Soil Science Commons^™

Climatic Influences During Flowering On Seed Dormancy And Seed Formation Of Stylosanthes Hamata Cv. Verano, P J. Argel, L R. Humphreys

IGC Proceedings (1977-2023)

Effects of variation in temperature, soil moisture supply, and illuminance on seed dormancy and seed formation of Srylosan­thes hamata cv. Verano were studied. Plants were grown in the open in successive seasons, in controlled-temperature cabinets, and in the greenhouse where shading and watering treatments were varied after the onset of flowering. Hardseededness was strongly developed and was positively related to temperature during seed formation. After seed matura­tion, seed moisture content was the main factor governing hardseededness, and this quality was negatively associated with temperature during seed formation. High levels of hardseededness developed in all seeds when seed moisture content was …

Strategies Of Seedling Development In Warm-Season Grass, L E. Moster, C J. Nelson

IGC Proceedings (1977-2023)

Establishment of warm-season prairie grasses is often difficult because of slow seedling growth and weed competition. Seed­

ling development of four perennial warm-season grasses was compared with that of a vigorous annual grass, giant foxtail (Setaria faberi Herrm.) Big bluestem (Andropogon gerardii Vitman), switchgrass (Panicum virgatum L.), indiangrass (Sorghrutrum nutans [L. J Nash), caucasian bluestem (Bothn'ochloa caucasica [Prin.] C .E. Hubb. ), and giant foxtail were grown in a greenhouse. Leaf elongation rate, collaring date, and leaf length were measured daily. Carbon-exchange rate (CER) was determined. Plants were harvested at the sixth and eighth leaf …

Phenology And Culm-Weight Variation Between Two Wheatgrass Species: Agropyron Smithii And A. Spicatum, M K. Owens, H G. Fisser

IGC Proceedings (1977-2023)

Knowledge of plant phenology and live weight dynamics is necessary for intensive management of semiarid rangelands. Thir­teen sites in Wyoming were sampled for plant phenological development and culm weights of western wheatgrass (AgroP.,ron smithii) and bluebunch wheatgrass (A. spicatum). These species are sympatric and allopatric within these rangelands. Such a distribution allows site comparisons between these species. Environmental data were collected for use in differentiating sites. Data on all variables were collected at 14-day intervals throughout the growing seasons of 1979 and 1980. Permanently marked plants were sampled for phenology, and plants of similar development were collected for culm-weight estimates. …

Simple Mixtures For Dry Mountain Regions: Relations Between Tall Fescue And Birdsfoot Trefoil During Five Years, G Haussmann, P Paoletti, C Locatelli

IGC Proceedings (1977-2023)

Grass-legume mixtures are of great interest, especially in central and northern Appennine regions with a summer dry season .. Birdsfoot trefoil (Lotus comiculatus L.) cv. Franco and tall fescue (Festuca anmdinaceaSchreb.) cv. Manade were grown in mixture and in pure stand at the experimental farm of the Institute. Our objectives were to determine the seeding rates in the mixtures and the most suitable method of sowing. The two species were seeded in mixture and alone to 20 seeding treatments: (a) 16 mixtures in alternate rows 12 cm apart, in factorial combinations of four seeding rates (5-10-12-15 kg/ha …

Utilization Of Hydromorphic And Alkaline Hydromorphic Soils In Sap Vojvodina By Establishing Cultivated Grassland, B Miskovic, P Eric

IGC Proceedings (1977-2023)

Hydromorphic and alkaline hydromorphic soils are heavy and unsuitable for the growing of row crops. Their poor structure and water and air properties make cultivation expensive. The establishment of cultivated grassland for production of fodder for 4 or 5 years requires less expenditure than that necessary for the production of row crops. Four years of experiments, conducted on hydromorphic and alkaline hydromorphic soils, included four grass cultivars and three legume cultivars. Yields, chemical composition and physical properties of hay, and soil properties were examined. The results indicated that cultivating grasses for the production of fodder is a good use of …

Interception Of Rainfall By Creosotebush (Larrea Tridentata), J M. Tromble

IGC Proceedings (1977-2023)

The objective of this study was to examine interception by creosotebush (Larrea tridentata [DC.] Cov.) of artificially applied rainfall for improved understanding of this phenomenon in hydrologic processes. This research was conducted near Las Cruces in southern New Mexico. Forty-four creosotebush shrubs were collected to obtain a representative sample of shrub size classes. Simulated rainfall was applied at the rate of 6 cm/hr. Measurements taken for each shrub were: (1) shrub height, (2) canopy area, (3) shrub volume, (4) number of stems, (5) leaf area, (6) green weight of stems, (7) oven-dry weight of stems, (8) green weight of …

Grassland Development In The Southern Highlands Of Peru, E J. Stevens, P Villalta

IGC Proceedings (1977-2023)

This paper describes grassland development in Peru. Vegetation of the high alpine region of Peru, which occupies some 4 million ha, is dominated by native grasses normally producing less than 2,000 kg/ha dry matter annually. On land with ade­quate soil moisture, pastures based on perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) were established successfully, but on drier sites alfalfa proved superior, producing over 12,000 kg/ha/yr in some trials. Alfalfa and clovers were also successfully introduced into improved native pastures by mechanical direct seeding and by hand sowing. With direct seeding, dry-matter production increased from about …

Pasture Evaluation In The Desertic Zone Of Venezuela For The Development Of Goat Production, A Gallardo, A Leone

IGC Proceedings (1977-2023)

The desertic zone of Venezuela is an area of approximately 4.1 million ha that represents 4.8 % of the total national territory, on which there are two million goats. Goats represent the main, if not the only, income source for 60,000 rural families. According to UNESCO (1973), the desertic zone of the country comprises two vegetation types, evergreen scrub and deciduous scrub. In each of these zones the plant species consumed by goats were collected and, for those plant parts consumed by the animals, chemically analyzed to determine nutritive value. Forage plants from other tropical countries were also in­troduced and …

Evaluation Of Biological Components In Decision-Making In Forage Allocation, J E. Skiles, G M. Van Dyne

IGC Proceedings (1977-2023)

Forage allocation to mixtures of large herbivores is accomplished by minimizing the difference between the available herbage and the required forage for animals on rangeland. Availability is determined in part by the plant's physiological tolerance to grazing or its allowable-use factor and the animal preference for that plant, measured in part by the proper-use factor. The mix of large herbivores on the rangeland must also be considered. The grazing requirements for animals are dependent on animal preference for plant species and on the total forage intake rates. This paper presents an analysis of these concepts and published information. The concept …

Nutritional Quality Of Leaf Proteins Prepared From Crops Containing Phenolic Compounds And Polyphenolase, T Horigome, S Uchida

IGC Proceedings (1977-2023)

Many studies have indicated that leaf protein prepared by green crop fractionation affords good potential as a protein supple­ment. It has been noted, however, that there were some marked differences between crops in the nutritional quality ofleaf pro­tein in spite of a similarity in amino-acid composition between leaf proteins made from different crops. We previously showed that brown casein, which was produced by the interaction of milk casein with phenolics undergoing enzymic oxidation, had lower nutritional value than original casein. In addition, it has been suggested that leaf proteins prepared from crops containing phenolics and polyphenolase were brown after extraction …

Hail As An Ecological Factor In The Increase Of Pricklypear Cactus, W A. Laycock

IGC Proceedings (1977-2023)

Detached joints or pads of plains pricklypear cactus (Opuntia pov,acantha) can root and form new plants. However, few data exist to quantify this phenomenon or to describe conditions under which rooting takes place. A severe hailstorm at the Central Plains Experimental Range in northeastern Colorado on 31 July 1978 broke segments from plants of plains pricklypear. This oc­currence provided an opportunity to determine the amount of joint dispersal and rooting from a natural destructive event. Cactus joints detached and scattered by the force of the hail were counted on permanent belt transects established in two pastures having different pricklypear populations. …

Savanna Ecosystems In Tropical South America: Findings From A Computerized Land-Resource Survey, T T. Cochrane

IGC Proceedings (1977-2023)

A land-resource survey is being made in tropical South America with the objective of creating a base for development and transfer of improved food-crop and pasture-plant germ plasm-based technology. Preference was given to study of the 200 million ha of native savannas, although the survey now stretches across the Amazon forests to southern Brazil. Land information is reduced to a common base, with land systems defined as repetitive patterns of climate, landscape, and soils. They are delineated directly onto satellite and side-looking radar imagery following field work and climatic analyses. Within land systems the vegetation and soils are separately described …

Effects Of Topsoil Depths And Species Selection On Reclamation Of Coal-Strip-Mine Spoils, W J. Mcginnies, P J. Nicholas

IGC Proceedings (1977-2023)

The research objectives were (1) to determine the effects of topsoil on establishment of seeded vegetation on strip-mine spoils, (2) to determine the effects of depth of topsoil placed over spoil on growth of herbage and roots, and (3) to evaluate 17 grass species grown on topsoil and mine spoil. In a field study in northwestern Colorado, a seed mixture of range grasses, forbs, and shrubs was drilled on five (0, 10, 20, 30, and 46 cm) depths of topsoil placed over surface coal-mine spoil, and the effect of topsoil depth on species establishment was measured. In a greenhouse study, …

Progress In Development Of Conservation Plant Cultivars By The Usda Soil Conservation Service, H W. Everett

IGC Proceedings (1977-2023)

The USDA Soil Conservation Service (SCS) operates a coordinated network of 22 plant materials centers in the U.S.A. to assemble, evaluate, select, cooperatively release, and provide for the commercial increase of native and introduced plants for the conservation and improvement of soil, water, and related resources. Standardized procedures have been developed and are being used for this comparative plant-testing program. Evaluation data can be retrieved from an automatic data-processing system through standardized reports. Over 140 SCS-released cultivars of conservation plants are available commercially for use in range, pasture, and other grassland improvement to reduce sediment movement and improve wildlife habitat. …

Pasture Production And Changes In Soil Fertility On A Long-Term Irrigated Superphosphate Trial At Winchmore, New Zealand, B F. Quin, D S. Rickard

IGC Proceedings (1977-2023)

The Winchmore trial was commenced in 1952 to investigate the superphosphate requirements of irrigated ryegrass-white clover pasture under grazing. Treatments receiving 0, 188, and 376 kg/ha annually of single superphosphate have produced average annual yields of 4.3, 10.0, and 11.2 metric tons (t)/ha dry matter, respectively. The control production is being main­tained by continuing weathering of soil P and by the input of S in irrigation water and rainfall. Topsoil organic C, N, and S reached plateaus on all treatments after 10-15 years. Organic P (P0) showed a linear increase on all treatments until the trial was limed (4 t/ha) …

Soil Nutrient Constraint For Legume-Based Pastures In The Brazilian Cerrados, W Couto, C Sanzonowics

IGC Proceedings (1977-2023)

Soil-nutrient deficiencies in two cerrados soils have been investigated as a preliminary to small-plot research oriented to estimate fertilizer requirements for establishment of legumes in grass-legume associations. The studies were conducted in the greenhouse, in 2-kg pots, with surface-soil samples taken from two sites representative of the dominant soils in the region. These are the dark red latoso1 (DRL) and the red-yellow latosol (RYL), which qualify as Haplustox and Acrusto:,:, respectively. Two kinds of e:,:periments were carried out. One consisted of a 1/4 replicate of a 28 factorial including potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), zinc (Zn), molybdenum …

Prediction Of The Supply Of Soil Nitrogen To Grass, D C. Whitehead

IGC Proceedings (1977-2023)

Predictions of the supply of soil nitrogen (N) to grass over a growing season requires an assessment of nitrate N plus am­monium N (1) present in the soil at the beginning of the season and (2) likely to be released from the potentially mineralizable organic N during the season. Although a number of methods have been proposed for predicting soil N supply, and in particular the component arising from the potentially mineralizable N, many are too time consuming for routine use, and others have not been proven effective over a range of soils. However, in recent studies, the measurement of …

Phytotoxic Response Of Five Range-Grass Species To Six In-Situ Fossil-Fuel Retort Waters, O D. Skinner, J C. Sexton, T S. Moore, D S. Farrier

IGC Proceedings (1977-2023)

Oil shale, tar sands, and undergrowid coal gasification represent viable sources of fossil fuel to assist in meeting U.S. energy needs. Development of fossil-fuel-processing technologies has progressed to a point where commercialization may soon become a reality. Concurrent with this development must be the assessment and solution of environmental problems. A particular and significant problem resides in the handling, containment, treatment, disposal, use, and eventual fate of waters recovered with the oil, gas, and subsurface waters associated with synfuel-processing techniques. The magnitude of plant responses and poten­tial phytotoxic effects resulting from exposure to these produced waters have not been evaluated, …

Suitability Of Early Pleistocene Sandy Lowlands For The Cultivation Of Alfalfa (Medicago Sativa L.), E Wojahn, G Mundel, W Kreil

IGC Proceedings (1977-2023)

The areas with sandy soils in the Pleistocene lowland of the GDR are being ameliorated on a large scale. In these lowlands, low bogs appear together with hydromorphic sandy soils. The latter are situated higher above the groundwater level. Because of the lowering of groundwater by drainage, these sandy soils are no longer suitable for intensive and high-yielding grass cultivation. Especially during summer the comparat:i.vely shallow-rooted grasses cannot gain their water requirement from ground water. Therefore, we investigated whether and under what conditions higher and more reliable forage yields could be obtained on such soils by cultivation of the deeper-rooted …

Impact Of Phosphorus And Potassium Fertilization On Maintaining Alfalfa-Orchardgrass Swards In Hokkaido, Japan, H Oohara, N Yoshida, K Fukunaga, W G. Colby, M Drake, W F. Wedin, G Kemmler, H R. Uxekull, M Hasegawa

IGC Proceedings (1977-2023)

In spite of the importance of alfalfa for all kinds of livestock, particularly for dairy cattle, the cultivation of alfalfa has not yet expanded in Hokkaido, Japan. A comprehensive research project has been undertaken, based on observations oflong-term'ef­fects of fertilization on longevity and productivity of alfalfa-orchardgrass mixtures. This report is concerned with (1) the dry­matter production of alfalfa and orchardgrass, cultivars of which were introduced from the U.S.A. and (2) the ratio of alfalfa to orchardgrass and uptake of nitrngen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg). The research began in 1960 and is continuing with close …