Cynodon Spp Research Articles

Environmental Influences on Yield and In Vitro True Digestibility of Warm‐Season Perennial Grasses and the Relationships to Fiber Components1

AbstractIn recent years climatic fluctuations have been increasingly associated with seasonal variation in yield and quality of forage crops. Although considerable information is available concerning environmental influences on yield and quality of many temperate and tropical grasses, very little is known about these relationships in the major grasses grown in the southern U.S.A. The objectives of this study were to determine the relative influences of temperature (T) and photon flux density (L) on dry matter yield (DMY) and in vitro true digestibility (IVD) of four warm‐season perennial grasses grown at two soil moisture levels and to relate the differences in IVD to fiber component concentrations. Coastal and common hermudagrass [Cynodon dactylon (L.) Pers.], Pensacola hahiagrass (Paspalurn notatum Flugge), and dallisgrass (P. dilatatum Poir.) were grown in an artificial growth medium at 4 day/night temperatures (35/24, 32/21, 29/18, 26/15 C), four photon Aux densities (1,050, 840, 630, 420 µEm−2 sec−1 PAR) and two soil moisture levels in growth cabinets. After 14 and 21 days regrowth, DMY and IVD were measured. Regression equations were developed to predict DMY and IVD as functions of T and L at each soil moisture level and regrowth period.The study clearly showed that DMY of all grasses increased with increasing T and L. The imposed moisture stress sharply reduced DMY of dallisgrass (DAL) hut not of the other grasses. In all grasses IVD consistently decreased as T increased, resulting in maximum IVD at the lowest T. The effect of L on IVD ranged from positive to negative, depending on the grass and T. Maximum IVD values occurred at the high soil moisture (HM) level after 14 days regrowth. At the HM level maximum IVD of Coastal bermudagrass (COA), common hermudagrass (COM), and Pensacolabahia grass (BAH), respectively, was 5.7, 4.9, and 3.6 percentage units higher after 14 than after 21 days regrowth. In DAL at the HM level and in all grasses at the low soil moisture level, these differences due to age were only about one percentage unit or less. The Paspalum spp. averaged about seven percentage units higher in IVD than the Cynodon spp. Significant (P ≤ 0.01) negative correlations were obtained between IVD and previously reported concentrations of acid detergent fiber (ADF), cellulose, permaganate lignin (LIG), and silica in all grasses and concentrations of neutral‐detergent fiber in COA and COM. Although correlation coefficients were ≤ 0.50, hemicellulose concentration and IVD were positively correlated in all grasses. Strongest correlations were obtained between IVD and concentrations of ADF and LIG.

Major weed problems of Libya

Abstract Farmland and orchards in Libya are regularly infested with dense weeds, primarily during the winter rainy season. The weed flora is rich both in graminaceous and non‐graminaceous species. The most common graminaceous weeds recorded were Avena, Phalaris, Erigeron, Lophochloa, Lolium, Poa, Aegilops, Dactylis, Cynodon, Setaria and Hordeum spp. Among the non‐grasses, a number of crucifers like Sinapis, Brassica, Eruca and Euclidium spp. and others like Anethum, Chrysanthemum, Silybum, Sonchus, Fagonia, Kochia and Chenopodium spp. were found dominating different agroclimatic zones and habitats. About 90 weed species of immediate importance were recorded in field crops, vegetables, orchards, vineyards and highway verges. Of these, 22 belonged to the family Gramineae; 15 to the Compositae; 12 to the Cruciferae and 11 to the Leguminosae. The rest of the weeds recorded were distributed over another 23 families. Libyan agriculture lacks farm manpower and so needs intensive research into and development of ...

Subtropical Grass Species Response to Different Irrigation and Harvest Regimes1

AbstractPerennial grasses can be grown in subtropical areas of the world having little frost damage, but, in many areas low temperatures (1 to 10 C) at higher elevations and lack of moisture may restrict growth of most subtropical forages and create critical feed shortages for livestock. A study of the seasonal distribution of forage production of subtropical grasses was conducted to determine production and quality and to develop improved management practices. Sixteen grasses (four Cynodons, three Paspalums, eight Digitarias, and one Brachiaria) were grown with and without irrigation and harvested at two stubble heights (5 and 10 cm) at 30‐day intervals for 30 consecutive months (March 1973 through August 1975). The experiment was conducted at the Immokalee Research Center in south Florida on a sandy siliceous, hyperthermic, Arenic Haplaquod (Immokalee fine sand) soil. Winter forage production (October through March) was highest for Cynodon spp (27% of total annual yield) and lowest for Paspalum spp. (14% of total annual yield). Plants cut at a 5‐cm stubble initially outyielded plants harvested at 10 cm. However, after 2.5 years little difference was observed in dry matter yield between stubble heights, except for the Paspalum spp. and Brachiaria sp. which continued to produce more forage at the 5‐cm stubble height. Little difference was observed in percentage crude protein and IVOMD between grass entries harvested during the summer growth period with the exception of Brachiaria which was significantly higher in IVOMD. Both crude protein and IVOMD were much lower in forage harvested during the summer than the winter for all grasses, again with the exception of the IVOMD for Brachiaria which had a summer‐winter range of 58 to 64%. This entry was one of the highest in dry matter yield, crude protein, and IVOMD percentage, but produced 83% of its dry matter during the summer. Irrigation had little effect on dry matter production at any season. Higher IVOMD was obtained from cut short with no irrigation. These data indicated that Cynodons harvested at a 5‐cm stubble produced highest dry matter production during the cool winter season, containing high crude protein and IVOMD levels. Dry matter yields in summer were 200 to 300% higher than in winter, however, forage quality was much lower during the summer.

Rearing and transmission techniques for Haplaxius sp. (Horn: Cixiidae), a suspected vector of lethal yellowing disease of coconuts

SUMMARYAdult Haplaxius sp., identified from Jamaica as H. crudus or H. cocois, are common on coconut foliage in both Jamaica and Florida and are suspected vectors of lethal yellowing disease in both regions. Nymphs, which are subterranean, were mass‐reared on roots of the grasses Stenotaphrum secundatum, Axenopus compressus and Cynodon spp. Transmission of the disease was tested by feeding the nymphs on roots of diseased palms, rearing them on grasses and transferring the emergent adults to foliage of test palms for infection feeds. No transmission was proven.

Performance ofcynodonspecies in the natal tall grassveld

Abstract A number of Cynodon lines were evaluated at two centres in the Natal Tall Grassveld. On a red clay soil in a relatively moist area good performance was recorded from several star grasses (Cynodon aethiopicus and C. nlemfuensis) and Cynodon hybrids, but herbage production was less satisfactory on a grey‐brown loamy soil at a drier site. Local C. dactylon strains did not compare well with the introduced Cynodon spp. Quality of the Cynodon herbage was good, and no problems were encountered with prussic acid poisoning,