination with heat treatment resulted in significantly lower DM, CP, and ADF digestibility. There was no significant change in voluntary feed intake, milk yield or its components, (except lactose content), with reduced hay particle size. Lactose content was significantly higher with long chop hay. Heat treatment of "alfalfa and short hay particle size resulted in lower DM and CP digestibility of the complete rations. ADF digestibility and voluntary feed intake were reduced with heat treatment. Hay particle size did not affect voluntary feed intake significantly. Milk yield and its components increased with heat treatment of alfalfa. Only total milk fat increased with the longer chop hay. / Land and Food Systems, Faculty of / Graduate

The objectives of the following research project were to 1) determine the optimum time and intensity of harvesting a wetland meadow in terms of forage yield, forage nutritive quality, and plant vigor; 2) to determine the carrying capacity of a wetland meadow under different seasons of use and; 3) to contribute to the development of a wetland classification scheme by characterizing a wetland meadow. The study site was located on the Fraser Plateau about 100 kms west of Williams Lake, British Columbia, at an elevation of 1250 m. Meadow water table, water pH, water conductivity, water calcium ion concentration, and soil temperatures were measured twice per month. The meadow and surrounding upland soils were classified. The species composition and foliar cover of 5 vegetation zones were described for the meadow and surrounding upland area. To asses meadow productivity and forage nutritive quality under different seasons of use 6 harvesting periods were employed, mid May to mid July, June and July, mid June to mid August, July and August and mid May through August. The standing crop seasonal trend was monitored by analysing forage samples collected twice monthly. Clipping samples were oven dried and weighed to determine harvest yields. The crude protein content of the samples was determined by a microkjeldhal technique. Phosphorus content was assessed by a vanadomolybdate method. Calcium, potassium, magnesium, zinc, copper, iron and manganese contents were determined by spectrophotometry. The relative plant stored food reserves were assessed by an etiolation experiment. Soil - vegetation plugs were collected from all harvest period treatment plots as well as undipped control plots and placed in a dark controlled environment chamber. The etiolated growth was collected, weighed and used to compare the relative plant stored food reserves among different harvest period treatments. A stepwise simple regression procedure was used to compare the seasonal trend data and a stepwise multiple regression procedure was used to compare the different harvest period treatments. A 2 step Student Newman Keuls multiple range test was performed on the etiolation experiment sod reserve indices and harvest treatment total yields data. Meadow water table, water pH, water calcium ion content, water conductivity, soil temperatures at 10 cm and soil temperatures at 50 cm ranged between +29 and -2 cm, 7.0 and 7.4, 14 and 89 ppm, 249 and 840 mmho/cm, 6.9 and 11.2°C and 6.8 and 10.6°C respectively. Meadow soils included a Typic Humisol - Mesic Humisol - Terric Mesic Humisol complex, a calcareous Gleyed Humic Regosol, a calcareous Gleyed Regosol, an Orthic Humic Gleysol and a Gleyed Gray Luvisol. The upland soil was an Orthic Gray Luvisol. The 5 vegetation zones were named according to the dominant plant species. Included were a Carex rostrata zone, a Carex - Betula glandulosa zone, a Carex praegracilis - Juncus balticus zone, a Salix - Betula glandulosa zone, arid a Pinus contorta - Calamagrostis rubescens zone. Productivity and nutritional data collection was restricted to the Carex rostrata zone. The standing crop varied from 1 to 6 mt/ha. The nutrient content of the standing crop varied between 0.35 and 0.51% of tissue, 2.1 - 5.7, 1.0 - 1.5% of tissue, 0.17 - 0.26% of tissue, 133 - 326 ppm, and 49 and 165 ppm for the calcium, calcium - phosphorus ratio, potassium, magnesium, manganese and iron contents respectively. The meadow forage crude protein, phosphorus, zinc and copper contents remained un- changed at 10.1% of tissue, 0.14% of tissue, 30 ppm and 11 ppm through the season. The 8 cm July and August harvest period produced the greatest treatment yield, 6807 kg/ha, followed by the 8 cm - mid June to mid August harvest treatment yield. The least productive treatments were the 8 and 23 cm harvests during the period mid May to mid August. The nutrient content of the meadow forage subjected to the 10 different harvest treatments varied as follows: crude protein - 8.3 to 12.0% of tissue, calcium - 0.368 to 0.646% of tissue, phosphorus - 0.21 to 0.27% of tissue, calcium: phosphorus ratio - 1.4 to 3.6, zinc - 35 to 46 ppm, copper - 13 ppm, potassium - 1.7 to 2.4% of tissue, magnesium-0.19 to 0.23% of tissue, manganese - 194 to 271 ppm and iron - 94 to 119 ppm. Repeated clipping increased the meadow forage crude protein, phosphorus, zinc, copper, potassium, manganese slightly, and iron contents. Repeated clipping reduced the meadow forage calcium: phosphorus ratio. The stored food reserves of the meadow vegetation was found not to vary with harvest treatment. Based on productivity, nutritive quality and plant vigot data, grazing during the period mid June to mid August and close utilization (an 8 cm as opposed to a 23 cm stubble height) appears most appropriate. Wet meadow hay should be cut as early as possible. The theoretical safe maximum carrying capacity is 23 AUM'S/ha (20 AUM'S/ ha when grazed to an 8 cm stubble height during the period mid June to mid August). The meadow characterization and productivity data will be useful to person(s) undertaking the task of formulating a classification scheme for British Columbia wetland meadows. / Land and Food Systems, Faculty of / Graduate

The agronomical evaluation and the comparative work of six multiannual forage species was conducted in the facilities of the Benson Institute, in the community of Contorno de Letanias, Ingavi province, La Paz. The objectives were to evaluate the agronomic behavior, as well as to evaluate the dry matter (DM) yield of six multiannual forage species (grasses) under local conditions, and to determine the partial cost of production of the studied species. The annual mean temperature was 9.14°C, and 517.6 mm of precipitation. The test was conducted under the random block design test, with six different forage species, and three repetitions. The evaluated species were: Hybrid grass (Agropyrum crisantum x A. desertorum), Bromus grass(Bromus inermis), Phleum grass (Phleum pratense), Pubescent grass (Agropyron trichophorum), Orchard grass (Dactylis glomerata), and Weeping lovegrass (Eragrostis curvula). The evaluated response variables were: Plant density (%), plant height (cm), base area (m²), tip area (m²), leaf/stem relationship, dry matter yield (kg/ha), and plant vigor. The forage species (grass) that presented a better behavior in relationship to plant density were the weeping lovegrass, Phleum, Orchard, Bromus, and Pubescent grass with: 92.17, 84.44, 75.95, 70.77, and 68.6%. The hybrid grass presented the least density with a 55.50% respectively. According to plant height at two different cut times, the Orchard, Pubescent, Weeping lovegrass, Bromus, Phleum, and Hybrid grass species presented a mean height of 23.0, 26.24, 15.31, 12.27, and 15.5 cm respectively, a tip area of.037, 0.26,.032, 0.32, 0.28, and 0.25 m², and a base area of 0.14, 0.09, 0.10, 0.16, and 0.10 m². The dry matter yield (The total sum of two cuts) was of 3936.0 kg/ha for Pubescent grass, 3459.0 kg/ha of Bromus grass, 2780.7 kg/ha of Weeping lovegrass, 2358.0 kg/ha of Hybrid grass, and 2089.0 kg/ha of Pleum grass. The relationship leaf/stem relationship resented an average of 1.13, 3.38, 3.71, 2.84, 2.49, and 2.93 respectively. The species: Orchard and pubescent grass presented a variable cost of 1384.9 and 1604.9 Bs/Ha in relationship to the other studied species. Also, both grasses (bromus and pubescent) presented a marginal return of 138%; therefore, Orchard grass (Dactylis glomerata) is recommended as an alternative species.

No description available.

No description available.

No description available.

This study was initiated to secure quantitative data on growth characteristics of the major species in the mixed grass prairie of western North Dakota; to determine the extent and range in yearly variations in growth patterns of the species and of the type as a whole; to assess the general influence of climate as a cause for seasonal and yearly variations in growth patterns; and to interpret the data obtained in terms of their possible application to the practical grazing management of these grasslands. / This project was supported by the North Dakota Agricultural Experiment Station as a part of project Hatch 9-5: "Native range plants -- their growth and development in relation to the establishment of standards for their proper utilization."

Ecological and environmental aspects relating to Cercocarpus montanus Raf. Communities were investigated. Twenty study sites were sampled and described. All factors were then analyzed utilizing statistical methods. Signigicantly correlated factors to C. montanus parameters (i.e., frequency, density, cover, height) were: positive correlation--percent clay, percent clay-silt, percent litter cover, and total soluble salts in soil; negative correlation--percent silt-sand, percent sand, soil pH; exposed surface rock, Amelanchier alnifolia cover, Gotierrezia sarothrae cover and altitude. Several individual factors were singled out as being of importance in C. montanus communities; howerver, it was shown that a combination of factors was most important in determining optimal growth conditions for C. montanus. Each site is exposed to different combinations of ecological conditions which are in a constant state of flux. The C. montanus communities studied were found in this condition. The actual successional patterns involved remain to be fully elucidated.

The data for this problem were collected at the Desert Range Experiment Station and on adjoining public domain lands during the summer of 1934, for the purpose of studying the influence of overgrazing on the increase of palatable and unpalatable desert forage plants. A vegetative description of the two areas studied has been prepared and presented.