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Manipulating the Plastic Response of White Clover Through Grazing, in a cool, Temperate Climate in New Zealand
Get PDFIn Southland, New Zealand, a wide range of grazing systems are practised, from continuous set-stocking to year round rotational grazing. A problem is the apparent decline in contribution of white clover (Trifolium repens L.) to total sward production in older pastures. Cereal and brassica crops, which depleted soil N, were traditionally sown each year and used to ensure that about 20 % of any farm consisted of clover-dominant two and three year old pastures. Carran (pers. comm.) suggests that all-grass-farming has removed the N-deficit incentive for clover growth. Farmlet trials at the Gore Regional Station, DSIR, have shown that 3 years after sowing, the clover contribution to sward DM yield is often in the 10-13 % range, a level too low for optimal animal performance (Hook 1978). Various winter management treatments had no effect on subsequent white clover production in pastures at Gore (Harris, Turner and Hickey) (pers. comm.). It was therefore decided to impose various grazing treatments during spring, a time when manipulation of sward morphology may influence later growth of pasture (Hay and Baxter, 1984)
Development of an International Collection of Tropical Forage Germplasm for Acid Soils
Get PDFSUMMARY A Program conducted by the Centro Internacional de Agricultura Tropical ( CIA T) to develop a collection of forage plant germplasm resources for tropical pasture research in acid, infertile soil areas is described. After an initial 5-year stage of preliminary work in germplasm collection and introduction, 28 major expeditions to collect native germplasm of tropical forage species were carried out in 10 countries on 3 continents, principally in regions with acid soils of low fertility during 1977 to 1984. Emphasis has been on legumes,mainly Centrosema, Desmodium, Stylosanthes, and Zornia, in tropical America, andDesmodium, its allied genera, andPueraria in Southeast Asia. Recent collecting endeavours in East Africa are emphasizing grass germplasm, particularly Brachiaria species. A total of 9900 accessions has been collected, which together with 4200 accessions received from other institutions, constitute one of the largest collections of tropical forage germplasm. The collection, of which 87% are legumes, is highly specialized in material originating from acid soils. The CIAT collection is primarily an international working collection which, in collaboration with national institutions, is utilized for cultivar development for the acid soil regions of the tropics. In view increasing genetic erosion and of the need for base collections, future responsibilities in the field of germplasm conservation are visualized
Annual Legumes for Integrating Rainfed Crop and Livestock Production
Get PDFA program aimed at integrating rainfed crop and livestock production in West Asia and North Africa is described, where the objective is to introduce pasture and forage legumes in place of existing fallows. Research has identified that suitable species of Medicago, Pisum and Vicia are well adapted to the climatic conditions of North Syria. This article describes studies evaluating mixtures of common vetch (Vicia sativa) and forage peas (Pisum sativum) with barley, triticale and oats for hay production. Mixtures including the two legumes were also evaluated for early grazing by sheep followed by hay making in spring. In a third study the above legumes plus narbon vetch (V. narbonensis) and woolly pod vetch (V. dasycarpa) were compared for palatability. The mixtures increased herbage yield and improved the process of hay making. Common vetch the most palatable of all legumes in the green stage seems more suitable for hay making, while forage pea, a less palatable legume at grazing, seems more suitable to be included in legume-cereal mixtures for early grazing and hay making afterwards
Mediterranean-Germplasm Trefoils in the Southeastern USA Piedmont
Get PDFExperimental birdsfoot trefoil (Lotus corniculatus) cultivars, selected from Mediterranean germplasm, were compared with northern trefoils in monoculture and in association with grasses to determine productivity and persistence in north Georgia where northern trefoils have not been successful. Productivity and forage quality of one trefoil was studied under four frequencies of defoliation. Mediterranean trefoils had higher total and earlier spring production, better stand persistence, and seedling vigor than a northern cultivar. The yield advantage of Mediterranean trefoils occurred in monoculture and when grown in association with tall fescue (Festuca arundinaceae) or orchardgrass (Dactylis glomerata). Maximum yields occurred when at least 4, but no more than 8 weeks were allowed between cuttings. Forage quality was high all season. The highest quality forage was produced at 3-week harvest intervals, but there were no differences in in-vitro dry matter disappearance when the initial harvest was deferred 4, 6, or 8 weeks. Our results indicate that Mediterranean germplasm can be useful in extending the range of birdsfoot trefoil much further south in the Northern Hemisphere than the current area of production
Problems Experienced with Forage Legumes in a Tropical Savanna Environment in Brazil
Get PDFSince 1978 some 1700 legumes from 17 genera and 50 species have been evaluated on soils at the Centro de Pesquisa Agropecuaria dos Cerrados (CPAC) at latitude 15° 36\u27 S in the tropical savanna region of Brazil. In characterizing the germplasm a number of problems have become evident. Plant dise4ses are primary limiting factors. Species of Stylosanthes are attacked by anthracnose ( Colletotrichum gloeosporioides) whilst other diseases affecting species of Centrosema, Desmodium and Zornia are described. Accessions collected in the acid soils with a high aluminium saturation are well adapted to these conditions. However, species such as Leucaena Jeucocephala from alkaline soils grow poorly, and root growth is limited by low levels of exchangeable calcium and magnesium and high aluminium saturation. Problems of flowering and seed production have been recorded in Stylosanthes guianensis ssp. guianensis var. pauciflora and Centrosema macrocarpum. A failure of some accessions to persist under grazing is related to disease susceptibility, low seed production and plant morphology. Accessions of Zornia brasiliensis have persisted, and grass-legume associations become legume dominant because steers refuse to consume the plants. Selected accessions are being evaluated at twelve other centres in the region from latitude 3° N to 22° S
Preliminary Observations with Accessions of Stylosanthes guianensis ssp. guianensis var. pauciflora in Brazil
Get PDFForty-two accessions of the morphologically distinct Stylosanthes guiansis ssp. guianensis var. pauciflora collected in Brazil and Venezuela were evaluated for their adaptation to environment in the tropical savanna region of central Brazil. The study was conducted on an Oxisol at the Centro de Pesquisa Agropecuaria dos Cerrados (CPAC), 35 km from Brasilia at latitude 15° 36\u27 S. Results showed that was marked variation in plant yield and, as a group, Brazilian accessions produced more dry matter than Venezuelan accessions. Anthracnose resistance and digestible dry matter content were also markedly higher in the accessions from Brazil. No significant differences in N and Ca contents were observed although Venezuelan accessions tended to have higher P levels. The potential of these types for the savannas of Brazil is discussed. It is suggested that further germ plasm collection should be concentrated in Brazil because of the higher susceptibility of Venezuelan accessions to anthracnose
Agroforestry in the Southeastern United States
Get PDFAgroforestry has been practiced for many years in the tropics by intermixing forages under palms, fruit trees, or hardwoods. Interest has increased in temperate zones for combining trees, pastures, crops, and livestock. Agroforestry in the United States is generally limited to the combining of pines, tame pastures, and cattle. Our purpose is to summarize results of research and developments in the southeastern United States on cool-and warm-season forages under planted pines and pine regeneration in tame pasture
Le Role des Plantes Herbageres dans la Limitation des Pertes des Principaux Elements Nutritifs par le Drainage
Get PDFDepuis longtemps on connait !\u27action anti-erosive des plantes herbageres qui empechent d\u27une fa\u3c ;on tres efficace l\u27affaissement des particules de sol, en particulier sur des surfaces en pente. Dans ces derniers temps on parle de plus en plus souvent du role des herbages dans la limitation du drainage des elements nutritifs du sol et de nombreuses recherches menees a cet effet dans plusieurs pays le confirment (Jones, 1972; Gachon et Triboi, 1967; Kopec, 1985). Dans cette etude on a presente les resultats des recherches lysimetriques Sur la quantite des principaux elements nutritifs draines par les eaux s\u27evacuant des terrains agricoles couverts d\u27herbages et d\u27autres cultures
Co2 Exchange of the Abovegrass and Belowground Components of Kleingrass (Panicum coloratum L.) During Drought in the Northern Chihuahuan Desert
No full textThe effect a 52 day drought had on the die! whole-plant carbon balance of kleingrass (Panicum coloratum L.) growing in the northern Chihuahuan desert was determined. Whole-plant CO2 inputs (photosynthesis) and outputs (belowground and aboveground respiration) were measured on day 52 of the drought (June 23, 1981) and 2 days following 1.12 cm of precipitation that occurred on June 24, 1981. Although net photosynthesis rates were severely depressed on June 23, a positive whole-plant carbon balance was determined prior to and following the rain. On a whole-plant basis,.002 g C/g DW/day was gained on June 23 and .015 g C/g DW/day on June 26. Respiration of the belowground components (roots plus root crown) was very low (.004 g C/g DW/day) due to the suberized condition of the entire root system. The ability of roots to change from a nonsuberized state to a suberized condition when soil dries reduces the root maintenance cost and, therefore, may enable a plant to maintain a large root biomass during drought
Regulating Grass and Clover Growth with Mefludide
No full textA three-year study on the use of mefluidide, a plant growth regulator, for suppressing seed-head production in a range of grass is reported. The first stage, involving the evaluation of a range of does and timings on up to nine grass species, indicated the potential of mefluidide applied at 150 g ha-1 in early spring to prevent the normal decline in herbage quality associated with flowering and to transfer growth from spring to mid-summer, albeit at a loss of some 30% in total dry-matter production. A supplementary investigation showed that white clover was reasonably tolerant to mefluidide treatment although a shortening of the main stolons undermined the plants\u27 exploitive character. A one-year grazing experiment, aimed at measuring sward and livestock responses to mefluidide at 160 g ha-1 applied either in March or April, confirmed the value of early spraying for evening out grass growth; losses in total yield were less than those recorded in the cutting experiments. Animal grazing days, corrected for increasing liveweights of core animals, indicated the usefulness of the March-applied treatment. There is now a need to devise a grazing system to exploit this potential