Plant Biology Commons^™

Diet Quality Considerations In The Design And Management Of Pastures In Seasonally Dry Tropics Of Australia, R L. Mccown, C J. Gardener

IGC Proceedings (1977-2023)

Much of Australian tropical-pasture research in the last 20 years has been aimed at filling the "protein gap" of the dry season with a well-adapted legume. Several such legumes are now available, but their contribution to an improved nutritional regimen has been variable. This paper puts forward generalizations as to the contribution of pasture components to cattle nutrition and attempts to apply this information in devising regional strategies for pasture design and management. The contribution of a forage component is a function of (1) its nutritive value and (2) its relative acceptability. Three components emerge as both highly nutritious and …

Development Of A Pasture Research Program For The Tropical Savanna Region Of Brazil, D Thomas, C P. Moore, W Couto, R P. De Andrade, C.M C. Da Rocha, D T. Gomes

IGC Proceedings (1977-2023)

The tropical savannas (cerrados) of west central Brazil contain almost 40% of the nation's cattle population. However, the low productivity and nutritive value of the native pastures is a serious limitation to cattle production. To improve the nutrition of the grazing animal, a research program has been developed with emphasis on the integrated use of cultivated pastures. The program aims (1) to select species adapted to the cerrados, (2) to determine their nutrient requirements, and (3) to develop methods of establishment and utilization. The program is being conducted at the Cerrados Agricultural Research Center (CP AC) at lat 15°S. Rainfall …

Advances In Pasture Research And Development In Santa Cruz, Bolivia, R T. Paterson, C R. Horrell

IGC Proceedings (1977-2023)

Cattle production is important in Santa Cruz but is low in productivity, due in part to low grazing value of natural pastures, particularly in the dry season. Other constraints to cattle production include low land values, poor management, high cost of in­puts, and relatively low product prices. This program is aimed at providing higher-quality, low-cost pastures for complemen­tary use within traditional grazing systems. Improved introduced species were identified for five agro-ecological zones, and commercial seed production of the following was encouraged: Petri guineagrass (Panicum maximum), Brachiaria decumbens, buf­felgrass (Cenchrus ciliaris), glycine (Neonotonia wightii, formerly Grycine wightii), Archer axillaris (Macroryloma axillare), …

Pasture Research Results In The Brazilian Amazon, E.A S. Serrao

IGC Proceedings (1977-2023)

Natural upland savanna grasslands are represented mainly by well-drained savannas, with the cerrado type predominant, and by poorly drained savannas with the campo alto-type being the most common. The main limitations are low forage­production potential and, especially, low forage quality. About 3 million ha of rain forest has been replaced by improved pastures of guineagrass (Panicum maximum, 80% ), jaraguagrass (Hyparrhenia rufa, 10% ), and Brachiaria spp. and other grasses (10% ). During the first few years after establish­ment, pastures are productive. However, with time, a gradual decline of productivity occurs, especially in P. maximum pastures. About 0.5 million ha …

Pasture Research Project In The Brazilian Amazon, H M. Saito, H W. Koster, E.J A. Khan, D F. Winslow, A M. Hollick, P M. Paollichi, A C. Costa, F A. Rolim

IGC Proceedings (1977-2023)

The procedure for pasture establishment in the Brazilian Amazon has been to cut down and burn forest and then to seed guineagrass (Panicum maximum L.). Under normal management, animal production has dropped significantly as pastures have deteriorated and have been invaded by weeds. A dearth of knowledge of climate, soils, and plant species; the manner in which pastures have been planted and managed; and a complete absence of fertilization have led to overgrazing and complete degrada­tion of the pastures. This study was undertaken to identify soil problems, adapted forage species, pasture-management practices, and ways of regenerating pastures. Two regions …

Intensive Beef Production In The Humid Tropics: An Evaluation Of Technical And Economic Feasibility, R O. Burton Jr, W B. Bryan

IGC Proceedings (1977-2023)

Some parts of the humid tropks show great potential for intensive livestock production from forages. However, in many cases, economic analyses have not been performed. In this study technical a.nd economic feasibility of three strategies for developing intensive pasture for beef production are evaluated. These st:rategies are fast development (no capital limitations) using commerdal nitrogen (N), slow development using commercial N, and slow development using legumes as a N source, The strategies are based on experimental data and experience from the Orinoco Delta, Venezuela. Pastures of pangolagrass (Digitaria decumbens) and Swazi (D. swazilandensis) were rotationally grazed with unselected Criollo/Zebu cattle. …

Yield And Quality Of Tropical Legumes During The Dry Season: Galactia Striata (Jacq.) Urb., R R. Vera, E A. Pizarro, M Martins, J.A. C. Viana

IGC Proceedings (1977-2023)

A small-plot experiment was conducted during 2 consecutive years in the cerrados of Brazil to evaluate the effect of four dates of deferment (21 February, 7 and 21 March, and 4 April, respectively) on rate of growth, chemical composition, and in-vitro dry-matter digestibility (IVDMD) of a pure stand of Galactia striata, a naturalized legume. The chosen dates of deferment em­braced the last 2 months of the rainy season. Yields were estimated at intervals of 28 days, over an experimental period of 237 days, ending with the beginning of the following rainy season. Asymptotic growth was observed throughout the experimental period. …

Potential Of Aeschynomene Sp. For Pastures In The Tropics, A E. Kretschmer Jr, G H. Snyder

IGC Proceedings (1977-2023)

The objectives of this study were to assess the forage potential of readily available world germ plasm of the genus Aeschynomene, which comprises 160 species; to compare some attributes of the commercial American jointvetch (Aeschynomene americana L.) with those of other accessions of the same and of other species; and to compare the seasonal growth pattern and response to phosphorus (P) of commercial jointvetch with two perennial tropical legumes. Evaluations were made of 342 accessions, including 25 identified species. Data collected from observational plots in 1978 and 1980 included initial flowering dates, plant vigor, and growth habit; from replicated plots, …

Some Initial Results Of Field Trials Conducted In Establishing A Pasture-Seed Industry In Cojedes State, Venezuela, E.J A. Khan, W H. Mark

IGC Proceedings (1977-2023)

In starting a pasture-seed industry on a farm located at lat 9°50' N that gets about 1,600 mm of rain yearly followed by a severe dry season from mid-December to April, four widely separated sites were selected to plant three grasses for commercial seed production in 1978. The objectives were to assess the fertility status of the soils, then to determine the fertilizer re­quirements of the grasses at each site and to establish an introduction garden with 70 cultivars of grasses and legumes to study their suitability for expanding seed production. Based on the results of soil analyses, a modified …

Insect Pests Of Tropical Forage Plants In South America, Mario Calderon

IGC Proceedings (1977-2023)

The objectives of this continuing research are to make a general survey of the insect populations occurring on tropical forage plants in South America and to identify the most important pests. To realize this investigation, pure stand plots 5 X 5 m were sampled every 14 days during 2 years using a D-Vac. Vacuum Sampler.

The following information was obtained:

• Most important families and/or genera of insects in tropical forage legumes and grasses. • Insect group frequency for each season. • Insect group frequency for each plant ecotype under study. • Preliminary data on insect preference. • Preliminary data …

Sown Grassland As An Alternative To Shifting Cultivation In Lowland Humid Tropics, H R. Chheda, O Babalola, M.A M. Saleem, M E. Aken'ova

IGC Proceedings (1977-2023)

Agriculture based on existing forms of shifting cultivation will not be able to support and feed adequately the rapidly increasing human population of the lowland humid tropics of Africa. The forest and natural fallows have shortened and even disap• peared in some areas because of rising food demands. Crop yields are low and continue to decline. What, then, are the alter­natives? Using Cynodon as an example, an attempt is made to show that mixed farming offers an alternative whereby the nutrient status and physical properties of the soil can be maintained, erosion can be checked, weeds can be kept under …

Animal Production From Brazilian Tropical Pastures, G L. Rocha, V.B G. Alcantara, P B. Alcantara

IGC Proceedings (1977-2023)

This review deals with the potential for beef production from nitrogen- and legume-based pastures in tropical Brazil. Possibilities for impr􀀞ving the beef industry supported by grass-legume pastures are very promising. According to the literature examined, legume-based pastures produced an annual average of 329 kg gain/ha, and nitrogen (N) fertilization resulted in 4.56 kg gain/ha. Phosphorus (P) was the main fertilizer utilized in addition to N, followed by potassium (K), lime, and micronutrients. An­nual rainfall averaged 1430 mm. Grasses used were of the genera Melinis, Hyparrhenia, Panicum, Cenchrus, Digitaria, Cynodon, Brachiaria, and Pennisetum, and the legumes were of the genera Macroptilium, …

Verano Stylo In Semiarid Northeastern Thailand, A Topark-Ngarm

IGC Proceedings (1977-2023)

Srylosanthes hamata cv. Verano was first introduced to Thailand in 197 5. In the northeastern part of the country where the climate is marginal and the soils are low in fertility, Verano appears to be one of the most suitable forage legumes used in pasture-improvement programs. Verano can be grown satisfactorily on most soils in the northeast. Oversowing the seed at 3.1 kg/ha on unploughed areas resulted in a density of 5-30 plants/m2, while in cultivated land the same amount of seed gave 20-45 plant/m2 • In a 3-year ex­periment under different seeding rates and cutting intervals Verano outyielded three …

Hemarthria Altissima: A Pasture Grass For The Tropics, K H. Quesenberry, W R. Ocumpaugh, O C. Ruelke

IGC Proceedings (1977-2023)

Limpograss (Hemarthria altissima [Poir] Stapf. et C.E. Hubb), introduced into the U.S. in 1964, has been evaluated for use as a pasture grass. Under Florida conditions it has shown yield potential equal to or greater than other tropical pasture grasses. The cultivar Bigalta has higher in-vitro organic-matter digestion (IVOMD) than other tropical grasses at comparable growth stages. Early evaluations of limpograss involved only three clones, but additional genotypes were collected and introduced during the late 1960s and early 1970s, and an evaluation scheme for this germ plasm was undertaken. Our objectives were to evaluate rapidly the available germ plasm of …

Level Of Nitrogen Fertilizer In Annual Winter Pasture (Oats-Ryegrass) And Summer Pasture (Millet): Effects On Milk Production, C J. Olivo, I L. Barreto, D A. Stiles

IGC Proceedings (1977-2023)

Two experiments were conducted with lactating Holstein cows to study the effects of different levels of nitrogen fertilizer (urea) on annual pasture: experiment 1, oats (Avena byzantina K. Koch) and ryegrass (Lolium multiflorum Lam.); experiment 2, millet (Pennisetum americanum (L.] Leche). Base fertilizer (8-28-18) was applied, and at the five-leaf stage three levels of nitrogen (N) (75, 150, and 225 kg/ha) were applied. The millet pasture followed the oat + ryegrass pasture, with the N treatments being maintained in the same areas. Two ha were planted for each treatment (total, 6 ha). In experiment 1, twelve lactating cows were randomly …

Effect Of Sheep And Cattle Grazing On A Mixed Pasture Of Perennial Ryegrass, Kikuyu, And White Clover, G J. Goold

IGC Proceedings (1977-2023)

Mixed pastlkes of perennial ryegrass (Lolium perenne L. ), kikuyugrass (Pennisetum clandestinum Hochst. ), and white clover (Trifolium repens L.) are commonly found within warm-zone areas of New Zealand but are frequently disliked because of prob­lems associated with kikuyugrass dominance. A grazing experiment was conducted to provide basic information on the response of such swards to grazing by cattle and sheep. The pastures were rotationally grazed with young sheep or cattle at two stocking levels each year from 1970 to 1975, with stocking rates adjusted twice yearly according to seasonal pasture growth. The pastures grazed by cattle …

A Comparative Evaluation Of Six Ryegrass Cultivars Under Grazing And Conservation Managements, M Ryan

IGC Proceedings (1977-2023)

Meat and dairy products command overriding importance in the Irish agricultural economy. They are derived primarily from Irish grasslands, which occupy 89% of the arable land area. Use of improved grass cultivars is probably the best means of increasing grassland output once the basics, optimal fertilizer use, and high stocking rates have been met. Objective identification of superior cultivars is the responsibility of state agencies. A recommended list, published annually in Ireland, presently contains 47 ryegrass (Lolium perenne) cultivars. There is some doubt, however, that results from small-plot cutting trials can be extrapolated to equivalent performance by grazing …

Dynamics Of Herbage Growth And Senescence In A Mixed-Species Temperate Sward Continuously Grazed By Sheep, J S. Bircham, J Hodgson

IGC Proceedings (1977-2023)

Four perennial ryegrass (Lolium perenne L.)-Poa annua L.-white clover (Trifolium repens L.) swards with herbage mass rang­ing from 500 to 1,700 kg organic matter (OM)/ha were established and maintained in as near a steady state as possible by con­tinuous but variahle stocking with sheep in order to study the influence of herbage mass on rates of herbage growth (G), senescence (S), and net production (NP), and on species balance. Estimates ofG, S, and NP were derived from measurements on individual grass tillers and clover stolon growth sites. The mean contributions to total G were 54, 20, and 4 ( ± …

Chinas Grassland Types: Their Locality And Improvement, Chia Shen-Siu

IGC Proceedings (1977-2023)

China's natural grassland is mainly distributed over the temperate zone to the west and north of the isohyet of 400 mm annual rainfall and over the hilly subtropical areas in the southern part of the country, amounting to 3 7 % of the country's total land area. Since 1949, comprehensive surveys have been conducted on several occasions in Tibet, Neimenggu Autonomous Region (Inner Mongolia), Xinjiang, and other regions. The resource of forage plants and grassland productivity has been studied. There are about 20 types and eight regions of grassland in China. On the natural steppe of the northern part of …

Production Response Of Russian Wildrye (Elymus Junceus Fisch.) To Fertilizer And Clipping, L Hofmann, J F. Karn

IGC Proceedings (1977-2023)

Experiments were conducted on nitrogen (N) fertilization of long-term Russian wildrye (RWR) (E?Jimus junceus Fisch.) pasture and the effect of simulated spring grazing on quantity of forage available for fall use. A stand of RWR that had been fer­tilized with 45 kg N/ha and grazed annually for 10 years at Mandan, North Dakota, was divided into two experiments in 1978. The first evaluated effects from all combinations of 0, 45, 90, 135, 180, and 225 kg N/ha; 0, 45, and 90 kg phosphorus (P)/ha; and 0 and 135 kg potassium (K)/ha on dry-matter (DM) yields, whereas the second compared ten …