Brachiaria dictyoneura (Fig. & De Not.) Stapf
|Author: L.t Mannetje|
Origin and geographic distribution
The origin and natural distribution of B. dictyoneura is eastern and southern Africa. It has been introduced to many tropical countries, but is mainly cultivated in tropical America.
A densely tufted, semi-erect, stoloniferous perennial with short rhizomes; stems 40-120
cm high; stolons slender but strong and of reddish colour. Leaf linear to lanceolate, 4-40
cm x 3-18 mm, glabrous and with strongly denticulate margins. Inflorescence consisting of
3-8 racemes on an axis 5-25 cm long; racemes 1-8 cm
B. dictyoneura is used as forage in grazed permanent pastures in humid tropical regions. It has potential for erosion control and also as ground cover in tree plantations. The cultivar 'Llanero' was released in Colombia in 1987.
The nutritive value of B. dictyoneura is regarded as moderate, yet higher than that of B. humidicola. Nitrogen concentrations range mostly between 1-2% but can be as low as 0.5% during the dry season. The range for in vitro DM digestibility is 55-70% (Carulla et al. 1991). There are about 170 seeds/g.
B. dictyoneura is well adapted to the humid and sub-humid tropics at altitudes up to 1800 m above sea level and annual rainfall between 1500 and 3500 mm; it withstands dry periods of up to 4-5 months.
It grows well on a wide range of well-drained soils, including acid and highly Al-saturated ones of low fertility. B. dictyoneura responds well to fertilization, particularly with N.
Propagation and planting
B. dictyoneura is preferably propagated by seed at 2-12 kg/ha, depending on seed quality; it can be propagated vegetatively. Germination of fresh seed can be very poor because of dormancy, mainly physiological. Scarification with sulphuric acid improves germination only slightly; therefore, it is recommended to use seed that is 6-8 months old. It can be grown with a range of legumes of varying growth habits, such as Desmodium heterocarpon ssp. ovalifolium (prostrate-stoloniferous), Centrosema pubescens or Pueraria phaseoloides (trailing-climbing), Stylosanthes guianensis (semi-erect herb/sub-shrub), and Leucaena leucocephala (shrub/tree). B. dictyoneura should be leniently grazed until it is fully established (Schulze-Kraft 1992).
Growth and development
B. dictyoneura has a slow initial growth. Flowering seems to be long-day induced and seed setting improves at higher latitudes. Cv. Llanero reaches maximum flowering in the Llanos Orientales of Colombia in June-July; its reproduction is apomictic.
Diseases and pests
B. dictyoneura is amongst the Brachiaria spp. least affected by spittlebug (species of the genera Aeneolamia, Deois, and Zulia in the Cercopidae family) and it recovers quickly after an attack (Ferrufino and Lapointe 1989). It is moderately resistant to foliar blight disease caused by Rhizoctonia solani (Kelemu et al. 1995)
Depending on growth conditions, including the severity of the dry season, B. dictyoneura produces DM yields ranging from 4-11 t/ha per year on acid, low-fertility soils. It can be grazed continuously or rotationally at stocking rates between 2-4 steers/ha, with seasonal adjustments as necessary. The grass should be grazed down to 15-20 cm height. Pure seed yields of up to 280 kg/ha have been obtained in Costa Rica (Diulgheroff et al. 1990). However, Cardozo et al. (1991) reported yields of 87, 49 and 29 kg/ha for manual, combine and "beater" harvesting, respectively, from Caramagua in Colombia. Acceptability by grazing animals of B. dictyoneura was lower than that of Andropogon gayanus, Panicum maximum cv. Makueni and Setaria sphacelata (Botrel et al. 1987). Daily liveweight gains of 250-500 g/steer have been recorded. Compared with other Brachiaria species adapted to acid, low-fertility soils, B. dictyoneura has the advantages of being less affected by spittlebug than B. decumbens and of better forage quality and better compatibility with legumes than B. humidicola. For these reasons, it has excellent potential for pasture development in humid tropical acid-soil regions.
Botrel M. de A. et al. (1987); Cardozo C. I. et al. (1991); Carulla J. E. et al. (1991); Diulgheroff S. et al. (1990); Ferrufino A. and Lapointe S. L. (1989); Kelemu S. et al. (1995); Schulze-Kraft R. (1992)